HR: 10:20h
AN: SA42A-01    [Abstracts]
TI: Electric fields in the equatorial ionosphere inferred from magnetic measurements of CHAMP, Oersted and SAC-C
AU: * Maus, S
EM: stefan.maus@noaa.gov
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: * Maus, S
EM: stefan.maus@noaa.gov
AF: NOAA/NGDC, 325 Broadway, Boulder, CO 80305, United States
AU: Alken, P
EM: Patrick.Alken@noaa.gov
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: Alken, P
EM: Patrick.Alken@noaa.gov
AF: NOAA/NGDC, 325 Broadway, Boulder, CO 80305, United States
AU: Luhr, H
EM: hluehr@gfz-potsdam.de
AF: GeoForschungsZentrum, Telegrafenberg, Potsdam, Germany
AB: The Equatorial Electrojet (EEJ) and its return currents create a strong signature in magnetic measurements of low-orbiting satellites. Seven years of data from CHAMP, Oersted and SAC-C with almost 100,000 equator crossings allow for a detailed characterization of the spatial and temporal structure of the EEJ. In addition to scalar measurements used in previous studies, we have now also inverted vector magnetic field measurements from CHAMP and Oersted. In contrast to scalar data, which only provide the magnitude of the EEJ current system, the vector data can be inverted for absolute current estimates along meridional profiles. These profiles confirm the presence of strong westward return currents on both sides of the eastward EEJ. In the climatological average, the peak eastward current strength correlates well with radar measurements of upward drift. As expected, the early morning hours are dominated by a reversed, westward electric field. A climatological model of the EEJ strength and variability, parametrized by longitude, local time, season and solar flux is now available online.
UR: http:geomag.colorado.edu/EEJmodel.html
DE: 2415 Equatorial ionosphere
DE: 2712 Electric fields (2411)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 6929 Ionospheric physics (1240, 2400)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly