170 results on '"Sha, Mahesh Kumar"'
Search Results
2. CO₂ in the Atmosphere: Growth and Trends Since 1850
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Ramonet, Michel, Chatterjee, Abhishek, Ciais, Philippe, Levin, Ingeborg, Sha, Mahesh Kumar, Steinbacher, Martin, and Sweeney, Colm
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- 2023
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3. Implementation and application of an improved phase spectrum determination scheme for Fourier Transform Spectrometry.
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Hase, Frank, Castracane, Paolo, Dehn, Angelika, García, Omaira Elena, Griffith, David W. T., Heizmann, Lukas, Jones, Nicholas B., Karppinen, Tomi, Kivi, Rigel, Mazière, Martine de, Notholt, Justus, and Sha, Mahesh Kumar
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NUMERICAL functions ,FOURIER transforms ,LEAST squares ,SPECTROMETRY ,INTERPOLATION - Abstract
Correct determination of the phase spectrum is a highly relevant task in Fourier Transform Spectrometry for concluding which spectral distribution connects with the measured interferogram. We present implementation of an improved scheme for phase determination in the operational Collaborative Carbon Column Observing Network (COCCON) processor. We introduce a robust unwrapping scheme for retrieving a connected phase spectrum at intermediate spectral resolution, which uses all spectral positions carrying enough signal to allow a significant determination of the phase. In the second step, we perform a least squares fit of model parameters of a suited analytical phase spectrum model through all reliable phase values constructed in the first step. The model fit exploits the fact that we expect the phase to be spectrally smooth. Still, it can be refined to reflect specific characteristics inherent to the optical and electronic layout of the interferometer. The proposed approach avoids the problems of the classical phase reconstruction method, which enforce a spectrally smooth phase by directly limiting spectral resolution when calculating the complex phase. Thereby, the phase is created from a very low number of interferogram points around the centerburst of the interferogram, which results in a suboptimal noise propagation from the interferogram into the spectral domain. Moreover, the interpolation of the phase spectrum across spectral subsections with reduced spectral signal is not well behaved and results depend strongly on the numerical apodization function used for creating the low-resolution phase. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Fiducial Reference Measurement for Greenhouse Gases (FRM4GHG).
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Sha, Mahesh Kumar, De Mazière, Martine, Notholt, Justus, Blumenstock, Thomas, Bogaert, Pieter, Cardoen, Pepijn, Chen, Huilin, Desmet, Filip, García, Omaira, Griffith, David W. T., Hase, Frank, Heikkinen, Pauli, Herkommer, Benedikt, Hermans, Christian, Jones, Nicholas, Kivi, Rigel, Kumps, Nicolas, Langerock, Bavo, Macleod, Neil A., and Makkor, Jamal
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ATMOSPHERIC composition , *CARBON cycle , *GREENHOUSE gases , *METEOROLOGICAL stations , *WEATHER , *TRACE gases - Abstract
The Total Carbon Column Observing Network (TCCON) and the Infrared Working Group of the Network for the Detection of Atmospheric Composition Change (NDACC-IRWG) are two ground-based networks that provide the retrieved concentrations of up to 30 atmospheric trace gases, using solar absorption spectrometry. Both networks provide reference measurements for the validation of satellites and models. TCCON concentrates on long-lived greenhouse gases (GHGs) for carbon cycle studies and validation. The number of sites is limited, and the geographical coverage is uneven, covering mainly Europe and the USA. A better distribution of stations is desired to improve the representativeness of the data for various atmospheric conditions and surface conditions and to cover a large latitudinal distribution. The two successive Fiducial Reference Measurements for Greenhouse Gases European Space Agency projects (FRM4GHG and FRM4GHG2) aim at the assessment of several low-cost portable instruments for precise measurements of GHGs to complement the existing ground-based sites. Several types of low spectral resolution Fourier transform infrared (FTIR) spectrometers manufactured by Bruker, namely an EM27/SUN, a Vertex70, a fiber-coupled IRCube, and a Laser Heterodyne spectro-Radiometer (LHR) developed by UK Rutherford Appleton Laboratory are the participating instruments to achieve the Fiducial Reference Measurements (FRMs) status. Intensive side-by-side measurements were performed using all four instruments next to the Bruker IFS 125HR high spectral resolution FTIR, performing measurements in the NIR (TCCON configuration) and MIR (NDACC configuration) spectral range. The remote sensing measurements were complemented by AirCore launches, which provided in situ vertical profiles of target gases traceable to the World Meteorological Organization (WMO) reference scale. The results of the intercomparisons are shown and discussed. Except for the EM27/SUN, all other instruments, including the reference TCCON spectrometer, needed modifications during the campaign period. The EM27/SUN and the Vertex70 provided stable and precise measurements of the target gases during the campaign with quantified small biases. As part of the FRM4GHG project, one EM27/SUN is now used as a travel standard for the verification of column-integrated GHG measurements. The extension of the Vertex70 to the MIR provides the opportunity to retrieve additional concentrations of N2O, CH4, HCHO, and OCS. These MIR data products are comparable to the retrieval results from the high-resolution IFS 125HR spectrometer as operated by the NDACC. Our studies show the potential for such types of spectrometers to be used as a travel standard for the MIR species. An enclosure system with a compact solar tracker and meteorological station has been developed to house the low spectral resolution portable FTIR systems for performing solar absorption measurements. This helps the spectrometers to be mobile and enables autonomous operation, which will help to complement the TCCON and NDACC networks by extending the observational capabilities at new sites for the observation of GHGs and additional air quality gases. The development of the retrieval software allows comparable processing of the Vertex70 type of spectra as the EM27/SUN ones, therefore bringing them under the umbrella of the COllaborative Carbon Column Observing Network (COCCON). A self-assessment following the CEOS-FRM Maturity Matrix shows that the COCCON is able to provide GHG data products of FRM quality and can be used for either short-term campaigns or long-term measurements to complement the high-resolution FTIR networks. [ABSTRACT FROM AUTHOR]
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- 2024
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5. TROPOMI Carbon Monoxide
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Borsdorff, Tobias, primary, Landgraf, Jochen, additional, and Sha, Mahesh Kumar, additional
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- 2022
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6. Comparisons of Greenhouse Gas Observation Satellite Performances Over Seoul Using a Portable Ground‐Based Spectrometer.
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Park, Hayoung, Jeong, Sujong, Sha, Mahesh Kumar, Lee, Jonghyuk, and Frey, Matthias Max
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GREENHOUSE gases ,FOURIER transform spectrometers ,METROPOLIS ,CITIES & towns ,MEGALOPOLIS ,SATELLITE-based remote sensing - Abstract
Satellites provide global coverage for monitoring atmospheric greenhouse gases, crucial for understanding global climate dynamics. However, their temporal and spatial resolutions fall short in detecting urban‐scale variations. To enhance satellite reliability over urban areas, this study presents the first comprehensive analysis of long‐term observations of column‐averaged dry air mole fractions of CO2, CH4, and CO (XCO2, XCH4, XCO) using two ground‐based fourier transform infrared spectrometers, EM27/SUNs, in a megacity. With over 2 years of observations, our study shows that EM27/SUN measurements can effectively capture the daily and seasonal variability of XCO2, XCH4, and XCO over Seoul, a megacity with complex topography and various emission sources. In addition, we use the advantage of having multiple greenhouse gas satellites targeting Seoul to compare with the EM27/SUNs. Our study highlights the importance of EM27/SUN observations in Seoul to identify the need for improvements in satellites to monitor greenhouse gas behaviors and emissions in urban areas. Plain Language Summary: This study examines how accurately satellites can monitor greenhouse gases over urban atmospheres to understand climate change. While satellites are good at covering large areas, they struggle to detect changes in cities. To improve these setbacks, this study uses ground‐based instruments to measure greenhouse gases over 2 years and test satellite reliability over Seoul, a megacity with various emission sources as well as a complex terrain for observation. This study shows that the newly developed ground‐based instruments, EM27/SUNs, are effective in tracking daily and seasonal changes in greenhouse gas concentrations and are useful tools in improving the validity of satellite observations in urban areas. The study suggests that using ground‐based observations in addition to satellite data adapted for urban area monitoring is important for understanding greenhouse gas emissions in major cities like Seoul. Key Points: First results of long‐term EM27/SUN measurements and satellite comparisons over SeoulEM27/SUN effective in monitoring greenhouse gases and assessing validity of satellite measurements over urban areasSatellites need higher resolutions and locally validated algorithms for urban monitoring [ABSTRACT FROM AUTHOR]
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- 2024
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7. Evidence of a dual African and Australian biomass burning influence on the vertical distribution of aerosol and carbon monoxide over the southwest Indian Ocean basin in early 2020.
