Geophysical research: article

Аnnotation: The influence of ambient temperature changes on the CG-5 Autograv gravimeter data was analyzed to determine the influence of meteorological factors on long-term gravimetric measurements. The CG-5 Autograv gravimeter provides continuous measurement of the body temperature, which is an objective assessment of the ambient temperature. Experimental results of long-term observations at the gravimetric point confirm the need to take into account the change in the drift velocity of the zero point of the gravimeter caused by the change in the ambient temperature that occurs despite the operation of the thermostat. It was found that the change in zero-point drift velocity is somewhat lagged in relation to the change in the temperature of gravimeter body. The magnitude of the inertial lag is essentially the duration of the temperature relaxation of the device, which develops depending on specific temperature dynamics. The inertial nature of the measuring system reaction of thermostated gravimeter to the change in the body temperature was described by the mathematical model of temperature relaxation. As such a model, it is proposed to consider the temperature that most accurately correlates with the drift velocity (“effective” temperature), represented as a set of first-order aperiodic links. In order to determine the parameters of the aperiodic links, reference gravimetric measurements were performed with simultaneous measurement of the gravimeter body temperature under various conditions of changing ambient temperature. The values of the parameters of aperiodic links were determined by the maximum correlation between the drift velocity of the gravimeter zero-point and the “ef-fective” temperature. After determining the coefficient of dependence of gravimeter drift velocity nonlinear component on the “effective” temperature, it became possible to build a model for compensating the gravimeter drift nonlinear component. As a result, the model of the nonlinear drift component compensation by the value of the “effective” temperature, together with the temperature relaxation model, can be presented as an algorithm for taking into account the influence of the ambient temperature on the nonlinear component of the gravimeter drift velocity.