Abstract
The recently launched Chinese GaoFen-4 (GF4) satellite provides valuable information to obtain geophysical parameters describing conditions in the atmosphere and at the Earth’s surface. The surface reflectance is an important parameter for the estimation of other remote sensing parameters linked to the eco-environment, atmosphere environment and energy balance. One of the key issues to achieve atmospheric corrected surface reflectance is to precisely retrieve the aerosol optical properties, especially Aerosol Optical Depth (AOD). The retrieval of AOD and corresponding atmospheric correction procedure normally use the full radiative transfer calculation or Look-Up-Table (LUT) methods, which is very time-consuming. In this paper, a Simplified AtmospHeric correction AlgoRithm for gAofen data (SAHARA) is presented for the retrieval of AOD and corresponding atmospheric correction procedure. This paper is the first part of the algorithm, which describes the aerosol retrieval algorithm. In order to achieve high-accuracy analytical form for both LUT and surface parameterization, the MODIS Dark-Target (DT) aerosol types and Deep Blue (DB) similar surface parameterization have been proposed for GF4 data. Limited Gaofen observations (i.e., all that were available) have been tested and validated. The retrieval results agree quite well with MODIS Collection 6.0 aerosol product, with a correlation coefficient of R2 = 0.72. The comparison between GF4 derived AOD and Aerosol Robotic Network (AERONET) observations has a correlation coefficient of R2 = 0.86. The algorithm, after comprehensive validation, can be used as an operational running algorithm for creating aerosol product from the Chinese GF4 satellite.
Highlights
The retrieval of aerosol optical properties is a difficult task due to the coupling of surface and aerosol information observed by the satellite Top of Atmosphere (TOA) reflectance
A new aerosol retrieval algorithm, Simplified AtmospHeric correction AlgoRithm for gAofen data (SAHARA) is presented, which enables the retrieval of the Aerosol Optical Depth (AOD), which will be further used for the atmospheric correction for Chinese GaoFen4 instrument
The asymmetry factor, Single Scattering Albedo (SSA) and the Angstrom coefficient are parameterized by the AOD at 0.55 μm using polynomial form for each aerosol type, which is proved to be accurate enough for the AOD range from 0.1 to 1.0
Summary
The retrieval of aerosol optical properties is a difficult task due to the coupling of surface and aerosol information observed by the satellite Top of Atmosphere (TOA) reflectance. The cloud twilight zone effect [3] is a challenging task in order to obtain accurate aerosol properties [4]. An aerosol retrieval algorithm is instrument-dependent, especially for the estimation of surface properties. The majority of aerosol retrieval algorithms like Moderate Resolution. The LUT method speeds up the retrieval procedure compared to full radiative transfer calculations. Accurate analytical/empirical equations provide a unique ability to undertake fast aerosol retrievals, which are especially useful for high-spatial resolution aerosol retrievals [7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
