Two record-breaking rainfalls in late June of 2015 led to widespread flooding in Eastern China, espe- cially over the Yangtze River Delta, and this in turn led to huge economic losses. Analysis suggests that the E1 Ni...Two record-breaking rainfalls in late June of 2015 led to widespread flooding in Eastern China, espe- cially over the Yangtze River Delta, and this in turn led to huge economic losses. Analysis suggests that the E1 Nifio- like sea surface temperature pattern during that month facilitated an intensified and southwestward-shifted west- ern Pacific subtropical high and enhanced water vapor convergence along the Meiyu front, which provided a favorable environment for the occurrence of heavy rainfall over Eastern China. Meanwhile, two midlatitude troughs were successively formed over East Asia in the second half of the month as a consequence of the downstream energy dispersions of two midlatitude blockings. These configu- rations facilitated the southward intrusion of the extrat- ropical high potential vorticity toward the Meiyu front. In this way, the ascent was enhanced along the Meiyu front over Eastern China, and the occurrence of heavy rainfalls was triggered. Moreover, a tropical intraseasonal active convection propagated northward and also contributed constructively to the heavy rainfall.展开更多
基金supported by the National Basic Research Program of China(2013CB430203)the National Natural Science Foundation of China(4123052741422501)
文摘Two record-breaking rainfalls in late June of 2015 led to widespread flooding in Eastern China, espe- cially over the Yangtze River Delta, and this in turn led to huge economic losses. Analysis suggests that the E1 Nifio- like sea surface temperature pattern during that month facilitated an intensified and southwestward-shifted west- ern Pacific subtropical high and enhanced water vapor convergence along the Meiyu front, which provided a favorable environment for the occurrence of heavy rainfall over Eastern China. Meanwhile, two midlatitude troughs were successively formed over East Asia in the second half of the month as a consequence of the downstream energy dispersions of two midlatitude blockings. These configu- rations facilitated the southward intrusion of the extrat- ropical high potential vorticity toward the Meiyu front. In this way, the ascent was enhanced along the Meiyu front over Eastern China, and the occurrence of heavy rainfalls was triggered. Moreover, a tropical intraseasonal active convection propagated northward and also contributed constructively to the heavy rainfall.