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Bègue, Nelson, Baron, Alexandre, Krysztofiak, Gisèle, Berthet, Gwenaël, Kloss, Corinna, Jégou, Fabrice, Khaykin, Sergey, Ranaivombola, Marion, Millet, Tristan, Portafaix, Thierry, Duflot, Valentin, Keckhut, Philippe, Vérèmes, Hélène, Payen, Guillaume, Sha, Mahesh Kumar, Coheur, Pierre-François, Clerbaux, Cathy, Sicard, Michaël, Sakai, Tetsu, and Querel, Richard
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BIOMASS burning ,CARBON monoxide ,STRATOSPHERIC aerosols ,AEROSOLS ,TROPOSPHERIC aerosols ,AIR masses - Abstract
During the 2020 austral summer, the pristine atmosphere of the southwest Indian Ocean (SWIO) basin experienced significant perturbations. This study examines the variability of aerosols and carbon monoxide (CO) over this remote oceanic region and investigates the underlying processes in the upper troposphere–lower stratosphere (UT-LS). Aerosol profiles in January and February 2020 revealed a multi-layer structure in the tropical UT-LS. Numerical models – the FLEXible PARTicle dispersion model (FLEXPART) and the Modèle Isentropique de transport Mésoéchelle de l'Ozone Stratosphérique par Advection (MIMOSA) – indicated that the lower-stratospheric aerosol content was influenced by the intense and persistent stratospheric aerosol layer generated during the 2019–2020 extreme Australian bushfire events. A portion of this layer was transported eastward by prevailing easterly winds, leading to increased aerosol extinction profiles over Réunion on 27 and 28 January. Analysis of advected potential vorticity revealed isentropic transport of air masses containing Australian biomass burning aerosols from extratropical latitudes to Réunion at the 400 K isentropic level on 28 January. Interestingly, we found that biomass burning (BB) activity in eastern Africa, though weak during this season, significantly influenced (contributed up to 90 % of) the vertical distribution of CO and aerosols in the upper troposphere over the SWIO basin. Ground-based observations at Réunion confirmed the simultaneous presence of African and Australian aerosol layers. This study provides the first evidence of African BB emissions impacting the CO and aerosol distribution in the upper troposphere over the SWIO basin during the convective season. [ABSTRACT FROM AUTHOR]
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- 2024
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8. The Total Carbon Column Observing Network's GGG2020 Data Version
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Laughner, Joshua L., primary, Toon, Geoffrey C., additional, Mendonca, Joseph, additional, Petri, Christof, additional, Roche, Sébastien, additional, Wunch, Debra, additional, Blavier, Jean-Francois, additional, Griffith, David W. T., additional, Heikkinen, Pauli, additional, Keeling, Ralph F., additional, Kiel, Matthäus, additional, Kivi, Rigel, additional, Roehl, Coleen M., additional, Stephens, Britton B., additional, Baier, Bianca C., additional, Chen, Huilin, additional, Choi, Yonghoon, additional, Deutscher, Nicholas M., additional, DiGangi, Joshua P., additional, Gross, Jochen, additional, Herkommer, Benedikt, additional, Jeseck, Pascal, additional, Laemmel, Thomas, additional, Lan, Xin, additional, McGee, Erin, additional, McKain, Kathryn, additional, Miller, John, additional, Morino, Isamu, additional, Notholt, Justus, additional, Ohyama, Hirofumi, additional, Pollard, David F., additional, Rettinger, Markus, additional, Riris, Haris, additional, Rousogenous, Constantina, additional, Sha, Mahesh Kumar, additional, Shiomi, Kei, additional, Strong, Kimberly, additional, Sussmann, Ralf, additional, Té, Yao, additional, Velazco, Voltaire A., additional, Wofsy, Steven C., additional, Zhou, Minqiang, additional, and Wennberg, Paul O., additional
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- 2023
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9. Reply on RC1
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Sha, Mahesh Kumar, primary
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- 2023
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10. Atmospheric N2O and CH4 total columns retrieved from low-resolution Fourier transform infrared (FTIR) spectra (Bruker VERTEX 70) in the mid-infrared region.
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Zhou, Minqiang, Langerock, Bavo, Sha, Mahesh Kumar, Hermans, Christian, Kumps, Nicolas, Kivi, Rigel, Heikkinen, Pauli, Petri, Christof, Notholt, Justus, Chen, Huilin, and De Mazière, Martine
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METHANE ,FOURIER transforms ,NITROUS oxide ,SOLAR spectra ,ATMOSPHERIC composition ,INFRARED absorption - Abstract
Nitrous oxide (N2O) and methane (CH4) are two important greenhouse gases in the atmosphere. In 2019, mid-infrared (MIR) solar absorption spectra were recorded by a Bruker VERTEX 70 spectrometer and a Bruker IFS 125HR spectrometer at Sodankylä, Finland, at spectral resolutions of 0.2 and 0.005 cm-1 , respectively. The N2O and the CH4 retrievals from high-resolution MIR spectra have been well investigated within the Network for the Detection of Atmospheric Composition Change (NDACC) but not for MIR spectra gathered with instruments operating at low spectral resolution. In this study, N2O and CH4 retrieval strategies and retrieval uncertainties from the VERTEX 70 MIR low-resolution spectra are discussed and presented. The accuracy and precision of the VERTEX 70 N2O and CH4 retrievals are assessed by comparing them with the coincident 125HR retrievals and AirCore measurements. The relative differences between the N2O total columns retrieved from 125HR and VERTEX 70 spectra are - 0.3 ± 0.7 (1 σ) % with a correlation coefficient (R) of 0.93. Regarding the CH4 total column, we first used the same retrieval microwindows for 125HR and VERTEX 70 spectra, but there is an underestimation in the VERTEX 70 retrievals, especially in summer. The relative differences between the CH4 total columns retrieved from the 125HR and VERTEX 70 spectra are -1.3±1.1 (1 σ) % with a R value of 0.77. To improve the VERTEX 70 CH4 retrievals, we propose alternative retrieval microwindows. The relative differences between the CH4 total columns retrieved from the 125HR and VERTEX 70 spectra in these new windows become 0.0±0.8 (1 σ) %, along with an increase in the R value to 0.87. The coincident AirCore measurements confirm that the VERTEX 70 CH4 retrievals using the latter window choice are better, with relative mean differences between the VERTEX 70 CH4 retrievals and AirCore measurements of - 1.9 % for the standard NDACC microwindows and of 0.13 % for the alternative microwindows. This study provides insight into the N2O and CH4 retrievals from the low-resolution (0.2 cm-1) MIR spectra observed with a VERTEX 70 spectrometer, and it demonstrates the suitability of this kind of instrument for contributing to satellite validation, model verification, and other scientific campaigns with the advantage of its transportability and lower cost compared to standard NDACC-type Fourier-transform infrared (FTIR) instruments. [ABSTRACT FROM AUTHOR]
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- 2023
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11. Remote sensing of columnar trace gases during the Ruisdael Rotterdam campaign in 2022
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Heimerl, Katharina, primary, Houweling, Sander, additional, Hase, Frank, additional, Sha, Mahesh Kumar, additional, Desmet, Filip, additional, Kumps, Nicolas, additional, Langerock, Bavo, additional, Warneke, Thorsten, additional, Hase, Nils, additional, Hachmeister, Jonas, additional, and Butz, Andre, additional
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- 2023
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12. An 11-year record of XCO2 estimates derived from GOSAT measurements using the NASA ACOS version 9 retrieval algorithm
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TAYLOR, Thomas E., ODELL, Christopher W., CRISP, David, LINDQVIST, Hannakaisa, WENNBERG, Paul O., CHATTERJEE, Abhishek, GUNSON, Michael, ELDERING, Annmarie, FISHER, Brendan, KIEL, Matthaus, NELSON, Robert R., MERRELLI, Aronne, OSTERMAN, Greg, CHEVALLIER, Frederic, PALMER, Paul I., FENG, Liang, DEUTSCHER, Nicholas M., DUBEY, Manvendra K., FEIST, Dietrich G., GARCIA, Omaira E., GRIFFITH, David W. T., HASE, Frank, IRACI, Laura T., KIVI, Rigel, LIU, Cheng, MAZIERE, Martine De, NOTHOLT, Justus, OH, Young-Suk, POLLARD, David F., RETTINGER, Markus, SCHNEIDER, Matthias, ROEHL, Coleen M., SHA, Mahesh Kumar, KUZE, Akihiko, MORINO, Isamu, OHYAMA, Hirofumi, and SHIOMI, Kei
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著者人数: 44名, 形態: カラー図版あり, Number of authors: 44, Physical characteristics: Original contains color illustrations, Accepted: 2021-11-25, 資料番号: PA2210055000
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- 2022
13. Retrievals of XCO2, XCH4 and XCO from portable, near-infrared Fourier transform spectrometer solar observations in Antarctica
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Pollard, David F., primary, Hase, Frank, additional, Sha, Mahesh Kumar, additional, Dubravica, Darko, additional, Alberti, Carlos, additional, and Smale, Dan, additional
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- 2022
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14. Copernicus Cal/Val Solution: Copernicus measurement network and supersites
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Ligi, Martin, Tison, Céline, Raynal, Matthias, Labroue, Sylvie, Nencioli, Francesco, Pflug, Bringfried, Gielen, Bert, Lambert, Jean-Christopher, Papale, Dario, Tack, Frederik, Holzwarth, Stefanie, Compernolle, Steven, Mazière, Martine, Sha, Mahesh Kumar, Verhoelst, Tijl, and Clerc, Sebastien
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Measurement networks ,Measurement campaigns ,Copernicus supersites ,Satellite validation - Abstract
Dokumendi eesmärgiks on leida olemasolevate Copernicus missiooni kalibreerimise ja valideerimismõõtmiste kitsaskohti ja pakkuda võimalikke lahendusi., Aim of the document is to identify measurement gaps, considering the existing ground-based Cal/Val measurement campaigns and networks for Copernicus mission and to suggest areas for improvement.
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- 2023
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15. National CO2 budgets (2015–2020) inferred from atmospheric CO2 observations in support of the global stocktake
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Byrne, Brendan, Baker, David F., Basu, Sourish, Bertolacci, Michael, Bowman, Kevin W., Carroll, Dustin, Chatterjee, Abhishek, Chevallier, Frédéric, Ciais, Philippe, Cressie, Noel, Crisp, David, Crowell, Sean, Deng, Feng, Deng, Zhu, Deutscher, Nicholas Michael, Dubey, Manvendra K., Feng, Sha, García Rodríguez, Omaira Elena, Griffith, David W. T., Herkommer, Benedikt, Hu, Lei, Jacobson, Andrew R., Janardanan, Rajesh, Jeong, Sujong, Johnson, Matthew S., Jones, Dylan B. A., Kivi, Rigel, Liu, Junjie, Liu, Zhiqiang, Maksyutov, Shamil, Miller, John B., Morino, Isamu, Notholt, Justus, Oda, Tomohiro, O'Dell, Christopher, Oh, Young-Suk, Ohyama, Hirofumi, Patra, Prabir K., Peiro, Hélène, Petri, Christof, Philip, Sajeev, Pollard, David F., Poulter, Benjamin, Remaud, Marine, Schuh, Andrew, Sha, Mahesh Kumar, Shiomi, Kei, Strong, Kimberly, Sweeney, Colm, Te, Yao, Tian, Hanqin, Velazco, Voltaire A., Vrekoussis, Mihalis, Warneke, Thorsten, Worden, John, Wunch, Debra, Yao, Yuamzhi, Yun, Jeongmin, Zammit Mangion, Andrew, and Zeng, Ning
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Temperature increase ,Carbon dioxide emission ,Climate change - Abstract
Accurate accounting of emissions and removals of CO2 is critical for the planning and verification of emission reduction targets in support of the Paris Agreement. Here, we present a pilot dataset of country-specific net carbon exchange (NCE; fossil plus terrestrial ecosystem fluxes) and terrestrial carbon stock changes aimed at informing countries’ carbon budgets. These estimates are based on “top-down” NCE outputs from the v10 Orbiting Carbon Observatory (OCO-2) modeling intercomparison project (MIP), wherein an ensemble of inverse modeling groups conducted standardized experiments assimilating OCO-2 column-averaged dry-air mole fraction (XCO2 ) retrievals (ACOS v10), in situ CO2 measurements or combinations of these data. The v10 OCO-2 MIP NCE estimates are combined with “bottom-up” estimates of fossil fuel emissions and lateral carbon fluxes to estimate changes in terrestrial carbon stocks, which are impacted by anthropogenic and natural drivers. These flux and stock change estimates are reported annually (2015–2020) as both a global 1◦ × 1 ◦ gridded dataset and a country-level dataset and are available for download from the Committee on Earth Observation Satellites’ (CEOS) website: https://doi.org/10.48588/npf6-sw92 (Byrne et al., 2022). Across the v10 OCO-2 MIP experiments, we obtain increases in the ensemble median terrestrial carbon stocks of 3.29–4.58 PgCO2 yr−1 (0.90–1.25 PgC yr−1 ). This is a result of broad increases in terrestrial carbon stocks across the northern extratropics, while the tropics generally have stock losses but with considerable regional variability and differences between v10 OCO-2 MIP experiments. We discuss the state of the science for tracking emissions and removals using top-down methods, including current limitations and future developments towards top-down monitoring and verification systems. This research has been supported by the European Commission, Horizon 2020 Framework Programme (CoCO2 (grant no. 958927 856612/EMME-CARE)) and Copernicus Atmosphere Monitoring Service (grant no. CAMS73), the Australian Research Council (grant nos. DP190100180, DE180100203, DP160100598, LE0668470, DP140101552, DP110103118, DP0879468 and FT180100327), the Environmental Restoration and Conservation Agency (grant no. JPMEERF21S20800), the Korea Meteorological Administration (grant no. KMA2018-00320), the National Aeronautics and Space Administration (grant nos. 20-OCOST20-0004, 80NSSC18K0908, 80NSSC18K0976, 80NSSC20K0006, 80NSSC21K1068, 80NSSC21K1073, 80NSSC21K1077, 80NSSC21K1080, 80HQTR21T0069, NAG512247, NNG05GD07G, NNH17ZDA001N-OCO2 and NNX15AG93G), and the National Oceanic and Atmospheric Administration (grant no. NA18OAR4310266).
