海潮负荷计算中几个问题的讨论  

DISCUSSION OF SOME PROBLEMS IN TIDAL LOADING COMPUTATION

作　　者：孙和平[1] 胡延昌[1] 

机构地区：[1]国家地震局地震研究所

出　　处：《地壳形变与地震》1989年第1期64-77,共14页Crustal Deformation and Earthquake

摘　　要：本文较系统地研究了目前重力和倾斜潮汐负荷计算中存在和需要解决的几个技术问题。文章给出了Sch。全球海图广州等10个测站的潮汐负荷数值,结果说明不同地球模型引起的重力负荷差为10％,沿海地区为15％,倾斜负荷差为15％,沿海地区为30％。是否考虑海水质量守恒可引起的重力负荷差小于10％,倾斜负荷差小于3％。文章对目前国际上通用的五种全球海图的重力和倾斜负荷计算结果进行了分析比较,同时还对褶积和球谐级数逼近两种计算方法作了讨论,并指出当ψ>15°时,两种方法引起的重力负荷差小于5％。最后文章将负荷潮结果同实际观测重力固体潮残差矢量进行了对比分析,结果说明经近海海潮图修正后的Schwiderski全球海图计算得到的负荷潮能较好地解释观测残差。Tidal loading computation is widely plaied close attention to by geophsists and seismologists as the responce of tidal load depends very much on the locally variable properties of the crust and upmantle and it can be used for inverse study of geophyical parameters variation during earthquake event. In this paper, some technique problems existed and need to be solved in gravity and tilt loading are systematically studied. First of all the discrepancy caused by different earth model, G-B, G-D1066A, 1066B and PREM is evaluated. The results show that the difference between different Green's function is obviously whan ψ<0.1°, it proves that the shallow structure of the earth only affect near area results of the tidal loading, the difference indeed shows that it is sensitivety to crust and upmantle structure. Gravity loading discrepancy is about 10% and 15% in the coast area, tilt loading discrepancy is adout 15% and 30% in the coast area. On the other hand, the discrepancy caused by different cotidal maps are also analysised, the discrepancy of the gravity loading is larger than that of the tilt loading because of the different open sea accuracy. We also discuss the problem of the conservation of the mass by use of Schwiderski's global cotidal maps, the effect of it on tilt loading is adout 3% and is 10% on the gravity loading (for M_2 wave ), it arrives the same magnitude with the different earth models. So it is also not negligible. The properties of the integral technique of the spatialc onvolution and the spherical hrarmonic expansion methods are futher discussed. At the end of the paper. the comperison of the gravity observation residues with loading tide are briefly given out, the result show that the Schwiderski cotidal maps modified by China local sea maps can be mainly used to explain the observation residues.

关 键 词：海潮 负荷 计算 潮汐 

分 类 号：P731.23[天文地球—海洋科学]