In this study,the anomalies of summer precipitation in China,and the atmospheric circulation over East Asia,were compared during the spring(SP) and summer(SU) El Niño developing and decaying years,in order to improve the understanding of the relationship between the El Niño events and climate anomalies in China,and to provide references for climate predictions.The percentages of the precipitation anomalies in China;horizontal wind anomalies at 850 hPa;geopotential height anomalies at 500 hPa;velocity potential anomalies;and divergent wind anomalies at 850 hPa and 200 hPa,respectively,were also analyzed.This study utilized the monthly precipitation data of 160 stations in China for the period ranging from 1950 to 2016,which were provided by the National Climate Center of China Meteorological Administration.The monthly geopotential height,wind,and specific humidity data were provided by the American National Centers for Environmental Prediction.The Niño 3.4 index data were provided by the American Climate Prediction Center.
The results obtained in the study were as follows:
1) During the SP El Niño developing years,the majority of China experienced below-normal precipitation levels,and displayed a "higher northern-lower southern" rain trend during the decaying years.During the SU El Niño developing years,the precipitation anomalies were observed to be "sandwich" formations,in which the regions receiving more rain were larger during the decaying years;
2) It was determined that at 850 hPa during the SP El Niño developing years,the summer monsoons were strong,and had maintained strong levels up to the decaying years.However,during the SU El Niño developing years,the East Asian summer monsoon were observed to be weak,before turning stronger in the decaying years;
3) It was found in this study that at 500 hPa during the SP El Niño developing years,the influences of the East Asian summer monsoons on China's climate were weaker,and the warm and moist water from the low latitude regions was insufficient to become transported to the mainland China.However,during the decaying years,the warm and moist water from the low latitude regions was affected by the stronger summer monsoons,and was easily transported to the hinterland of China.During the SU El Niño developing years,having been affected by the relatively active cold air movements,it was observed that the Inner Mongolia and northern China regions had experienced above-normal rain levels.However,during the decaying years,having been affected by the strong summer monsoons,the cold and warm air had intersected north of the Yellow River;
4) This study's comparison results of the lower and upper levels of the troposphere revealed the following:During the SU El Niño developing years,there were sinking anomalies observed over China,with the exceptions of Inner Mongolia and Northeast China;During the decaying years,there were rising anomalies observed over China.During the SU El Niño developing years,there were significant subsidence anomalies observed over China,and during the decaying years,there were weaker subsidence anomalies evident.However,having been affected by stronger summer monsoons,the regions which had experienced below-normal precipitation became larger.