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An integrated portable, dual-channel all-fibered laser heterodyne radiometer (portable dc-LHR) with a high spectral resolution (0.0044 cm−1) for simultaneous remote sensing of atmospheric dry-air column-averaged mole fraction of CO2 and CH4 (XCO2 and X $_{\text {CH4}}$ ) has been developed. Sunlight is modulated by a dual-channel fiber optical switch and mixed with two laser beams, which were step-scanned across two strong absorption features centered at 1603.59–1657.39 nm, respectively. Digital lock-in amplifiers (DLIAs) are designed to demodulate the laser heterodyne signal, while self-design interferometric devices are used to monitor laser wavelength. A forward model based on relative transmittance in a narrow band and an optimal estimation inversion algorithm are used for data inversion. The portable instrument was carried out in a field campaign in Dachaidan (Qinghai Province, China, 37.744°N, 95.342°E), together with co-located Aircore and EM27/SUN measurements, in August 2020. The retrieval uncertainties of portable dc-LHR XCO2 and XCH4 are 0.9 ppm and 3.4 ppb, respectively. Comparison in XCO2 and XCH4 observations between portable dc-LHR and EM27/SUN show a good agreement.

Measurements of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) are of great importance in the Qinghai-Tibetan region, as it is the highest and largest plateau in the world affecting global weather and climate systems. In this study, for the first time, we present CO2, CH4, and CO column measurements carried out by a Bruker EM27/SUN Fourier-transform infrared spectrometer (FTIR) at Golmud (36.42°E, 94.91°N, 2808 m) in August 2021. The mean and standard deviation of the column-average dry-air mixing ratio of CO2, CH4, and CO (XCO2, XCH4, and XCO) are 409.3 ± 0.4 ppm, 1905.5 ± 19.4 ppb, and 103.1 ± 7.7 ppb, respectively. The differences between the FTIR co-located TROPOMI/S5P satellite measurements at Golmud are 0.68 ± 0.64% (13.1 ± 12.2 ppb) for XCH4and 9.81 ± 3.48% (−10.7 ± 3.8 ppb) for XCO, which are within their retrieval uncertainties. High correlations for both XCH4and XCO are observed between the FTIR and S5P satellite measurements. Using the FLEXPART model and satellite measurements, we find that enhanced CH4and CO columns in Golmud are affected by anthropogenic emissions transported from North India. This study provides an insight into the variations of the CO2, CH4, and CO columns in the Qinghai-Tibetan Plateau.

China’s first carbon dioxide (CO2) measurement satellite mission, TanSat, was launched in December 2016. This paper introduces the first attempt to detect anthropogenic CO2emission signatures using CO2observations from TanSat and NO2measurements from the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Copernicus Sentinel-5 Precursor (S5P) satellite. We focus our analysis on two selected cases in Tangshan, China and Tokyo, Japan. We found that the TanSat XCO2measurements have the capability to capture the anthropogenic variations in the plume and have spatial patterns similar to that of the TROPOMI NO2observations. The linear fit between TanSat XCO2and TROPOMI NO2indicates the CO2-to-NO2ratio of 0.8 × 10−16ppm (molec cm−2)−1in Tangshan and 2.3 × 10−16ppm (molec cm−2)−1in Tokyo. Our results align with the CO2-to-NOxemission ratios obtained from the EDGAR v6 emission inventory.

In this study, we introduce our newly developed measurement-fed-perception self-adaption Low-cost UAV Coordinated Carbon Observation Network (LUCCN) prototype. The LUCCN primarily consists of two categories of instruments, including ground-based and UAV-based in-situ measurement. We use the GMP343, a low-cost non-dispersive infrared sensor, in both ground-based and UAV-based instruments. The first integrated measurement campaign took place in Shenzhen, China, 4 May 2023. During the campaign, we found that LUCCN’s UAV component presented significant data-collecting advantages over its ground-based counterpart owing to the relatively high altitudes of the point emission sources, which was especially obvious at a gas power plant in Shenzhen. The emission flux was calculated by a cross-sectional flux (CSF) method, the results of which differed from the Open-Data Inventory for Anthropogenic Carbon dioxide (ODIAC). The CSF result was slightly larger than others because of the low sampling rate of the whole emission cross section. The LUCCN system will be applied in future carbon monitoring campaigns to increase the spatiotemporal coverage of carbon emission information, especially in scenarios involving the detection of smaller-scale, rapidly varying sources and sinks.

