基于标准化降水蒸散指数（SPEI）的毛乌素沙地1981

Atmospheric drought is an important factor affecting vegetation construction， ecological restoration and social-economically sustainable development in the semi-arid sand areas. To understand the spatiotemporal characteristics of drought events in the Mu Us Sandy Land during the past 40 years， this paper estimated the standardized precipitation evapotvanspiration index （SPEI） at monthly， seasonal and annual scales， based on the monthly meteorological data from 1981 to 2020. The results showed that： （1） The average annual precipitation （351.61 mm） and the temperature （8.49 ℃） in nearly 40a both showed a significant upward trend （Pvery severe drought； and the drought frequency had an order of winter>summer， autumn>spring. The light drought mainly occurred in the north， central， southeast and southwest regions； the middle drought occurred mainly in the eastern， northern and western edges regions； the severe drought mainly occurred in the eastern， central and southern regions； while the very severe drought events mainly occurred in the northwest， south and southeast regions of Mu Us Sandy Land. These results will contribute to the water resources planning， ecological restoration， disaster prevention and mitigation in the Mu Us Sandy Land.

Keywords： Mu Us Sandy Land ; standardized precipitation evapotranspiration index ; spatiotemporal characteristics ; drought frequency