赤道西太平洋海面增暖对早春北极平流层极涡的调控  

Stratospheric Arctic Polar Vortex Modulated by the Sea Surface Temperature Warming in the Western Equatorial Pacific in Early Spring

作　　者：姚彬彬 施春华[1] 郭栋[1] 饶建 YAO Binbin;SHI Chunhua;GUO Dong;RAO Jian(Key Laboratory of Meteorological Disaster,Ministry of Education(KLME)/School of Atmospheric Sciences,Nanjing University of Information Science&Technology,Nanjing 210044)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/大气科学学院,南京210044

出　　处：《大气科学》2023年第4期1217-1230,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家重点研发计划项目2022YFF0801703;国家自然科学基金项目41875048。

摘　　要：平流层极涡异常对冬春季极端天气和极地臭氧亏损有重要指示意义。在1979~2020年ERA5再分析资料中,早春北极平流层极涡年际变率与热带太平洋海温第二模态(主要空间型为赤道西太平洋海温异常)有关。通过CAM5数值模拟,进一步揭示了赤道西太平洋海温异常影响平流层极涡的途径:冬春季赤道西太平洋增暖时,在暖海温区深对流降水加强,异常的潜热加热通过Matsuno-Gill响应在其西北侧激发了Rossby波(对流层上层的高压异常)。该Rossby波沿大圆路径在北太平洋调整了北半球最强的槽脊系统的强度和位置,从而使得经向风1波分量的振幅减小,经向风3波和温度3波分量的位相差增大。两者分别减弱了下平流层的1波和3波的波作用通量上传,更少的涡动热量通量向极输送促进了春季北极平流层极涡增强。Stratospheric Arctic vortex(SAV)anomalies can provide indications for severe weather and Arctic ozone losses in winter and spring.In early spring,the SAV is connected to the second mode of the interannual sea surface temperature(SST)in the Tropical Pacific from 1979 to 2020 and the spatial pattern of SST anomalies in the western equatorial Pacific from the ERA5 reanalysis data.The specific progress of the western equatorial Pacific SST anomalies affecting the SAV is revealed using CAM5 numerical simulations.In winter and spring,the SST warming in the western equatorial Pacific can intensify local deep convective precipitation.The anomalous latent heating induces a Rossby wave(high-pressure anomalies in the upper troposphere)to its northwest side via the Matsuno–Gill atmospheric response.The Rossby wave modifies the strength and position of the strongest trough-ridge system of the Northern Hemisphere in the North Pacific along the great circle path,decreasing the amplitude of the meridional winds’wave 1 and an increase in the phase difference of wave 3 between the meridional wind and temperature,resulting in less wave activity fluxes of waves 1 and 3 propagating to the stratosphere.Finally,in the spring,decreased poleward transmission of eddy heat flux enhances the SAV.

关 键 词：平流层 极涡 赤道西太平洋 海面温度 ROSSBY波 

分 类 号：P434[天文地球—大气科学及气象学]