摘要
利用1961—2010年NCEP/NCAR的月平均和逐日再分析资料、中国区域589个站月降水量和气温月平均资料,研究夏季亚洲—太平洋涛动(APO)异常与我国西北地区东部秋季干湿变化的关系。结果表明:夏季亚洲—太平洋涛动指数(APOI)的异常变化与我国西北地区东部干湿指数(DROI)呈显著正相关。夏季APOI正异常年对应的秋季中高纬度地区500 hPa高度场乌拉尔山以西高压脊加强、巴尔喀什湖至贝加尔湖之间的低压槽加深、鄂霍次克海东部高压脊加强;东亚西风急流轴偏北;经阿拉伯海、印度半岛—孟加拉湾的西风水汽以及北太平洋反气旋底部的偏东水汽输送均为加强趋势,并结合中纬度西风水汽输送使研究区秋季偏湿,反之亦然。进一步研究表明,夏季APO为正异常时,秋季西北地区东部上升运动加强、暖湿气流加强(均在第54—56候最为明显)。
The eastern of Northwest China is recognized universally as a sensitive area of climate change and ecologically fragile region.Being adjacent to the Tibetan Plateau,effects of the Plateau terrain on atmospheric heating leads to thermal difference between the atmosphere above the Tibet Plateau and this area.The Asian — Pacific oscillation（APO） is defined as a zonal seesaw of the tropospheric temperature in the mid latitudes of the Asian —Pacific region.When the troposphere is cooling in mid-latitudes of the Asian continent,it is warming in mid-latitudes of the central and eastern North Pacific,and vice versa.In essence,the Tibetan Plateau thermal effects arouse likeness APO large scale teleconnection pattern.Used as an index of the thermal contrast between Asia and the North Pacific,it provides a new way to explore the Asian atmospheric circulations and climate change.Based the NCEP/NCAR reanalysis data,the monthly precipitation and temperature from 589 stations of China during 1961 — 2010,the relationship between the summer APO and the following autumn drought in China is examined statistically.Results show there are a significantly positive correlation between the APO index and the following autumn in the eastern part of Northwest China.A positive phase of summer APO,characterized by two high ridges strengthened located near the Ural Mountains and east of the Okhotsk Sea,respectively,and a trough deepened between the Balkhash and the Baykal.A positive phase of summer APO associated with east Asian subtropical westerly jet stream turns to be weakened and northward.These changes provide favoring conditions for enhanced wet in the eastern part of Northwest China.The situation is reversed in the negative phase of summer APO,leading to drought in this region.The east wind strengthening at the bottom of the northeastern Pacific anticyclone and the moisture transport that roots in the Arabian Sea and the Bay of Bengal strengthening has very important contribution to the variability of the atmospheric water va
出处
《应用气象学报》
CSCD
北大核心
2016年第4期454-462,共9页
Journal of Applied Meteorological Science
基金
国家重点基础研究发展计划(2013CB430206,2012CB955304)
公益性行业(气象)科研专项(GYHY201506001-04)
公益性行业(气象)科研专项(GYHY201306027-01)
中国博士后特别资助基金(2013T60901)
关键词
夏季亚洲—太平洋涛动
西北地区东部
干湿指数
summer Asian-Pacific oscillation
the eastern part of Northwest China
drought index
