Research progress of passive microwave remote sensing from snow and its application in the eastern Qinghai-Tibet Plateau

Abstract

Snow disasters are common in pastoral areas of China's northern, which is the large and wide range of hazards of natural disasters, and it is also the one of the main meteorological disasters that constrain sustainable development of livestock in pastoral areas .Passive microwave remote sensing of snow is used as all-weather monitoring data, which is an important supplement about the changes of snow depth and the spatial and temporal distribution of the visible data. By passive microwave remote sensing of snow at home and abroad in recent years, having an overview of research progress, and meanwhile the characteristic parameters were compared with the common passive microwave sensors SMMR (Scanning Microwave Scanning Radiometer), AMSR-E (Advanced Microwave Scanning Radiometer-EOS) and MWRI (Microwave Radiation Imager) each other, this paper collected data of SSM/ I daily brightness temperature and corresponding measured ground snow depth from 79 meteorological stations in the study area from October to next March during 1995 to 1996 , 2000 to 2001 and 2005to 2006. And snow depth model in the easternQinghai-Tibet Plateau was inversed, then the model was applied to estimate snow area and snow depth of three quarters of the snow cover in the study area. The results showed that: 3 months areas of snow season and snow cover are the first increase in ten days in December to next January to the maximum, then decrease; snow depth of the snow season is based on the range to <;5 cm, in October and the following year during February and March, there is basically no >;10 cm above the snow, the snow of 5 ~ 10 cm in the snow season of 3 mainly distributes in Yushu and Guoluo states in the south of Qinghai; by the sight of the snow depth data of the snow season of 3, the mid-three-level areas of snow depth change in different seasons basically followed the trend of first increase and then decrease, including the snow area of snow depth <;5 cm having greatest change, while >;10 cm of snow area change having Minimum. Currently, the use of passive microwave data can basically meet the range of large-scale snow cover monitoring requirements, but the representative of the measured values of snow depth at weather stations is not still strong, the data resolution (25 km) is so small that it is needed further validating to the brightness temperature threshold on the snow tree removed the rain of affecting snow deep inversion, cold desert and frozen soil factors, and these factors will affect the accuracy of snow cover monitoring. With the accumulation of experimental data and the extensive application of remote sensing data of higher resolution AMSR-E and MWRI, It is expected to further improve the monitoring method and the monitoring model so as to improve the accuracy of snow cover monitoring.