宋成玉,汪靖,柳艳菊,李巧萍,丁一汇,沈新勇. 2022. 北大西洋多年代际振荡(AMO)对南海夏季风撤退年代际变率的影响及可能机理[J]. 气象学报, (0):-, doi:[doi]
北大西洋多年代际振荡(AMO)对南海夏季风撤退年代际变率的影响及可能机理
Impacts of AMO on the interdecadal variability of South China Sea summer monsoon withdrawal and associated mechanisms
投稿时间:2021-12-18  修订日期:2022-05-04
DOI:
中文关键词:  南海夏季风撤退,年代际变率,北大西洋多年代际振荡(AMO),机理
英文关键词:South China Sea summer monsoon withdrawal, Interdecadal variability, North Atlantic Multidecadal Oscillation (AMO), Mechanism
基金项目:广东省基础与应用基础研究重大项目(2020B0301030004)、第二次青藏高原综合科学考察研究项目(2019QZKK0102,2019QZKK0208)、中国科学院战略性先导科技专项(XDA20100304)
作者单位邮编
宋成玉 南京信息工程大学 210044
汪靖 天津市气象科学研究所 300074
柳艳菊 国家气候中心 100081
李巧萍 国家气候中心 100081
丁一汇 国家气候中心 100081
沈新勇 南京信息工程大学 210044
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中文摘要:
      基于美国国家海洋和大气管理局(NOAA)物理科学实验室(PSL)和科罗拉多大学环境科学研究所(CIRES)重建的NOAA-CIRES 20th再分析数据和国际综合海洋大气数据集(ICOADS)的全球月海表温度数据(ERSST),并结合数值试验,分析了南海夏季风撤退的年代际变率特征及北大西洋多年代际振荡(AMO)对其产生的影响。结果表明,南海夏季风撤退时间具有明显的年代际变率,南海夏季风撤退偏晚(早)年代,南海及其附近区域上空有显著的气旋性(反气旋性)环流异常,降水偏多(少)。进一步研究发现,AMO与南海夏季风撤退年代际变率呈显著正相关,即AMO为正位相时,南海夏季风撤退偏晚;AMO为负位相时,南海夏季风撤退偏早。北大西洋海温变暖(即AMO位于正位相),从海洋释放了更多的热通量到大气,导致了北大西洋上空对流层的对流活动明显增强,通过海气相互作用激发北大西洋上空的波活动异常,进而影响着与东北亚关键区域大气环流变化密切相关的中纬度欧亚遥相关波列的形成和传播,引起东北亚关键区域的正位势高度异常和明显的下沉运动,并在其对流层低层产生辐散运动,能量伴随着偏北的辐散风气流传播至南海及临近区域辐合上升,进一步加强了南海区域的气旋性环流异常,使得南海夏季风撤退偏晚。AMO负位相时,异常情况与之大致相反,使得南海夏季风撤退偏早。
英文摘要:
      The present study investigates the interdecadal variability characteristics of South China Sea summer monsoon withdrawal (SCSSMW) and impact of the North Atlantic Multidecadal Oscillation (AMO) on it based on the NOAA-CIRES 20th Reanalysis data reconstructed by the Physical Sciences Laboratory (PSL) of the National Oceanic and Atmospheric Administration (NOAA) and the Cooperative Institute for Research in Environmental Sciences (CIRES), the Extended Reconstructed Sea Surface Temperature (ERSST) dataset from the International Comprehensive Ocean Atmosphere Data Set (ICOADS), and combined with numerical experiments. The results show that the timing of SCSSMW has obvious interdecadal variability. During the late (early) years of SCSSMW, there are significant cyclonic (anticyclonic) circulation anomalies and more (less) convective precipitation over the South China Sea and its nearby areas. Further studies show that there is a significant positive correlation between AMO with the interdecadal variability of SCSSMW. In other words, when AMO is in the positive phase, SCSSMW is later. When AMO is in the negative phase, SCSSMW is earlier. The warming SST over the North Atlantic (i.e., AMO in the positive phase) releases more heat flux from the ocean to the atmosphere, leading to significant increase of convective activity in the troposphere over the North Atlantic, which can then stimulate the abnormal wave activity over the North Atlantic through sea-air interaction and enhanced convective activity. And this further affects the formation and propagation of mid-latitude Eurasian teleconnection wave train that is closely related to the variation of atmospheric circulation over the key area of Northeast Asia, causing the positive geopotential height anomaly and obvious descending motions in the whole troposphere over the key area of Northeast Asia, and producing a divergent motion in its lower troposphere. The energy is transfered to the South China Sea and its adjacent areas with the divergent wind flow and produced convergence upward motion. The cyclonic circulation anomaly over the South China Sea is further enhanced, making the SCSSMW later. Roughly opposite mechanism works during the negative phase of AMO, making the SCSSMW earlier.
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