| 全球大气位势高度场气候变率的球函数分析 |
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| 引用本文： | 闫巨盛,王盘兴,段明铿,李巧萍,叶玲萍.全球大气位势高度场气候变率的球函数分析[J].应用气象学报,2006,17(2):145-151. |
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| 作者姓名： | 闫巨盛 王盘兴 段明铿 李巧萍 叶玲萍 |
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| 作者单位： | 1.南京信息工程大学大气科学系, 南京 210044 |
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| 基金项目： | 国家高技术研究发展计划(863计划) |
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| 摘 要： | 为了研究全球大气位势高度场的气候变率, 利用NCEP/NCAR再分析资料, 按照距平高度场平均强度指数 (Ia) 分析发现, 半球距平高度场强度呈年单周振荡, 冬大夏小, 冬季随高度单调增大, 夏季有弱高、低值中心出现, 而北、南半球的差异明显表现在季节变化上; 进一步根据半球大气位势高度距平场球函数谱低维、低阶的基本特征, 将半球环流异常分为半球均匀异常 ( H ′00)、纬向均匀异常 ( H ′0)、超长波尺度异常 ( H ′ul) 和长波尺度异常 ( H ′l) 4种类型, 用波数域0≤m, k≤6上的球函数系数资料求得它们的方差贡献, 给出了4类异常的方差贡献随高度、季节变化的规律以及它们的半球际差异。由此得到异常环流球函数谱结构的总体特征为:对流、平流层之间存在明显变化。从对流层进入平流层, 一般由超长波异常为主转为纬向均匀异常为主 (冬半球) 或半球均匀为主 (夏半球); 半球均匀异常在对流层中不重要, 长波尺度异常在平流层中不重要, 它们拟合异常方差一般均小于10%; 北、南半球最大差异表现在冬季平流层R′00和冬、夏季对流层R′0南半球大于北半球, 冬、夏季对流层R′l北半球大于南半球。
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| 关 键 词： | 全球大气 位势高度场 气候变率 球函数分析 |
| 收稿时间： | 2005-03-23 |
| 修稿时间： | 2005-11-17 |
Analysis on Spherical Function Structures of Climatic Variability for Global Atmospheric Geopotential Height Fields |
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| Yan Jusheng,Wang Panxing,Duan Mingkeng,Li Qiaoping,Ye Lingping.Analysis on Spherical Function Structures of Climatic Variability for Global Atmospheric Geopotential Height Fields[J].Quarterly Journal of Applied Meteorology,2006,17(2):145-151. |
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| Authors: | Yan Jusheng Wang Panxing Duan Mingkeng Li Qiaoping Ye Lingping |
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| Institution: | 1.Department of Atmospheric Sciences, Nanjing University of Information Science & Technology, Nanjing 2100442.National Climate Center, Beijing 1000813.Jiaojiang District Meteorological Observatory, Taizhou 318000 |
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| Abstract: | The anomaly of height fields is set up based on the temporal decomposition of these fields, and even continuations from hemisphere to globe at certain level in certain month are made. During the study, two kinds of monthly averaged geopotential fields dataset is used, namely 2.5° by 2.5° resolution even rectangular grid data and spherical function coefficient data derived from 1958—1997 NCEP/NCAR reanalyzed geopotential height fields dataset. Firstly based on the previously defined intensity index of climate anomaly fields (Ia), it demonstrates the intensity variations of hemispheric anomaly fields at the different height and seasons, and the differences between Northern and Southern Hemisphere are also investigated. Then according to the low-dimension and low-order characteristics of the spherical function spectrum in the hemispherical geopotential height anomaly fields, hemispherical circulation anomaly is divided into four types:hemispherical homogeneous anomaly, zonal homogeneous anomaly, ultra-long and long wave scale anomaly. The corresponding variance contributions (R′00, R′0, R′ul, R′l) are also calculated respectively by using spherical function coefficient data with the wavenumber of m≥0, k≤6. Finally the variations and their hemispheric differences of the four anomalies above as the function of height and seasons are discussed in detail.The main results are as follows:① Ia shows a yearly periodic oscillation and is stronger in winter than in summer. The index always increases with the height, especially in winter. However in summer Ia has a weak high (low) value center near the tropopause (the upper stratosphere) respectively. The difference between the two hemispheres is that the seasonal variation of Ia in the Southern is weaker than the Northern at the troposphere. ② For the spectral structure of the anomaly circulations, there are some obvious changes from the troposphere to the stratosphere. In the troposphere the ultra-long wave circulation is predominant. Hemispherical homogeneous anomaly (Long wave scale anomaly) is not important in the troposphere (stratosphere) respectively. ③ The characteristics of the variance contributions of the Northern Hemisphere can be concluded that in January, R′00 at all the levels are very little (less than 10%); R′l is only significant in the troposphere; R′0 and R′ul predominate at all the levels, whereas R′ul(R′0) is more important in the troposphere (stratosphere), and in July, R′00 dominates in the medium and upper stratosphere; R′0 takes second place; R′ul and R′l are predominant in the troposphere with equivalent magnitude. ④ For the Southern Hemisphere, in July, R′00(R′l) in the troposphere (stratosphere) is very little; just as the January's situation in the Northern Hemisphere, R′0 and R′ul are dominant through the atmosphere; R′ul is a little larger. In January, the characteristics in the stratosphere are similar to July's situation in Northern Hemisphere. The difference is that R′ul and R′0 dominate through the troposphere with the comparable im portance. |
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| Keywords: | global atmosphere geopotential height fields climatic variability spherical function analysis |
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