The Experts below are selected from a list of 15054 Experts worldwide ranked by ideXlab platform
Su Keun Kuk - One of the best experts on this subject based on the ideXlab platform.
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relating Geostationary Satellite measurements of aerosol optical depth aod over east asia to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and geos chem model simulations
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite measurements of aerosol optical depth (AOD) over East Asia from the Geostationary Ocean Color Imager (GOCI) and Advanced Himawari Imager (AHI) instruments can augment surface monitoring of fine particulate matter (PM 2.5 ) air quality, but this requires better understanding of the AOD–PM 2.5 relationship. Here we use the GEOS-Chem chemical transport model to analyze the critical variables determining the AOD–PM 2.5 relationship over East Asia by simulation of observations from Satellite, aircraft, and ground-based datasets. This includes the detailed vertical aerosol profiling over South Korea from the KORUS-AQ aircraft campaign (May–June 2016) with concurrent ground-based PM 2.5 composition, PM 10 , and AERONET AOD measurements. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate–nitrate–ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and high hygroscopicity of the PBL aerosols. We updated SNA and organic aerosol size distributions in GEOS-Chem to represent aerosol optical properties over East Asia by using in situ measurements of particle size distributions from KORUS-AQ. We find that SNA and organic aerosols over East Asia have larger size (number median radius of 0.11 µ m with geometric standard deviation of 1.4) and 20 % larger mass extinction efficiency as compared to aerosols over North America (default setting in GEOS-Chem). Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM 2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM 2.5 nitrate. The GOCI–AHI AOD data over East Asia in different seasons show agreement with AERONET AODs and a spatial distribution consistent with surface PM 2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM 2.5 . This is due to low PBL depths compounded by high residential coal emissions in winter and high relative humidity (RH) in summer. Seasonality of AOD and PM 2.5 over South Korea is much weaker, reflecting weaker variation in PBL depth and lack of residential coal emissions.
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interpretation of Geostationary Satellite aerosol optical depth aod over east asia in relation to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and seasonality
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite sensors over East Asia (GOCI and AHI) are now providing continuous mapping of aerosol optical depth (AOD) at 550 nm to improve monitoring of fine particulate matter (PM2.5) air quality. Here we evaluate our understanding of the physical relationships between AOD and PM2.5 over East Asia by using the GEOS-Chem atmospheric chemistry model to simulate observations from multiple sources: 1) the joint NASA-NIER Korea – United States Air Quality aircraft campaign over South Korea (KORUS-AQ; May–June 2016); 2) AODs from the AERONET ground-based network; 3) AOD from a new GOCI/AHI fused product; and 4) surface PM2.5 networks in South Korea and China. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate-nitrate-ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and the high hygroscopicity of the PBL aerosols. Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM2.5 nitrate. A broader analysis of the GOCI/AHI AOD data over East Asia in different seasons shows agreement with AERONET AODs and a spatial distribution consistent with surface PM2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM2.5. This is due to low PBL depths compounded by high residential coal emissions in winter, and high relative humidity (RH) in summer. Seasonality of AOD and PM2.5 over South Korea is much weaker, reflecting weaker variation of PBL depth and lack of residential coal emissions. Physical interpretation of the Satellite AOD data in terms of surface PM2.5 is sensitive to accurate information on aerosol size distributions, PBL depths, RH, the role of coarse particles, and diurnal variation of PM2.5.
Jhoon Kim - One of the best experts on this subject based on the ideXlab platform.
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relating Geostationary Satellite measurements of aerosol optical depth aod over east asia to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and geos chem model simulations
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite measurements of aerosol optical depth (AOD) over East Asia from the Geostationary Ocean Color Imager (GOCI) and Advanced Himawari Imager (AHI) instruments can augment surface monitoring of fine particulate matter (PM 2.5 ) air quality, but this requires better understanding of the AOD–PM 2.5 relationship. Here we use the GEOS-Chem chemical transport model to analyze the critical variables determining the AOD–PM 2.5 relationship over East Asia by simulation of observations from Satellite, aircraft, and ground-based datasets. This includes the detailed vertical aerosol profiling over South Korea from the KORUS-AQ aircraft campaign (May–June 2016) with concurrent ground-based PM 2.5 composition, PM 10 , and AERONET AOD measurements. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate–nitrate–ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and high hygroscopicity of the PBL aerosols. We updated SNA and organic aerosol size distributions in GEOS-Chem to represent aerosol optical properties over East Asia by using in situ measurements of particle size distributions from KORUS-AQ. We find that SNA and organic aerosols over East Asia have larger size (number median radius of 0.11 µ m with geometric standard deviation of 1.4) and 20 % larger mass extinction efficiency as compared to aerosols over North America (default setting in GEOS-Chem). Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM 2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM 2.5 nitrate. The GOCI–AHI AOD data over East Asia in different seasons show agreement with AERONET AODs and a spatial distribution consistent with surface PM 2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM 2.5 . This is due to low PBL depths compounded by high residential coal emissions in winter and high relative humidity (RH) in summer. Seasonality of AOD and PM 2.5 over South Korea is much weaker, reflecting weaker variation in PBL depth and lack of residential coal emissions.
