对2015年海洋和大气环流异常特征进行分析,讨论这些异常特征对中国气候的主要影响。结果表明:2015年东亚冬季风强度较常年略偏弱,冬季风季内变化特征显著,初冬强度偏强,隆冬和后冬转为偏弱。受其影响,冬季我国大部分地区气温较常年同期偏高,但季内变化显著,初冬冷、隆冬和后冬暖。2015年,赤道太平洋出现了一次超强厄尔尼诺事件,2014年5月至2015年11月厄尔尼诺综合区累计海温指数已达23.0℃,成为历史上最强厄尔尼诺事件。加之,4月以来印度洋一致偏暖模态及偶极模态正位相发展,使得夏季太平洋副热带高压偏强、偏西、偏南,导致我国南方多雨而北方少雨。2015年南海夏季风爆发时间与常年一致,结束偏晚2候,强度偏弱。
Anomalies of oceanic and atmospheric circulations are analyzed and their impacts on temperature and precipitation anomalies of 2015 in China are investigated in this paper.It is found that the East Asian Winter Monsoon (EAWM)was weaker than normal during the 2015 winter with an obvious phase transi-tion from the strong to the weak at the end of December 2014.A warmer winter was experienced in most areas of China due to the effect of weaker EAWM.In association with the phase transition of EAWM,a reverse of temperature anomalies over China occurred simultaneously with negative temperature anomalies in December 2014 and positive temperature anomalies in January and February 2015.A super strong El Ni?no event occurred over the tropical Pacific Ocean,with the accumulative Ni?no Z index from May to No-vember 2015 reaching to 23.0℃,was the strongest event on record.In addition,the remarkable Indian O-cean basin-wide warming mode and the dipole mode with positive phases persisted since April of 2015.As a response of atmospheric circulation to the anomalous tropical oceanic condition,the western Pacific sub-tropical high intensified and extended further southward and westward,leading to less precipitation over North China and more precipitation over South China during summer.In 2015,onset of South China Sea summer monsoon was near normal and the ending time was 2 pentads later than normal with the intensity being weaker than normal.