Atmospheric circulation of regional spring drought and its controls in Liaoning province

Based on NCEP/NCAR reanalysis data and HadiSST data as well as daily precipitation data in Liaoning province, the characteristics of atmospheric circulation of regional spring drought and its controlling factors were analyzed. The results indicate that Wulaer mountain ridge and East Asia trough are weakened, the phase leans to east, and the meridionality of atmospheric circulation in middle and upper latitude decreases, the above-mentioned are the atmospheric circulation background leading to the regional spring precipitation decrease in Liaoning province. Air pressure in the continent increases during spring drought, while that on the sea decreases. The humidity over Liaoning province is lower than the multi-year average. The northwest air current is prevailing from Lake Baikal to Liaoning province. There is a positive anomaly in 200 hPa height field over Liaoning province in winter before regional spring drought. Surface air temperature is higher than the historical value in the same time, and SST of Nino3 is abnormally low.