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- 2023
16. Validation of methane and carbon monoxide from Sentinel-5 Precursor using TCCON and NDACC-IRWG stations
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SHA, Mahesh Kumar, LANGEROCK, Bavo, BLAVIER, Jean-François L., BLUMENSTOCK, Thomas, BORSDORFF, Tobias, BUSCHMANN, Matthias, DEHN, Angelika, DEMAZIERE, Martine, DEUTSCHER, Nicholas M., FEIST, Dietrich G., GARCIA, Omaira E., GRIFFITH, David W. T., GRUTTER, Michel, HANNIGAN, James W., HASE, Frank, HEIKKINEN, Pauli, HERMANS, Christian, IRACI, Laura T., JESECK, Pascal, JONES, Nicholas, KIVI, Rigel, KUMPS, Nicolas, LANDGRAF, Jochen, LORENTE, Alba, MAHIEU, Emmanuel, MAKAROVA, Maria V., MELLQVIST, Johan, METZGER, Jean-Marc, NOTHOLT, Justus, ORTEGA, Ivan, PALM, Mathias, PETRI, Christof, POLLARD, David F., RETTINGER, Markus, ROBINSON, John, ROCHE, Sebastien, ROEHL, Coleen M., ROHLING, Amelie N., ROUSOGENOUS, Constantina, SCHNEIDER, Matthias, MORINO, Isamu, NAGAHAMA, Tomoo, OYAMA, Hirofumi, SHIOMI, Kei, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Sentinel 5P ,TCCON ,Environmental engineering ,010502 geochemistry & geophysics ,Atmospheric sciences ,01 natural sciences ,Methane ,Atmosphere ,Atmospheric composition ,Troposphere ,chemistry.chemical_compound ,Earthwork. Foundations ,Validation ,ddc:550 ,NDACC ,Total Carbon Column Observing Network ,0105 earth and related environmental sciences ,[PHYS]Physics [physics] ,CH4 ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,TA715-787 ,Network data ,TA170-171 ,On board ,CO ,Earth sciences ,chemistry ,13. Climate action ,Environmental science ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Carbon monoxide - Abstract
著者人数: 60名, 形態: カラー図版あり, Number of authors: 60, Physical characteristics: Original contains color illustrations, Accepted: 2021-08-18, 資料番号: PA2210074000
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- 2021
17. Update on the GOSAT TANSO–FTS SWIR Level 2 retrieval algorithm
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Someya, Yu, primary, Yoshida, Yukio, additional, Ohyama, Hirofumi, additional, Nomura, Shohei, additional, Kamei, Akihide, additional, Morino, Isamu, additional, Mukai, Hitoshi, additional, Matsunaga, Tsuneo, additional, Laughner, Joshua L., additional, Velazco, Voltaire A., additional, Herkommer, Benedikt, additional, Té, Yao, additional, Sha, Mahesh Kumar, additional, Kivi, Rigel, additional, Zhou, Minqiang, additional, Oh, Young Suk, additional, Deutscher, Nicholas M., additional, and Griffith, David W. T., additional
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- 2022
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18. Supplementary material to "Update on the GOSAT TANSO–FTS SWIR Level 2 retrieval algorithm"
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Someya, Yu, primary, Yoshida, Yukio, additional, Ohyama, Hirofumi, additional, Nomura, Shohei, additional, Kamei, Akihide, additional, Morino, Isamu, additional, Mukai, Hitoshi, additional, Matsunaga, Tsuneo, additional, Laughner, Joshua L., additional, Velazco, Voltaire A., additional, Herkommer, Benedikt, additional, Té, Yao, additional, Sha, Mahesh Kumar, additional, Kivi, Rigel, additional, Zhou, Minqiang, additional, Oh, Young Suk, additional, Deutscher, Nicholas M., additional, and Griffith, David W. T., additional
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- 2022
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19. Evidence of a dual African and Australian biomass burning influence on the vertical distribution of aerosol and carbon monoxide over the Southwest Indian Ocean basin in early 2020.
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Bègue, Nelson, Baron, Alexandre, Krysztofiak, Gisèle, Berthet, Gwenaël, Bencherif, Hassan, Kloss, Corinna, Jégou, Fabrice, Khaykin, Sergey, Ranaivombola, Marion, Millet, Tristan, Portafaix, Thierry, Duflot, Valentin, Keckhut, Philippe, Vérèmes, Hélène, Payen, Guillaume, Sha, Mahesh Kumar, Coheur, Pierre-François, Clerbaux, Cathy, Sicard, Michaël, and Tetsu Sakai
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The pristine atmosphere of the southwest Indian Ocean (SWIO) basin underwent significant perturbations during the 2020 austral summer. This study documents the complex variability of aerosols and carbon monoxide (CO) over this remote oceanic region and identifies the processes governing it in the upper troposphere - lower stratosphere (UT-LS). Aerosol profiles exhibit a multi-layer structure in the tropical UT-LS in January and February 2020. The numerical models (FLEXPART and MIMOSA) showed that the modulation of the aerosol content in the lower stratosphere is due to the intense and persistent stratospheric aerosol smoke layer generated during the 2019-20 extreme Australian bushfire events. One part of this stratospheric aerosol smoke layer was advected zonally by the prevailing easterly winds and its passage over Reunion was recorded by increased aerosol extinction profiles on 27th and 28th January. The analysis of the advected potential vorticity highlights an isentropic transport of air masses containing Australian biomass burning aerosol from extra-tropical latitudes to Reunion at the 400 K isentropic level, on 28th January. Interestingly, our results show that the BB activity in eastern Africa, weak during this season, contributed to modulate (up to 90%) the vertical distribution of CO and aerosols in the upper troposphere over the SWIO basin. The simultaneous presence of African and Australian aerosols smoke layers has been recorded by ground-based observations at Reunion. This study highlights for the first time the influence of the African emissions from BB to the CO and aerosols distribution in the upper troposphere over the SWIO basin during the convective season. The results show that besides PyroCb - driven injection of BB products to the stratosphere, an alternative pathway may exist during the regular deep-convection season in the tropics. [ABSTRACT FROM AUTHOR]
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- 2023
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20. XCO2 retrieval for GOSAT and GOSAT-2 based on the FOCAL algorithm
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NOEL, Stefan, REUTER, Maximilian, BUCHWITZ, Michael, BORCHARDT, Jakob, HILKER, Michael, BOVENSMANN, Heinrich, BURROWS, John P., DI, NOIA Antonio, BUSCHMANN, Matthias, DEUTSCHER, Nicholas M., FEIST, Dietrich G., GRIFFITH, David W. T., HASE, Frank, KIVI, Rigel, NOTHOLT, Justus, PETRI, Christof, PODOLSKE, James R., POLLARD, David F., SHA, Mahesh Kumar, SUTO, Hiroshi, YOSHIDA, Yukio, MORINO, Isamu, OYAMA, Hirofumi, and SHIOMI, Kei
- Abstract
著者人数: 28名, 形態: カラー図版あり, Number of authors: 28, Physical characteristics: Original contains color illustrations, Accepted: 2021-04-09, 資料番号: PA2210072000
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- 2021
21. Retrievals of XCO2, XCH4 and XCO from portable, near-infrared Fourier transform spectrometer solar observations in Antarctica
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Pollard, David Frank, primary, Hase, Frank, additional, Sha, Mahesh Kumar, additional, Dubravica, Darko, additional, Alberti, Carlos, additional, and Smale, Dan, additional
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- 2022
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22. Variations in land types detected using methane retrieved from space-borne sensor
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Bhatnagar, Saheba, primary, Sha, Mahesh Kumar, additional, Gill, Laurence, additional, Langerock, Bavo, additional, and Ghosh, Bidisha, additional
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- 2022
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23. Retrieval of greenhouse gases from GOSAT and GOSAT-2 using the FOCAL algorithm
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Noël, Stefan, primary, Reuter, Maximilian, additional, Buchwitz, Michael, additional, Borchardt, Jakob, additional, Hilker, Michael, additional, Schneising, Oliver, additional, Bovensmann, Heinrich, additional, Burrows, John P., additional, Di Noia, Antonio, additional, Parker, Robert J., additional, Suto, Hiroshi, additional, Yoshida, Yukio, additional, Buschmann, Matthias, additional, Deutscher, Nicholas M., additional, Feist, Dietrich G., additional, Griffith, David W. T., additional, Hase, Frank, additional, Kivi, Rigel, additional, Liu, Cheng, additional, Morino, Isamu, additional, Notholt, Justus, additional, Oh, Young-Suk, additional, Ohyama, Hirofumi, additional, Petri, Christof, additional, Pollard, David F., additional, Rettinger, Markus, additional, Roehl, Coleen, additional, Rousogenous, Constantina, additional, Sha, Mahesh Kumar, additional, Shiomi, Kei, additional, Strong, Kimberly, additional, Sussmann, Ralf, additional, Té, Yao, additional, Velazco, Voltaire A., additional, Vrekoussis, Mihalis, additional, and Warneke, Thorsten, additional
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- 2022
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24. Atmospheric N<sub>2</sub>O and CH<sub>4</sub> total columns retrieved from low-resolution FTIR spectra (Bruker Vertex 70) in the mid-infrared region
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Zhou, Minqiang, primary, Langerock, Bavo, additional, Sha, Mahesh Kumar, additional, Hermans, Christian, additional, Kumps, Nicolas, additional, Kivi, Rigel, additional, Heikkinen, Pauli, additional, Petri, Christof, additional, Notholt, Justus, additional, Chen, Huilin, additional, and De Mazière, Martine, additional
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- 2022
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25. Improved calibration procedures for the EM27/SUN spectrometers of the COllaborative Carbon Column Observing Network (COCCON)
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Alberti, Carlos, Hase, Frank, Frey, Matthias, Dubravica, Darko, Blumenstock, Thomas, Dehn, Angelika, Castracane, Paolo, Surawicz, Gregor, Harig, Roland, Baier, Bianca, Bès, Caroline, Bi, Jianrong, Boesch, Hartmut, Butz, André, Cai, Zhaonan, Chen, Jia, Crowell, Sean, Deutscher, Nicholas, Ene, Dragos, Franklin, Jonathan, García, Omaira, Griffith, David, Grouiez, Bruno, Grutter, Michel, Hamdouni, Abdelhamid, Houweling, Sander, Humpage, Neil, Jacobs, Nicole, Jeong, Sujong, Joly, Lilian, Jones, Nicholas, Jouglet, Denis, Kivi, Rigel, Kleinschek, Ralph, Lopez, Morgan, Medeiros, Diogo, Morino, Isamu, Mostafavipak, Nasrin, Müller, Astrid, Ohyama, Hirofumi, Palmer, Paul, Pathakoti, Mahesh, Pollard, David, Raffalski, Uwe, Ramonet, Michel, Ramsay, Robbie, Sha, Mahesh Kumar, Shiomi, Kei, Simpson, William, Stremme, Wolfgang, Sun, Youwen, Tanimoto, Hiroshi, Té, Yao, Tsidu, Gizaw Mengistu, Velazco, Voltaire, Vogel, Felix, Watanabe, Masataka, Wei, Chong, Wunch, Debra, Yamasoe, Marcia, Zhang, Lu, Orphal, Johannes, Sha, Mahesh, Tsidu, Gizaw, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-RAMCES (ICOS-RAMCES), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment - Abstract
International audience; Abstract. In this study, an extension on the previously reported status of the COllaborative Carbon Column Observing Network's (COCCON) calibration procedures incorporating refined methods is presented. COCCON is a global network of portable Bruker EM27/SUN FTIR spectrometers for deriving column-averaged atmospheric abundances of greenhouse gases. The original laboratory open-path lamp measurements for deriving the instrumental line shape (ILS) of the spectrometer from water vapour lines have been refined and extended to the secondary detector channel incorporated in the EM27/SUN spectrometer for detection of carbon monoxide (CO). The refinements encompass improved spectroscopic line lists for the relevant water lines and a revision of the laboratory pressure measurements used for the analysis of the spectra. The new results are found to be in good agreement with those reported by Frey et al. (2019) and discussed in detail. In addition, a new calibration cell for ILS measurements was designed, constructed and put into service. Spectrometers calibrated since January 2020 were tested using both methods for ILS characterization, open-path (OP) and cell measurements. We demonstrate that both methods can detect the small variations in ILS characteristics between different spectrometers, but the results of the cell method indicate a systematic bias of the OP method. Finally, a revision and extension of the COCCON network instrument-to-instrument calibration factors for XCO2, XCO and XCH4 is presented, incorporating 47 new spectrometers (of 83 in total by now). This calibration is based on the reference EM27/SUN spectrometer operated by the Karlsruhe Institute of Technology (KIT) and spectra collected by the collocated TCCON station Karlsruhe. Variations in the instrumental characteristics of the reference EM27/SUN from 2014 to 2017 were detected, probably arising from realignment and the dual-channel upgrade performed in early 2018. These variations are considered in the evaluation of the instrument-specific calibration factors in order to keep all tabulated calibration results consistent.
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- 2022
26. Update on the GOSAT TANSO–FTS SWIR Level 2 retrieval algorithm.
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Someya, Yu, Yoshida, Yukio, Ohyama, Hirofumi, Nomura, Shohei, Kamei, Akihide, Morino, Isamu, Mukai, Hitoshi, Matsunaga, Tsuneo, Laughner, Joshua L., Velazco, Voltaire A., Herkommer, Benedikt, Té, Yao, Sha, Mahesh Kumar, Kivi, Rigel, Zhou, Minqiang, Oh, Young Suk, Deutscher, Nicholas M., and Griffith, David W. T.
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SOLAR spectra ,CIRRUS clouds ,GAS absorption & adsorption ,ALGORITHMS ,ABSORPTION coefficients ,SPECTRAL irradiance ,MAXIMUM power point trackers - Abstract
The National Institute for Environmental Studies has provided the column-averaged dry-air mole fraction of carbon dioxide and methane (XCO 2 and XCH 4) products (L2 products) obtained from the Greenhouse gases Observing SATellite (GOSAT) for more than a decade. Recently, we updated the retrieval algorithm used to produce the new L2 product, V03.00. The main changes from the previous version (V02) of the retrieval algorithm are the treatment of cirrus clouds, the degradation model of the Thermal And Near-infrared Spectrometer for carbon Observation–Fourier Transform Spectrometer (TANSO–FTS), solar irradiance spectra, and gas absorption coefficient tables. The retrieval results from the updated algorithm showed improvements in fitting accuracies in the O 2 A, weak CO 2 , and CH 4 bands of TANSO–FTS, although the residuals increase in the strong CO 2 band over the ocean. The direct comparison of the new product obtained from the updated (V03) algorithm with the previous version V02.90/91 and the validations using the Total Carbon Column Observing Network revealed that the V03 algorithm increases the amount of data without diminishing the data qualities of XCO 2 and XCH 4 over land. However, the negative bias of XCO 2 is larger than that of the previous version over the ocean, and bias correction is still necessary. Additionally, the V03 algorithm resolves the underestimation of the XCO 2 growth rate compared with the in situ measurements over the ocean recently found using V02.90/91 and V02.95/96. [ABSTRACT FROM AUTHOR]
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- 2023
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27. Nitrous Oxide Profiling from Infrared Radiances (NOPIR): Algorithm Description, Application to 10 Years of IASI Observations and Quality Assessment
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Vandenbussche, Sophie, primary, Langerock, Bavo, additional, Vigouroux, Corinne, additional, Buschmann, Matthias, additional, Deutscher, Nicholas M., additional, Feist, Dietrich G., additional, García, Omaira, additional, Hannigan, James W., additional, Hase, Frank, additional, Kivi, Rigel, additional, Kumps, Nicolas, additional, Makarova, Maria, additional, Millet, Dylan B., additional, Morino, Isamu, additional, Nagahama, Tomoo, additional, Notholt, Justus, additional, Ohyama, Hirofumi, additional, Ortega, Ivan, additional, Petri, Christof, additional, Rettinger, Markus, additional, Schneider, Matthias, additional, Servais, Christian P., additional, Sha, Mahesh Kumar, additional, Shiomi, Kei, additional, Smale, Dan, additional, Strong, Kimberly, additional, Sussmann, Ralf, additional, Té, Yao, additional, Velazco, Voltaire A., additional, Vrekoussis, Mihalis, additional, Warneke, Thorsten, additional, Wells, Kelley C., additional, Wunch, Debra, additional, Zhou, Minqiang, additional, and De Mazière, Martine, additional
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- 2022
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28. Retrieval of greenhouse gases from GOSAT and greenhouse gases and carbon monoxide from GOSAT-2 using the FOCAL algorithm
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Noël, Stefan, primary, Reuter, Maximilian, additional, Buchwitz, Michael, additional, Borchardt, Jakob, additional, Hilker, Michael, additional, Schneising, Oliver, additional, Bovensmann, Heinrich, additional, Burrows, John P., additional, Di Noia, Antonio, additional, Parker, Robert J., additional, Suto, Hiroshi, additional, Yoshida, Yukio, additional, Buschmann, Matthias, additional, Deutscher, Nicholas M., additional, Feist, Dietrich G., additional, Griffith, David W. T., additional, Hase, Frank, additional, Kivi, Rigel, additional, Liu, Cheng, additional, Morino, Isamu, additional, Notholt, Justus, additional, Oh, Young-Suk, additional, Ohyama, Hirofumi, additional, Petri, Christof, additional, Pollard, David F., additional, Rettinger, Markus, additional, Roehl, Coleen M., additional, Rousogenous, Constantina, additional, Sha, Mahesh Kumar, additional, Shiomi, Kei, additional, Strong, Kimberly, additional, Sussmann, Ralf, additional, Té, Yao, additional, Velazco, Voltaire A., additional, Vrekoussis, Mihalis, additional, and Warneke, Thorsten, additional
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- 2022
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29. Ground-based Remote Sensing of Total Columnar CO2, CH4, and CO using EM27/SUN FTIR spectrometer at a suburban location in India and validation of Sentinel-5p/TROPOMI
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Sagar, Vijay Kumar, primary, P, Mahesh, primary, D.V., Mahalakshmi, primary, K.S., Rajan, primary, M.V.R, Sesha Sai, primary, Hase, Frank, primary, Dubravica, Darko, primary, and Sha, Mahesh Kumar, primary
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- 2022
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30. Ground-Based Remote Sensing of Total Columnar CO2, CH4, and CO Using EM27/SUN FTIR Spectrometer at a Suburban Location (Shadnagar) in India and Validation of Sentinel-5P/TROPOMI
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Sagar, Vijay Kumar, primary, Pathakoti, Mahesh, additional, D.V., Mahalakshmi, additional, K.S., Rajan, additional, M.V.R., Sesha Sai, additional, Hase, Frank, additional, Dubravica, Darko, additional, and Sha, Mahesh Kumar, additional
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- 2022
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31. Retrieval of atmospheric CH4 vertical information from ground-based FTS near-infrared spectra
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Zhou, Minqiang, Langerock, Bavo, Sha, Mahesh Kumar, Kumps, Nicolas, Hermans, Christian, Petri, Christof, Warneke, Thorsten, Chen, Huilin, Metzger, Jean-Marc, Kivi, Rigel, Heikkinen, Pauli, Ramonet, Michel, de Mazière, Martine, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Laboratoire de Physiologie et de Génétique Moléculaire des Plantes, Université libre de Bruxelles (ULB), Institut für Umweltphysik [Bremen] (IUP), Universität Bremen, Observatoire des Sciences de l'Univers de La Réunion (OSU-Réunion), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR), Finnish Meteorological Institute (FMI), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-RAMCES (ICOS-RAMCES), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Isotope Research, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
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CALIBRATION ,[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,TROPOSPHERIC METHANE ,lcsh:TA715-787 ,IN-SITU ,lcsh:Earthwork. Foundations ,TCCON ,COLUMN-AVERAGED CH4 ,PROFILES ,VALIDATION ,lcsh:Environmental engineering ,GAS ,[SDU]Sciences of the Universe [physics] ,MOLE FRACTION ,CO2 ,lcsh:TA170-171 - Abstract
The Total Carbon Column Observing Network (TCCON) column-averaged dry air mole fraction of CH4 (XCH4) measurements have been widely used to validate satellite observations and to estimate model simulations. The GGG2014 code is the standard TCCON retrieval software used in performing a profile scaling retrieval. In order to obtain several vertical pieces of information in addition to the total column, in this study, the SFIT4 retrieval code is applied to retrieve the CH4 mole fraction vertical profile from the Fourier transform spectrometer (FTS) spectrum at six sites (Ny-Ålesund, Sodankylä, Bialystok, Bremen, Orléans and St Denis) during the time period of 2016–2017. The retrieval strategy of the CH4 profile retrieval from ground-based FTS near-infrared (NIR) spectra using the SFIT4 code (SFIT4NIR) is investigated. The degree of freedom for signal (DOFS) of the SFIT4NIR retrieval is about 2.4, with two distinct pieces of information in the troposphere and in the stratosphere. The averaging kernel and error budget of the SFIT4NIR retrieval are presented. The data accuracy and precision of the SFIT4NIR retrievals, including the total column and two partial columns (in the troposphere and stratosphere), are estimated by TCCON standard retrievals, ground-based in situ measurements, Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) satellite observations, TCCON proxy data and AirCore and aircraft measurements. By comparison against TCCON standard retrievals, it is found that the retrieval uncertainty of SFIT4NIR XCH4 is similar to that of TCCON standard retrievals with systematic uncertainty within 0.35 % and random uncertainty of about 0.5 %. The tropospheric and stratospheric XCH4 from SFIT4NIR retrievals are assessed by comparison with AirCore and aircraft measurements, and there is a 1.0 ± 0.3 % overestimation in the SFIT4NIR tropospheric XCH4 and a 4.0 ± 2.0 % underestimation in the SFIT4NIR stratospheric XCH4, which are within the systematic uncertainties of SFIT4NIR-retrieved partial columns in the troposphere and stratosphere respectively.
