Recent Reversal of the Upper-Tropospheric Temperature Trend and its Role in Intensifying the East Asian Summer Monsoon
At the beginning of the 21st century, the July and August (JA) mean upper-tropospheric temperature over East Asia shows a significant increasing trend, contrary to the decreasing trend in the late 1970s.The largest warming center is over northern China (between 30°N-45°N and 85°E-120°E) around 300 hPa.Together with the temperature rising, the geo-potential height rises above the warming center and drops below, which connects closely to a correspondingly significant decadal shift of the general circulation over East Asia.In the upper-level of the atmosphere, an anomalous anti-cyclone dominates, and the 200-hPa westerly jet strengthens due to the increasing pole-ward geo-potential height gradient.In the lower-troposphere, the anomalous southerly wind increases around Yangtze River Valley and the East Asian summer monsoon intensifies.The integrated circulation changes seriously impact summer precipitation over East Asia.The so-called ”southern flood and northern drought” (SFND) pattern since the 1970s over eastern China has changed.As the cooling center in the 1970s moves southward, the dry belt moves southward as well.A wet belt dominates the Huaihe River Valley alter the temperature trend reversal at 2005 while southern China experiences a dry condition.
upper-troposphere warming inter-decadal changes East Asian summer monsoon
Siyao Zhao Jian Li Rucong Yu Haoming Chen
State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, No.46 Zhong-Guan-Cun South Street, Beijing, 100081, China
国内会议
天津
英文
1-23
2015-10-01（万方平台首次上网日期，不代表论文的发表时间）