Temporal variations in the Earth’s gravity field with emphasis on atmospheric effects
نویسندگان
چکیده
The determination of the Earth’s gravity field is the main goal of the dedicated gravity field missions CHAMP, GRACE and GOCE. The gravity field comprises always a static part and a much smaller timevariable one in the order of millimeters to centimeters, if expressed in geoid heights. As the measurements always consist of both parts, one has to separate them to get a highly accurate static field with high resolution. In this paper, we give a short description of the mathematical model of the time variations in the Earth’s gravity field. We briefly discuss the spatial and spectral behaviour of the main processes causing the variations. In detail, the atmospheric impact on the gravity field variations is investigated, and its effect on the satellite missions resp. their measurements is shown. Finally the basic relationship between gravity field coefficients and Earth rotation parameters is given.
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