摘要
运用我国160站月平均气温、NCEP/NCAR再分析和NOAA海温资料,结合1979-2011年我国1月地面气温年际异常变化可能机理,对比分析了2008与2011年1月气温异常变化的原因.结果表明,不同于2008年1月属典型低温年,2011年表现出相反的北大西洋涛动(或北极涛动)住相异常,但在亚洲中高纬度地区这2年的环流异常均与典型年一致,即高空乌拉尔山高压脊偏强,地面贝加尔湖南侧气压偏高,冷空气活动偏强.进一步分析发现,中高纬度乌拉尔山和贝加尔湖区域环流异常是影响我国大部地区气温异常的主要环流系统,NAO则是影响我国东北地区气温的重要因子;正是由于NAO的反位相异常使得2011年1月我国东北地区气温偏低.2008年1月欧亚中高纬环流异常受平流层扰动的影响,在前期9月就有明显的异常反映,但2011年前期平流层的环流与2008年及典型冷年前期情况相反,表明2011年我国1月气温偏低的主要原因不是来源平流层.前期7月热带西印度洋、西太平洋和中东太平洋海温异常与后期乌拉尔山和贝加尔湖环流有较好的关系,上述区域海温异常对应后期1月从北大西洋到亚洲中高纬出现与我国气温密切相关的NAO型遥相关环流异常.
Abstract
In terms of the monthly NCEP/NCAR data and the temperature data in 160 sites from the National Climate Center (NCC) ,causes of January surface air temperature anomaly of 2011 and 2008 were comparatively analyzed based on the possible mechanism of typical anomaly from 1979 t0 2011 in China. Results showed that the anomalous January circulations of 2011 were different from those of 2008 with reversed phase anomalies of Northern Atlantic Oscillation (NAO). However,circulation anomalies over mid-high Asia in recent two years were the same as those in typical years: high-pressure ridge was relatively strong over Ural area; south Baikal Lake had relatively high pressure; and the cold air was stronger than normal. Further analysis showed that the circu18tion anomalies over Ural and Baikal were responsible for the an omalous surface air temperature in most part of China , while the NAO anomaly circulation mainly led to the anomalies in North East China,which was why the anomalous lower temperature occurred in North East China in 2011. The circulation anomalies in the stratosphere occurred earlier in September 2007 than those in the troposphere , but those occurred in 2011 were reversed. It was suggested that the cause for the low tem perature in 2011 January might be not from the stratosphere. And the anomalous sea surface temperature( SSTA) in leading July in Westem Indian O cean(WI) , Westem (WP)and Eastem Pacific(EP) of the tropic had close relationship with later January circulation over Ural and Baikal. Positive SSTA occurred in leading July of both 2008 and 2011,resulting in the similar January circulation over Ural and Baikal and associated cold events,while opposite SSTA occurred in tropical Pacific might he responsible for the reversed phase of NAO in the troposphere.
国家科技期刊平台
NSTL
维普
万方数据