The Study on Drought Trend Evolution in Liaoning Province in recent 50 years based on SPEI

摘要

Taking Liaoning Province as the study area, Standardized Precipitation Evapotranspiration Index (SPEI) was constructed by using the daily precipitation and temperature data from 25 stations during 1965-2014. The annual precipitation and annual average SPEI were tested for by Mann-Kendall method to discuss the changes of inter-decadal drought trend in the study area. The coverage of each drought level was analyzed based on the ratios of the number of drought stations at each drought level to the total number of stations. The results show that: precipitation in Liaoning Province had dramatic changes in recent 50 years; the annual average SPEI showed a trend of first increase and then decrease; from the 1980s, the drought trend increased significantly; the coverages of all drought levels had an upward trend, and the light drought coverage had the fastest growing trend. It indicated that the frequency of drought events in the study area was increasing. This study can provide decision-making basis for drought prevention and drought relief in Liaoning Province.