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interpretation of Geostationary Satellite aerosol optical depth aod over east asia in relation to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and seasonality
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite sensors over East Asia (GOCI and AHI) are now providing continuous mapping of aerosol optical depth (AOD) at 550 nm to improve monitoring of fine particulate matter (PM2.5) air quality. Here we evaluate our understanding of the physical relationships between AOD and PM2.5 over East Asia by using the GEOS-Chem atmospheric chemistry model to simulate observations from multiple sources: 1) the joint NASA-NIER Korea – United States Air Quality aircraft campaign over South Korea (KORUS-AQ; May–June 2016); 2) AODs from the AERONET ground-based network; 3) AOD from a new GOCI/AHI fused product; and 4) surface PM2.5 networks in South Korea and China. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate-nitrate-ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and the high hygroscopicity of the PBL aerosols. Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM2.5 nitrate. A broader analysis of the GOCI/AHI AOD data over East Asia in different seasons shows agreement with AERONET AODs and a spatial distribution consistent with surface PM2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM2.5. This is due to low PBL depths compounded by high residential coal emissions in winter, and high relative humidity (RH) in summer. Seasonality of AOD and PM2.5 over South Korea is much weaker, reflecting weaker variation of PBL depth and lack of residential coal emissions. Physical interpretation of the Satellite AOD data in terms of surface PM2.5 is sensitive to accurate information on aerosol size distributions, PBL depths, RH, the role of coarse particles, and diurnal variation of PM2.5.
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retrieval of aerosol optical depth over east asia from a Geostationary Satellite mtsat 1r
Asia-pacific Journal of Atmospheric Sciences, 2007Co-Authors: Jongmin Yoon, Jhoon Kim, Jaehwa Lee, Hi Ku Cho, Byungju Sohn, Myunghwan AhnAbstract:Using 30 days of hourly visible channel data and DIScrete Ordinate Radiative Transfer (DISORT) model (6S), we retrieved aerosol optical depth (AOD) at 0.55 ㎛ over the East Asia. In contrast to the aerosol optical depth retrieval using low-earth-orbit (LEO) Satellites such as MODIS (Moderate-Resolution Spectroradiometer) or MISR (Multiangle Imaging Spectro Radiometer), this algorithm for Geostationary orbit (GEO) Satellite can improve the monitoring of aerosol to over-come the limitation of temporal resolution in LEO Satellites. There has been limitation in the number of imager channels onboard the GEO Satellites. Thus, it is worthwhile to introduce an AOD algorithm utilizing a single visible channel in the conventional meteorological imager onboard Geostationary Satellites. This single channel algorithm has relatively larger retrieval error of AOD than other multiple-channel algorithm due to the limitation in characterizing surface reflectance and aerosol property. In this study, the effects of atmospheric and surface properties are investigated on the retrieval of AOD from the Geostationary Satellite, and the retrieved results are compared with the AOD of AERONET and MODIS.
Daniel J Jacob - One of the best experts on this subject based on the ideXlab platform.
