基于SPEI 指数的京津冀地区干旱特征分析.

In order to define the spatial temporal distribution of drought characteristics and its response to climate change in the Beijing-Tianjin- Hebei region at different time scales, daily climatic data of 24 meteorological stations from 1961 to 2016 were selected in this study. The standardized precipitation evapotranspiration index ( SPEI) was established by using precipitation and reference crop evapotranspiration (ET0) data at different time scales, in which ET0 was calculated by FAO Penman Monteith equation. In order to find out the drought characteristics, Mann Kendall test, drought indices, climate tendency rate and rotated empirical orthogonal function (REOF) analysis were carried out on the SPEI. The results show that from the inter annual changes, there is a humid trend in Beijing-Tianjin-Hebei region; from the seasonal perspective, it is getting wet in spring, autumn (P<0. 05) and winter, and there is a drought trend in summer. The drought coverage appears as the features of the domain drought at the annual scale and the intensity of drought is light and moderate mainly. Viewing form spatial distribution, the western region has a humid trend, while it is dry in the eastern part of Beijing-Tianjin-Hebei region. According to spatial abnormal distribution of loading vectors in the Beijing Tianjin Hebei region, it can be divided into 4 sub regions: central area in the north region (sub-regionⅠ), east area in the north region (sub-region II), west area in the north region (sub-region III) and southern region (subregion IV). Drought in Ⅲ and Ⅳ sub regions gradually alleviates, while Ⅰ and Ⅱ sub regions shows a trend of getting dry. [ABSTRACT FROM AUTHOR]