A Semi-Physical Approach for Downscaling Satellite Soil Moisture Data in a Typical Cold Alpine Area, Northwest China
نویسندگان
چکیده
Microwave remote sensing techniques provide a direct measurement of surface soil moisture (SM), with advantages for all-weather observations and solid physics. However, most satellite microwave products fail to meet the requirements land studies high-resolution data due their coarse spatial resolutions. Although many approaches have been proposed downscale resolution products, them tested in flat areas where is relatively homogeneous. Thus, those established are often inapplicable downscaling cold alpine complex terrain multiple factors control variations moisture. In this work, we re-inferred verified mathematical assumption behind semi-physical approach extended areas. Instead directly deriving SM from proxy variables, relies on relationship between two standardized variables apparent thermal inertia (ATI), which sub grid standard deviation estimated by physical hydraulic model taking texture as input. The was applied active passive (SMAP) daily typical basin, i.e., Babao River basin located Qilian Mountains Northwest China. We observed good linearity computed ATI wireless sensor network sites installed study justifies underlying assumption. deviations SMAP through Mualem-van Genuchten can broadly represent real characteristics. downscaled 1-km results correlated well in-situ observations, an average correlation coefficient 0.74 small root mean square error (0.096 cm3/cm3). show more consistent textural details than original data. After removal biases even higher agreements be achieved. These demonstrate adequacy areas, resultant fine-resolution serve useful databases hydrological
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ژورنال
عنوان ژورنال: Remote Sensing
سال: 2021
ISSN: ['2315-4632', '2315-4675']
DOI: https://doi.org/10.3390/rs13030509