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relating Geostationary Satellite measurements of aerosol optical depth aod over east asia to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and geos chem model simulations
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite measurements of aerosol optical depth (AOD) over East Asia from the Geostationary Ocean Color Imager (GOCI) and Advanced Himawari Imager (AHI) instruments can augment surface monitoring of fine particulate matter (PM 2.5 ) air quality, but this requires better understanding of the AOD–PM 2.5 relationship. Here we use the GEOS-Chem chemical transport model to analyze the critical variables determining the AOD–PM 2.5 relationship over East Asia by simulation of observations from Satellite, aircraft, and ground-based datasets. This includes the detailed vertical aerosol profiling over South Korea from the KORUS-AQ aircraft campaign (May–June 2016) with concurrent ground-based PM 2.5 composition, PM 10 , and AERONET AOD measurements. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate–nitrate–ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and high hygroscopicity of the PBL aerosols. We updated SNA and organic aerosol size distributions in GEOS-Chem to represent aerosol optical properties over East Asia by using in situ measurements of particle size distributions from KORUS-AQ. We find that SNA and organic aerosols over East Asia have larger size (number median radius of 0.11 µ m with geometric standard deviation of 1.4) and 20 % larger mass extinction efficiency as compared to aerosols over North America (default setting in GEOS-Chem). Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM 2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM 2.5 nitrate. The GOCI–AHI AOD data over East Asia in different seasons show agreement with AERONET AODs and a spatial distribution consistent with surface PM 2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM 2.5 . This is due to low PBL depths compounded by high residential coal emissions in winter and high relative humidity (RH) in summer. Seasonality of AOD and PM 2.5 over South Korea is much weaker, reflecting weaker variation in PBL depth and lack of residential coal emissions.
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interpretation of Geostationary Satellite aerosol optical depth aod over east asia in relation to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and seasonality
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite sensors over East Asia (GOCI and AHI) are now providing continuous mapping of aerosol optical depth (AOD) at 550 nm to improve monitoring of fine particulate matter (PM2.5) air quality. Here we evaluate our understanding of the physical relationships between AOD and PM2.5 over East Asia by using the GEOS-Chem atmospheric chemistry model to simulate observations from multiple sources: 1) the joint NASA-NIER Korea – United States Air Quality aircraft campaign over South Korea (KORUS-AQ; May–June 2016); 2) AODs from the AERONET ground-based network; 3) AOD from a new GOCI/AHI fused product; and 4) surface PM2.5 networks in South Korea and China. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate-nitrate-ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and the high hygroscopicity of the PBL aerosols. Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM2.5 nitrate. A broader analysis of the GOCI/AHI AOD data over East Asia in different seasons shows agreement with AERONET AODs and a spatial distribution consistent with surface PM2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM2.5. This is due to low PBL depths compounded by high residential coal emissions in winter, and high relative humidity (RH) in summer. Seasonality of AOD and PM2.5 over South Korea is much weaker, reflecting weaker variation of PBL depth and lack of residential coal emissions. Physical interpretation of the Satellite AOD data in terms of surface PM2.5 is sensitive to accurate information on aerosol size distributions, PBL depths, RH, the role of coarse particles, and diurnal variation of PM2.5.
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spatially resolving methane emissions in california constraints from the calnex aircraft campaign and from present gosat tes and future tropomi Geostationary Satellite observations
Atmospheric Chemistry and Physics, 2014Co-Authors: K Wecht, Daniel J Jacob, Melissa P Sulprizio, G W Santoni, Steven C Wofsy, Robert J Parker, H Bosch, J WordenAbstract:Abstract. We apply a continental-scale inverse modeling system for North America based on the GEOS-Chem model to optimize California methane emissions at 1/2° × 2/3° horizontal resolution using atmospheric observations from the CalNex aircraft campaign (May–June 2010) and from Satellites. Inversion of the CalNex data yields a best estimate for total California methane emissions of 2.86 ± 0.21 Tg a−1, compared with 1.92 Tg a−1 in the EDGAR v4.2 emission inventory used as a priori and 1.51 Tg a−1 in the California Air Resources Board (CARB) inventory used for state regulations of greenhouse gas emissions. These results are consistent with a previous Lagrangian inversion of the CalNex data. Our inversion provides 12 independent pieces of information to constrain the geographical distribution of emissions within California. Attribution to individual source types indicates dominant contributions to emissions from landfills/wastewater (1.1 Tg a−1), livestock (0.87 Tg a−1), and gas/oil (0.64 Tg a−1). EDGAR v4.2 underestimates emissions from livestock, while CARB underestimates emissions from landfills/wastewater and gas/oil. Current Satellite observations from GOSAT can constrain methane emissions in the Los Angeles Basin but are too sparse to constrain emissions quantitatively elsewhere in California (they can still be qualitatively useful to diagnose inventory biases). Los Angeles Basin emissions derived from CalNex and GOSAT inversions are 0.42 ± 0.08 and 0.31 ± 0.08 Tg a−1 that the future TROPOMI Satellite instrument (2015 launch) will be able to constrain California methane emissions at a detail comparable to the CalNex aircraft campaign. Geostationary Satellite observations offer even greater potential for constraining methane emissions in the future.
