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We present the first estimate of the global distribution of CO_2 surface fluxes from 14 stations of the Total Carbon Column Observing Network (TCCON). The evaluation of this inversion is based on 1) comparison with the fluxes from a classical inversion of surface air-sample-measurements, and 2) comparison of CO_2 mixing ratios calculated from the inverted fluxes with independent aircraft measurements made during the two years analyzed here, 2009 and 2010. The former test shows similar seasonal cycles in the northern hemisphere and consistent regional carbon budgets between inversions from the two datasets, even though the TCCON inversion appears to be less precise than the classical inversion. The latter test confirms that the TCCON inversion has improved the quality (i.e., reduced the uncertainty) of the surface fluxes compared to the assumed or prior fluxes. The consistency between the surface-air-sample-based and the TCCON-based inversions despite remaining flaws in transport models opens the possibility of increased accuracy and robustness of flux inversions based on the combination of both data sources and confirms the usefulness of space-borne monitoring of the CO_2 column.

Continuous validation of data observed by satellites, such as Greenhouse gases Observing SATellite (GOSAT), is important to qualify the long-term trends of greenhouse gases. High-precision data over the restricted region measured by ground-based high-resolution Fourier transform spectrometers (g-b FTS), airborne in-situ instruments, and flask sampling devices have been used for the validation of satellite data. As part of CAL/VAL (Calibration/Validation) activities of the GOSAT, airborne flight campaigns were performed over Tsukuba and Moshiri using the ground-based FTS, airborne in-situ and flask devices, and 1.57-μm Laser Absorption Sensor (LAS). Airborne flask sampling and insitu carbon dioxide (CO 2 ) sensors were carried out to obtain vertical profiles of the CO 2 mixing ratio while ground-based FTS and LAS measured solar direct spectra and weighted column-averaged CO 2 , respectively. Those results were used to decide a calibration factor of the ground-based FTS and compared with GOSAT products over Tsukuba. We will report the comparison results of the aircraft campaign measurements and the retrieval value from the FTS.

Column-averaged volume mixing ratios of carbon dioxide and methane retrieved from the Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed observation (GOSAT SWIR XCO2 and XCH4) were compared with the reference calibrated data obtained by ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) participating in the Total Carbon Column Observing Network (TCCON). Preliminary results are as follows: the GOSAT SWIR XCO2 and XCH4 (Version 01.xx) are biased low by 8.85 ± 4.75 ppm (2.3 ± 1.2 %) and 20.4 ± 18.9 ppb (1.2 ± 1.1 %), respectively. The standard deviation of the GOSAT SWIR XCO2 and XCH4 is about 1 % (1 σ) after correcting the negative biases of XCO2 and XCH4 by 8.85 ppm and 20.4 ppb, respectively. The latitudinal distributions of zonal means of the GOSAT SWIR XCO2 and XCH4 show similar features to those of the g-b FTS data except for the negative biases in the GOSAT data.

S. Houweling1,2, M. Krol1,2,3, P. Bergamaschi4, C. Frankenberg5, E. J. Dlugokencky6, I. Morino7, J. Notholt8, V. Sherlock9, D. Wunch10, V. Beck11, C. Gerbig11, H. Chen12,13, E. A. Kort14, T. Rockmann2, and I. Aben1 1SRON Netherlands Institute for Space Research, Utrecht, the Netherlands 2Institute for Marine and Atmospheric Research (IMAU), Utrecht University, Utrecht, the Netherlands 3Department of Meteorology and Air Quality (MAQ), Wageningen University and Research Centre, Wageningen, the Netherlands 4European Commission Joint Research Centre, Institute for Environment and Sustainability, Ispra (Va), Italy 5Jet Propulsion Laboratory, Pasadena, CA, USA 6NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, CO, USA 7Center for Global Environmental Research, National Institute for Environmental Studies (NIES) Onogawa 16-2, Tsukuba, Ibaraki 305-8506, Japan 8Institute of Environmental Physics, University of Bremen, Bremen, Germany 9National Institute of Water and Atmospheric Research (NIWA), P.O. Box 14-901, Wellington, New Zealand 10Caltech, Pasadena, CA, USA 11Max Planck Institute for Biogeochemistry, Jena, Germany 12Center for Isotope Research (CIO), University of Groningen, the Netherlands 13CIRES, University of Colorado, Boulder, CO, USA 14Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI, USA

The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO2, CO, CH4, N2O and H2O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measurements. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. The aircraft campaigns are the Stratosphere-Troposphere Analyses of Regional Transport 2008 (START-08), which included a profile over the Park Falls site, the HIAPER Pole-to-Pole Observations (HIPPO-1) campaign, which included profiles over the Lamont and Lauder sites, a series of Learjet profiles over the Lamont site, and a Beechcraft King Air profile over the Tsukuba site. These calibrations are compared with similar observations made during the INTEX-NA (2004), COBRA-ME (2004) and TWP-ICE (2006) campaigns. A single, global calibration factor for each gas accurately captures the TCCON total column data within error.

