Long term soil moisture mapping over the Tibetan plateau using Special Sensor Microwave/Imager

This paper discusses soil moisture retrievals over the Tibetan Plateau from brightness temperature ( T B 's) observed by the Special Sensor Microwave Imagers (SSM/I's) during the warm seasons of the period from July 1987 to December 2008. The Fundamental Climate Data Record (FCDR) of F08,...

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Bibliographic Details
Published in:Hydrology and Earth System Sciences
Main Authors: R. van der Velde, M. S. Salama, T. Pellarin, M. Ofwono, Y. Ma, Z. Su
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2014
Subjects:
Technology
T
Environmental technology. Sanitary engineering
TD1-1066
Geography. Anthropology. Recreation
G
Environmental sciences
GE1-350
permafrost
Online Access:https://doi.org/10.5194/hess-18-1323-2014
https://doaj.org/article/823f6a33fc36477980df3c616792cce0
Description
Summary:This paper discusses soil moisture retrievals over the Tibetan Plateau from brightness temperature ( T B 's) observed by the Special Sensor Microwave Imagers (SSM/I's) during the warm seasons of the period from July 1987 to December 2008. The Fundamental Climate Data Record (FCDR) of F08, F11 and F13 SSM/I satellites by the Precipitation Research Group of Colorado State University is used for this study. A soil moisture retrieval algorithm is developed based on a radiative transfer model that simulates top-of-atmosphere T B 's whereby effects of atmosphere are calculated from near-surface forcings obtained from a bias-corrected dataset. Validation of SSM/I retrievals against in situ measurements for a two-and-half year period (225 matchups) gives a Root Mean Squared Error of 0.046 m 3 m −3 . The agreement between retrievals and Noah simulations from the Global Land Data Assimilation System is investigated to further provide confidence in the reliability of SSM/I retrievals at the Plateau-scale. Normalised soil moisture anomalies ( N ) are computed on a warm seasonal (May–October) and on a monthly basis to analyse the trends present within the products available from July 1987 to December 2008. The slope of linear regression functions between N and time is used to quantify the trends. Both the warm season and monthly N indicate severe wettings of 0.8 to almost 1.6 decade −1 in the centre of the Plateau. Correlations are found by the trend with elevation for the warm season as a whole and the individual months May, September and October. The observed wetting of the Tibetan Plateau agrees with recent findings on permafrost retreat, precipitation increase and potential evapotranspiration decline.

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