Characterization of Remote sensing Albedo Over Sloped Surfaces Based on DART Simulations and In Situ Observations

作者:Wu, SB (Wu, Shengbiao)[ 1,2 ] ; Wen, JG (Wen, Jianguang)[ 1,2,3 ] ; You, DQ (You, Dongqin)[ 1,3 ] ; Hao, DL (Hao, Dalei)[ 1,2 ] ; Lin, XW (Lin, Xingwen)[ 1,2 ] ; Xiao, Q (Xiao, Qing)[ 1,3 ] ; Liu, QH (Liu, Qinhuo)[ 1,2,3 ] ; Gastellu-Etchegorry, JP (Gastellu-Etchegorry, Jean-Philippe)[ 4 ]

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES

卷: 123  期: 16  页: 8599-8622

DOI: 10.1029/2018JD028283

摘要

In situ albedo measurement over sloped surfaces is pivotal to a wide range of remote sensing applications, such as the estimation and evaluation of surface energy budget at regional and global scales. However, existing albedo measurements over rugged terrain are limited and controversial and remain a major challenge. In this paper, two commonly measured broadband albedos, which depend on incoming/outgoing geometric conditions, were characterized over sloped surfaces and illustrated. These albedos are the horizontal/horizontal sloped surface albedo (HHSA) and inclined/inclined sloped surface albedo (IISA). The 3-D Discrete Anisotropic Radiative Transfer (DART) model simulations over varying slopes were utilized to quantify differences in the albedos. In particular, the effects of the slope, aspect, the solar zenith angle, and the proportion of diffuse skylight were investigated. The results show that absolute (relative) biases between HHSA and IISA are significant, reaching up to 0.026 (61.8%), 0.134 (62.4%), and 0.114 (62.3%) in the visible, near-infrared, and shortwave broadbands, respectively. In addition, the diurnal cycle differences between HHSA and IISA were also compared using DART simulations and in situ observations over four typical slopes. Comparisons reveal that topographic parameters (e.g., slope and aspect) and atmospheric conditions (e.g., diffuse skylight and atmospheric visibility) are the primary factors, while the optical and structural parameters have a smaller effect.

通讯作者地址: Wen, JG (通讯作者)

Chinese Acad Sci, Inst Remote Sensing & Digital Earth, State Key Lab Remote Sensing Sci, Beijing, Peoples R China.

通讯作者地址: Wen, JG (通讯作者)

Beijing Normal Univ, Joint Ctr Global Change Studies, Beijing, Peoples R China.

通讯作者地址: Wen, JG (通讯作者)

Joint Ctr Global Change Studies, Beijing, Peoples R China.

地址:

[ 1 ] Chinese Acad Sci, Inst Remote Sensing & Digital Earth, State Key Lab Remote Sensing Sci, Beijing, Peoples R China

[ 2 ] Beijing Normal Univ, Joint Ctr Global Change Studies, Beijing, Peoples R China

[ 3 ] Joint Ctr Global Change Studies, Beijing, Peoples R China

[ 4 ] Univ Toulouse, IRD, CNRS, Ctr Etud Spatiales BIOsphere CNES, Toulouse, France