Analyses of GOCE Accelerometer Data During Geomagnetically Active Days
19/09/2016 | 16:45 | Session 1: Current and future satellite gravity missions
Author(s): E. Sinem Ince, Spiros Pagiatakis, Oleg Martynenko, Victor Fomichev, Anja Schlicht and Rune Floberghagen
E. Sinem Ince, Spiros Pagiatakis, Oleg Martynenko, Victor Fomichev, Anja Schlicht and Rune Floberghagen
The Gravity field and steady-state Ocean Circulation Explorer (GOCE) completed its mission with great success in November, 2011. During the 5th GOCE International User Workshop, the main results of the mission were discussed and summarized, and recommendations were made for data processing and modelling methodologies. It was confirmed that the mission had exceeded its proposed aims. Moreover, it was claimed that there is still great potential to improve the gradiometer data analysis, such that the cross-track gradient could be improved near the geomagnetic poles which is directly related to this presentation.
It is known that GOCE data processing is challenging and has several shortcomings. Our preliminary analyses and literature review reveal that GOCE gradiometer measurements are affected by unknown non-gravitational sources around the magnetic poles. In this study, the disturbances observed in GOCE Vyy gravity gradients and the gravity gradient tensor trace that can reach up to 5 times the expected noise level of the gradiometer around magnetic poles are investigated by using external datasets.
Electric field and interplanetary magnetic field components that are measured by solar monitoring satellites ACE (Advanced Composition Explorer) and WIND have shown that the disturbances observed over the polar regions agree with the increased solar activity and occur during geomagnetically active days. Moreover, equivalent ionospheric currents that are computed along ascending satellite tracks over North America and Greenland have shown a noticeable correlation with the cross-track and vertical currents and with the Poynting vector (E×B) components in the satellite cross track direction. Lastly, the Canadian Ionosphere and Atmosphere Model (C-IAM) electric field and neutral wind simulations have shown a strong enhancement in the ionospheric dynamics during geomagnetically active days and similarities with the disturbances measured by the GOCE accelerometers over high latitudes. We use the above listed external datasets to understand the causes of the disturbances observed in the gravity gradients and reduce/eliminate them by using response analyses. Based on our results, significant improvement of the gravity gradients is possible.