干旱区生态环境知识资源中心

The unavailability of sufficient data at higher elevations causes many uncertainties in research on cold regions. This study considers a cryosphere-hydrology observation system established in 2008 at the Hulu small alpine watershed in the Qilian Mountains of Northwest China. The altitudinal gradient of weather factors is analyzed using data from the Hulu watershed and routine stations located in the Heihe upstream. The data presented here provide the following knowledge of mountain meteorology at elevations from 3367 m to 4166 m/4248 m in the Qilian Mountains: (1) the yearly precipitation altitude relationship is linear in regions below 4248 m in the Heihe upstream, where the precipitation gradient increased marginally from 1960 to 2011; (2) the yearly air temperature lapse rate (TLR) is weaker at higher elevations (>3000 m), and the seasonal TLR became more divergent between winter and summer half-years from 1960 to 2011 (yearly mean 5.6 degrees C km(-1)); (3) in the Hulu watershed, the LRs of water vapor pressure and absolute humidity are higher in warm seasons with yearly means of 1.1 hpa km(-1) and 0.84 g km(-1), respectively, and the maximum relative humidity value is found at elevations between 3500 and 3700 m in the Heihe upstream; (4) the long-term existence of snow increases the albedo to yearly means of 0.22, 0.30, 0.35, and 0.27 in areas of grassland, meadow, marshy meadow, and alpine desert in the Hulu watershed, respectively. The relationship between monthly net radiation and soil surface temperature (Ts) is linear, and the mean Ts LR was about 7.5 degrees C km(-1) from July 2009 to September 2011.