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monitoring high ozone events in the us intermountain west using tempo Geostationary Satellite observations
Atmospheric Chemistry and Physics, 2014Co-Authors: P Zoogman, Daniel J Jacob, K Chance, Arlene M Fiore, Xi Liu, Meiyun Lin, Katherine R TravisAbstract:Abstract. High-ozone events, approaching or exceeding the National Ambient Air Quality Standard (NAAQS), are frequently observed in the US Intermountain West in association with subsiding air from the free troposphere. Monitoring and attribution of these events is problematic because of the sparsity of the current network of surface measurements and lack of vertical information. We present an Observing System Simulation Experiment (OSSE) to evaluate the ability of the future Geostationary Satellite instrument Tropospheric Emissions: Monitoring of Pollution (TEMPO), scheduled for launch in 2018–2019, to monitor and attribute high-ozone events in the Intermountain West through data assimilation. TEMPO will observe ozone in the ultraviolet (UV) and visible (Vis) bands to provide sensitivity in the lower troposphere. Our OSSE uses ozone data from the GFDL AM3 chemistry-climate model (CCM) as the "true" atmosphere and samples it for April–June 2010 with the current surface network (CASTNet –Clean Air Status and Trends Network– sites), a configuration designed to represent TEMPO, and a low Earth orbit (LEO) IR (infrared) Satellite instrument. These synthetic data are then assimilated into the GEOS-Chem chemical transport model (CTM) using a Kalman filter. Error correlation length scales (500 km in horizontal, 1.7 km in vertical) extend the range of influence of observations. We show that assimilation of surface data alone does not adequately detect high-ozone events in the Intermountain West. Assimilation of TEMPO data greatly improves the monitoring capability, with little information added from the LEO instrument. The vertical information from TEMPO further enables the attribution of NAAQS exceedances to background ozone. This is illustrated with the case of a stratospheric intrusion.
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improved monitoring of surface ozone by joint assimilation of Geostationary Satellite observations of ozone and co
Atmospheric Environment, 2014Co-Authors: P Zoogman, Daniel J Jacob, K Chance, H M Worden, D P Edwards, Lin ZhangAbstract:Abstract Future Geostationary Satellite observations of tropospheric ozone aim to improve monitoring of surface ozone air quality. However, ozone retrievals from space have limited sensitivity in the lower troposphere (boundary layer). Data assimilation in a chemical transport model can propagate the information from the Satellite observations to provide useful constraints on surface ozone. This may be aided by correlated Satellite observations of carbon monoxide (CO), for which boundary layer sensitivity is easier to achieve. We examine the potential of concurrent Geostationary observations of ozone and CO to improve constraints on surface ozone air quality through exploitation of ozone–CO model error correlations in a joint data assimilation framework. The hypothesis is that model transport errors diagnosed for CO provide information on corresponding errors in ozone. A paired-model analysis of ozone–CO error correlations in the boundary layer over North America in summer indicates positive error correlations in continental outflow but negative regional-scale error correlations over land, the latter reflecting opposite sensitivities of ozone and CO to boundary layer depth. Aircraft observations from the ICARTT campaign are consistent with this pattern but also indicate strong positive error correlations in fine-scale pollution plumes. We develop a joint ozone–CO data assimilation system and apply it to a regional-scale Observing System Simulation Experiment (OSSE) of the planned NASA GEO-CAPE Geostationary mission over North America. We find substantial benefit from joint ozone–CO data assimilation in informing US ozone air quality if the instrument sensitivity for CO in the boundary layer is greater than that for ozone. A high-quality Geostationary measurement of CO could potentially relax the requirements for boundary layer sensitivity of the ozone measurement. This is contingent on accurate characterization of ozone–CO error correlations. A finer-resolution data assimilation system resolving the urban scale would need to account for the change in sign of the ozone–CO error correlations between urban pollution plumes and the regional atmosphere.
K Chance - One of the best experts on this subject based on the ideXlab platform.
