Title: RELATIONSHIPS BETWEEN SUMMER NORTHERN POLAR VORTEX WITH SUB-TROPICAL HIGH AND THEIR INFLUENCE ON PRECIPITATION IN NORTH CHINA
Abstract: The northern polar vortex and subtropical high (SH) are two important members of the atmospheric circulation which affect the weather and climate changes in China. They interact with each other closely and have great influence on summer precipitation in North China. Using the NCEP reanalysis data, 74 factors of the atmospheric circulation and monthly precipitation data from 160 stations in China provided by National Climate Center (NCC), the relationships among the northern polar vortex and the atmospheric circulation and SH during summer have been discussed and the joint effect of the polar vortex and SH on the precipitation in North China have been analyzed by means of composite analysis, correlative analysis and the SVD. The results show that the activity of the northern polar vortex is not only subject to geopotential heights in high latitudes, but also closely related to the circulation in middle and low latitudes. When the area and intensity of the polar vortex are anomalously large, the geopotential heights in the middle and low latitudes are much lower, so that the area and intensity of SH are the smaller, and the northern boundary of SH is more southward, especially for the change of the intensity. There is distinctively negative correlation between most indexes of polar vortex and factors of SH in Northern Hemisphere and transitional zones, while the polar vortex indexes are positively related to the northern boundary and ridge line indexes of SH in West Pacific and South China Sea. Most indexes of the polar vortex, north boundary and ridge line of SH are positively related to summer precipitation in North China, while the area and intensity indexes of SH are negatively correlated with it. In particular, the precipitation in North China increases obviously when the polar vortex anomaly in Asia and Europe enlarges, SH in North Africa, Atlantic, and North America shrink and weaken, and SH in West Pacific and South China Sea jumps northward.
Publication Year: 2008
Publication Date: 2008-01-01
Language: en
Type: article
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Cited By Count: 6
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