Basic research on the gravity changes due to the effect of mass variations in the atmosphere and ocean

大气和海洋中质量变化影响引起的重力变化的基础研究

基本信息

批准号：
13440135
负责人：
SATO Tadahito
金额：
$ 9.28万
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 (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440135/
关键词：
Ocean bottom pressure gauge Satellite altimetry Satellite gravimetry Absolute gravimeter Superconducting gravimeter Sea surface height variability Variation in gravity Free core resonance 衛星高度計観測海水面変動による質量移動衛星高度計衛星重力地球重力場の変動

项目摘要

Seafloor pressure monitoring is an indispensable approach to study the effect of seawater mass changes on the Earth's gravity, which also link to the air mass motions. For example, Cox and Chao (2002) claimed the mass exchange in the Pacific Ocean as a major source of the recent rapid and large change in the J2 term of the Earth's gravity may related to the huge ENSO event terminated in the end of 1997. Our group detected the actual pressure changes at that event from the ocean bottom pressure (OBP) observations (Fujimoto et al., Geophysical Research Letters, 2003).Satellite gravimetry (CHAMP and GRACE) is expected to reveal the global relation between the ocean variability and the gravity change. Since 2001, we are carrying out OBP observations at the cross-over points of the TOPEX/Poseidon (TIP) altimeter tracks in the western Pacific Ocean (off Sanriku) in order to investigate the effect of OBP changes on the gravity. We have compared the observations at two sites of OBP-A (about 100 km from sea coast) and OBP-B (about 350 km) with the thee different kinds of data sets. These are (1) the four ocean tide models based on the T/P data, (2) the sea surface height (SSH) variations obtained from the T/P and (3) the pressure changes derived from the ECCO model (Stammer et al., 2002). Our comparison results suggest that it is still needed to carefully examine the effects of ocean mass transportations on the satellite gravimetry which aims at monthly geoid determination at an accuracy of 1 cm or better, and the OBP observation is a useful method for validation of the satellite gravimetry (submitted to GRL).The supper-conducting gravimeter at Esashi well calibrated with the absolute gravimeters have been used to check the tide models and to revise the free core resonance parameters (Sato et al., Journal Geodynamics, 2004, accepted).

海底压力监测是研究海水质量变化对地球重力的影响的必不可少的方法，这也与空气质量运动有关。例如，Cox and Chao（2002）声称太平洋中的大规模交流是地球重力的J2迅速变化的主要来源，这可能与1997年底终止的巨大ENSO事件有关。我们的小组检测到该事件的实际压力从海洋底部压力（OBP）观察（fujimoto et al and alleys and al。预计宽限期）将揭示海洋变异性与重力变化之间的全球关系。自2001年以来，我们正在西太平洋（Sanriku）的Topex/Poseidon（TIP）高度计轨道的交叉点进行OBP观测，以研究OBP变化对重力的影响。我们已经将观察结果与OBP-A（距离海岸约100公里）和OBP-B（约350公里）的两个地点进行了比较，并将其与不同种类的数据集进行了比较。这些是（1）基于T/P数据的四个海浪模型，（2）从T/P和（3）（3）从ECCO模型得出的压力变化（Stammer等，2002）。我们的比较结果表明，仍然需要仔细检查海量传输对卫星重量测定的影响，该卫星重量测定的旨在以1 cm或更高的精度确定地质测定，OBP观察是验证卫星重量的有用方法，可用于将其用于Esashi calliber callibriper callibrime。修改自由核心共振参数（Sato等人，期刊地球动力学，2004年，接受）。