Jet Stream Analysis of A Heavy Rain in Western Liaoning

The conventional observation data and NCEP global reanalysis data were used to analyze a heavy rainfall on 4~5th August 2010 in the coastal areas of western Liaoning.We found that the extra-low level of souther jet stream provided the main water vapor for the heavy rainfall.Low level of souther jet stream caused the convective instability of the lower atmosphere,and provided the conditions for the strong convection.The high level of west-wind jet stream caused the symmetric instability of the upper atmosphere,prompting the convection to the high altitude.Secondary circumfluence excited by jet stream coupling at both high and low levels kept strong upward motion for the maintenance of the heavy rain.