摘要
Abstract
This study investigates the interannual variability of landfalling tropical cyclones(TCs)in Guangdong during the post-flood season(1968-2022),using TC frequency data,reanalysis products,and sea surface temperature(SST)data.Through wavelet and composite analysis,we specifically explore the prominent bimodal characteristics in their interannual variability and their asymmetric relationship with SST.The main findings are as follows:(1)The frequency of landfalling TCs in Guangdong exhibits significant quasi-3-year and quasi-8-year bimodal periodic oscillations,with comparable amplitudes.(2)Under different modes,significant variations exist in atmospheric circulation configurations that influence TC landfalls.During years with more landfalling TCs for both quasi-3-year and quasi-8-year timescales,the Western Pacific Subtropical High(WPSH)shifts westward and strengthens,facilitating TC landfalls in Guangdong.Conversely,the WPSH configurations during less landfalling TC years are distinct for each mode.On the quasi-biennial timescale,the WPSH is weaker and retreats eastward,causing TCs to recurve northward prematurely;however,on the quasi-3-year timescale,the WPSH remains westward and strong,with significant anomalous easterlies on its southern flank that guide TCs westward.(3)The relationship between the landfalling TC frequency in Guangdong and SST is asymmetric.On the quasi-3-year timescale,years with more landfalling TCs are associated with significant positive winter SST anomalies in the equatorial eastern Pacific and from the tropical North Indian Ocean to the South China Sea(SCS).On the quasi-8-year timescale,more TC landfall years correspond to significant positive winter SST anomalies mainly in the equatorial central Pacific,while less TC landfall years generally exhibit positive winter SST anomalies across the entire tropical Indian Ocean.In addition,landfalling TC frequency tends to be higher in transition years from winter El Niño to summer La Niña conditions.This study enhances our understanding of the variability characteristics of landfalling TCs in Guangdong,and the identified asymmetric relationship with SST provides valuable guidance for improving short-term climate predictions of landfalling TC frequency in this region.关键词
热带气旋/副热带高压/年际双模态特征/非对称关系Key words
tropical cyclone(TC)/subtropical high/interannual bimodal characteristics/asymmetric rela-tionship分类
天文与地球科学
