Interrelations between snow cover and climate and topographic factors in Upper Heihe River basin, northwestern China

Abstract:

As the second largest inland river in China, snow cover in the Upper Heihe River Basin is the most important water resource for sustainable development of natural environment and social economics of the entire Heihe River Basin, an arid and semi-arid region of northwestern China. In this study, snow cover area (SCA) dynamics of the Upper Heihe River Basin are examined based on the flexible multiday combined MODIS snow cover products during hydrological years 2001–2014 (September through August) and are correlated with precipitation (P) and temperature (T) at five ecoregions of different land cover types and elevations (mean elevations of 3968.91 m (P1), 3819.82 m (P2), 4113.29 m (P3), 3179.60 m (P4), and 2898.64 m (P5)) (Figure 1). Our hypothesis is that temperature is the main explanatory variable for low elevation zone and precipitation is a better predictor of snow cover area at high elevation zones. However, our preliminary results does not indicate strong evidence to support or against the hypothesis due to the low correlation coefficients. The potential reason for such a result could be due to the coarse resolution of precipitation (25 km ×25 km) as compared with SCA data (500 m ×500 m) and T data ( 1 km ×1 km). High resolution datasets based on point measurements might be needed to test the hypothesis.