雅鲁藏布江流域生长季NDVI对湿季降水的响应

Responses of Vegetation Changes in Growing Season to Precipitation in Yarlung Zangbo River Basin

运用经验正交函数和奇异值分解法对2000—2010年雅鲁藏布江流域生长季植被覆盖与降水量的时空分布及时空相关性进行研究。结果表明:研究期间,雅鲁藏布江流域湿季降水的主要空间分布型是东西差异分布型,每年7,8,9月份这一特征逐渐显著,且长期变化趋势的显著性逐渐增强。植被覆盖的主要模态贡献率达到55.7%。东部米林宽谷地区植被覆盖度较高,时间系数震荡周期明显且呈微弱的上升趋势。研究区内的植被覆盖与湿季降水的耦合模态基本成正相关,最大耦合贡献率达到61.8%。植被覆盖受季风气候的影响最为直接,其次受地形地貌因素以及土地利用类型特征的影响较大。

Using empirical orthogonal functions（EOF） and singular value decomposition（SVD）, this paper an- alyzed the temporal and spatial distribution characteristics and the spatial-temporal correlation between vege- tation cover in growing season and precipitation in Yarlung Zangbo River Basin in 2000--2010. The results are shown as follows. During the period of 11 years, the characteristics are becoming more significant in Ju- ly, August and September each year, and the spatial distribution of the trends is becoming ever more obvious in recent years. The contribution rate of the main mode of vegetation reached up to 55.7 ~. The vegetation coverage in eastern millin wide area is higher than other regions, and time coefficient oscillation cycle is obvi- ous and presents the rising trend. The coupling mode relationship between vegetation cover and wet season precipitation shows a positive correlation, and the highest contribution rate is 61.8%. Monsoon climate has the direct influence on vegetation cover, the landscape factors and the land use type characteristics were the secondary factors affecting the vegetation cover.