地球主慣性矩的精密確定及三軸分層地球自轉動力學研究

鐘敏++羅少聰++申文斌+++陳巍++玄松柏

摘 要：該研究目標是利用重力場模型精確確定地球主慣性矩及其時變性，基于高精度地球主慣性矩建立三軸分層地球自轉理論，更精確地描述地球自轉狀態，研究地球自轉規律，特別是三軸分層地球自轉及其對物質遷移的響應，揭示地球自轉、物質遷移與全球變化、地球動力學事件和重大自然災害的關聯，為精化地球參考系、航天器高精度定位定向以及相關學科研究提供支持，揭示地球系統物質遷移動力學機理。根據任務計劃安排及研究進展的實際情況，該年度取得的主要研究進展有：基于GRACE重力衛星觀測數據，利用短弧長法成功解算出全球時變重力場模型（IGG-CAS系列模型），優于RL04 模型，但比RL05略差；進一步完善了確定地球主慣性矩的理論模型，并利用重力場模型及時變重力場模型精確確定了地球主慣性矩及其時變性；建立了一組聯合大氣、海洋和陸地水模型（數據），顯著改進了大氣、海洋和陸地水對極移的激發作用；在地球極移激發中考慮了地球的頻率依賴響應，計算結果表明，考慮了頻率依賴響應和滯彈性之后可以更好地解釋地球的極移激發。

關鍵詞：地球主慣性矩 地球自轉 三軸分層地球

Abstract：Study on precise determination of the earths principal moments of inertia and tri-axial layered Earth rotation dynamic is the fifth topic of 973 project of “the Study on high resolution and accuracy of static and time-variable Earth gravity field and its dynamics”. The research aim of this topic is to use gravity field models to determine the Earths principal moments of inertia and its changes， establish a tri-axial layered Earth rotation theory based on precisely determined Earths principal moments of inertia， more precisely describe the Earth rotation status， study Earth rotation laws and rules， especially the response of tri-axial layered Earth rotation due to mass migration， reveal the relation among the Earth rotation， mass migration and global change， geodynamics events and significant natural disasters， in order to provide basic information for Earth reference system refinement， space craft positioning and orientation with high accuracy， and other science research branches， reveal the dynamic mechanism of the Earths system mass migration. According to the project plan arrangement and research development in practice， the main achievements obtained in this year are stated as follows： Using short-arc approach， the first version of the temporal gravity field model series IGG-CAS was successfully established in this year based upon GRACE data， and the IGG-CAS model is better than the RL04， but worse than RL05； we further refined a theoretical model for determining the Earths principal moments of inertia， and determined the Earths principal moments of inertia and their temporal variations； combining the current atmospheric， oceanic and land-water models， we established a joint model which could significantly improve the excitation response of the polar motion； further， we considered the frequency dependence response in the excitation of polar motion， and it demonstrates that the results with considering the frequency dependence response and elasticity of the Earth can better explain the excitation of the polar motion. Supported by the project （No. 2013CB733305）， 10 relevant papers were published or accepted， including 8 SCI papers.

Key Words：The earths principal moments of inertia；Earth rotation；Tri-axial layered earth

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