[1] We retrieved CO2 volume mixing ratios (VMRs) from solar absorption spectra in the 1.6-μm CO2 (30012-00001) band measured with a ground-based high-resolution Fourier transform spectrometer (FTS) at Tsukuba, Japan, using profile retrieval and scaling retrieval algorithms. We derived the time series of the column-averaged CO2 VMRs (XCO2) from December 2001 to December 2007. The average difference between the XCO2 values obtained with the two algorithms was approximately 0.8 ppm. This difference was attributed to differences between the column averaging kernels of the algorithms. We corrected the distortion effect of an instrumental line shape (ILS) on XCO2 retrieval by determining information about the ILS simultaneously with XCO2. Aircraft in situ measurements were made simultaneously with the FTS measurements over the FTS site on 10 August 2004 and 30 March 2005. The differences between the XCO2 values derived from the FTS measurements and from the aircraft in situ measurements complemented by model data were less than 1%. The diurnal variations of XCO2 derived from the FTS measurements demonstrated that XCO2 could be retrieved with a precision of ∼0.2%. The retrieved XCO2 values were compared with CO2 VMRs obtained from aircraft sampling measurements up to 7 km altitude over Sagami Bay, Japan. The seasonal amplitude of the retrieved XCO2 agreed within 1 ppm with those of the CO2 VMRs obtained from the aircraft sampling measurements above 3 km. The average seasonal amplitude of XCO2 over Tsukuba was ∼8 ppm. In addition, XCO2 showed an increasing trend, with a growth rate of ∼2 ppm/a.

[1] Nondispersive infrared (NDIR) CO2 analyzer could produce erroneous CO2 mole fraction measurements for an air sample when CO2-in-air mixtures having different isotopic compositions than atmospheric CO2 are used as the NDIR calibration gases. This is because (1) an optical band-pass filter equipped in a typical NDIR analyzer to minimize the interference effect from the other infrared-active species is basically designed to transmit only the absorption band of 12C16O2 and (2) absorption bands for the other CO2-related isotopologues, for example, 13C16O2, are shifted to lower wave numbers depending on their isotope effects. To evaluate the effect of the isotopic composition on the NDIR response, we computed the theoretical relative molar response of the instrument to each isotopologue based on the infrared absorptance by the individual isotopologues. We then prepared a gravimetric 13CO2-in-air mixture with CO2 mole fraction of 380 ppm to experimentally determine the optical filter property. The apparent mole fractions of the 13CO2-in-air mixture determined by three NDIR analyzers used in this study were 46, 94, and 27 ppm, indicating that the optical filters in these instruments substantially reduced the response to 13C16O2. Based on these theoretical and experimental analyses, we evaluated the apparent difference in the CO2 mole fraction determined by the three NDIR analyzers from the true value when isotopically lighter CO2-in-air mixtures (δ13C = −32.4‰ and δ18O = +11.7‰), as compared to atmospheric CO2 (δ13C = ∼−8‰ and δ18O = ∼+40‰), are used as calibration gases. The estimated difference varied with NDIR analyzers, ranging from −0.04 to −0.08 ppm for air samples with 380 ppm CO2.

The tunneling-rotation transitions of malonaldehyde, 43 a-type Q-branch lines, were observed in the submillimeter-wave region of 643–651 GHz. The proton tunneling splitting in the ground state, ΔE0=647 046.208±0.019 MHz, and the interaction constant, F=45.8965±0.0082 MHz, were determined, as well as the molecular constants for each tunneling sublevel.

In order to validate and calibrate the GOSAT satellite data, and also to develop the retrieval algorism for deriving the column density of CO 2 and CH 4 from spectra, the airborne SWIR (Short Wave Infrared Region) FTS (Fourier transform spectrometer) has been developed and characterized. This instrument is called as TSUKUBA model. The initial performance test of TSUKUBA model was carried out in our laboratory, and the measured modulation efficiencies are 70% (Band1), 85% (Band2) and 88% (Band3), respectively. The measured values of SNR with the equivalent black body temperature for 30% surface albedo are 190 (13050cm -1 ), 148 (6200cm -1 ), and 165 (5000cm -1 ). The measured values of full width at half maximum (FWHM) of instrumental line shape functions are 0.38cm -1 , 0.26cm -1 , 0.25 cm -1 for band 1, 2, and 3, respectively. The instrumental design and the results of performance tests are presented.

