气象2023，Vol.49Issue(12)：1468-1480,13.DOI:10.7519/j.issn.1000-0526.2023.101201
2021年南海夏季风爆发偏迟原因分析
Possible Causes for Late Onset of the South China Sea Summer Monsoon in 2021
摘要
Abstract
The South China Sea summer monsoon usually breaks out earlier in the La Nina year,but a late onset(6th pentad of May)appeared in 2021,though 2020/2021 was the year of La Nina.Using NCEP/NCAR reanalysis data,the reasons for the late onset of the South China Sea summer monsoon in 2021 are analyzed from the perspective of tropical sea surface temperature anomaly(SSTA)and intraseasonal oscil-lation(ISO)northward propagation.The results show that La Nina did weaken the Western Pacific sub-tropical high in spring,especially before April.However,the tropical Indian Ocean sea surface tempera-ture in the winter and spring continued to be warmer,offsetting the impact of La Nina,especially in May.The influence of La Nina was less than that of the tropical Indian Ocean,resulting in the stronger Western Pacific subtropical high in May and the late onset of the South China Sea summer monsoon.In addition,due to the influence of La Nina,the Western Pacific subtropical high in April was weak and the back-ground barotropic southerly in the South China Sea was weak,which unfavored the equatorial ISO in the South China Sea propagating northward.As the influence of tropical Indian Ocean SSTA became more and more significant,the Western Pacific subtropical high has gradually strengthened,and the background barotropic southerly did not extend to the area south of 10°N until late May,casusing a late northward propagation of the equatorial ISO in the South China Sea in 2021,which is the opposite of the climatic state.This is also an important reason for the late onset of the South China Sea summer monsoon in 2021.The tropical Indian Ocean and Pacific SSTAs together have an impact on the onset of the South China Sea summer monsoon through competition,so it is very important to pay attention to the development of the two in winter and spring.关键词
南海/夏季风/爆发/海表温度Key words
South China Sea/summer monsoon/onset/sea surface temperature分类
大气科学引用本文复制引用
郑彬,谷德军,林爱兰,陈静,屈静玄,朱泳..2021年南海夏季风爆发偏迟原因分析[J].气象,2023,49(12):1468-1480,13.基金项目
山东省自然科学基金项目(ZR2021MD010、ZR2022MD088)、山东省气象局精准预报技术创新团队(SDCXTD2021-1)、中国气象局预报员专项(CMAYBY2018-041)、中国气象局复盘总结专项(FPZJ2023-072)、山东省气象局重点课题(2022sdqxz11)、环渤海区域科技协同基金项目(QYXM202105)共同资助 （ZR2021MD010、ZR2022MD088）