We present characterizations of the dynamic turbulence in the lower stratosphere measured by a new balloon-based system designed for detecting finer scale dynamic turbulence. The balloon-based system included a constant temperature anemometer (CTA) operating at a sampling rate of 2 kHz at an ascent speed of 5 m s−1(corresponding to a vertical resolution of 2.5 mm), an industrial personal computer, batteries, sensors for ambient temperature and humidity, an A/D converter, and others. The system was successfully launched to 24 km altitude over Bayannur City, Inner Mongolia Province. Results show the spatial intermittence of the turbulence layers, with clear boundaries between turbulent and nonturbulent regions. This is the first time that the dynamic turbulence spectrum down to the viscous sub-range has been obtained throughout the lower stratosphere over China. With that, the energy dissipation rates of dynamic turbulence could be calculated with high precision. The profile of the dissipation rates varied from 7.37 × 10−7to 4.23 W kg−1and increased with altitude in the stratosphere.

Measurements of column-averaged dry-air mole fractions of carbon dioxide and carbon monoxide, CO2(XCO2) and CO (XCO), were performed throughout 2019 at an urban site in Beijing using a compact Fourier Transform Spectrometer (FTS) EM27/SUN. This data set is used to assess the characteristics of combustion-related CO2emissions of urban Beijing by analyzing the correlated daily anomalies of XCO and XCO2(e.g., ΔXCO and ΔXCO2). The EM27/SUN measurements were calibrated to a 125HR-FTS at the Xianghe station by an extra EM27/SUN instrument transferred between two sites. The ratio of ΔXCO over ΔXCO2(ΔXCO:ΔXCO2) is used to estimate the combustion efficiency in the Beijing region. A high correlation coefficient (0.86) between ΔXCO and ΔXCO2is observed. The CO:CO2emission ratio estimated from inventories is higher than the observed ΔXCO:ΔXCO2(10.46 ± 0.11 ppb ppm−1) by 42.54%–101.15%, indicating an underestimation in combustion efficiency in the inventories. Daily ΔXCO:ΔXCO2are influenced by transportation governed by weather conditions, except for days in summer when the correlation is low due to the terrestrial biotic activity. By convolving the column footprint [ppm (µmol m−2s−1)−1] generated by the Weather Research and Forecasting-X-Stochastic Time-Inverted Lagrangian Transport models (WRF-X-STILT) with two fossil-fuel emission inventories (the Multi-resolution Emission Inventory for China (MEIC) and the Peking University (PKU) inventory), the observed enhancements of CO2and CO were used to evaluate the regional emissions. The CO2emissions appear to be underestimated by 11% and 49% for the MEIC and PKU inventories, respectively, while CO emissions were overestimated by MEIC (30%) and PKU (35%) in the Beijing area.

Sulfur dioxide (SO2) measured by satellites is widely used to estimate anthropogenic emissions. The Sentinel-5 Precursor (S-5P) operational SO2product is overestimated compared to the ground-based multiaxis differential optical absorption spectroscopy (MAX-DOAS) measurements in China and shows an opposite variation to the surface measurements, which limits the application of TROPOspheric monitoring instrument (TROPOMI) products in emissions research. Radiometric calibration, a priori profiles, and fitting windows might cause the overestimation of S-5P operational SO2product. Here, we improve the optimal-estimation-based algorithm through several calibration methods. The improved retrieval agrees reasonably well with the ground-based measurements (R> 0.70, bias <13.7%) and has smaller biases (−28.9%) with surface measurements over China and India. It revealed that the SO2column in March 2020 decreased by 51.6% compared to March 2019 due to the lockdown for curbing the spread of the COVID-19 pandemic, and there was a decrease of 50% during the lockdown than those after the lockdown, similar to the surface measurement trend, while S-5P operational SO2product showed an unrealistic increase of 19%. In India, the improved retrieval identified obvious “hot spots” and observed a 30% decrease of SO2columns during the lockdown.

