中纬度大气超长波与欧亚关键区阻塞高压关系的研究

Study on the Relationship between Atmospheric Ultra-Long Waves and Blocking Highs in Key Eurasian Areas

摘要: 本文通过使用美国国家环境预报中心能源部(National Centers for Environmental Predic-tion-Department of Energy，简称：NCEP-DOE)提供的1979~2014年的再分析资料，利用谐波分析法将北半球中纬度大气按波数分类，再借助国际上通用的T & M方法检索欧亚关键区阻高，系统研究中纬度大气1~3波(超长波)的时空变化特征及其与欧亚关键区阻高的关系，主要结论如下：北半球中纬度地区(30˚N~60˚N) 1~8波波谱比重在0.93~0.96变化，其中1~3波波谱比重超过0.5，表明超长波是大气运动中最主要的组成部分，且30˚N和60˚N两条纬圈上超长波的波谱比重有准2年的周期变化，冬季振荡更为显著；当1~3波波谱比重偏强时，乌山地区位势高度(geopotential height，简称：GPH)明显偏低，贝湖地区的偏高，鄂海地区GPH变化不明显，反之，鄂海地区GPH偏强，其他两个区域GPH变化不显著，尤其60˚N上1~3波波谱比重异常时，欧亚地区GPH异常表现更为突出；1波(3波)振幅与乌山阻高指数呈正(负)相关关系，与鄂海的呈负(正)相关，2波振幅的激增可能会导致乌山阻高持续时间增长。

Abstract: By using the reanalysis data from the National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) from 1979 to 2014, this paper classifies the atmospheric fluctuations in the mid-latitudes of the Northern Hemisphere by wave number, and then retrieves the blocking highs in key Eurasian areas by using the internationally accepted T & M method. The spatial and temporal variations of atmospheric 1 - 3 waves (ultra-long waves) at middle latitudes and their relationship with blocking highs in key Eurasian regions are systematically studied. The main conclusions are as follows: The proportion of the 1 - 8 wave spectrums in the mid-latitudes of the Northern Hemisphere varies from 0.93 to 0.96, and the proportion of 1 - 3 wave spectrums exceeds 0.5, which demonstrate that the ultra-long wave is the most important component of atmospheric motions. There is a quasi-two-year periodic variation of proportions of the 1 - 8 wave and 1 - 3 wave spectrums at 30˚N or 60˚N, and the oscillation in winter is more significant. When the proportion of 1 - 3 wave spectrums is strong, the geopotential height (GPH) in Urals area is low, and the GPH in the Baikal area is high, but the changes of GPH in the Okhotsk areas are not significant. Conversely, as the proportion of 1 - 3 wave spectrums is weak, the GPH in Okhotsk areas is high, yet the changes of GPH in other two regions are not obvious. In addition, when the proportion of 1 - 3 wave spectrums is abnormal at 60˚N, the anomalies of GPH are more significant. The amplitude of 1 (3) wave is positively (negatively) related to the blocking indexes of Urals regions, and negatively (positively) related to blocking indexes in Okhotsk areas. The sharp increase of the amplitude of 2 waves may lead to a longer duration of blocking highs in Urals areas.