基于标准化降水指数的1981—2013年西藏干旱时空特征分析

为了研究西藏干旱时空分布特征,利用西藏38个气象站点1980—2013年的月降水资料,采用标准化降水指数(SPI)作为干旱指标,分析了西藏旱季和雨季的干旱及重旱频率分布特点。结果表明:东南部旱季干旱频率较高,西部雨季干旱频率较高;而旱季和雨季的重旱频率高的地区都在中、东部;20世纪90年代旱季干旱和重旱发生频率最高,21世纪初雨季干旱和重旱频率最高。对西藏不同区域干旱强度演变情况分析表明,各区域1981—2013年旱季和雨季干旱强度变化都不一致,总体来说,沿江一线和东部地区变化相对稳定,南部边缘变化相对较剧烈。

Temporal and Spatial Patterns of Drought Based on Standard Precipitation Index (SPI) in Tibet During 1981-2013

The paper aims to study the drought changes in Tibet,The evolution characteristics of the dry season and rainy season frequency of drought and severe drought in the Tibet Region for the past 34 years were analyzed based on the standardized precipitation index (SPI) as a drought index with the data of monthly precipitation of 38 ground meteorological stations during the period from 1981 to 2013. The results showed that: southeast drought frequency was higher in the dry season, the western drought frequency was higher in the rainy season, during the rainy season and dry season, the severe drought had high frequency in the central and East; drought and severe drought during the dry season occurred highest frequency in the 1990s, drought and severe drought during the rainy season frequency was highest at the beginning of the 21st century. The evolution of drought intensity in Tibet showed that the southern edge of Tibet had the most dramatic changes.