摘要
利用欧洲中心全球客观分析的7层月平均位势高度距平资料,分别计算了相同格点上12—2月和6—8月各层高度距平之间的同时相关分布。结果表明:全球月平均位势高度距平场的正压、斜压性随地理区域变化很大,并有较明显的季节变化。其中12—2月对流层下部大气环流距平场在海洋上空有较好的相当正压性,在大陆上空正压性较差;对流层上部大气环流异常的正、斜压性分布与下部不同,赤道附近地区是相关系数的高值区,副热带地区主要是低值区;在对流层下部与上部大气环流距平场的相关系数分布图上,海洋上空并不总是高值区,在热带东太平洋区域就出现最强的负相关中心。与6—8月的相关系数分布型比较发现:特别明显的季节变化在非洲大陆和热带印度洋区域,12—2月为强正压区,6—8月为强斜压区。
Based on the ECMWF global objective analysis of 7-level mean geopotential height anomaly, a study is made of the simultaneous correlations of the corresponding points of these level with the sea surface level as the base for December, January and February (DJF) and June, July and August (JJA), respectively. Results show that the barotropy and baroclinity change greatly geographically, as shown in the height departures, with remarkable seasonality: the DJF lower troposphere anomaly is marked by higher (poor) equivalent barotropy over the oceans (continent); the upper troposhere circulation anomaly is illustrated by a high-value region of correlation coefficient around the equator and a low area dominating subtropics; the correlation pattern between the circulation departure fields of the low and upper troposphere indicates that a high region is not always over the waters and a strongest negative correlation center arises in the tropical eastern Pacific. Its comparison to the JJA pattern reveals that a particular significant seasonality occurs in Africa and the tropical Indian Ocean with a DJF vigorous barotropic sector and a JJA baroclinic one, respectively.
出处
《南京气象学院学报》
CSCD
1993年第3期308-313,共6页
Journal of Nanjing Institute of Meteorology
关键词
高度距平场
斜压性
季节变化
global height anomaly field, barotropy and baroelinity, correlation coefficient, seasonal variation
