北半球夏季亚洲—北太平洋间大气质量迁移规律及其与气候异常的联系
投稿时间: 2016-04-19  最后修改时间: 2016-05-11  点此下载全文
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尹旸艳 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044  
管兆勇 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044 guanzy@nuist.edu.cn 
张茜 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044  
周游 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044  
基金项目:国家自然科学基金资助项目(41175062);公益性行业(气象)科研专项(GYHY201406024)
中文摘要:通过构建海陆间大气质量迁移(MAMLO,Migration of Atmospheric Mass over regions between Lands and Oceans)指数,对北半球夏季亚洲—北太平洋上空大气质量的迁移规律及其与气候异常的联系进行了研究。结果表明:在北半球中高纬亚洲大陆和中低纬北太平洋上空异常大气质量呈现反相变化。夏季MAMLO指数总体呈缓慢下降的趋势,同时还具有准3 a振荡周期以及显著的年代际变化特征。亚洲大陆中高纬地表气压变化与北太平洋低纬气压变化的反相关关系主要归因于:异常大气质量环流;海陆异常加热对比;Rossby波能传播。MAMLO与欧亚、太平洋地区夏季气候异常关系密切,尤其在中国地区。MAMLO为正(负)时,中国大体呈现出北方降水偏多(偏少)南方降水偏少(偏多)、北方偏冷(偏暖)南方偏暖(偏冷)的空间分布。
中文关键词:夏季  大气质量迁移  气候异常  亚洲  北太平洋  中国
 
Summertime migration of atmospheric mass over regions between Asia and North Pacific and its associations with climate anomalies
Abstract:Using the NCEP/NCAR monthly mean reanalysis data for the period of 1979—2014,CMAP(CPC Merged Analysis of Precipitation) precipitation data,in situ observational data at 160 stations in China,SST(Sea Surface Temperature) data provided by British Hadley Centre as well as CRU high-resolution surface temperature data by the University of East Anglia,this paper has investigated the migration of atmospheric mass over regions between Asia and North Pacific in boreal summer and its associations with climate anomalies by employing some statistical methods.
An index based on surface air pressure anomaly is defined to describe the Migration of Atmospheric Mass over regions between Lands and Oceans(MAMLO) on interannual time-scale.It is found that an anti-phase variation of anomalous atmospheric mass exists between mid-high latitudes in Asia and mid-low latitudes in North Pacific.This anti-phase relation can also be referred to Asia-North Pacific teleconnection pattern(ANPT).The summer MAMLO index varies with a dominant period of three years,a slowly decreasing trend,and distinct interdecadal variations in the study period.The ANPT is formed due to three factors.Firstly,the atmospheric mass fluxes anomalously diverge in lower and converge in upper troposphere in Siberia,and in North Pacific the opposite situations are observed,forming the anomalous vertical circulation characterized by anomalous downward motion in Asia and upward motion in Pacific,which links surface pressure variations along with horizontal circulation changes between Asia and Pacific.Secondly,MAMLO is mainly dominated by the contrast of anomalous heating between lands and oceans.Water vapor content is higher over the subtropical Pacific than that over eastern Asia,facilitating the atmosphere to absorb surface long wave radiation and solar short wave radiation over oceans more than over Asia continent.The striking contrast of the anomalous atmospheric diabatic heating between Asia and North Pacific is in favor of driving atmospheric mass to exchange between them.Thirdly,the energy dispersion of quasi-stationary Rossby wave also plays an important role in the anomalous loss and accumulation of atmospheric mass.
MAMLO is closely related to the summer climate anomalies in Eurasia and Pacific.When the MAMLO index is positive,the precipitation decreases significantly in Siberia,the southern area of Europe and the east coast of China,as opposed to the increase over northern China,the Hawaiian Islands and the south of Gulf of Alaska.At the same time,the temperature increases obviously over the West Siberian Plain and the central and eastern Pacific,along with the anomalous decrease in much of Eurasia,northern China and Northwest Pacific.Further researches by use of observational data over Chinese 160 stations conclusively indicate that correlations of MAMLO with variations of anomalous precipitation and temperature are particularly significant in China.When the MAMLO index is positive(negative),precipitation increases(decreases) and surface temperature decreases(increases) prominently over northern China.Instead,there is a decrease(an increase) in precipitation and an increase(a decrease) in surface temperature over southern China.
All the results above are helpful for us to better understand the mechanisms behind circulation changes and the causes of climate anomalies in Eurasia and Pacific during boreal summer and to provide useful clues to prediction of the summer climate anomalies.
keywords:summer  migration of atmospheric mass  climate anomaly  Asia  North Pacific  China
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