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- 2019
32. Update on the GOSAT TANSO-FTS SWIR Level 2 retrieval algorithm.
- Author
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Yu Someya, Yukio Yoshida, Hirofumi Ohyama, Shohei Nomura, Akihide Kamei, Isamu Morino, Hitoshi Mukai, Tsuneo Matsunaga, Laughner, Joshua L., Velazco, Voltaire A., Herkommer, Benedikt, Yao Té, Sha, Mahesh Kumar, Kivi, Rigel, Minqiang Zhou, Young Suk Oh, Deutscher, Nicholas M., and Griffith, David W. T.
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FOURIER transform spectrometers ,SOLAR spectra ,SPECTRAL irradiance ,CIRRUS clouds ,GAS absorption & adsorption ,MAXIMUM power point trackers ,ALGORITHMS - Abstract
The National Institute for Environmental Studies has provided the column-averaged dry-air mole fraction of carbon dioxide and methane (XCO
2 and XCH4 ) products (L2 products) obtained from the Greenhouse gases Observing SATellite for more than a decade. Recently, we updated the retrieval algorithm used to produce the new L2 product, V03.00. The main changes from the previous version (V02) of the retrieval algorithm are the treatment of cirrus clouds, the degradation model of the Thermal And Near-infrared Spectrometer for carbon Observation - Fourier Transform Spectrometer (TANSO-FTS), solar irradiance spectra, and gas absorption coefficient tables. The retrieval results from the updated algorithm showed improvements in fitting accuracies in the O2 A, weak CO2 , and CH4 bands of TANSO-FTS, although the residuals increase in the strong CO2 band over the ocean. The direct comparison of the new product obtained from the updated (V03) algorithm with the previous version V02.90/91 and the validations using the Total Carbon Column Observing Network revealed that the V03 algorithm increases the amount of data without diminishing the data qualities of XCO2 and XCH4 over land. Further, the negative bias of XCO2 is larger than that of the previous version over the ocean, and bias correction is still necessary. Additionally, the V03 algorithm resolves the underestimation of the XCO2 growth rate compared with the in situ measurements over the ocean recently found using V02.90/91 and V02.95/96. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
33. Mercury in the Free Troposphere and Bidirectional Atmosphere-Vegetation Exchanges – Insights from Maïdo Mountain Observatory in the Southern Hemisphere Tropics.
- Author
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Koenig, Alkuin Maximilian, Magand, Olivier, Verreyken, Bert, Brioude, Jerome, Amelynck, Crist, Schoon, Niels, Colomb, Aurélie, Araujo, Beatriz Ferreira, Ramonet, Michel, Sha, Mahesh Kumar, Cammas, Jean-Pierre, Sonke, Jeroen E., and Dommergue, Aurélien
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TROPOSPHERE ,ATMOSPHERIC mercury ,DIURNAL variations in meteorology ,ATMOSPHERIC boundary layer - Abstract
Atmospheric mercury (Hg) observations in the lower free troposphere (LFT) can give important insights into Hg redox chemistry and can help constrain Hg background concentrations on a regional level. Relatively continuous sampling of LFT air, inaccessible to most ground-based stations, can be achieved at high-altitude observatories. However, such high-altitude observatories are rare, especially in the Southern Hemisphere (SH), and atmospheric Hg in the SH LFT is unconstrained. To fill this gap, we continuously measured gaseous elemental mercury (GEM; hourly) and reactive mercury (RM; integrated over ~6–14 days) for 9 months at Maïdo mountain observatory (2160 masl) on remote Réunion Island (21.1° S, 55.5° E) in the tropical Indian Ocean. GEM exhibits a marked diurnal variation characterized by a midday peak (mean: 0.95 ng m
-3 ; SD: 0.08 ng m-3 ) and a nighttime low (mean: 0.78 ng m-3 ; SD: 0.11 ng m-3 ). We find that this diurnal variation is likely driven by the interplay of important GEM photo-reemission from the islands' vegetated surface during daylight hours (8–22 ng m-2 h-1 ), boundary layer influences during the day, and predominant LFT influences at night. We estimate GEM in the LFT based on nighttime observations in particularly dry airmasses and find a notable seasonal variation, with LFT GEM being lowest from December to March (mean 0.66 ng m-3 ; SD: 0.07 ng m-3 ) and highest from September to November (mean: 0.79 ng m-3 ; SD: 0.09 ng m-3 ). Such a clear GEM seasonality contrasts the weak seasonal variation reported for the SH marine boundary layer, but goes in line with modeling results, highlighting the added value of continuous Hg observations in the LFT. Maïdo RM is 10.6 pg m-3 (SD: 5.9 pg m-3 ) on average, but RM in the cloud-free LFT might be about twice as high, as weekly-biweekly sampled RM observations are likely diluted by low-RM contributions from the boundary layer and clouds. [ABSTRACT FROM AUTHOR]- Published
- 2022
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34. Long-term column-averaged greenhouse gas observations using a COCCON spectrometer at the high-surface-albedo site in Gobabeb, Namibia
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Frey, Matthias M., primary, Hase, Frank, additional, Blumenstock, Thomas, additional, Dubravica, Darko, additional, Groß, Jochen, additional, Göttsche, Frank, additional, Handjaba, Martin, additional, Amadhila, Petrus, additional, Mushi, Roland, additional, Morino, Isamu, additional, Shiomi, Kei, additional, Sha, Mahesh Kumar, additional, de Mazière, Martine, additional, and Pollard, David F., additional
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- 2021
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35. An eleven year record of XCO<sub>2</sub> estimates derived from GOSAT measurements using the NASA ACOS version 9 retrieval algorithm
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Taylor, Thomas E., primary, O'Dell, Christopher W., additional, Crisp, David, additional, Kuze, Akhiko, additional, Lindqvist, Hannakaisa, additional, Wennberg, Paul O., additional, Chatterjee, Abhishek, additional, Gunson, Michael, additional, Eldering, Annmarie, additional, Fisher, Brendan, additional, Kiel, Matthäus, additional, Nelson, Robert R., additional, Merrelli, Aronne, additional, Osterman, Greg, additional, Chevallier, Frédéric, additional, Palmer, Paul I., additional, Feng, Liang, additional, Deutscher, Nicholas M., additional, Dubey, Manvendra K., additional, Feist, Dietrich G., additional, Garcia, Omaira E., additional, Griffith, David, additional, Hase, Frank, additional, Iraci, Laura T., additional, Kivi, Rigel, additional, Liu, Cheng, additional, De Mazière, Martine, additional, Morino, Isamu, additional, Notholt, Justus, additional, Oh, Young-Suk, additional, Ohyama, Hirofumi, additional, Pollard, David F., additional, Rettinger, Markus, additional, Roehl, Coleen M., additional, Schneider, Matthias, additional, Sha, Mahesh Kumar, additional, Shiomi, Kei, additional, Strong, Kimberly, additional, Sussmann, Ralf, additional, Té, Yao, additional, Velazco, Voltaire A., additional, Vrekoussis, Mihalis, additional, Warneke, Thorsten, additional, and Wunch, Debra, additional
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- 2021
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36. Reply on RC1
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Sha, Mahesh Kumar, primary
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- 2021
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37. Long-term column-averaged greenhouse gas observations using a COCCON spectrometer at the high-surface-albedo site in Gobabeb, Namibia
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Frey, Matthias M., Hase, Frank, Blumenstock, Thomas, Dubravica, Darko, Groß, Jochen, Göttsche, Frank, Handjaba, Martin, Amadhila, Petrus, Mushi, Roland, Morino, Isamu, Shiomi, Kei, Sha, Mahesh Kumar, Mazière, Martine, and Pollard, David F.
