For example, in the central TP, the dominant sandy soil would allow infiltrated water drain quickly down to the deep soil; whereas the dominant loam soil in the eastern periphery of the TP could hold more water for soil

and vegetation evapotranspiration while desert basins in the northwest would have lower evapotranspiration than forest covered southeastern basins (FAO, 2008). There have been limited studies on the TP about hydrological processes and water balance as most studies have focused on the streamflow climatology and its relation to precipitation and temperature changes. The mechanisms for streamflow changes could be studied through complementary approaches such as modeling and analyses of field observations including hydrometeorological observations and environmental tracer collections. Hydrometeorological observations can reveal the state and fluxes buy Cabozantinib of hydrometeorological elements such as precipitation and temperature. Environmental tracers such as isotopes and chemicals can be used to separate streamflow into surface, subsurface and baseflow components, and describe the sources of each component (Asano et al., 2002, Michel, 2004, Vache and McDonnell, 2006 and Zhang et al., 2009). Unlike the observations that are often collected over points or small-scale basins, physically based hydrological models that are vigorously evaluated can be set up for small or large domains and can be used to study

hydrological processes and water balance at various spatial and temporal scales. In other words, hydrological modeling can reveal historical trends and can project future trends of hydrological variables for larger river basins given reasonable forcings (e.g., Silmitasertib Cuo et al., 2013a). Although there are quite a few studies that used isotopes to examine streamflow components on the TP (Nie et al., 2005, Liu et al., 2008, Pu et al., 2013 and Meng and Liu, 2013), very few, for example, Nie et al. (2005), used multiple environmental tracers including stable isotopes and chemical

tracers combined with hydrometeorological observations Nutlin-3 chemical structure such as precipitation, streamflow and groundwater measurements to investigate the sources, components and traveling paths of the components of streamflow on the TP. Sources, components and their paths for most rivers of large or small scales are still unknown on the TP. Modeling the cryospheric processes from coherent mass and energy perspectives is another important aspect of TP hydrological research. A majority of cryospheric modeling studies on the TP focused on the specific aspects of water and energy balances for frozen soil and glacier (Fujita and Ageta, 2000, Zhang et al., 2004a, Zhang et al., 2004b, Zhang et al., 2005, Chen et al., 2010, Guo et al., 2012, Zhang et al., 2013a and Molg et al., 2013); while a few other studies looked at the integrated hydrological processes and water and energy balances for the entire basins (Yang et al., 2011, Zhang et al., 2012b, Zhang et al.