关键词: 高寒退化草甸, 瑞香狼毒, 牧草, 盖度, 光谱特征参量

Abstract: Surface moisture index is more objective than precipitation in describing regional drying-wetting feature and its changing trend under the background of global warming. Based on the meteorological data from 21 stations in 1962-2009, and by using detrended fluctuation analysis, spline interpolation, and least square fitting, this paper analyzed the spatiotemporal variations of  surface moisture index, precipitation, and air temperature in different sub-regions of north Tianshan Mountains, Xinjiang of Northwest China in 1962-2009. During the past 48 years, the temporal pattern of the moisture index showed a weak Hurst’s effect, i.e., the moisture index exhibited relatively weak persistence and relatively strong randomness through the time. There was a significant seasonal difference among the sub-regions. In desert oasis sub-region, the annual precipitation had an overall increase, but the moisture index varied spatially. The sub-regions that experienced significant drying also experienced significant warming, and the sub-regions with the most significant drying were the Ili Valley, followed by the west mountainous area and the eastern edge of Junggar basin. The ground surface drying-wetting also varied seasonally, with a trend of becoming drier in winter and autumn, followed by in spring, and wetter in summer.  

Key words: degraded alpine meadow, Stellera chamaejasme, herbage, coverage, spectral feature parameter.