Zhang, GQ; Xie, HJ; Yao, TD; Liang, TG; Kang, SC (2012). Snow cover dynamics of four lake basins over Tibetan Plateau using time series MODIS data (2001-2010). WATER RESOURCES RESEARCH, 48, W10529.
Snow over the Tibetan Plateau (TP) is an important water source of major Asian rivers and greatly influences water availability in the downstream areas. In this study, snow cover dynamics of the four characteristic lake basins, Cedo Caka, Selin Co, Nam Co, and Yamzhog Yumco during hydrological years 2001-2010 (September through August) are examined at the basin scale using the flexible multiday combined MODIS snow cover products. The time series of multiday, seasonal, and annual snow covered area (SCA), onset/disappearance dates of snow, snow covered days (SCD), peaks of maximum SCA, and snow cover index (SCI) for each hydrological year (HY) are examined. Results show there is no obvious trend of snow cover change in the examined period, although Nam Co basin has the greatest SCA in all four basins and in all years, and Cedo Caka and Selin Co basins show the smallest SCA in most of the years. Overall, the HY2007 shows a greater snow extent and HY2010 a smaller for the region, with exceptions for the Nam Co basin where the HY2003 is the greatest and for Cedo Caka basin where the HY2004 is the smallest. Statistical analysis between lake level changes and lake basin's SCA, precipitation and pan evaporation (ETpan) changes shows that (1) Cedo Caka's water level rise was highly correlated with the basin's SCA changes (r = 0.94, p = 0.063); (2) Selin Co's water level rise was significantly correlated with the basin's SCA, precipitation and ETpan changes (r = 0.99, p = 0.029); and (3) lake level changes of Nam Co and Yamzhog Yumco were correlated with their corresponding lake basin's SCA, precipitation and ETpan changes (r = 0.87 and r = 0.86, respectively), although insignificant at the 95% level. This could have been due to precipitation and ETpan data of a distant meteorological station for Nam Co lake basin and the complex hydrological processes in the Yamzhog Yumco basin. This study suggests that the examination of time series snow cover dynamics is important to evaluate the water budget of lake basins with snow as a major component of water balance.