Long-term trend and variability of China´s arid climate and drought area based on the standardized precipitation index

Drought is one of the major agricultural and meteorological disasters in China that occurs at high frequency, affects wide areas, and causes considerable agricultural loss. Research on the long-term spatiotemporal variability of arid climate and drought area in the context of global climate change is important and practically significant to the intention to cope with drought. Standardized precipitation index (SPI) was calculated using long-term monthly data of surface precipitation with 0.5^o × 0.5^o resolution at 12-month timescales. The capacity of the SPI index to describe arid climate was verified using three drought cases that occurred in Southern China in the early 2000s. The spatiotemporal variability of China´s arid climate and drought area from the perspective of meteorological drought was analyzed. All categories of drought (i.e., mild, moderate, severe, and extreme) exhibited slight downward trend in terms of drought area, but variation was observed from region to region. Over the past 50 years, Southwest and Northeast China experienced more arid, while Southeast and Northwest China experienced the opposite.