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sensitivity of formaldehyde hcho column measurements from a Geostationary Satellite to temporal variation of the air mass factor in east asia
Atmospheric Chemistry and Physics, 2017Co-Authors: Hyeongahn Kwon, Rokjin J Park, Jaein I Jeong, Seungun Lee, Gonzalo Gonzalez Abad, T P Kurosu, Paul I Palmer, K ChanceAbstract:Abstract. We examine upcoming Geostationary Satellite observations of formaldehyde (HCHO) vertical column densities (VCDs) in East Asia and the retrieval sensitivity to the temporal variation of air mass factors (AMFs) considering the presence of aerosols. Observation system simulation experiments (OSSE) were conducted using a combination of a global 3-D chemical transport model (GEOS-Chem), a radiative transfer model (VLIDORT), and a HCHO retrieval algorithm developed for the Geostationary Environment Monitoring Spectrometer (GEMS), which will be launched in 2019. Application of the retrieval algorithm to simulated hourly radiances yields the retrieved HCHO VCDs, which are then compared with the GEOS-Chem HCHO VCDs as true values for the evaluation of the retrieval algorithm. In order to examine the retrieval sensitivity to the temporal variation of AMF, we examine three AMF specifications, AMFm, AMFh, and AMFmh, using monthly, hourly, and monthly mean hourly input data for their calculation, respectively. We compare the retrieved HCHO VCDs using those three AMFs and find that the HCHO VCDs with AMFh are in better agreement with the true values than the results using AMFmh and AMFm. AMFmh reflects diurnal variation of planetary boundary layer and other meteorological parameters, so that the results with AMFmh show a better performance than those with AMFm. The differences between AMFh and AMFm range from −0.76 to 0.74 in absolute value and are mainly caused by temporal changes in aerosol chemical compositions and aerosol vertical distributions, which result in −27 to 58 and −34 to 43 % changes in HCHO VCDs over China, respectively, compared to HCHO VCDs using AMFm. We apply our calculated AMF table together with OMI aerosol optical properties to OMI HCHO products in March 2006, when Asian dust storms occurred, and find −32 to 47 % changes in the retrieved HCHO columns due to temporal changes in aerosol optical properties in East Asia. The impact of aerosol temporal variability cannot be neglected for future Geostationary observations.
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sensitivity of formaldehyde hcho column measurements from a Geostationary Satellite to aerosol temporal variation in east asia
Atmospheric Chemistry and Physics, 2016Co-Authors: Hyeongahn Kwon, Rokjin J Park, Jaein I Jeong, Seungun Lee, Gonzalo Gonzalez Abad, T P Kurosu, Paul I Palmer, K ChanceAbstract:We examine upcoming Geostationary Satellite observations of formaldehyde 15 (HCHO) columns in East Asia and the retrieval sensitivity to the temporal variation of air mass factor (AMF) considering the presence of aerosols. Observation system simulation experiments (OSSE) were conducted using a combination of a global 3-D chemical transport model (GEOS-Chem), a radiative transfer model (VLIDORT), and a HCHO retrieval algorithm developed for Geostationary Environment Monitoring Spectrometer (GEMS), 20 which will be launched in 2019. Application of the retrieval algorithm to simulated hourly radiances yields the retrieved HCHO column concentrations, which are then compared with the GEOS-Chem HCHO columns as a true value for the evaluation of the retrieval algorithm. In order to examine the retrieval sensitivity to the temporal variation of AMF, we compare the retrieved HCHO columns using monthly versus hourly AMF values and find that the HCHO 25 vertical columns with hourly AMF are in better agreement with the true values, relative to those with monthly AMF. The differences between hourly and monthly AMF range from - 0.70 to 0.73 in absolute value and are mainly caused by temporal changes of aerosol chemical composition: scattering aerosol enhances AMF, whereas absorbing aerosol reduces it. The temporal variations of AMF caused by aerosols increase and decrease HCHO VCDs by 84% 30 and 34%, respectively, compared to HCHO VCDs using monthly AMF. We apply our
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a numerical testbed for remote sensing of aerosols and its demonstration for evaluating retrieval synergy from a Geostationary Satellite constellation of geo cape and goes r
Journal of Quantitative Spectroscopy & Radiative Transfer, 2014Co-Authors: Jun Wang, K Chance, Xiong Liu, Shouguo Ding, Jing Zeng, Robert Spurr, Michael I MishchenkoAbstract:We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a Geostationary Satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) Satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASA's Decadal Survey Mission GEOCAPE (Geostationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O2 A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the synergic use of two future Geostationary Satellites, GOES-R (Geostationary Operational Environmental Satellite R-series) and TEMPO (Tropospheric Emissions: Monitoring of Pollution). Strong synergy between GEOS-R and TEMPO are found especially in their characterization of surface bi-directional reflectance, and thereby, can potentially improve the AOD retrieval to the accuracy required by GEO-CAPE.
