TY - JOUR
T1 - Double-delta-function adjustment in thermal radiative transfer
AU - Wu, Kun
AU - Zhang, Feng
AU - Iwabuchi, Hironobu
AU - Shi, Yi Ning
AU - Duan, Mingkeng
N1 - Funding Information:
This work is funded by the National Natural Science Foundation of China (Grant Nos. 41675003 and 41675056 ), the National Key R&D Program of China (Grant No. 2017YFA0603504 ), the Grant-in-Aid for Scientific Research (KAKENHI Grant No. 16F16031 ) of the Japan Society for the Promotion of Science, and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). The ESMC contribution number is ESMC 182.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017/11
Y1 - 2017/11
N2 - For atmospheric scattering, the weak backward scattering peak is always ignored, in contrast with the strong forward scattering peak. In this paper, the backward peak contribution is incorporated in multiple scattering, along with the forward peak contribution. Thus, a new parameterization, the double-δ-function adjustment, is proposed and its application in a two-stream approximation for infrared radiative transfer is shown. The accuracy of the adding method for the double-δ-two-stream discrete-ordinates approximation (2δ-2DDA) is evaluated by the emissivities in a single layer of atmosphere and the fluxes and heating rate in a multi-layer atmosphere with a realistic atmospheric profile. The results show that 2δ-2DDA produces less bias than the δ-two-stream approximation (δ-2DDA) for thick optical depths, such as water cloud conditions. For thin optical depths, such as ice cloud, δ-2DDA and 2δ-2DDA produce similar errors. Generally, 2δ-2DDA is more accurate than δ-2DDA, and it can be easily applied in climate models.
AB - For atmospheric scattering, the weak backward scattering peak is always ignored, in contrast with the strong forward scattering peak. In this paper, the backward peak contribution is incorporated in multiple scattering, along with the forward peak contribution. Thus, a new parameterization, the double-δ-function adjustment, is proposed and its application in a two-stream approximation for infrared radiative transfer is shown. The accuracy of the adding method for the double-δ-two-stream discrete-ordinates approximation (2δ-2DDA) is evaluated by the emissivities in a single layer of atmosphere and the fluxes and heating rate in a multi-layer atmosphere with a realistic atmospheric profile. The results show that 2δ-2DDA produces less bias than the δ-two-stream approximation (δ-2DDA) for thick optical depths, such as water cloud conditions. For thin optical depths, such as ice cloud, δ-2DDA and 2δ-2DDA produce similar errors. Generally, 2δ-2DDA is more accurate than δ-2DDA, and it can be easily applied in climate models.
KW - Backward scattering
KW - Infrared radiative transfer
KW - Two-stream approximation
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U2 - 10.1016/j.infrared.2017.07.006
DO - 10.1016/j.infrared.2017.07.006
M3 - Article
AN - SCOPUS:85029506658
VL - 86
SP - 139
EP - 146
JO - Infrared Physics
JF - Infrared Physics
SN - 1350-4495
ER -
