Estimating Snow Water Equivalent with Backscattering at X and Ku Band Based on Absorption Loss

作者:Cui, YR (Cui, Yurong)[ 1 ] ; Xiong, C (Xiong, Chuan)[ 1 ] ; Lemmetyinen, J (Lemmetyinen, Juha)[ 2 ] ; Shi, JC (Shi, Jiancheng)[ 1 ] ; Jiang, LM (Jiang, Lingmei)[ 3 ] ; Peng, B (Peng, Bin)[ 1 ] ; Li, HX (Li, Huixuan)[ 4 ] ; Zhao, TJ (Zhao, Tianjie)[ 1 ] ; Ji, DB (Ji, Dabin)[ 1 ] ; Hu, TX (Hu, Tongxi)[ 1 ]

REMOTE SENSING

卷: 8  期: 6

文献号: 505

DOI: 10.3390/rs8060505

出版年: JUN 2016

摘要

Snow water equivalent (SWE) is a key parameter in the Earth's energy budget and water cycle. It has been demonstrated that SWE can be retrieved using active microwave remote sensing from space. This necessitates the development of forward models that are capable of simulating the interactions of microwaves and the snow medium. Several proposed models have described snow as a collection of sphere- or ellipsoid-shaped ice particles embedded in air, while the microstructure of snow is, in reality, more complex. Natural snow usually forms a sintered structure following mechanical and thermal metamorphism processes. In this research, the bi-continuous vector radiative transfer (bi-continuous-VRT) model, which firstly constructs snow microstructure more similar to real snow and then simulates the snow backscattering signal, is used as the forward model for SWE estimation. Based on this forward model, a parameterization scheme of snow volume backscattering is proposed. A relationship between snow optical thickness and single scattering albedo at X and Ku bands is established by analyzing the database generated from the bi-continuous-VRT model. A cost function with constraints is used to solve effective albedo and optical thickness, while the absorption part of optical thickness is obtained from these two parameters. SWE is estimated after a correction for physical temperature. The estimated SWE is correlated with the measured SWE with an acceptable accuracy. Validation against two-year measurements, using the SnowScat instrument from the Nordic Snow Radar Experiment (NoSREx), shows that the estimated SWE using the presented algorithm has a root mean square error (RMSE) of 16.59 mm for the winter of 2009-2010 and 19.70 mm for the winter of 2010-2011.

通讯作者地址: Xiong, C (通讯作者)

Chinese Acad Sci, Inst Remote Sensing & Digital Earth, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China.

地址:

[ 1 ] Chinese Acad Sci, Inst Remote Sensing & Digital Earth, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China

[ 2 ] Finnish Meteorol Inst, POB 503, FIN-00101 Helsinki, Finland

[ 3 ] Beijing Normal Univ, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China

[ 4 ] Univ South Carolina, Dept Geog, Callcott Bldg 709 Bull St, Columbia, SC 29208 USA