The characteristics of cloud image, radar image and precipitation during the heavy rains caused by the northeast cold vortex are analyzed using some cases including June 8, 2009. Based on the NCEP FNLs analysis data, the three dimensional structure characteristics, the possible establishing process and releasing mechanism of convective instability are studied further. The results show that the northeast cold vortex has dynamic and thermal asymmetric characteristics except for the middle layer of atmosphere. In the upper level troposphere the cold vortex evolves to a trough accompanied by a warm center and an upper-level jet stream, but in the low level troposphere itturns to an inverted though and a warm tongue while the cold center is not obvious.The main negative vorticity, divergence and upward motion distribute in the south by east of the cold vortex. The dry and cold advection in the middle atmosphere superimposes on the low-level warm and moist advection in the southeast part of the rotating cold vortex,causing rapid growth of the convective instability which can be enhancedby the warming of surface air due to the net radiation in afternoon. While the cold vortex produces convective instability, the upward motion in its southeast part provides favorable triggering conditions leading to the convection development and the releasing of instable energy.
WANG Zongmin
,
LI Jiangbo
,
WANG Fuxia
,
LIN Chaoxu
. Asymmetric Characteristics of the Northeast Cold Vortex and Its Effect on Heavy Rain[J]. Plateau Meteorology, 2015
, 34(6)
: 1721
-1731
.
DOI: 10.7522/j.issn.1000-0534.2014.00084
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