Space-borne measurements of atmospheric greenhouse gas concentrations provide global observation constraints for top-down estimates of surface carbon flux. Here, the first estimates of the global distribution of carbon surface fluxes inferred from dry-air CO2column (XCO2) measurements by the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite (TanSat) are presented. An ensemble transform Kalman filter (ETKF) data assimilation system coupled with the GEOS-Chem global chemistry transport model is used to optimally fit model simulations with the TanSat XCO2observations, which were retrieved using the Institute of Atmospheric Physics Carbon dioxide retrieval Algorithm for Satellite remote sensing (IAPCAS). High posterior error reduction (30%–50%) compared with a priori fluxes indicates that assimilating satellite XCO2measurements provides highly effective constraints on global carbon flux estimation. Their impacts are also highlighted by significant spatiotemporal shifts in flux patterns over regions critical to the global carbon budget, such as tropical South America and China. An integrated global land carbon net flux of 6.71 ± 0.76 Gt C yr−1over 12 months (May 2017–April 2018) is estimated from the TanSat XCO2data, which is generally consistent with other inversions based on satellite data, such as the JAXA GOSAT and NASA OCO-2 XCO2retrievals. However, discrepancies were found in some regional flux estimates, particularly over the Southern Hemisphere, where there may still be uncorrected bias between satellite measurements due to the lack of independent reference observations. The results of this study provide the groundwork for further studies using current or future TanSat XCO2data together with other surface-based and space-borne measurements to quantify biosphere-atmosphere carbon exchange.

We present data and analysis of a set of balloon‐borne sounding profiles, which includes co‐located O3, CO, CH4, and particles, over the northern Tibetan Plateau during an Asian summer monsoon (ASM) season. These novel measurements shed light on the ASM transport behavior near the northern edge of the anticyclone. Joint analyses of these species with the temperature and wind profiles and supported by back trajectory modeling identify three distinct transport processes that dominate the vertical chemical structure in the middle troposphere, upper troposphere (UT), and the tropopause region. The correlated changes in profile structures in the middle troposphere highlight the influence of the strong westerly jet. Elevated constituent concentrations in the UT identify the main level of convective transport at the upstream source regions. Observed higher altitude maxima for CH4characterize the airmasses' continued ascent following convection. These data complement constituent observations from other parts of the ASM anticyclone. Asian summer monsoon deep convection transports surface pollutants to the stratosphere. Although satellite data have provided clear evidence of this transport, in situ measurements are critical for characterizing how monsoon is vertically re‐distributing the regional emissions. We report new balloon‐borne measurements over the Tibetan Plateau that provide a unique data set on the northern edge of the anticyclone, complementing other observations. A novel set of in‐situ profile measurements of O3, CO, CH4and particles from Tibetan Plateau during Asian summer monsoon are presentedJoint analyses of the profiles provide insights into transport processes controlling the northern edge of the Asian monsoon anticycloneObserved CO profile maxima at 13–14 km (∼360–370 K) identify the level of convective transport at the upstream source regions A novel set of in‐situ profile measurements of O3, CO, CH4and particles from Tibetan Plateau during Asian summer monsoon are presented Joint analyses of the profiles provide insights into transport processes controlling the northern edge of the Asian monsoon anticyclone Observed CO profile maxima at 13–14 km (∼360–370 K) identify the level of convective transport at the upstream source regions