Greenhouse gases Observing SATellite (GOSAT) is a Japanese satellite to monitor column density of greenhouse gases such as carbon dioxide (CO 2 ) and methane (CH 4 ) globally from space. GOSAT will be launched in 2008. The data measured by a GOSAT sensor and ground-based monitoring station data will be used into an atmospheric transport inverse model to identify source/sink amount of CO 2 in a sub-continental scale. One of the main GOSAT sensors is a nadir-looking Fourier Transform Spectrometer (FTS), which covers Short Wavelength Infrared (SWIR) region to measure column density of CO 2 . National Institute for Environmental Studies (NIES) is promoting researches on CO 2 and CH 4 sensitivity analysis, error analysis, data retrieval algorithm study, ground-based/air-borne validation strategy, and a plan of inverse model study for the SWIR FTS. A Bread-board model (BBM) of the SWIR FTS was built and tested by ground-based and airborne measurements. Several sets of the CO 2 and CH 4 radiance spectra over rice fields were obtained by the test measurements, and it was confirmed that the airborne measurements with a vibration insulator are effective for onboard measurements. Moreover, several improvement items of BBM have become clear.

The buffer-gas pressure broadening coefficients and the temperature dependent parameter of the third overtone band of NO at 1.35–1.38 μm by N2 and rare gases for two ground electronic states, 2Π1⁄2...

We have measured and analyzed rotational transitions of N2O in the following vibrational states, 01(1e,f)0, 02(0,2e,f)0, 03(1,3e,f)0, 00(0)1, 01(1e,f)1, and 10(0)0. The NAIR terahertz spectrometer was used to measure the frequencies of transitions in the range J = 25-- 24 to J = 31-- 30 with accuracies of +/-0.020 MHz in most cases. These measurements were fit, along with other microwave and infrared measurements involving the same states, to obtain improved rovibrational term values for those vibrational states. It is shown that the measurements can be fit with fewer constants if both l-type resonance and the Fermi resonance among the levels 00(0)1 and 02(0,2)0 or 01(1)1 and 03(1,3)0 are included in the least-squares fit. These measurements also contribute to improving the N2O wavenumber calibration standards for the infrared region. Copyright 1999 Academic Press.

The rotational spectrum of the NH2 radical in itsXtilde;2B1 ground vibronic state was investigated between 614 and 1003 GHz. One hundred fifty-nine newly observed lines (188 hyperfine components) of six rotational transitions with 0/= N/= 5 and 0/= Ka/= 4 were used in the final, global fit of field-free data for the (000) vibrational state. Recent results from Fourier transform far-infrared (FT-FIR), and millimeter- and submillimeter-wave spectroscopy, as well as microwave optical double resonance (MODR) and recent FIR laser sideband data, were also used in the fit. A large set of spectroscopic constants reproduces the input data within experimental uncertainties and permits the precise prediction of low-N, low-Ka transitions of interest for the astrophysical community. In particular, the astrophysically important 111-000 transition of ortho NH2 was observed near 952.57 and 959.50 GHz. Copyright 1999 Academic Press.

The gas-phase far-infrared absorption spectra of the NH2, NHD, and ND2 radicals have been observed in the 51-366 cm-1 region with a high-resolution Fourier transform spectrometer. The NH2 radical was generated in a multiple-traversal absorption cell by a dc discharge in an NH3 and Ar mixture. A discharge in an NH3, D2, and Ar mixture was used for production of NHD and ND2. The observed spectra with a resolved fine structure were analyzed by Watson's A-reduced Hamiltonian including a spin-rotation interaction term. The rotational and spin-rotation constants were determined to higher order. In the same experiment of NH2, the rotational spectrum of the NH radical was also observed. From the rotational constants, inertia defect Delta and r0 structure were determined, as follows, with one standard deviation in parentheses:NH2ND2r0 (A)1.0245(37)1.0239(19)theta0 (degree)103.34(51)103.33(27)Deltaobs (amuA2)0.049561(4)0.06770(4);Dgr;calc (amuA2)0.0476530.066566 Copyright 1997Academic Press