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Earth sciences ,ddc:550 - Abstract
In this study, we present column-averaged dry-air mole fractions of CO2 (XCO2), CH4 (XCH4) and CO (XCO) from a recently established measurement site in Gobabeb, Namibia. Gobabeb is a hyperarid desert site at the sharp transition zone between the sand desert and the gravel plains, offering unique characteristics with respect to surface albedo properties. Measurements started in January 2015 and are performed utilizing a ground-based Fourier transform infrared (FTIR) EM27/SUN spectrometer of the COllaborative Carbon Column Observing Network (COCCON). Gobabeb is the first measurement site observing XCO2 and XCH4 on the African mainland and improves the global coverage of ground-based remote-sensing sites. In order to achieve the high level of precision and accuracy necessary for meaningful greenhouse gas observations, we performed calibration measurements for 8 d between November 2015 and March 2016 with the COCCON reference EM27/SUN spectrometer operated at the Karlsruhe Institute of Technology. We derived scaling factors for XCO2, XCH4 and XCO with respect to the reference instrument that are close to 1.0. We compare the results obtained in Gobabeb to measurements from the Total Carbon Column Observing Network (TCCON) sites at Réunion Island and Lauder. We choose these TCCON sites because, while 4000 km apart, the instruments at Gobabeb and Réunion Island operate at roughly the same latitude. The Lauder station is the southernmost TCCON station and functions as a background site without a pronounced XCO2 seasonal cycle. We find a good agreement for the absolute Xgas values, apart from an expected XCH4 offset between Gobabeb and Lauder due to significantly different tropopause height, as well as representative intraday variability between TCCON and COCCON. Together with the absence of long-term drifts, this highlights the quality of the COCCON measurements. In the southern hemispheric summer, we observe lower XCO2 values at Gobabeb compared to the TCCON stations, likely due to the influence of the African biosphere. We performed coincident measurements with the Greenhouse Gases Observing Satellite (GOSAT), where GOSAT observed three nearby specific observation points, over the sand desert south of the station, directly over Gobabeb and over the gravel plains to the north. GOSAT H-gain XCO2 and XCH4 agree with the EM27/SUN measurements within the 1σ uncertainty limit. The number of coincident soundings is limited, but we confirm a bias of 1.2–2.6 ppm between GOSAT M-gain and H-gain XCO2 retrievals depending on the target point. This is in agreement with results reported by a previous study and the GOSAT validation team. We also report a bias of 5.9–9.8 ppb between GOSAT M-gain and H-gain XCH4 measurements which is within the range given by the GOSAT validation team. Finally, we use the COCCON measurements to evaluate inversion-optimized CAMS model data. For XCO2, we find high biases of 0.9 ± 0.5 ppm for the Orbiting Carbon Observatory-2 (OCO-2) assimilated product and 1.1 ± 0.6 ppm for the in situ-driven product with R2 > 0.9 in both cases. These biases are comparable to reported offsets between the model and TCCON data. The OCO-2 assimilated model product is able to reproduce the drawdown of XCO2 observed by the COCCON instrument at the beginning of 2017, as opposed to the in situ-optimized product. Also, for XCH4, the observed biases are in line with prior model comparisons with TCCON.
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- 2021
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38. An eleven year record of XCO2 estimates derived from GOSAT measurements using the NASA ACOS version 9 retrieval algorithm
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Taylor, Thomas E., O'Dell, Christopher, Crisp, David, Kuze, Akhiko, Lindqvist, Hannakaisa, Wennberg, Paul O., Chatterjee, Abhishek, Gunson, Michael R., Eldering, Annmarie, Fisher, Brendan, Kiel, Matthaeus, Nelson, Robert R., Merrelli, Aronne, Osterman, Gregory, Chevallier, Frédéric, Palmer, Paul I., Feng, Liang, Deutscher, Nicholas Michael, Dubey, Manvendra K., Feist, Dietrich G., García Rodríguez, Omaira Elena, Griffith, David W. T., Hase, Frank, Iraci, Laura, Kivi, Rigel, Liu, Cheng, De Mazière, Martine, Morino, Isamu, Notholt, Justus, Oh, Young-Suk, Ohyama, Hirofumi, Pollard, David F., Rettinger, Markus, Roehl, Coleen M., Schneider, Matthias, Sha, Mahesh Kumar, Shiomi, Kei, Strong, Kimberly, Sussmann, Ralf, Te, Yao, Velazco, Voltaire A., Vrekoussis, Mihalis, Warneke, Thorsten, and Wunch, Debra
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Greenhouse gases ,Total Carbon Column Observing Network ,Spectrometer - Abstract
The Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer (TANSO-FTS) on the Japanese Greenhouse gases Observing SATellite (GOSAT) has been returning data since April 2009. The version 9 (v9) Atmospheric Carbon Observations from Space (ACOS) Level 2 Full Physics (L2FP) retrieval algorithm (Kiel et al., 2019) was used to derive estimates of carbon dioxide (CO2) dry air mole fraction (XCO2) from the TANSO-FTS measurements collected over it's first eleven years of operation. The bias correction and quality filtering of the L2FP XCO2 product were evaluated using estimates derived from the Total Carbon Column Observing Network (TCCON) as well as values simulated from a suite of global atmospheric inverse modeling systems (models). In addition, the v9 ACOS GOSAT XCO2 results were compared with collocated XCO2 estimates derived from NASA's Orbiting Carbon Observatory-2 (OCO-2), using the version 10 (v10) ACOS L2FP algorithm. These tests indicate that the v9 ACOS GOSAT XCO2 product has improved throughput, scatter and bias, when compared to the earlier v7.3 ACOS GOSAT product, which extended through mid 2016. Of the 37 million (M) soundings collected by GOSAT through June 2020, approximately 20 % were selected for processing by the v9 L2FP algorithm after screening for clouds and other artifacts. After post-processing, 5.4 % of the soundings (2M out of 37M) were assigned a “good” XCO2 quality flag, as compared to 3.9 % in v7.3 (
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- 2021
39. Retrievals of ..., ... and XCO from portable, near-infrared Fourier transform spectrometer solar observations in Antarctica.
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Pollard, David F., Hase, Frank, Sha, Mahesh Kumar, Dubravica, Darko, Alberti, Carlos, and Smale, Dan
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FOURIER transform spectrometers ,SOLAR spectra ,SERVER farms (Computer network management) ,POLAR vortex ,ABSORPTION spectra ,IR spectrometers ,INFRARED absorption - Abstract
The Collaborative Carbon Column Observing Network (COCCON), uses low-resolution, portable EM27/SUN Fourier Transform Spectrometers (FTSs) to make retrievals of dry air mole fractions (DMFs, represented as X
gas ) of CO2 , CH4 , CO and H2 O from near infrared solar absorption spectra. The COCCON has developed rapidly over recent years and complements the Total Carbon Column Observing Network (TCCON). In this work we provide details of the first seasonal timeseries of near infrared ..., ... and XCO retrievals from measurements made in Antarctica during the deployment of an EM27/SUN to the Arrival Heights laboratory on Ross Island (77.83° S, 166.66° E, 205m AMSL) over the austral summer of 2019/20 under the auspices of the COCCON. The DMFs of all three species were lower in Antarctica than at mid-latitude and for ... and XCO the retrieved values were less variable. For ... however, the variability was significantly greater and it was found that this was strongly correlated to the proximity of the polar vortex. In order to ensure the stability of the instrument and the traceability of the retrievals, side-by-side comparisons to the TCCON station at Lauder, New Zealand (45.04° S, 169.68° E, 370m AMSL) and retrievals of the Instrument Line Shape (ILS) were made before and after the measurements in Antarctica. These indicate that over the course of the deployment the instrument stability was such that the change in retrieved ... was well below 0.1%. The value of this data for satellite validation is demonstrated by making comparisons with the Tropospheric Monitoring Instrument (TROPOMI) on the Sentinel-5 Precursor (S5P) satellite. The data set is available from the COCCON Central Facility hosted by the ESA Atmospheric Validation Data Centre (EVDC) https://doi.org/10.48477/coccon.pf10.arrivalheights.R02 (Pollard, 2021). [ABSTRACT FROM AUTHOR]- Published
- 2022
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40. Variations in land types detected using methane retrieved from space-borne sensor.
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Bhatnagar, Saheba, Sha, Mahesh Kumar, Gill, Laurence, Langerock, Bavo, and Ghosh, Bidisha
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GLOBAL warming ,WASTE management ,WETLANDS ,GREENHOUSE gases ,GRASSLANDS ,AIR quality management - Abstract
Methane (CH
4 ), a potent greenhouse gas, traps heat in the atmosphere and significantly contributes to global warming. Atmospheric CH4 comes from various natural and anthropogenic sources. CH4 emissions from the decomposition of organic material by bacteria in natural wetlands, other land types, agriculture, and waste management constitute the major component of global emissions. Although there is no clear evidence that CH4 emissions from wetlands and other natural sources have increased substantially in the last decade, uncertainties remain regarding sources and their spatial extent causing discrepancies between emission estimates from inventories/models and estimates inferred by an ensemble of atmospheric inversions. Here we show that satellite-based CH4 total column measurements along with surface albedo from Sentinel-5 Precursor (S-5p) show unique sensitivity to certain land types. Consequently, the areal extent of six land types (marsh, swamp, forest, grassland, cropland, and barren-land) could be identified with high overall accuracy by analysing S-5p data over Canada utilising our classification-segmentation algorithm. Monthly and yearly inventory maps were created, which can be used to validate or complement global models where data from other sources are missing and may help in further constraining the methane budget. [ABSTRACT FROM AUTHOR]- Published
- 2022
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41. Atmospheric N2O and CH4 total columns retrieved from low-resolution FTIR spectra (Bruker Vertex 70) in the mid-infrared region.
