关键词: 气象干旱, 干旱强度, 陕西省, 标准化降水蒸散指数

Abstract:

Drought disaster is one of the main natural disasters in Shaanxi Province, suffering from it often "nine out of ten years". It impacts the people's daily life and social production to different extent. In this paper, the observed meteorological data of 18 meteorological stations from 1961 to 2010 in Shaanxi Province were collected and the standardized precipitation evapotranspiration index (SPEI) was used. Based on the monthly SPEI values of each station in recent 50 years, the drought processes of each station were confirmed one by one and the occurrence frequencies, scopes and severities of the meteorological droughts were computed and the annual, seasonal and monthly drought occurrence frequency, coverage and intensity over years were analyzed, and the spatial and temporal evolution and the intensity of drought occurrence of the province were revealed. Research results show that there was an obviously growing trend in frequency of drought in recent 50 years, especially in recent 20 years since 1990; drought occurred without exception in the annual, spring, summer, autumn, winter and monthly scales. Among them, the most serious drought occurred in autumn and spring. In decadal variability, the province witnessed the worst drought in the 1990s, next since the year 2000; drought in Shaanxi was either widespread throughout the province or locally, with quite uneven distribution regionally, the overall distribution characteristics are more in the north and less in the south; the strongest drought distribution intensity presented in Guanzhong of Shaanxi, followed by southern Shaanxi and northern Shaanxi is the weakest.

Key words: Shaanxi Province, meteorological drought, standardized precipitation evapotranspiration index, intensity of the drought