MODIS/Terra observed snow cover over the Tibet Plateau: distribution, variation and possible connection with the East Asian Summer Monsoon (EASM)

Abstract

Based on the snow cover fraction (SCF) data acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA Terra spacecraft from 2000–2006, statistical analyses are performed to explore the spatial and temporal distribution and variation of the snow cover over the Tibetan Plateau (TP). It is found that the snow persistence over the TP varies in different elevation ranges 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 terrain features, such as aspect, slope, and curvature in the local areas. With 7-year observational data, seasonal and interannual variability of snow cover has been detected. There are slight decreasing trends in SFCs from 2000–2006. With MODIS satellite snow-cover fraction data and the National Centers for Environmental Predictions and U.S. Department of Energy NCEP/DOE reanalysis II dataset, the relationship between snow cover anomalies over the TP and the East Asian Summer Monsoon (EASM) is examined. Results indicate that the onset of the EASM is closely associated with snow cover anomalies in the spring. Specifically, a positive (negative) snow cover anomaly is followed by a later (earlier) onset of the EASM.