Variations in High-frequency Oscillations of Tropical Cyclones over the Western North Pacific  

作　　者：Shumin CHEN Weibiao LI Zhiping WEN Mingsen ZHOU Youyu LU Yu-Kun QIAN Haoya LIU Rong FANG 

机构地区：[1]School of Atmospheric Sciences/Center for Monsoon and Environment Research/Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-Sen University [2]Guangzhou Institute of Tropical and Marine Meteorology, China Meteorological Administration [3]Bedford Institute of Oceanography, Fisheries and Oceans Canada [4]State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology,Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2018年第4期423-434,共12页大气科学进展（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41405048, 41675043, 41375050, 41205032 and 41775094);Independent Research Project Program of State Key Laboratory of Tropical Oceanography (Grant No. LTOZZ1603)

摘　　要：Variations in the high-frequency oscillations of tropical cyclones （TCs） over the western North Pacific （WNP） are studied in numerical model simulations. Power spectrum analysis of maximum wind speeds at 10 m （MWS10） from an ensemble of 15 simulated TCs shows that oscillations are significant for all TCs. The magnitudes of oscillations in MWS10 are similar in the WNP and South China Sea （SCS）; however, the mean of the averaged significant periods in the SCS （1.93 h） is shorter than that in the open water of the WNP （2.83 h）. The shorter period in the SCS is examined through an ensemble of simulations, and a case simulation as well as a sensitivity experiment in which the continent is replaced by ocean for Typhoon Hagupit （2008）. The analysis of the convergence efficiency within the boundary layer suggests that the shorter periods in the SCS are possibly due to the stronger terrain effect, which intensifies convergence through greater friction. The enhanced convergence strengthens the disturbance of the gradient and thermal wind balances, and then contributes to the shorter oscillation periods in the SCS.Variations in the high-frequency oscillations of tropical cyclones （TCs） over the western North Pacific （WNP） are studied in numerical model simulations. Power spectrum analysis of maximum wind speeds at 10 m （MWS10） from an ensemble of 15 simulated TCs shows that oscillations are significant for all TCs. The magnitudes of oscillations in MWS10 are similar in the WNP and South China Sea （SCS）; however, the mean of the averaged significant periods in the SCS （1.93 h） is shorter than that in the open water of the WNP （2.83 h）. The shorter period in the SCS is examined through an ensemble of simulations, and a case simulation as well as a sensitivity experiment in which the continent is replaced by ocean for Typhoon Hagupit （2008）. The analysis of the convergence efficiency within the boundary layer suggests that the shorter periods in the SCS are possibly due to the stronger terrain effect, which intensifies convergence through greater friction. The enhanced convergence strengthens the disturbance of the gradient and thermal wind balances, and then contributes to the shorter oscillation periods in the SCS.

关 键 词：tropical cyclone high-frequency oscillation western North Pacific South China Sea 

分 类 号：P732.3[天文地球—海洋科学]