热带月平均风场谱结构的傅立叶分析Ⅰ——气候风场分析  

THE FOURIER ANALYSIS OF SPECTRUM STRUCTURE OF THE TROPICAL MONTHLY MEAN WIND FIELD Ⅰ——Climatic Wind Field Analysis

作　　者：吴幸毓[1,2] 王盘兴[2] 周国华[2] 华文漪[2] 李丽平[2] 

机构地区：[1]福建省气象台,福建福州350001 [2]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《热带气象学报》2012年第1期50-60,共11页Journal of Tropical Meteorology

基　　金：公益性行业(气象)科研专项课题(GYHY201006038;GYHY201006017);国家自然科学基金重点项目(40633018)共同资助

摘　　要：用风场傅立叶分析方案,分析了NCEP/NCAR再分析资料的热带(30°S^30°N)850、200 hPa气候风场V8 50、V2 00的谱结构,讨论热带风场定常波的成因,以弥补热带气候风场此类分析工作的空白。研究结果表明,(1)有低维、低阶特征,|m|=0,4-、0,3-波对月8 50、2 00的累积模方拟合率年均达90%、98%。(2)纬向平均分量0最重要,它对8 50、2 00的单波拟合率ρ0年均达52%、85%。850 hPa0主要由北、南半球的两支信风带构成,冬半球强、夏半球弱,轴线位置与所在半球Hadley环流中心对应;200 hPa0由强的外热带西风带和弱的内热带东风带构成。0的季节变化850 hPa层明显强于200 hPa,北半球明显强于南半球。(3)风场定常波的最大波分量全年两层均为|1|*,它对850*、200*的拟合率ρ|*1|年均达39%、55%;ρ|1|*作年双周振荡,北半球夏、冬季达极大,秋、春季达极小。次大波分量在北半球冬、夏季时同为3、2波,过渡季节也以3、2波为主(10—12月850*4波是例外)。(4)1、7月射出长波辐射定常波OLR*最大、次大波与同期V*相同,1月为1、3波,7月为1、2波;OLR*重要波分量上的极值区与*相应波分量散度场的垂直配置符合动力学原理。(5)7月青藏高原及以东以南的广阔区域,*的主要分量|1|*、|2|*同为下层辐合、上层辐散,1OLR*、2OLR*同为负值,是同纬度上最有利于降水和潜热释放的气候区。The spectral smacture of the climatic wind fields at the levels of 850 hPa（ ^-V850 ） and 200 hPa （ ^-V200 ） are investigated for a tropical region from 30 °S to 30 °N by the Fourier analysis scheme and the National Centers for Environmental Prediction/National Center fro Atmospheric Reseach （USA） reanalysis data, and the cause is discussed for the stationary wave of the tropical wind field to fill the gap of research in this regard. The basic conclusions are as follows： （1） I7 is of low-dimensional and low-order features, with the annual average of the cumulative module square fitting rate up to 90% and 98% for I m t= 0,4 and 0,3 waves for the monthly ^-V850 and ^-V200 respectively. （2） The zonal mean component ^-V0 is the most important, and its annual average of the single-wave fitting rate ^-ρ0 is up to 52% and 85% for ^-V850 and ^-V200 respectively. The 850 hPa ^-V0 mainly consists of two branches of trade wind belts from the Northern and Southern Hemisphere and is strong in the winter hemisphere and weak in the summer hemisphere, and its axis position corresponds to the centers of hemispheric Hadley circulation. The 200 hPa fro is composed of a strong westerly wind belt outside the tropics and weak easterlies within the tropics. The seasonal variations are stronger at 850 hPa than at 200 hPa, and much stronger in the Northern Hemisphere than in the Southern Hemisphere. （3） The maximal components of the stationary wave of the wind field are both ^-V[1] for 850 hPa and 200 hPa levels throughout the year, the annual average fitting rate ^-ρ[1], of annual biweekly oscillation, is up to 39% and 55% for 850 hPa and 200 hPa respectively, and its amplitude reaches maximum in the summer and winter and minimum in the autumn and spring of the Northern Hemisphere. The second wave components are 3- and 2-wave in the winter and summer of the Northern Hemisphere and the same for the transitional seasons, with the exception of 4 waves for ^-V850 in October to December. （4） The maximal and s

关 键 词：气候学 波谱基本特征 傅立叶分析 热带气候风场 射出长波辐射场 青藏高原 

分 类 号：P434[天文地球—大气科学及气象学]