洱海近区非潮汐重力变化的研究

STUDY ON NON-TIDAL GRAVITY CHARGE NEAR ERHAI LAKE

本文给出了洱海水体变化对局部重力场影响的解析式和量级,并且将理论结果与实测的水文、流动重力及定点重力分析结果作了比较,结果表明:影响的程度因距洱海的距离而异。在台站重力测量中,由水体变化产生的干扰淹没在零漂之中(约占每日零漂量的2％),潮汐主频段上没有明显的干扰信号;而对流动重力测量,在水体变化大的情况下,部分测点所产生的变化可以达到10×10^(-8)m/s^2。

In the paper,the analytic expression and the magnitude that the change of water level in Erhai lake has influence on local gravitational field are given, and the influence is compared with analytical results of hydrology, relative gravimetry and gravity tidal observation. The comparision shows that the influence varies as the inverse of distance from Erhai lake. In gravity tidal observation, the preturbation is not clear on main frequence band, and the influence is drowned in the drift and amounts to 2% of daily drift. In relative gravimetry, the magnitude of parturbation in some station can reach 10×10^(-8)m/s^2, when the change of water level is large.