基于本征微观态方法探究全球地表气压变化特征及其与降水的联系

利用ERA5和GPCP再分析资料及NOAA提供的气候指数,基于本征微观态和传统气象学方法,探讨了全球1950—2022年地表气压变化特征及其与全球降水和环流变化之间的关系。结果表明:全球地表气压的第一大本征微观态主要以南极一致性变化为主,与南极涛动显著相关;第二大本征微观态以北极一致性变化为主,与北极涛动和北大西洋涛动显著相关;第三大本征微观态在热带太平洋呈现纬向偶极子结构,与厄尔尼诺—南方涛动(EI Niño-Southern Oscillation,ENSO)联系紧密。不同本征微观态对全球降水的影响存在显著的区域性差异。第一大本征微观态处于正位相时,南极绕极环流增强,南半球高纬度地区降水增多,中纬度地区降水减少。第二大本征微观态处于正位相时对应北极降水增多,北大西洋及其周边地区降水减少。第三大本征微观态影响范围较广,主要表现为西太平洋降水减少和中东太平洋降水增多。

Exploring the characteristics of global surface pressure variations and their relationship with precipitation based on the eigen microstate method

By using ERA5,GPCP reanalysis dataset, and climate indices provided by the NOAA, this study discusses the characteristics of global surface pressure changes from 1950 to 2022 and its relationship with global precipitation and circulation changes based on the eigen microstates and traditional meteorological methods. Results show that the first leadingeigen microstate of global surface pressure is dominated by coherent changes in the Antarctic, significantly related to the Antarctic oscillation. The second mode mainly features consistent changes in the Arctic, which is significantly related to the Arctic Oscillation (AO) and North Atlantic Oscillation(NAO). The third mode exhibits an east-west dipole structure in the tropical Pacific, closely related to the El Niño-Southern Oscillation (ENSO). Each mode is primarily characterized by annual variations, and there are significant regional differences in their impacts on global precipitation. When the first mode is in a positive phase, the Antarctic polar vortex strengthens, causing an increase in precipitation in high-latitude regions and a decrease in mid-latitude regions of the Southern Hemisphere. The second mode is closely related to precipitation in the mid-to-high latitudes of the Northern Hemisphere, with its positive phase corresponding to increased Arctic precipitation and decreased precipitation in the North Atlantic and its surrounding areas. The third mode could affect global precipitation, mainly manifested as decreased precipitation in the western Pacific and increased precipitation in the East Central Pacific.