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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2018-35
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
07 Mar 2018
Review status
This discussion paper is a preprint. A revision of the manuscript is under review for the journal Atmospheric Chemistry and Physics (ACP).
Retrieval of Desert Dust and Carbonaceous Aerosol Emissions over Africa from POLDER/PARASOL Products Generated by GRASP Algorithm
Cheng Chen1, Oleg Dubovik1, Daven K. Henze2, Tatyana Lapyonak1, Mian Chin3, Fabrice Ducos1, Pavel Litvinov4, Xin Huang4, and Lei Li1 1Laboratoire d'Optique Atmosphérique (LOA), UMR8518 CNRS, Université de Lille 1, Villeneuve D'ASCQ, 59655, France
2Department of Mechanical Engineering, University of Colorado, Boulder, Colorado, 80309, USA
3NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771, USA
4GRASP-SAS, Remote Sensing Developments, Université de Lille 1, Villeneuve D'ASCQ, 59655, France
Abstract. Understanding the role atmospheric aerosols play in the earth-atmosphere system is limited by uncertainties in the knowledge of their distribution, composition and sources. In this paper, we use the GEOS-Chem based inverse modelling framework for retrieving desert dust (DD), black carbon (BC) and organic carbon (OC) aerosol emissions simultaneously from aerosol data retrieved from the polarimetric POLDER/PARASOL Aerosol Optical Depth (AOD) and Aerosol Absorption Optical Depth (AAOD) produced with the GRASP algorithm (hereafter PARASOL/GRASP). First, the inversion framework is validated in a series of numerical tests conducted with synthetic PARASOL-like data. These show that the framework allows for retrieval of the distribution and strength of aerosol emissions. For example, the uncertainty of retrieved daily emissions in error free conditions is bellow 25.8 % for DD, 5.9 % for BC and 26.9 % for OC. In addition, BC refractive index is sensitive to BC emission retrieval, which could produce an additional about 1.8 times differences for total BC emission. The approach is then applied to one-year (December 2007 to November 2008) of data over the African and Arabian Peninsula region using PARASOL/GRASP spectral AOD and AAOD at six wavelengths (443, 490, 565, 670, 865 and 1020 nm). Analysis of the resulting retrieved emissions indicates 1.8 times overestimation of the prior DD online mobilization and entrainment model. For total BC and OC, the retrieved emissions show a significant increase of 209.9–271.8 % in comparison to the prior GEOS-Chem inventory of carbonaceous aerosol emissions. The model posterior simulation with retrieved emissions shows good agreement both with the AOD and AAOD PARASOL/GRASP products used in the inversion. The fidelity of the results is evaluated by comparison of posterior simulations with measurements from AERONET that are completely independent of and more temporally frequent than PARASOL observations. To further test the robustness of our posterior emissions constrained using PARASOL/GRASP, the posterior emissions are implemented in the GEOS-5/GOCART model and the consistency of simulated AOD (prior: R = 0.77, RMSE = 0.14, MAE = 0.09; posterior: R = 0.81, RMSE = 0.10, MAE = 0.06) and AAOD (prior: R = 0.65, RMS = 0.019, MAE = 0.014; posterior: R = 0.69, RMSE = 0.015, MAE = 0.011) with other independent measurements (MODIS and OMI) demonstrates promise in applying this database for modelling studies.
Citation: Chen, C., Dubovik, O., Henze, D. K., Lapyonak, T., Chin, M., Ducos, F., Litvinov, P., Huang, X., and Li, L.: Retrieval of Desert Dust and Carbonaceous Aerosol Emissions over Africa from POLDER/PARASOL Products Generated by GRASP Algorithm, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2018-35, in review, 2018.
Cheng Chen et al.
Cheng Chen et al.
Cheng Chen et al.

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Short summary
This paper introduces a method to use satellite observed spectral Aerosol Optical Depth (AOD) and Aerosol Absorption Optical Depth (AAOD) to derive three types of aerosol emission sources simultaneously based on inverse modeling. This study is an important contribution to improve the atmospheric aerosol simulation using detailed aerosol optical and microphysical information from space-borne satellite observations.
This paper introduces a method to use satellite observed spectral Aerosol Optical Depth (AOD)...
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