MODIS Snow Monitoring Over the Tibetan Plateau

Abstract

Permanent and seasonal snowpack over the Tibetan Plateau (TP) is an important component of earth climate system. Due to the limitation of conventional observations and previous satellite image, however, the snow cover variability over the TP has been a challenging problem for climate study. High-resolution (500 m) snow mapping obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) provided an excellent opportunity to define details in the spatial and temporal snow cover distribution and variability in this region. In previous evaluation, the accuracy of MODIS/Terra snow cover data is evaluated by comparing the data with in situ Chinese station snow observations and show a overall 90% accuracy over the TP. Statistical analysis is then performed to explore the distribution and variability of snow cover based on the available data from 2000 to 2006. The most persistent snow cover is located in the southern and western edges of the TP, especially major mountain ridges and the western Yarlung Zangbo Valley. The higher snow cover fractions (SCFs) are mainly concentrated in the regions where the elevation is higher than 6000 m. The snow persistence varies in different elevation ranges and generally becomes longer with increases in the terrain elevation. In addition, the spatial distribution of the snow cover not only depends on the elevation, but also varies with the terrain features (e.g., aspects and slopes) in the local areas. With 7-year observational data, seasonal and interannual variability of snow cover has been detected, but the persistence of the seasonal and interannual anomalies in snow cover is generally lacking due to the small sample of data available. There are slight decreasing trends in SFCs over the TP during 2000–2006.