Horizontal and Vertical Wind Measurements from GOCE Angular Accelerations

Tim Visser, Eelco Doornbos, Coen de Visser, Pieter Visser

Research output: Contribution to conferenceAbstractScientific

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Abstract

Because of the highly accurate accelerometers, the GOCE mission has proven to be a unique source of thermosphere neutral density and cross-wind data. In the current methods, in which only the horizontal linear accelerations are used, the vertical winds cannot be obtained. In the algorithm proposed in this paper, angular accelerations derived from the individual gradiometer accelerations are used to obtain the vertical wind speeds as well. To do so, the measured angular rate and acceleration are combined to find a measurement of the torque acting on the spacecraft. This measurement is then corrected for modeled control torque applied by the magnetic torquers, aerodynamic torque, gravity gradient torque, solar radiation pressure torque, the torque caused by the misalignment of the thrust with respect to the center of gravity, and magnetic torque caused by the operation of several different subsystems of the spacecraft bus. Since the proper documentation of the magnetic properties of the payload were not available, a least squares estimate is made of one hard- and one soft-magnetic dipole pertaining to the payload, on an aerodynamically quiet day. The model for aerodynamic torque uses moment coefficients from Monte-Carlo Test Particle software ANGARA. Finally the neutral density, horizontal cross-wind, and vertical wind are obtained from an iterative process, in which the residual forces and torques are minimized. It is found that, like horizontal wind, the vertical wind responds strongly to geomagnetic storms. This response is observed over the whole latitude range, and shows seasonal variations.
Original languageEnglish
Pages81-81
Number of pages1
Publication statusPublished - 2017
Event4th Swarm Science Meeting & Geodetic Missions Workshop - Banff, Canada
Duration: 20 Mar 201724 Mar 2017
Conference number: 4
http://www.swarm2017.org/

Conference

Conference4th Swarm Science Meeting & Geodetic Missions Workshop
Country/TerritoryCanada
CityBanff
Period20/03/1724/03/17
Internet address

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