The Chinese Carbon Dioxide Observation Satellite Mission (TanSat) is the third satellite for global CO2monitoring and is capable of detecting weak solar-induced chlorophyll fluorescence (SIF) signals with its advanced technical characteristics. Based on the Institute of Atmospheric Physics Carbon Dioxide Retrieval Algorithm for Satellite Remote Sensing (IAPCAS) platform, we successfully retrieved the TanSat global SIF product spanning the period of March 2017 to February 2018 with a physically based algorithm. This paper introduces the new TanSat SIF dataset and shows the global seasonal SIF maps. A brief comparison between the IAPCAS TanSat SIF product and the data-driven SVD (singular value decomposition) SIF product is also performed for follow-up algorithm optimization. The comparative results show that there are regional biases between the two SIF datasets and the linear correlations between them are above 0.73 for all seasons. The future SIF data product applications and requirements for SIF space observation are discussed.

The 1st Chinese carbon dioxide (CO2) monitoring satellite mission, TanSat, was launched in 2016. The 1st TanSat global map of CO2dry-air mixing ratio (XCO2) measurements over land was released as version 1 data product with an accuracy of 2.11 ppmv (parts per million by volume). In this paper, we introduce a new (version 2) TanSat global XCO2product that is approached by the Institute of Atmospheric Physics Carbon dioxide retrieval Algorithm for Satellite remote sensing (IAPCAS), and the European Space Agency (ESA) Climate Change Initiative plus (CCI+) TanSat XCO2product by University of Leicester Full Physics (UoL-FP) retrieval algorithm. The correction of the measurement spectrum improves the accuracy (@#@0.08 ppmv) and precision (1.41 ppmv) of the new retrieval, which provides opportunity for further application in global carbon flux studies in the future. Inter-comparison between the two retrievals indicates a good agreement, with a standard deviation of 1.28 ppmv and a bias of -0.35 ppmv.

The balloon-borne Aircore campaign was conducted in Inner Mongolia, China, on June 13 and 14 2018, which detected carbon dioxide (CO2) and carbon monoxide (CO) profiles from surface to 24 km, showing strong positive and negative correlations between 8 km and 10 km on 13 and 14 June, respectively. Backward trajectories, meteorological analyses, and CO2horizontal distributions were combined to interpret this phenomenon. The results indicated that the source region experienced a stratospheric intrusion and exhibited a large horizontal CO2gradient; namely, lower CO concentrations corresponded to higher CO2concentrations and vice versa. The laminar structure with multiple origins resulted in the highly negative correlation between CO2and CO in the upper troposphere on 14 June. The contribution of stratospheric air mass to the upper troposphere and that of tropospheric air mass to the lower stratosphere were 26.7% and 24.3%, respectively, based on a mass balance approach. Another interesting phenomenon is that CO2and CO concentrations increased substantially at approximately 8 km on 13 June. An analysis based on the backward trajectory implied that the air mass possibly came from anthropogenic sources. The slope of CO2/CO representing the anthropogenic sources was 87.3 ppm ppm−1. In addition, the CO2profile showed that there was a large CO2gradient of 4 ppm km−1within the boundary layer on 13 June, and this gradient disappeared on 14 June.

ABSTRACTAccurate measurements of the vertical distribution of carbon dioxide (CO2) in the atmosphere are critical to validate the vertical columns recorded by satellite and ground-based spectrometers and to estimate sources and sinks of CO2. This work describes an in-situ air-sampler system (Aircore). Profiles of CO2and carbon monoxide (CO) were retrieved from two soundings of this system in Xilin Hot on 13 and 14 June 2018, and compared with observations from the Tropospheric Monitoring Instrument (TROPOMI), Orbiting Carbon Observatory-2 (OCO-2), and Copernicus Atmosphere Monitoring Service (CAMS). The column-averaged mixing ratio of CO (XCO) monitored by TROPOMI agreed well with that calculated from the in-situ CO profile, with a small mean difference of 5 ± 1.89 ppb. The column-averaged mixing ratio of CO2(XCO2) monitored by OCO-2 also agreed well with that calculated from the in-situ CO2profile, with a slight bias of 0.4 ± 0.6 ppm. The OCO-2 a posteriori profile had an obvious bias compared with the in-situ CO2profile on 13 June, with an underestimation between 600 hPa and 250 hPa and an overestimation below 600 hPa. CAMS also had the same bias compared with the in-situ CO profile; however, CAMS agreed well with the in-situ CO profile on 14 June in the troposphere because a weak cold vortex passed Xilin Hot on 13 June and disappeared on 14 June. In the stratosphere, there were significant biases in the vertical degradation. The striking agreement between the column-averaged mixing ratios and the differences in the vertical distribution suggests new exciting applications for the profile product.

