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An improved Eddington approximation method for irradiance calculation in a vertical inhomogeneous medium

Shi, Yi-Ning and Zhang, Feng and Chan, Ka Lok and Li, Wenwen and Lin, Han and Duan, Mingkeng (2019) An improved Eddington approximation method for irradiance calculation in a vertical inhomogeneous medium. Journal of Quantitative Spectroscopy and Radiative Transfer, 226, 40 - 50. Elsevier. ISSN 0022-4073

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Official URL: http://www.sciencedirect.com/science/article/pii/S0022407318306277

Abstract

It is well known that including the delta-scaling in the radiative transfer calculation improves the accuracy of radiative transfer in a cloud layer. An improved scheme is proposed to handle the delta-scaling in the radiative transfer calculation. The improved scheme is able to calculate irradiance of a vertical inhomogeneous cloud layer. The inherent optical properties (IOPs) in a cloud layer vary with height. Linear functions are used to represent the variation of IOPs. Compared to the exponential expression, the linear functions simplified the representation of IOPs. A perturbation method based on Eddington approximation is applied to solve the radiative transfer equation. The accuracy of the proposed scheme is evaluated by comparing reflectance and absorptance to the benchmark Discrete Ordinates Radiative Transfer (DISORT) simulation for two ideal layers and two water cloud cases. Results show that the error limited to 3.4 for reflectance calculation and 7 for absorptance in using the proposed scheme, while the error of the conventional Eddington approximation is > 20 for both reflectance and absorptance. The proposed scheme also improved the accuracy of calculation by considering the vertical inhomogeneity of the IOPs in water cloud cases.

Item URL in elib:https://elib.dlr.de/129087/
Document Type:Article
Title:An improved Eddington approximation method for irradiance calculation in a vertical inhomogeneous medium
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Shi, Yi-NingNanjing University of Information Science and TechnologyUNSPECIFIED
Zhang, FengNanjing University of Information Science and TechnologyUNSPECIFIED
Chan, Ka Lokka.chan (at) dlr.deUNSPECIFIED
Li, WenwenNanjing University of Information Science and TechnologyUNSPECIFIED
Lin, HanNanjing University of Information Science and TechnologyUNSPECIFIED
Duan, MingkengNanjing University of Information Science and TechnologyUNSPECIFIED
Date:8 January 2019
Journal or Publication Title:Journal of Quantitative Spectroscopy and Radiative Transfer
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:226
Page Range:40 - 50
Publisher:Elsevier
ISSN:0022-4073
Status:Published
Keywords:Solar irradiance calculation, Vertical inhomogeneity, Delta-scaling, Perturbation method
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):Vorhaben Spectroscopic Methods in Remote Sensing
Location: Oberpfaffenhofen
Institutes and Institutions:Remote Sensing Technology Institute > Atmospheric Processors
Deposited By: Chan, Ka Lok
Deposited On:19 Sep 2019 13:37
Last Modified:19 Sep 2019 13:37

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