Remote Sensing of Snow in the Himalayas Using TRMM PR

Ana P. Barros
Duke University

Monitoring solid precipitation parameters, snow cover and snow storage from space remains one of the challenging problems in remote sensing applications. Some outstanding science issues include: 1) the radiative behavior of dry versus wet snow at different frequencies; 2) the effect of grain-size distribution on the dielectric behavior of snow; and 3) the effect of layers (snow stratigraphy) and water routing on the scatter response of snowpacks. With much higher spatial resolution than existing space-borne sensors, TRMM provided a first opportunity to study snow properties in mountainous regions. Five high altitude tower stations (> 3,000m) were installed in the Central Himalayas and equipped with sensors to measure air temperature, relative humidity, wind speed and wind direction in the boundary layer, and with sonic rangers and gamma-ray loggers to make snow depth, snow water equivalent and snow density measurements at high resolution over a small area (10 km²). In addition snow stakes were used to quantify the uncertainty associated with spatial variability of snow depth around the tower (i.e. wind effects). We present preliminary results of our efforts to derive generalized parameterizations of the electromagnetic signature of snow in mountainous regions using TRMM PR data. It was a privilege to conduct this work under the guidance of Alfred T.C. Chang.

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