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Minqiang Zhou, Langerock, Bavo, Sha, Mahesh Kumar, Hermans, Christian, Kumps, Nicolas, Kivi, Rigel, Heikkinen, Pauli, Petri, Christof, Notholt, Justus, Chen, Huilin, and De Mazière, Martine
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ATMOSPHERIC composition ,ABSORPTION spectra ,NITROUS oxide ,UNITS of measurement ,GREENHOUSE gases - Abstract
Nitrous oxide (N
2 O) and Methane (CH4 ) are two important greenhouse gases in the atmosphere. In 2019, midinfrared (MIR) solar absorption spectra were recorded by a Bruker Vertex 70 spectrometer and a Bruker IFS 125HR spectrometer at Sodankylä, Finland at spectral resolutions of 0.2 cm−1 and 0.005 cm−1 , respectively. The N2 O and the CH4 retrievals from high-resolution MIR spectra have been well investigated within the Network for Detection of Atmospheric Composition Change (NDACC), but not for MIR spectra gathered with instruments operating at low spectral resolution. In this study, N2 O and CH4 retrieval strategies and retrieval uncertainties from the Vertex 70 MIR low-resolution spectra are discussed and presented. The accuracy and precision of the Vertex 70 N2 O and CH4 retrievals are assessed by comparing them with the colocated 125HR retrievals and AirCore measurements. The relative differences between the N2 O total columns retrieved from 125HR and Vertex 70 spectra are -0.3±0.7(1σ)% with a correlation coefficient (R) of 0.93. Regarding CH4 total column, we first used the same retrieval microwindows for 125HR and Vertex 70 spectra, but there is an underestimation in the Vertex 70 retrievals, especially in summer. The relative differences between the CH4 total columns retrieved from the 125HR and Vertex spectra are -1.3±1.1% with a R value of 0.77. To improve the Vertex 70 CH4 retrievals, we propose an alternative retrieval microwindows. The relative differences between the CH4 total columns retrieved from the 125HR and Vertex spectra in these new windows become 0.0±0.8%, along with an increase in R value to 0.87. The co-located AirCore measurements confirm that the Vertex 70 CH4 retrievals using the latter window choice are better, with the relative mean differences between the Vertex CH44 retrievals and AirCore measurements of -1.9% for the standard NDACC mircrowindows, and of 0.13% for the alternative microwindows. This study provides an insight into the N2 O and CH4 retrievals from the low-resolution (0.2 cm−1 ) MIR spectra observed with a Vertex 70 spectrometer, and demonstrates the suitability of this kind of instruments for contributing to satellite validation, model verification, and other scientific campaigns with the advantage of their transportability and lower cost compared to standard NDACC-type FTIR instruments. [ABSTRACT FROM AUTHOR]- Published
- 2022
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42. Validation of Methane and Carbon Monoxide from Sentinel-5 Precursor using TCCON and NDACC-IRWG stations
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Sha, Mahesh Kumar, primary, Langerock, Bavo, additional, Blavier, Jean-François L., additional, Blumenstock, Thomas, additional, Borsdorff, Tobias, additional, Buschmann, Matthias, additional, Dehn, Angelika, additional, De Mazière, Martine, additional, Deutscher, Nicholas M., additional, Feist, Dietrich G., additional, García, Omaira E., additional, Griffith, David W. T., additional, Grutter, Michel, additional, Hannigan, James W., additional, Hase, Frank, additional, Heikkinen, Pauli, additional, Hermans, Christian, additional, Iraci, Laura T., additional, Jeseck, Pascal, additional, Jones, Nicholas, additional, Kivi, Rigel, additional, Kumps, Nicolas, additional, Landgraf, Jochen, additional, Lorente, Alba, additional, Mahieu, Emmanuel, additional, Makarova, Maria V., additional, Mellqvist, Johan, additional, Metzger, Jean-Marc, additional, Morino, Isamu, additional, Nagahama, Tomoo, additional, Notholt, Justus, additional, Ohyama, Hirofumi, additional, Ortega, Ivan, additional, Palm, Mathias, additional, Petri, Christof, additional, Pollard, David F., additional, Rettinger, Markus, additional, Robinson, John, additional, Roche, Sébastien, additional, Roehl, Coleen M., additional, Röhling, Amelie N., additional, Rousogenous, Constantina, additional, Schneider, Matthias, additional, Shiomi, Kei, additional, Smale, Dan, additional, Stremme, Wolfgang, additional, Strong, Kimberly, additional, Sussmann, Ralf, additional, Té, Yao, additional, Uchino, Osamu, additional, Velazco, Voltaire A., additional, Vrekoussis, Mihalis, additional, Wang, Pucai, additional, Warneke, Thorsten, additional, Wizenberg, Tyler, additional, Wunch, Debra, additional, Yamanouchi, Shoma, additional, Yang, Yang, additional, and Zhou, Minqiang, additional
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- 2021
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43. Intercomparison of atmospheric CO2 and CH4 abundances on regional scales in boreal areas using Copernicus Atmosphere Monitoring Service (CAMS) analysis, COllaborative Carbon Column Observing Network (COCCON) spectrometers, and Sentinel-5 Precursor satellite observations
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Tu, Qiansi, Hase, Frank, Blumenstock, Thomas, Kivi, Rigel, Heikkinen, Pauli, Sha, Mahesh Kumar, Raffalski, Uwe, Landgraf, Jochen, Lorente, Alba, Borsdorff, Tobias, Chen, Huilin, Dietrich, Florian, Chen, Jia, and Isotope Research
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SCIAMACHY ,Earth sciences ,REANALYSIS ,TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES ,METHANE ,RETRIEVALS ,ddc:550 ,INSTRUMENTAL LINE-SHAPE ,TROPOMI ,PERFORMANCE ,XCO2 ,HIGH-RESOLUTION ,MISSION - Abstract
We compare the atmospheric column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) measured with a pair of COllaborative Carbon Column Observing Network (COCCON) spectrometers at Kiruna and Sodankylä (boreal areas). We compare model data provided by the Copernicus Atmosphere Monitoring Service (CAMS) between 2017 and 2019 with XCH4 data from the recently launched Sentinel-5 Precursor (S5P) satellite between 2018 and 2019. In addition, measured and modeled gradients of XCO2 and XCH4 (ΔXCO2 and ΔXCH4) on regional scales are investigated. Both sites show a similar and very good correlation between COCCON retrievals and the modeled CAMS XCO2 data, while CAMS data are biased high with respect to COCCON by 3.72 ppm (±1.80 ppm) in Kiruna and 3.46 ppm (±1.73 ppm) in Sodankylä on average. For XCH4, CAMS values are higher than the COCCON observations by 0.33 ppb (±11.93 ppb) in Kiruna and 7.39 ppb (±10.92 ppb) in Sodankylä. In contrast, the S5P satellite generally measures lower atmospheric XCH4 than the COCCON spectrometers, with a mean difference of 9.69 ppb (±20.51 ppb) in Kiruna and 3.36 ppb (±17.05 ppb) in Sodankylä. We compare the gradients of XCO2 and XCH4 (ΔXCO2 and ΔXCH4) between Kiruna and Sodankylä derived from CAMS analysis and COCCON and S5P measurements to study the capability of detecting sources and sinks on regional scales. The correlations in ΔXCO2 and ΔXCH4 between the different datasets are generally smaller than the correlations in XCO2 and XCH4 between the datasets at either site. The ΔXCO2 values predicted by CAMS are generally higher than those observed with COCCON with a slope of 0.51. The ΔXCH4 values predicted by CAMS are mostly higher than those observed with COCCON with a slope of 0.65, covering a larger dataset than the comparison between S5P and COCCON. When comparing CAMS ΔXCH4 with COCCON ΔXCH4 only in S5P overpass days (slope = 0.53), the correlation is close to that between S5P and COCCON (slope = 0.51). CAMS, COCCON, and S5P predict gradients in reasonable agreement. However, the small number of observations coinciding with S5P limits our ability to verify the performance of this spaceborne sensor. We detect no significant impact of ground albedo and viewing zenith angle on the S5P results. Both sites show similar situations with the average ratios of XCH4 (S5P/COCCON) of 0.9949±0.0118 in Kiruna and 0.9953±0.0089 in Sodankylä. Overall, the results indicate that the COCCON instruments have the capability of measuring greenhouse gas (GHG) gradients on regional scales, and observations performed with the portable spectrometers can contribute to inferring sources and sinks and to validating spaceborne greenhouse gas sensors. To our knowledge, this is the first published study using COCCON spectrometers for the validation of XCH4 measurements collected by S5P.
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- 2020
44. New ground-based Fourier-transform near-infrared solar absorption measurements of XCO2, XCH4 and XCO at Xianghe, China
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Yang, Yang, Zhou, Minqiang, Langerock, Bavo, Sha, Mahesh Kumar, Hermans, Christian, Wang, Ting, Ji, Denghui, Vigouroux, Corinne, Kumps, Nicolas, Wang, Gengchen, Mazière, Martine, and Wang, Pucai
- Abstract
The column-averaged dry-air mole fractions of CO2 (XCO2), CH4 (XCH4) and CO (XCO) have been measured with a Bruker IFS 125HR Fourier-transform infrared (FTIR) spectrometer at Xianghe (39.75∘ N, 116.96∘ E, north China) since June 2018. This paper presents the site, the characteristics of the FTIR system and the measurements. The instrumental setup follows the guidelines of the Total Carbon Column Observing Network (TCCON): the near-infrared spectra are recorded by an InGaAs detector together with a CaF2 beam splitter, and the HCl cell measurements are recorded regularly to derive the instrument line shape (ILS) showing that the instrument is correctly aligned. The TCCON standard retrieval code (GGG2014) is applied to retrieve XCO2, XCH4 and XCO. The resulting time series between June 2018 and July 2019 are presented, and the observed seasonal cycles and day-to-day variations in XCO2, XCH4 and XCO at Xianghe are discussed. In addition, the paper shows comparisons between the data products retrieved from the FTIR measurements at Xianghe and co-located Orbiting Carbon Observatory-2 (OCO-2) and Tropospheric Monitoring Instrument (TROPOMI) satellite observations. The comparison results appear consistent with validation results obtained at TCCON sites for XCO2 and XCH4, while for XCO they highlight the occurrence of frequent high-pollution events. As Xianghe lies in a polluted area in north China where there are currently no TCCON sites, this site can fill the TCCON gap in this region and expand the global coverage of the TCCON measurements. The Xianghe FTIR XCO2, XCH4 and XCO data can be obtained at https://doi.org/10.18758/71021049 (Yang et al., 2019).
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- 2020
45. Atmospheric CO2 and CH4 abundances on regional scales in boreal areas using CAMS reanalysis, COCCON spectrometers and Sentinel-5 Precursor satellite observations
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Tu, Qiansi, Hase, Frank, Blumenstock, Thomas, Kivi, Rigel, Heikkinen, Pauli, Sha, Mahesh Kumar, Raffalski, Uwe, Landgraf, Jochen, Lorente, Alba, Borsdorff, Tobias, and Chen, Huilin
- Abstract
We compare the atmospheric column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) measured with a pair of COCCON spectrometers at Kiruna and Sodankylä sites in boreal areas with model data provided by the Copernicus Atmosphere Monitoring Service (CAMS) and with XCH4 from the recently launched Sentinel-5 Precursor (S5P) satellite. Both sites show a similar and very good correlation between COCCON retrievals and the modeled CAMS XCO2 and XCH4 data. CAMS data are biased high with respect to COCCON in both XCO2 and XCH4, while the S5P satellite generally measures lower atmospheric XCH4 than the COCCON spectrometers. The gradients of XCO2 and XCH4 (ΔXCO2 and ΔXCH4) between Kiruna and Sodankylä derived from CAMS reanalysis and COCCON and S5P measurements are investigated to study the capability of detecting sources and sinks on regional scales. CAMS, COCCON and S5P predict gradients in reasonable agreement. However, the small number of observations coinciding with S5P limits our ability to verify the performance of this sensor. Overall, the results indicate that the COCCON instrument has the capability of measuring greenhouse gas (GHG) gradients on regional scales and observations performed with the portable spectrometers can contribute to inferring sources and sinks and to validating space borne greenhouse gas sensors.
