THE STUDY OF STORM RAINFALL CAUSED BY INTERACTION BETWEEN THE NON-ZONAL HIGH LEVEL JET STREAK AND THE FAR DISTANT TYPHOON
DING Zhi-ying
ZHANG Xin-qiang
HE Jin-hai
XU Hai-ming
Abstract：In this paper, correlation statistics and analysis between the storm rainfall far from typhoon and non-zonal high level jet streak(NHJ) were carried out. The results show that: The high level jet streak(HJ) in 200 hPa is constantly SW(90.2 percent) during the period of which storm rainfall occurs. Rainfall area lies in the right behind regions of HJ axes. While storm is being intensive, the HJ has a trend that non-zonal feature become stronger. In terms of MM4 model, numerical simulation and diagnosis were carried out for 9711 typhoon on 19th to 20th August, 1997. The far distant rainfall storm is tightly correlative to the NHJ and low level typhoon trough. The divergence field of HJ is related to v component. The upper level can caused the allobaric wind convergence at low level. This is the result of the form of low level typhoon trough and the strength of the storm. By scale analysis , there exists one branch of middle scale transverse inverse circulation in the right entrance regions behind the HJ below the 300 hPa level, which is very important to the keeping and strengthening of rainfall storm. This branch of inverse circulation is relative to the reinforcement of HJ's non-zonal characteristics. From the field of middle scale divergence field and non-zonal wind field we can find that: The stronger symmetry caused by transverse circulation in the two sides of HJ, rainfall's feedback and reinforcement of HJ's non-zonal characteristics leaded to positive feedback mechanism that was favorable of storm rainfall's strengthening.
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Publication Date：2001-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 144-154 )