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《热带气象学报(英文版)》 2009-02
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DIAGNOSIS OF WAVE ACTIVITY OVER RAINBAND OF LANDFALL TYPHOON

RAN Ling-kun1,Abdul REHIM2,AL RAMANATHAN3 (1. Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029 China; 2. Bangladesh Meteorological Department,Dhaka,Bangladesh; 3. School of Environmental Science,Jawaharlal Nehru University,New Delhi,India)  
A generalized wave-activity density,which is defined as an absolute value of production of three-dimensional vorticity vector perturbation and gradient of general potential temperature perturbation,is introduced and its wave-activity law is derived in Cartesian coordinates. Constructed in an agoestrophic and nonhydrostatic dynamical framework,the generalized wave-activity law may be applicable to diagnose mesoscale weather systems leading to heavy rainfall. The generalized wave-activity density and wave-activity flux divergence were calculated with the objective analysis data to investigate the character of wave activity over heavy-rainfall regions.The primary dynamical processes responsible for disturbance associated with heavy rainfall were also analyzed. It was shown that the generalized wave-activity density was closely correlated to the observed 6-h accumulative rainfall. This indicated that the wave activity or disturbance was evident over the frontal and landfall-typhoon heavy-rainfall regions in middle and lower troposphere. For the landfall-typhoon rainband,the portion of generalized wave-activity flux divergence,denoting the interaction between the basic-state cyclonic circulation of landfall typhoon and mesoscale waves,was the primary dynamic process responsible for the evolution of generalized wave-activity density.
【Fund】: National Basic Research Program of China (2009CB421505);; National Natural Sciences Foundations of China (40875032)
【CateGory Index】: P444
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