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Estimating Snow Water Storage in North America Using CLM4, DART, and Snow Radiance Data AssimilationThis paper addresses continental-scale snow estimates in North America using a recently developed snow radiance assimilation (RA) system. A series of RA experiments with the ensemble adjustment Kalman filter are conducted by assimilating the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) brightness temperature T(sub B) at 18.7- and 36.5-GHz vertical polarization channels. The overall RA performance in estimating snow depth for North America is improved by simultaneously updating the Community Land Model, version 4 (CLM4), snow/soil states and radiative transfer model (RTM) parameters involved in predicting T(sub B) based on their correlations with the prior T(sub B) (i.e., rule-based RA), although degradations are also observed. The RA system exhibits a more mixed performance for snow cover fraction estimates. Compared to the open-loop run (0.171m RMSE), the overall snow depth estimates are improved by 1.6% (0.168m RMSE) in the rule-based RA whereas the default RA (without a rule) results in a degradation of 3.6% (0.177mRMSE). Significant improvement of the snow depth estimates in the rule-based RA as observed for tundra snow class (11.5%, p < 0.05) and bare soil land-cover type (13.5%, p < 0.05). However, the overall improvement is not significant (p = 0.135) because snow estimates are degraded or marginally improved for other snow classes and land covers, especially the taiga snow class and forest land cover (7.1% and 7.3% degradations, respectively). The current RA system needs to be further refined to enhance snow estimates for various snow types and forested regions.
Document ID
20170002754
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kwon, Yonghwan (Texas Univ. Austin, TX, United States)
Yang, Zong-Liang (Texas Univ. Austin, TX, United States)
Zhao, Long (Texas Univ. Austin, TX, United States)
Hoar, Timothy J. (National Center for Atmospheric Research Boulder, CO, United States)
Toure, Ally M. (Universities Space Research Association Columbia, MD, United States)
Rodell, Matthew (NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
March 31, 2017
Publication Date
November 10, 2016
Publication Information
Publication: Journal of Hydrometeorology
Volume: 17
ISSN: 1525-755X
Subject Category
Earth Resources and Remote Sensing
Report/Patent Number
GSFC-E-DAA-TN39548
Funding Number(s)
CONTRACT_GRANT: NNX11AJ43G
Distribution Limits
Public
Copyright
Other
Keywords
snow depth
land covers