| The temporal and spatial variation characteristics of drought and its relationship with ENSO events in Hexi region in last 55 years |
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| DOI：10.7606/j.issn.1000-7601.2019.01.35 |
| Key Words: drought SPEI-index temporal and spatial variation characteristics ENSO events Hexi region |
| Author Name | Affiliation | | PEI Wen-tao | College of Geography and Environmental Science, Northwest Normal University, Lanzhou, Gansu 730070, China | | CHEN Dong-dong | College of Geography and Environmental Science, Northwest Normal University, Lanzhou, Gansu 730070, China | | XUE Wen-hui | College of Geography and Environmental Science, Northwest Normal University, Lanzhou, Gansu 730070, China | | ZHANG Guo-bin | College of Geography and Environmental Science, Northwest Normal University, Lanzhou, Gansu 730070, China |
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| Abstract: |
| Combining SPEI index and Mann-Kendall trend test with inverse distance weighted, we analyzed the temporal and spatial characteristics change of drought and its relation with ENSO events in Hexi region based on monthly meteorological data of 14 meteorological stations from 1961 to 2015. We found that the drought frequency was increasing and aggravating since the 1990s in Hexi region. On seasonal changes, the drought happened more often in spring, summer, and autumn but it was wet in winter. Spring drought is more severe. Spatially, the whole Hexi region had a drought trend in spring that the tendency of drought was very significant in most of regions and the worst drought location was Jinta. The study area overall had a humid winter. The high frequency of drought occurred in Jinta and Minqin in spring, the northwestern Hexi in summer, and central and eastern Hexi, Anxi to Yumen, and western part of the study area in autumn. In winter, it happened in west of 101°E, the Hexi region. The SPEI of autumn had the most significant correlation with SSTA index, followed by that of spring while summer had the least correlation. The fitting relationship between the intensity of ENSO events and SPEI influence factors showed that the intensity of ENSO event had more influence on temperature than precipitation. In the years of the ENSO warm events (El Nio), temperature had a significant upward trend. The ENSO cold events (La Nio) had less effect on temperature but slightly increased precipitation in few years. |
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