高频大气角动量变化对天极偏差的激发研究  

Excitation Effects on Celestial Pole Offsets by High-Frequency Atmospheric Angular Momentum Variations

作　　者：李宁 崔小明 杨伟伟 闫昊明 孙和平 LI Ning;CUI Xiaoming;YANG Weiwei;YAN Haoming;SUN Heping(State Key Laboratory of Geodesy and Earth’s Dynamics,Innovation Academy for Precision Measurement Science and Technology,CAS,Wuhan 430077,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Hubei Luojia Laboratory,Wuhan 430079,China)

机构地区：[1]中国科学院精密测量科学与技术创新研究院大地测量与地球动力学国家重点实验室,武汉市430077 [2]中国科学院大学地球与行星科学学院,北京市100049 [3]湖北珞珈实验室,武汉市430079

出　　处：《大地测量与地球动力学》2024年第11期1167-1172,共6页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(42394114,42174108);湖北珞珈实验室专项基金(220100033)。

摘　　要：天极偏差是观测天球中间极与岁差-章动模型之间的差异,主要包含自由核章动和受迫章动两部分。本文利用欧洲中期天气预报中心发布的第五代大气再分析资料计算的1h采样的大气角动量函数,与国际地球自转服务中心提供的3h和6h采样的大气角动量函数进行对比研究,分析不同采样率的高频大气角动量变化对天极偏差的激发影响。结果表明,不同采样率的大气角动量变化对受迫章动和自由核章动的激发总体趋势一致,但在部分谐波频段及细节上存在明显差异;基于1h采样的大气角动量函数能够更加有效地分离与受迫章动项对应的周日频段谐波分量,在自由核章动激发中也体现出一定的优势,表明更高采样率的大气数据在高频地球自转变化研究中具有重要作用。Celestialpole offset is the difference between observed celestial intermediate pole and precession-nutation model,mainly including free core nutation and forced nutation.Using ERA5 atmospheric reanalysis data,we calculate the atmospheric angular momentum function sampled at 1 hour and compare it with the atmospheric angular momentum functions sampled at 3 hours and 6 hours provided by IERS.We analyze the excitation effects on celestial pole offsets by high-frequency atmospheric angular momentum variations under different sampling rates.The results show that excitation effects on forced nutation and free core nutation by atmospheric angular momentum variations with different sampling rates have the same overall trend,but there are obvious differences in some harmonic frequency bands and other details.The atmospheric angular momentum function sampled at 1 hour can more effectively separate the harmonic components corresponding to diurnal frequency band in forced nutation term,and shows a certain advantage in the excitation of free core nutation,indicating the necessity of higher sampling rate atmospheric data in the study of high-frequency Earth rotation changes.

关 键 词：大气角动量 自由核章动 受迫章动 天极偏差 

分 类 号：P228[天文地球—大地测量学与测量工程] P126[天文地球—测绘科学与技术]