The unique geographical location and high altitude of the Tibetan Plateau can greatly influence regional weather and climate. In particular, the Asian summer monsoon (ASM) anticyclone circulation system over the Tibetan Plateau is recognized to be a significant transport pathway for water vapor and pollutants to enter the stratosphere. To improve understanding of these physical processes, a multi‐location joint atmospheric experiment was performed over the Tibetan Plateau from late July to August in 2018, funded by the five‐year (2018–2022) STEAM (stratosphere and troposphere exchange experiment during ASM) project, during which multiple platforms/instruments—including long‐duration stratospheric balloons, dropsondes, unmanned aerial vehicles, special sounding systems, and ground‐based and satellite‐borne instruments—will be deployed. These complementary methods of data acquisition are expected to provide comprehensive atmospheric parameters (aerosol, ozone, water vapor, CO2, CH4, CO, temperature, pressure, turbulence, radiation, lightning and wind); the richness of this approach is expected to advance our comprehension of key mechanisms associated with thermal, dynamical, radiative, and chemical transports over the Tibetan Plateau during ASM activity.

We simulated geostationary satellite observations to assess the potential for high spatial- and temporal-resolution monitoring of air pollution in China with a focus on tropospheric ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and formaldehyde (HCHO). Based on the capabilities and parameters of the payloads onboard sun-synchronous satellites, we simulated the observed spectrum based on a radiative transfer model using a geostationary satellite model. According to optimal estimation theory, we analyzed the sensitivities and retrieval uncertainties of the main parameters of the instrument for the target trace gases. Considering the retrieval error requirements of each trace gas, we determined the major instrument parameter values (e.g., observation channel, spectral resolution, and signal-to-noise ratio). To evaluate these values, retrieval simulation was performed based on the three-dimensional distribution of the atmospheric components over China using an atmospheric chemical transportation model. As many as 90% of the experiments met the retrieval requirements for all target gases. The retrieval precision of total-column and stratospheric O3was 2%. In addition, effective retrieval of all trace gases could be achieved at solar zenith angles larger than 70°. Therefore, the geostationary satellite observation and instrument parameters provided herein can be used in air pollution monitoring in China. This study offers a theoretical basis and simulation tool for improving the design of instruments onboard geostationary satellites.