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- 2020
46. Intercomparison of low- and high-resolution infrared spectrometers for ground-based solar remote sensing measurements of total column concentrations of CO2, CH4, and CO
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Sha, Mahesh Kumar, De Mazière, Martine, Notholt, Justus, Blumenstock, Thomas, Chen, Huilin, Dehn, Angelika, Griffith, David W. T., Hase, Frank, Heikkinen, Pauli, Hermans, Christian, Hoffmann, Alex, Huebner, Marko, Jones, Nicholas, Kivi, Rigel, Langerock, Bavo, Petri, Christof, Scolas, Francis, Tu, Qiansi, Weidmann, Damien, and Isotope Research
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CALIBRATION ,Earth sciences ,METHANE ,X-CO2 ,lcsh:TA715-787 ,lcsh:Earthwork. Foundations ,TCCON ,ddc:550 ,INSTRUMENTAL LINE-SHAPE ,lcsh:TA170-171 ,CARBON-MONOXIDE ,lcsh:Environmental engineering - Abstract
The Total Carbon Column Observing Network (TCCON) is the baseline ground-based network of instruments that record solar absorption spectra from which accurate and precise column-averaged dry-air mole fractions of CO2 (XCO2), CH4 (XCH4), CO (XCO), and other gases are retrieved. The TCCON data have been widely used for carbon cycle science and validation of satellites measuring greenhouse gas concentrations globally. The number of stations in the network (currently about 25) is limited and has a very uneven geographical coverage: the stations in the Northern Hemisphere are distributed mostly in North America, Europe, and Japan, and only 20 % of the stations are located in the Southern Hemisphere, leaving gaps in the global coverage. A denser distribution of ground-based solar absorption measurements is needed to improve the representativeness of the measurement data for various atmospheric conditions (humid, dry, polluted, presence of aerosol), various surface conditions such as high albedo (>0.4) and very low albedo, and a larger latitudinal distribution. More stations in the Southern Hemisphere are also needed, but a further expansion of the network is limited by its costs and logistical requirements. For this reason, several groups are investigating supplemental portable low-cost instruments. The European Space Agency (ESA) funded campaign Fiducial Reference Measurements for Ground-Based Infrared Greenhouse Gas Observations (FRM4GHG) at the Sodankylä TCCON site in northern Finland aims to characterise the assessment of several low-cost portable instruments for precise solar absorption measurements of XCO2, XCH4, and XCO. The test instruments under investigation are three Fourier transform spectrometers (FTSs): a Bruker EM27/SUN, a Bruker IRcube, and a Bruker Vertex70, as well as a laser heterodyne spectroradiometer (LHR) developed by the UK Rutherford Appleton Laboratory. All four remote sensing instruments performed measurements simultaneously next to the reference TCCON instrument, a Bruker IFS 125HR, for a full year in 2017. The TCCON FTS was operated in its normal high-resolution mode (TCCON data set) and in a special low-resolution mode (HR125LR data set), similar to the portable spectrometers. The remote sensing measurements are complemented by regular AirCore launches performed from the same site. They provide in situ vertical profiles of the target gas concentrations as auxiliary reference data for the column retrievals, which are traceable to the WMO SI standards. The reference measurements performed with the Bruker IFS 125HR were found to be affected by non-linearity of the indium gallium arsenide (InGaAs) detector. Therefore, a non-linearity correction of the 125HR data was performed for the whole campaign period and compared with the test instruments and AirCore. The non-linearity-corrected data (TCCONmod data set) show a better match with the test instruments and AirCore data compared to the non-corrected reference data. The time series, the bias relative to the reference instrument and its scatter, and the seasonal and the day-to-day variations of the target gases are shown and discussed. The comparisons with the HR125LR data set gave a useful analysis of the resolution-dependent effects on the target gas retrieval. The solar zenith angle dependence of the retrievals is shown and discussed. The intercomparison results show that the LHR data have a large scatter and biases with a strong diurnal variation relative to the TCCON and other FTS instruments. The LHR is a new instrument under development, and these biases are currently being investigated and addressed. The campaign helped to characterise and identify instrumental biases and possibly retrieval biases, which are currently under investigation. Further improvements of the instrument are ongoing. The EM27/SUN, the IRcube, the modified Vertex70, and the HR125LR provided stable and precise measurements of the target gases during the campaign with quantified small biases. The bias dependence on the humidity along the measurement line of sight has been investigated and no dependence was found. These three portable low-resolution FTS instruments are suitable to be used for campaign deployment or long-term measurements from any site and offer the ability to complement the TCCON and expand the global coverage of ground-based reference measurements of the target gases.
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- 2020
47. Improved Constraints on Northern Extratropical CO2 Fluxes Obtained by Combining Surface-Based and Space-Based Atmospheric CO2 Measurements
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Byrne, B, Liu, J, Lee, M, Baker, I, Bowman, K, Deutscher, Nicholas M, Feist, Dietrich G, Griffith, David W. T, Iraci, Laura T, Kiel, Matthaus, Kimball, J, Miller, Charles E, Morino, Isamu, Parazoo, N., Petri, Christof, Roehl, C M, Sha, Mahesh Kumar, Strong, Kimberly, Velazco, Voltaire A, Wennberg, Paul O, Wunch, Debra, Byrne, B, Liu, J, Lee, M, Baker, I, Bowman, K, Deutscher, Nicholas M, Feist, Dietrich G, Griffith, David W. T, Iraci, Laura T, Kiel, Matthaus, Kimball, J, Miller, Charles E, Morino, Isamu, Parazoo, N., Petri, Christof, Roehl, C M, Sha, Mahesh Kumar, Strong, Kimberly, Velazco, Voltaire A, Wennberg, Paul O, and Wunch, Debra
- Abstract
© 2020. The Authors. Top-down estimates of CO2 fluxes are typically constrained by either surface-based or space-based CO2 observations. Both of these measurement types have spatial and temporal gaps in observational coverage that can lead to differences in inferred fluxes. Assimilating both surface-based and space-based measurements concurrently in a flux inversion framework improves observational coverage and reduces sampling related artifacts. This study examines the consistency of flux constraints provided by these different observations and the potential to combine them by performing a series of 6-year (2010–2015) CO2 flux inversions. Flux inversions are performed assimilating surface-based measurements from the in situ and flask network, measurements from the Total Carbon Column Observing Network (TCCON), and space-based measurements from the Greenhouse Gases Observing Satellite (GOSAT), or all three data sets combined. Combining the data sets results in more precise flux estimates for subcontinental regions relative to any of the data sets alone. Combining the data sets also improves the accuracy of the posterior fluxes, based on reduced root-mean-square differences between posterior flux-simulated CO2 and aircraft-based CO2 over midlatitude regions (0.33–0.56 ppm) in comparison to GOSAT (0.37–0.61 ppm), TCCON (0.50–0.68 ppm), or in situ and flask measurements (0.46–0.56 ppm) alone. These results suggest that surface-based and GOSAT measurements give complementary constraints on CO2 fluxes in the northern extratropics and can be combined in flux inversions to improve constraints on regional fluxes. This stands in contrast with many earlier attempts to combine these data sets and suggests that improvements in the NASA Atmospheric CO2 Observations from Space (ACOS) retrieval algorithm have significantly improved the consistency of space-based and surface-based flux constraints.
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- 2020
48. Long-term column-averaged greenhouse gas observations using a COCCON spectrometer at the high surface albedo site Gobabeb, Namibia
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Frey, Matthias M., primary, Hase, Frank, additional, Blumenstock, Thomas, additional, Dubravica, Darko, additional, Groß, Jochen, additional, Göttsche, Frank, additional, Handjaba, Martin, additional, Amadhila, Petrus, additional, Mushi, Roland, additional, Morino, Isamu, additional, Shiomi, Kei, additional, Sha, Mahesh Kumar, additional, de Mazière, Martine, additional, and Pollard, David F., additional
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- 2021
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49. Evaluation and optimization of ICOS atmosphere station data as part of the labeling process
- Author
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Yver-Kwok, Camille, primary, Philippon, Carole, additional, Bergamaschi, Peter, additional, Biermann, Tobias, additional, Calzolari, Francescopiero, additional, Chen, Huilin, additional, Conil, Sebastien, additional, Cristofanelli, Paolo, additional, Delmotte, Marc, additional, Hatakka, Juha, additional, Heliasz, Michal, additional, Hermansen, Ove, additional, Komínková, Kateřina, additional, Kubistin, Dagmar, additional, Kumps, Nicolas, additional, Laurent, Olivier, additional, Laurila, Tuomas, additional, Lehner, Irene, additional, Levula, Janne, additional, Lindauer, Matthias, additional, Lopez, Morgan, additional, Mammarella, Ivan, additional, Manca, Giovanni, additional, Marklund, Per, additional, Metzger, Jean-Marc, additional, Mölder, Meelis, additional, Platt, Stephen M., additional, Ramonet, Michel, additional, Rivier, Leonard, additional, Scheeren, Bert, additional, Sha, Mahesh Kumar, additional, Smith, Paul, additional, Steinbacher, Martin, additional, Vítková, Gabriela, additional, and Wyss, Simon, additional
- Published
- 2021
- Full Text
- View/download PDF
50. XCO2 retrieval for GOSAT and GOSAT-2 based on the FOCAL algorithm
- Author
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Noël, Stefan, primary, Reuter, Maximilian, additional, Buchwitz, Michael, additional, Borchardt, Jakob, additional, Hilker, Michael, additional, Bovensmann, Heinrich, additional, Burrows, John P., additional, Di Noia, Antonio, additional, Suto, Hiroshi, additional, Yoshida, Yukio, additional, Buschmann, Matthias, additional, Deutscher, Nicholas M., additional, Feist, Dietrich G., additional, Griffith, David W. T., additional, Hase, Frank, additional, Kivi, Rigel, additional, Morino, Isamu, additional, Notholt, Justus, additional, Ohyama, Hirofumi, additional, Petri, Christof, additional, Podolske, James R., additional, Pollard, David F., additional, Sha, Mahesh Kumar, additional, Shiomi, Kei, additional, Sussmann, Ralf, additional, Té, Yao, additional, Velazco, Voltaire A., additional, and Warneke, Thorsten, additional
- Published
- 2020
- Full Text
- View/download PDF
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