澜沧江流域干旱变化的时空特征

干旱是澜沧江流域的突出自然灾害，研究气候变化背景下的流域干旱变化特征具有重要科学意义与应用价值。该文基于澜沧江流域及其周边35个气象站点1960－2005年的日降水数据，利用多时间尺度下的标准化降水指数（SPI）分析了流域干旱变化的时空特征。研究发现，主成份分析与K-means聚类的多元统计方法可分别将流域在空间上分为4个具有不同干旱演化特征的区域，2种分区方案具有很高的空间一致性。对划分的4个区域典型站点的小波分析表明，流域干旱变化的周期一般在3～6 a。研究结论可为相关部门的决策提供参考。

Spatial and temporal variability of droughts in the Lancang River basin

Drought is one of the outstanding natural disasters of the Lancang River basin, studying on the variation characteristic of drought in the basin under the context of climate change is of great importance for scientific research and society. Using 46-year (1960-2005) daily precipitation records from 35 meteorological stations in and around the Langcang River basin, Southwest China, the Standardized Precipitation Index (SPI) was used to analyze the drought characteristics in the basin. By means of Principal Component Analysis (PCA) and K-means clustering (KMC) methods the study area was divided into 4 sub-regions, each sub-region had its own distinctive temporal evolution patterns of droughts. The wavelet analysis further revealed that there was a 3-6 year period of drought events for the entire basin. The results can be referenced by the decision-makers of government in future.