An updated GOCI algorithm for retrieving water-leaving radiance

Title
An updated GOCI algorithm for retrieving water-leaving radiance
Author(s)
안재현; 박영제; 김원국; 이보람
KIOST Author(s)
Ahn, Jae Hyun(안재현)Park, Young Je(박영제)
Publication Year
2016-09-28
Abstract
This study describes the updated atmospheric correction scheme that designed to retrieve the remote-sensing reflectance (Rrs) by the Geostationary Ocean Color Imager (GOCI) at the top-of-the-atmosphere (TOA). The algorithm update includes an absorption correction model of atmospheric gasses in red and near-infrared (NIR) bands and a new aerosol reflectance correction scheme that is methodologically more straightforward and accurate.We found water vapor absorption considerably effects on 660, 745, and 865 nm band of the GOCI for large zenith angles although the GOCI bands are designed to avoid its effect. The absorption correction model is developed and tested by using a radiative transfer simulation. After the correction of gaseous absorption, vicarious calibration gains has changed significantly that all gains are within the ranges of onboard calibration uncertainties, 3.8%.For the aerosol reflectance correction, we suggest a more direct and accurate aerosol correction scheme compared to previous methods. The method is based on the spectral relationships in the aerosol multiple-scattering reflectance between different wavelengths (called SRAMS) that directly determines the two most appropriate aerosol models and their mixing ratio with no residual errors in the NIR.We tested the updated algorithms regarding errors in the Rrs retrieval by in situ match-ups and the mean errors for bands from 412 to 555 nm were 1n absorption correction model of atmospheric gasses in red and near-infrared (NIR) bands and a new aerosol reflectance correction scheme that is methodologically more straightforward and accurate.We found water vapor absorption considerably effects on 660, 745, and 865 nm band of the GOCI for large zenith angles although the GOCI bands are designed to avoid its effect. The absorption correction model is developed and tested by using a radiative transfer simulation. After the correction of gaseous absorption, vicarious calibration gains has changed significantly that all gains are within the ranges of onboard calibration uncertainties, 3.8%.For the aerosol reflectance correction, we suggest a more direct and accurate aerosol correction scheme compared to previous methods. The method is based on the spectral relationships in the aerosol multiple-scattering reflectance between different wavelengths (called SRAMS) that directly determines the two most appropriate aerosol models and their mixing ratio with no residual errors in the NIR.We tested the updated algorithms regarding errors in the Rrs retrieval by in situ match-ups and the mean errors for bands from 412 to 555 nm were 1
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/24588
Bibliographic Citation
International GOCI Symposium 2016, pp.44, 2016
Publisher
해양위성센터/한국해양과학기술원
Type
Conference
Language
English
Publisher
해양위성센터/한국해양과학기술원
Related Researcher
Research Interests

Ocean Color Remote Sensing,Satellite Applications,Ocean color Algorithm,해양원격탐사,위성활용,해색 알고리즘

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