A theoretical method to characterize the resistance effects of nonflat terrain on wind fields in a parametric wind field model for tropical cyclones  

作　　者：Gengjiao Ye Pingzhi Fang Hui Yu 

机构地区：[1]Shanghai Typhoon Institute of China Meteorological Administration,Shanghai,China [2]Key Laboratory of Numerical Modeling for Tropical Cyclone/CMA,Shanghai,China [3]School of Geography Sciences,East China Normal University,Shanghai,China [4]Asia-Pacific Typhoon Collaborative Research Center,Shanghai,China

出　　处：《Tropical Cyclone Research and Review》2024年第3期161-174,共14页热带气旋研究与评论（英文版）

基　　金：supported by the Key Program of National Natural Science Foundation of China (Grant No.U2142206);the Shanghai Science and Technology Commission Project (Grant No.23DZ204701);the Natural Science Foundation of Shanghai (Grant No.19ZR1469200).

摘　　要：Traditionally,an empirical speed-up factor was introduced to reflect the effects of nonflat terrain on near-surface wind speeds.In this paper,the resistance effects of nonflat terrain are considered by introducing the terrain drag coefficient in the parametric wind field model for tropical cyclones(TCs)with a theoretical method.Terrain effects on wind fields are investigated in complex areas along the coastal zone in China under TC conditions.The results show that the terrain drag coefficient is the function of the slope angle and is sensitive to the spatial resolution.After including the resistance effect of nonflat terrain,the TC intensities weaken overall during landfall,with a slight enhancement near the coastal zone.The wind speeds outside the radius of the maximum wind speed decrease,while the wind speeds within the radius of the maximum wind speed increase.Both the TC eye and the radius of maximum wind speed shrink,which is more obvious when the TC center is entirely over land.As a result,the location and magnitude of the maximum wind speed are affected by the nonflat terrain.The changed structure of the wind fields demonstrates the necessity of considering the effects of nonflat terrain in simulating the wind fields under TC conditions.

关 键 词：Parametric wind field model Tropical cyclones Nonflat terrain Slope angle Terrain drag coefficient Pressure coefficient 

分 类 号：P444[天文地球—大气科学及气象学]