南京夏季高温日数异常的分析

利用南京气象观测站1951—2007年逐日最高气温观测资料,美国NCEP/NCAR再分析资料中1951年1月—2006年12月的平均高度场、风场资料,运用小波分析、二项式滑动平均、合成分析等方法,分析了南京57a来高温日数的月、季、年际、年代际变化的时间变化特征和异常年份同期7、8月的大气环流特征。发现:(1)南京57a来年平均出现高温的日数为14.7d,高温日主要出集中在7、8月份;(2)南京高温日数具有明显的年际变化,其年际变化最高可达29d(1965年为8天,1966年有37d),57a来南京高温日数异常偏多年有8a、偏少年有7a;(3)南京高温日数1950s到1960s相对偏多,1970s到1990s初处在一个相对偏少的时期,1990s至今,都处在高温日数偏多的阶段;(4)南京高温日数异常偏多时,南亚高压异常偏东、偏北,副高异常偏西、偏北,出现了纬向上"相向而行"的趋势。

Analysis of high temperature days anomaly in Nanjing

The data of daily maximum temperature observed by Nanjing station during the period of 1951-2007 and the NCEP/NCAR reanalysis data of mean geopotential height and wind fields are analyzed using Morlet wavelet, binomial moving average method and composite analysis.The characteristics of lunar, seasonal interannual and decadal temporal change of maximum temperature days and atmospheric circulation in Jul. and Aug. of the corresponding period in Nanjing have been investigated. The results are as follows: (1) the high temperature frequency is 14.7 d in the recent 57 a in Nanjing; high temperature mainly occurs in Jul. and Aug.; (2) there are distinct interannual change with a maximal change of 29 d(8 d in 1965, 37 d in 1966); there are 8 a on the high side and 7 a on the low side in the recent 57 a in Nanjing;(3)the high temperature days from 1950s to 1960s and from 1990s until now is on the high side, while from 1950s to 1960s on the low side; (4) during the increasing stage of the high temperature days, south Asia high was found to be eastward and northward and subtropical high westward and northward.