1979年以来南极平流层冬季变暖  

ANTARCTIC STRATOSPHERIC WINTER WARMING SINCE 1979

作　　者：胡永云[1] 朱金奎[1] 刘骥平[2] 

机构地区：[1]北京大学物理学院大气科学系,北京100871 [2]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029

出　　处：《气象学报》2007年第5期773-784,共12页Acta Meteorologica Sinica

基　　金：教育部科学技术研究重点项目(106002);国家自然科学基金面上项目(40575031);国家自然科学基金重点项目(40533016);国家重点基础研究发展计划项目(2006CB403605和2007CB411801)

摘　　要：极地气候比其他区域有着更为显著的变化,这不仅反映在极地近地面和对流层,也同样反映在平流层。使用NCEP/NCAR、NCEP/DOE和ERA40月平均再分析资料,研究了南极平流层温度和位势高度的年代际变化趋势。结果表明,自1979年以来在冬季南极平流层存在变暖的趋势。分析NCEP/NCAR和NCEP/DOE再分析资料的结果是变暖主要出现在7—10月,最大增温位于30hPa,27a(1979—2005年)的最大增温幅度超过7℃。分析ERA40的结果是变暖主要出现在6—9月,较NCEP/NCAR和NCEP/DOE早1个月,最大增温位于平流层上层(5和3hPa),23a(1979—2001年)的最大增温幅度超过10℃。在平流层高层,最大增温位于极区中心;在平流层中低层,最大增温位于极区外围偏向澳大利亚一侧。伴随着温度的升高,南极平流层的位势高度也存在升高的趋势。在NCEP/NCAR和NCEP/DOE再分析资料中,最大位势高度升高位于10hPa,27a里的升高幅度超过450m。ERA40给出的结果相对弱一些,23a里的最大升高幅度接近300m。进一步的计算结果表明,进入南半球平流层的波动通量也有增加的趋势,可能是平流层波动增强导致了向南极的残余环流增强,与之相关的极圈内下沉运动也随之增强,下沉运动产生绝热加热,从而造成南极平流层增温和位势高度升高。Polar climate has much larger changes than other areas over the globe, which is reflected not only near the surface but also in the stratosphere. Using the NCEP/NCAR, NCEP/DOE and ERA40 reanalysis, the decadal trends in temperatures and geopotential heights in the Southern Hemisphere winter stratosphere were studied, and found that the Antarctic stratosphere has displayed statistically significant warming trends since the late 1970s. The warming mainly occurred in July - October with the maximum warming of about 7 ℃ at 30 hPa over the past 27 years （1979- 2005） in the NCEP/NCAR and NCEP/DOE reanalysis, and in June- September, one month earlier than that in the NCEP/NCAR and NCEP/DOE data, with the maximum warming of more than 10 ℃ in the upper stratosphere （5 and 3 hPa） over the past 23-year （1979 - 2001） in the ERA40 data. The significant warming was centered over the polar cap in the upper stratosphere, however, it lay in the Australian side of the polar region in the middle and lower stratosphere. Geopotential heights in the Antarctic stratosphere also exhibited positive trends in response to temperature increasing. The maximum increase in geopotential heights was 450 meters at 10 hPa over the 27-year in the NCEP/NCAR and NCEP/DOE, but the increase was relatively smaller, about 300 meters over the 23 years in the ERA40. Further analysis shows that wave fluxes from the troposphere into the stratosphere also increased. It is the increasing in wave fluxes that leads to a stronger poleward residual meridional circulation in the stratosphere, thus a stronger subsidence in the polar region, which causes enhanced adiabatic heating in the polar region.

关 键 词：南极平流层增温 温室气体增加 臭氧损耗 行星波动 E-P通量 

分 类 号：P467[天文地球—大气科学及气象学]