Publication Date:
2023-07-26
Description:
Currently, snow depth products generated using passive microwave remote sensing are widely used for variation analysis of snow water storage on global and regional scales. Notwithstanding many remote sensing snow depth and snow water equivalent products, high-quality product in mountain areas is still lacking, due to the large uncertainties of microwave emission simulation caused by complicated terrain. Therefore, terrain factors should be considered in the microwave emission transfer process of snowpack. Among these factors, slope-slope radiation increases the downward sky radiation into snowpack surface, leading to the increase of brightness temperature and decrease of brightness temperature difference between low and high frequencies. In Qilian Mountains in the Qinghai-Tibetan plateau, the slope-slope radiation occupies up to 40 % of downward radiation, which leads to the downward sky brightness temperature increasing to approximately 120 K. Given the snowpack is characterized by snow depth of 30 cm, snow density of 200 kg/m3 and the correlation length of 0.15 mm, the increase of the downward radiation results in that the brightness temperatures increase approximately 6 K and 17 GHz at 18 GHz and 36 GHz, respectively, and the brightness temperature difference between these two frequencies decreases approximately 11 K. The change of the brightness temperature difference leads to underestimating 30 % of snow depth for the snowpack with depth less than 50 cm. However, this underestimation decreases with increase of snow depth.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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