Abstract:

To quantify the spatio-temporal variation in drought intensity and its effects on crop yield in semi-arid area of northern Shanxi Province, based on the measured meteorological data (1972 to 2017) from 6 meteorological stations in Shuozhou, the variation trends of precipitation and temperature were investigated whilst the spatial and temporal characteristics of drought frequency and intensity at different time scales were analyzed using standardized precipitation evapotranspiration index (SPEI). The results indicated that the variation in annual average precipitation was insignificant. Average precipitation showed increasing trends in spring, autumn and winter, but a decreasing trend in summer. Specifically, only the average precipitation in autumn increased significantly. Meanwhile, the annual average temperature showed a significant upward trend, in which the most significant increment was discovered in spring. The drought frequency was the highest in 1992-2001, which was also the high frequency period of extreme drought. At the 10-year scale, the longest drought duration of SPEI-3 which represented the SPEI at short time scale (3 months) was 8 months between 1992 and 2001, while the longest drought duration of SPEI-12 was 7 months between 1982 and 1991. In Shuozhou City, crop yield was directly affected by drought characteristics with the relationship in the form of a quadratic function. Our results are expected to provide reference for the development of regional rain-fed agriculture.

Key words: drought, SPEI index, Shuozhou, drought intensity, climate change