Monitoring atmospheric carbon dioxide (CO2) from space-borne state-of-the-art hyperspectral instruments can provide a high precision global dataset to improve carbon flux estimation and reduce the uncertainty of climate projection. Here, we introduce a carbon flux inversion system for estimating carbon flux with satellite measurements under the support of “The Strategic Priority Research Program of the Chinese Academy of Sciences—Climate Change: Carbon Budget and Relevant Issues”. The carbon flux inversion system is composed of two separate parts: the Institute of Atmospheric Physics Carbon Dioxide Retrieval Algorithm for Satellite Remote Sensing (IAPCAS), and CarbonTracker-China (CT-China), developed at the Chinese Academy of Sciences. The Greenhouse gases Observing SATellite (GOSAT) measurements are used in the carbon flux inversion experiment. To improve the quality of the IAPCAS-GOSAT retrieval, we have developed a post-screening and bias correction method, resulting in 25%–30% of the data remaining after quality control. Based on these data, the seasonal variation of XCO2(column-averaged CO2dry-air mole fraction) is studied, and a strong relation with vegetation cover and population is identified. Then, the IAPCAS-GOSAT XCO2product is used in carbon flux estimation by CT-China. The net ecosystem CO2exchange is −0.34 Pg C yr−1(±0.08 Pg C yr−1), with a large error reduction of 84%, which is a significant improvement on the error reduction when compared with in situ-only inversion. 基于高光谱分辨率短波红外卫星观测可以获取高精度的全球大气CO2浓度资料, 有效提高碳通量的计算精度, 从而降低温室气体排放在气候变化研究中的不确定性. 本文介绍在中国科学院“应对气候变化的碳收支认证及相关问题”战略性科技先导专项的支持下建立的碳通量计算系统, 实现了从卫星观测到碳通量计算. 该系统由两部分构成: 中国科学院大气物理研究所研发的基于卫星观测的大气CO2浓度反演算法(The Institute of Atmospheric PhysicsCarbon Dioxide Retrieval Algorithm for Satellite Remote Sensing, IAPCAS)和中国科学院地理科学与资源研究所研发的CarbonTracker-China(CT-China)碳同化系统. 本研究使用日本Greenhouse gases Observing SATellite(GOSAT)卫星观测资料进行大气CO2浓度反演和碳通量计算. 为提高IAPCAS反演产品的质量, 研发了一种基于观测参数和反演参数的质量控制方法, 用于数据筛选和偏差订正等反演产品的优化, 最终25%–30%被认为是高质量产品, 可供数据分析和碳通量反演使用. 结合地表覆盖类型和人口密度, 本研究分析了大气CO2浓度的季节变化特征. 使用IAPCAS的反演产品, 应用CT-China开展了中国地区碳通量的计算实验, 结果表明净生态系统CO2交换量为−0.34 Pg C yr−1(±0.08 Pg C yr−1). 理论上讲, 与仅使用地基观测相比, 使用卫星资料的碳通量计算可以有效降低85%的不确定性.

We present a study on the retrieval sensitivity of the column-averaged dry-air mole fraction of CO2(XCO2) for the Chinese carbon dioxide observation satellite (TanSat) with a full physical forward model and the optimal estimation technique. The forward model is based on the vector linearized discrete ordinate radiative transfer model (VLIDORT) and considers surface reflectance, gas absorption, and the scattering of air molecules, aerosol particles, and cloud particles. XCO2retrieval errors from synthetic TanSat measurements show solar zenith angle (SZA), albedo dependence with values varying from 0.3 to 1 ppm for bright land surface in nadir mode and 2 to 8 ppm for dark surfaces like snow. The use of glint mode over dark oceans significantly improves the CO2information retrieved. The aerosol type and profile are more important than the aerosol optical depth, and underestimation of aerosol plume height will introduce a bias of 1.5 ppm in XCO2. The systematic errors due to radiometric calibration are also estimated using a forward model simulation approach.

The Arctic stratospheric polar vortex was exceptional strong, cold and persistent in the winter and spring of 2019–2020. Based on reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research and ozone observations from the Ozone Monitoring Instrument, the authors investigated the dynamical variation of the stratospheric polar vortex during winter 2019–2020 and its influence on surface weather and ozone depletion. This strong stratospheric polar vortex was affected by the less active upward propagation of planetary waves. The seasonal transition of the stratosphere during the stratospheric final warming event in spring 2020 occurred late due to the persistence of the polar vortex. A positive Northern Annular Mode index propagated from the stratosphere to the surface, where it was consistent with the Arctic Oscillation and North Atlantic Oscillation indices. As a result, the surface temperature in Eurasia and North America was generally warmer than the climatology. In some places of Eurasia, the surface temperature was about 10 K warmer during the period from January to February 2020. The most serious Arctic ozone depletion since 2004 has been observed since February 2020. The mean total column ozone within 60°–90°N from March to 15 April was about 80 DU less than the climatology.