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monitoring high ozone events in the us intermountain west using tempo Geostationary Satellite observations
Atmospheric Chemistry and Physics, 2014Co-Authors: P Zoogman, Daniel J Jacob, K Chance, Arlene M Fiore, Xi Liu, Meiyun Lin, Katherine R TravisAbstract:Abstract. High-ozone events, approaching or exceeding the National Ambient Air Quality Standard (NAAQS), are frequently observed in the US Intermountain West in association with subsiding air from the free troposphere. Monitoring and attribution of these events is problematic because of the sparsity of the current network of surface measurements and lack of vertical information. We present an Observing System Simulation Experiment (OSSE) to evaluate the ability of the future Geostationary Satellite instrument Tropospheric Emissions: Monitoring of Pollution (TEMPO), scheduled for launch in 2018–2019, to monitor and attribute high-ozone events in the Intermountain West through data assimilation. TEMPO will observe ozone in the ultraviolet (UV) and visible (Vis) bands to provide sensitivity in the lower troposphere. Our OSSE uses ozone data from the GFDL AM3 chemistry-climate model (CCM) as the "true" atmosphere and samples it for April–June 2010 with the current surface network (CASTNet –Clean Air Status and Trends Network– sites), a configuration designed to represent TEMPO, and a low Earth orbit (LEO) IR (infrared) Satellite instrument. These synthetic data are then assimilated into the GEOS-Chem chemical transport model (CTM) using a Kalman filter. Error correlation length scales (500 km in horizontal, 1.7 km in vertical) extend the range of influence of observations. We show that assimilation of surface data alone does not adequately detect high-ozone events in the Intermountain West. Assimilation of TEMPO data greatly improves the monitoring capability, with little information added from the LEO instrument. The vertical information from TEMPO further enables the attribution of NAAQS exceedances to background ozone. This is illustrated with the case of a stratospheric intrusion.
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improved monitoring of surface ozone by joint assimilation of Geostationary Satellite observations of ozone and co
Atmospheric Environment, 2014Co-Authors: P Zoogman, Daniel J Jacob, K Chance, H M Worden, D P Edwards, Lin ZhangAbstract:Abstract Future Geostationary Satellite observations of tropospheric ozone aim to improve monitoring of surface ozone air quality. However, ozone retrievals from space have limited sensitivity in the lower troposphere (boundary layer). Data assimilation in a chemical transport model can propagate the information from the Satellite observations to provide useful constraints on surface ozone. This may be aided by correlated Satellite observations of carbon monoxide (CO), for which boundary layer sensitivity is easier to achieve. We examine the potential of concurrent Geostationary observations of ozone and CO to improve constraints on surface ozone air quality through exploitation of ozone–CO model error correlations in a joint data assimilation framework. The hypothesis is that model transport errors diagnosed for CO provide information on corresponding errors in ozone. A paired-model analysis of ozone–CO error correlations in the boundary layer over North America in summer indicates positive error correlations in continental outflow but negative regional-scale error correlations over land, the latter reflecting opposite sensitivities of ozone and CO to boundary layer depth. Aircraft observations from the ICARTT campaign are consistent with this pattern but also indicate strong positive error correlations in fine-scale pollution plumes. We develop a joint ozone–CO data assimilation system and apply it to a regional-scale Observing System Simulation Experiment (OSSE) of the planned NASA GEO-CAPE Geostationary mission over North America. We find substantial benefit from joint ozone–CO data assimilation in informing US ozone air quality if the instrument sensitivity for CO in the boundary layer is greater than that for ozone. A high-quality Geostationary measurement of CO could potentially relax the requirements for boundary layer sensitivity of the ozone measurement. This is contingent on accurate characterization of ozone–CO error correlations. A finer-resolution data assimilation system resolving the urban scale would need to account for the change in sign of the ozone–CO error correlations between urban pollution plumes and the regional atmosphere.
