Analysis of the drought characteristics of Longdong Loess Plateau based on the daily SPEI

doi:10.14088/j.cnki.issn0439-8114.2023.03.039

Abstract

Abstract: According to daily meteorological data from 8 national meteorological stations in Longdong region from 1969 to 2020, the drought climate characteristics of the Longdong Loess Plateau based on the Copula function were analyzed by using daily SPEI drought index, drought frequency and drought intensity. The results showed that Longdong region appeared more droughts in Zhengning, Ningxian and Qingcheng, extreme droughts in Huachi and Zhenyuan, severe droughts in Heshui and Ningxian, moderate droughts in Huanxian and Qingcheng, and light droughts in Qingcheng and Zhengning. During the extreme drought process, the precipitation at each station varied greatly in the drought period, indicating local characteristics existed in spatial distribution and temporal changes of drought. The inter-annual and inter-month variations of the SPEI drought index at each station showed the same phase fluctuation feature. Specifically, drought or humidity occurred simultaneously in most years, but there was a temporal and spatial difference in the degree of drought and humidity. During the 1990s and 2004—2013, droughts frequently occurred, and the number of drought occurrences varied greatly among stations. The Copula simulation results indicated that, the BB1 model at Zhengning Station provided a better fitting effect than Fischer-Hinzmann and Roch-Alegre model, followed by Marshal-Olkin at Zhenyuan Station, and t model at Qingcheng Station. However, the simulation model at Xifeng Station and Heshui Station showed the worst fitting effects. The analysis also found that SPEI drought index made the drought comparable in space and time, but it had limitations in reflecting the difference in drought under different climatic background conditions. There was no significant difference in the drought index between the regions with the largest and smallest climatic humidities in the region, thus resulting in a generally lighter judgment on the drought-prone areas.

Key words: SPEI, drought index, Copula function, drought characteristics

CLC Number:

P426.616

ZHANG Tian-feng, JIANG Hui-feng, ZHANG Ke-xin, CHE Xiang-jun, ZHANG Xue-jiao, HE Shu-zhou. Analysis of the drought characteristics of Longdong Loess Plateau based on the daily SPEI[J]. HUBEI AGRICULTURAL SCIENCES, 2023, 62(3): 249-256.

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