ABSTRACT
With climate warming and increased occurrence of extreme weather and climate events, drought is more frequent in China. The Standardized Precipitation Evapotranspiration Index (SPEI), combining the advantage of Standardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI), is computed at different time scales in Northeast China, based on monthly meteorological data from the China surface climatological daily data set provided by the National Meteorological Information Center. Remote sensing is another method used to monitor drought conditions on a regional scale, especially in the areas with few meteorological stations. The Drought Severity Index (DSI) was selected to analyze drought conditions on a regional scale, and the correlation between SPEI and DSI was calculated. The results showed that between 1968 and 2017 there were drought trends in Northeast China, except in winter, and were more obvious in autumn. From 1975 to 1987 there was a trend of drought but this was not significant, and in the mid-1980s, there were signs of wetting in Northeast China but disappeared quickly. Before that, inter-annual drought fluctuated slightly and after that, the region was referred to as dry. After 2009, dry and wet conditions fluctuated again, but more extremely. Spatial distribution of drought in Northeast China was heterogeneous and complex. The western region was the most seriously affected area, with the highest drought frequency. Correlation analysis between DSI and SPEI showed that positive relationships existed. Combing this stationary index SPEI and remote-sensing index DSI may improve the accuracy of drought monitoring. The results of this study can provide a scientific basis for early drought prediction and risk management of water resources and agricultural production in Northeast China.
