A211-0017
An Improved Aerosol Retrieval for Himawari-8/AHI Using GRASP Algorithm.

Wednesday, 16 December 2020
Poster
Chong Li, Peking University, Beijing, China; Laboratoire d’Optique Atmosphérique, CNRS/University of Lille, Lille, France, Oleg Dubovik, Laboratoire d'Optique Atmosphérique, CNRS/University of Lille, Lille, France, Jing Li, Peking University, Department of Atmospheric and Oceanic Sciences, Beijing, China and Anton Lopatin, GRASP SAS, Remote Sensing Developments, Lille, France
Abstract:
The knowledge of aerosol optical properties is of high importance for environmental and climate studies. This presentation discusses the development of aerosol property retrieval from the Advanced Himawari Imager (AHI), on board the next-generation geostationary meteorological satellite Himawari-8 that is a 16 channel multispectral imager to capture visible light and infrared images of the Asia-Pacific region. Observations are obtained every 10 min at a spatial resolution of 0.5-2 km, which provide great advantage of tracking aerosols and characterizing aerosol daily variability.

In proposed approach the aerosol and underlying surface are retrieved simultaneously. Namely, spectral Aerosol Optical Depth (AOD) and height of aerosol layer are derived together with surface BRDF parameters using GRASP algorithm. The performance of the developed AHI/GRASP algorithm is illustrated using both synthetic data and real Himawari-8/AHI observations.

The results of synthetic tests show that both aerosol and surface parameters can be robustly derived with a high correlation of 0.97, 0.67 and 0.99 for AOD, AE and surface albedo respectively. The AOD and AE retrievals from real Himawri-8/AHI data were performed over sites in China and Japan and the obtained aerosol parameters were validated against the AERosol RObotic NETwork (AERONET) version 3 level 1.5 measurements. The results show good consistency of AOD retrievals with the AERONET values, with correlation coefficient of ~ 0.9, slope = 0.97, and intercept = 0.07; However, the AE retrievals are less satisfactory, with overall overestimation of AE and correlation coefficient as low as 0.22.

In addition to satellite only applications, a combined retrieval using passive (Himawri-8/AHI) and active (Micro-pulse Lidar) observations was performed over Beijing-PKU site. Satellite observations and coincident lidar were inverted. Such synergetic retrieval resulted in further improvements in derived aerosol properties benefiting from additional information provided by the back-scattering observations by lidar, which significantly improved sensitivity to the vertical variability of aerosol properties.

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