Shixian Zhai - One of the best experts on this subject based on the ideXlab platform.
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relating Geostationary Satellite measurements of aerosol optical depth aod over east asia to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and geos chem model simulations
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite measurements of aerosol optical depth (AOD) over East Asia from the Geostationary Ocean Color Imager (GOCI) and Advanced Himawari Imager (AHI) instruments can augment surface monitoring of fine particulate matter (PM 2.5 ) air quality, but this requires better understanding of the AOD–PM 2.5 relationship. Here we use the GEOS-Chem chemical transport model to analyze the critical variables determining the AOD–PM 2.5 relationship over East Asia by simulation of observations from Satellite, aircraft, and ground-based datasets. This includes the detailed vertical aerosol profiling over South Korea from the KORUS-AQ aircraft campaign (May–June 2016) with concurrent ground-based PM 2.5 composition, PM 10 , and AERONET AOD measurements. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate–nitrate–ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and high hygroscopicity of the PBL aerosols. We updated SNA and organic aerosol size distributions in GEOS-Chem to represent aerosol optical properties over East Asia by using in situ measurements of particle size distributions from KORUS-AQ. We find that SNA and organic aerosols over East Asia have larger size (number median radius of 0.11 µ m with geometric standard deviation of 1.4) and 20 % larger mass extinction efficiency as compared to aerosols over North America (default setting in GEOS-Chem). Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM 2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM 2.5 nitrate. The GOCI–AHI AOD data over East Asia in different seasons show agreement with AERONET AODs and a spatial distribution consistent with surface PM 2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM 2.5 . This is due to low PBL depths compounded by high residential coal emissions in winter and high relative humidity (RH) in summer. Seasonality of AOD and PM 2.5 over South Korea is much weaker, reflecting weaker variation in PBL depth and lack of residential coal emissions.
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interpretation of Geostationary Satellite aerosol optical depth aod over east asia in relation to fine particulate matter pm 2 5 insights from the korus aq aircraft campaign and seasonality
Atmospheric Chemistry and Physics, 2021Co-Authors: Shixian Zhai, Daniel J Jacob, Jhoon Kim, Jared F Brewer, Jonathan M Moch, Seoyoung Lee, Hyunkwang Lim, Hyun Chul Lee, Su Keun KukAbstract:Abstract. Geostationary Satellite sensors over East Asia (GOCI and AHI) are now providing continuous mapping of aerosol optical depth (AOD) at 550 nm to improve monitoring of fine particulate matter (PM2.5) air quality. Here we evaluate our understanding of the physical relationships between AOD and PM2.5 over East Asia by using the GEOS-Chem atmospheric chemistry model to simulate observations from multiple sources: 1) the joint NASA-NIER Korea – United States Air Quality aircraft campaign over South Korea (KORUS-AQ; May–June 2016); 2) AODs from the AERONET ground-based network; 3) AOD from a new GOCI/AHI fused product; and 4) surface PM2.5 networks in South Korea and China. The KORUS-AQ data show that 550 nm AOD is mainly contributed by sulfate-nitrate-ammonium (SNA) and organic aerosols in the planetary boundary layer (PBL), despite large dust concentrations in the free troposphere, reflecting the optically effective size and the high hygroscopicity of the PBL aerosols. Although GEOS-Chem is successful in reproducing the KORUS-AQ vertical profiles of aerosol mass, its ability to link AOD to PM2.5 is limited by under-accounting of coarse PM and by a large overestimate of nighttime PM2.5 nitrate. A broader analysis of the GOCI/AHI AOD data over East Asia in different seasons shows agreement with AERONET AODs and a spatial distribution consistent with surface PM2.5 network data. The AOD observations over North China show a summer maximum and winter minimum, opposite in phase to surface PM2.5. This is due to low PBL depths compounded by high residential coal emissions in winter, and high relative humidity (RH) in summer. Seasonality of AOD and PM2.5 over South Korea is much weaker, reflecting weaker variation of PBL depth and lack of residential coal emissions. Physical interpretation of the Satellite AOD data in terms of surface PM2.5 is sensitive to accurate information on aerosol size distributions, PBL depths, RH, the role of coarse particles, and diurnal variation of PM2.5.