A study of Global Wind Structure Exciting the Chandler Wobble

激发钱德勒摆动的全球风结构研究

• 批准号: 12640427
• 负责人: NAITO Isao
• 金额: $ 1.15万
• 依托单位: National Astronomical Observatory
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640427/
• 关键词: Earth Rotational Variation; Polar Motion; Chandler Wobble; Excitation Source; Wind; Atmospheric Relative Angular Momentum; チャンドラーウオブル; 角運動量収支; データ同化; 数値予報; 地球回転; 風ベクトル

The Chandler wobble (hereafter CW), a free oscillation of the Earth's pole with the longest period among the Earth's free oscillations. However, its excitation source has never been identified since its discovery more than a hundred years ago. Lately, the author and collaborators have found its excitation source to be wind from its evaluations based upon global atmospheric analysis data from numerical weather prediction system of the Japan Meteorological Agency. Since there are two kinds of data setin the analysis data (initialized and un-initialized data), they also pointed out a possibility that the evaluations depend upon the analysis data used for. In this study, the author reevaluated atmospheric excitation of CW based on the two kinds of the ECMWF reanalysis data for the period of 1980-1994, and reconfirmed wind to be the CW source. The wind excitation reconfirmed here totally opposes the oceanic excitation proposed lately. Interesting is a fact that CW is excited by the wind variation with a remarkable peak at near the CW frequency in its power spectrum. Also, the differences in the used two analysis data have almost no effect on the evaluations for the CW excitation, though they strongly affect the excitatlbn for the annual wobble.

钱德勒摆动（以下简称CW），是地球自由振荡中周期最长的一种地球极点的自由振荡。然而，自一百多年前发现以来，它的激发源一直没有被确定。最近，作者和合作者利用日本气象厅数值天气预报系统的全球大气分析数据对其进行了评估，发现其激发源为风。由于分析数据中有两种数据集（初始化和未初始化数据），他们还指出了评估依赖于用于的分析数据的可能性。本文利用ECMWF 1980 ~ 1994年的两种再分析资料，重新评价了连续波的大气激发，再次确认了风是连续波源。这里再次确认的风激励与最近提出的海洋激励完全相反。有趣的是，连续波被风的变化所激发，在其功率谱的连续波频率附近有一个显著的峰值。此外，两种分析数据的差异对连续波激励的评估几乎没有影响，尽管它们强烈影响年摆动的激励。

项目成果

Aoyama, Y., I.Naito: "Wind contribution to the Earths angular momentum budgets in seasonal variation"J. Geophys. Res.. 105. 12417-12431 (2000)

Aoyama, Y., I.Naito：“风对季节变化中地球角动量收支的贡献”J.

内藤勲夫: "地球自転軸の自由振動の謎"パリティー. 16. 13-19 (2001)

内藤功：“地球自转轴自由振动之谜”宇称16。13-19（2001）。

Aoyama, Y and Naito,: "Atmospheric excitation of the Ohandler wobble, 1983-1998"J. Geophys. Res. 106. 8941-8954 (2001)

Aoyama, Y 和 Naito，：“Ohandler 摆动的大气激励，1983-1998”J。

内藤勲夫: "地球自転軸の自由振動の謎"パリテイー. 16・2. 13-19 (2001)

内藤功：“地球自转轴的自由振动之谜”16・2（2001）。

Zong et al.: "Atmospheric hydrologicm, and Ocean current contributions to Earth's annual wobble and LOD signals based on out put from"J. Geophys. Res.. (in press). (2002)

Zong 等人：“大气水文和洋流对地球年度摆动和 LOD 信号的贡献基于”J.