Column-averaged dry air mole fractions of carbon dioxide (XCO2) retrieved from Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed (SWIR) observations were validated with aircraft measurements by the Comprehensive Observation Network for TRace gases by AIrLiner (CONTRAIL) project, the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the HIAPER Pole-to-Pole Observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. To calculate XCO2 based on aircraft measurements (aircraft-based XCO2), tower measurements and model outputs were used for additional information near the surface and above the tropopause, respectively. Before validation, we investigated the impacts of GOSAT SWIR column averaging kernels (CAKs) and the shape of a priori profiles on the aircraft-based XCO2 calculation. The differences between aircraft-based XCO2 with and without the application of GOSAT CAK were evaluated to be less than ±0.4 ppm at most, and less than ±0.1 ppm on average. Therefore, we concluded that the GOSAT CAK produces only a minor effect on the aircraft-based XCO2 calculation in terms of the overall uncertainty of GOSAT XCO2. We compared GOSAT data retrieved within ±2 or ±5° latitude/longitude boxes centered at each aircraft measurement site to aircraft-based data measured on a GOSAT overpass day. The results indicated that GOSAT XCO2 over land regions agreed with aircraft-based XCO2, except that the former is biased by −0.68 ppm (−0.99 ppm) with a standard deviation of 2.56 ppm (2.51 ppm), whereas the averages of the differences between the GOSAT XCO2 over ocean and the aircraft-based XCO2 were −1.82 ppm (−2.27 ppm) with a standard deviation of 1.04 ppm (1.79 ppm) for ±2° (±5°) boxes.

Buffer-gas pressure broadening for the nu(1)+nu(3) band of H(2)O at 1.34-1.44 mum for a variety of buffer gases was investigated at room temperature using continuous-wave cavity ring-down spectroscopy. The effective interaction energy of water dimer under room temperature conditions was evaluated from the pressure broadening coefficients for rare gases using Permenter-Seaver's relation. Monte Carlo simulations were performed using ab initio molecular orbital calculations to evaluate the interaction energies for the water dimer at 300 K. In this theoretical calculation, the orientations of the two water molecules were statistically treated.

Since molecular observations in interstellar space have very important role to understand physical conditions - density and temperature - and produciton mechanisms of molecules, many molecules are studied in laboratory and in astronomical observation. A lot of informaiton in interstellar space has been mainly obtained by millimeter-wave astronomical observations, but in millimeter wave region relatively heavy molecules have their rotational transitions. Observations of small molecules such as hydrides are limited, although they are important to understand the produciton mechanism related hydrogen compounds. Most of hydrides have rotational transitions in submillimeter-wave or far-infrared region. Recently, the astronomical observation techniques in submillimeter-wave, far-infrared, and infrared regions are greatly developed, and the observations in these regions become possible. However, there are a few laboratory data for molecules in these regions. In the present study, far-infrared and infrared Fourier transform spectroscopy was applied to measure transient molecules of astronomical interest in laboratory and the results were applied to astronomically observed data. The dc discharge cell with multi-reflection system was constructed for far-infrared absorption measurement. The author applied to observe the pure rotational spectra of the SH, NH2, NHD, and ND2 radicals and the vibration rotaiton spectrum of NH2OH. The measurement of SH was the first applicaiton of far-infrared Fourier transform spectroscopy to transient molecules, and detection limit of this measurement system was estimated. About 600 rotational lines of NH2, NHD, ND2 and about 5000 rovibrational lines of NH2OH were observed in high-resolution and wide frequency coverage. By the anlysis of the observed spectra, precise molecular parameters were obtained. The information obtained by these measurements is very useful for sub-millimeter and far-infrared astronomical observation. The positive column discharge cell was constructed for infrared emission observation. The author applied to measure the vibration rotational specta of the CD and 18OH radicals. By analysis, precise molecular constants in the vibrationally excited states were obtained. From intensity analysis using Herman-Wallis effect, the vibration transition moment of CH was determined, and applied to determination of column density in infrared astronomical observation. The observed intensity of 18OH was discussed. Some result of laboratory spectroscopy were applied to astronomical observational results. The upper limit of column density of SH was estimated from the submillimeter-wave emission spectrum in Orion-KL. For clarifying the production mechanism of SHn, it is clear that more deep search for SH is necessary. Using the transition moment of CH in this study, the column density of CH was determined from infrared absorption spectrum in late-type star TX Psc. The author found that the column density in envelope of C-type late star was almost same as diffuse cloud. The rotational spectrum of NHD was not found in the published millimeter and submillimeter line survey data in Orion-KL and Sgr B2.