Simultaneous Radar and Satellite Observations of the Polar Cusp/Cleft at Sondre Stromfjord
On February 9, 1988 a multi-instrument observation of the dayside polar ionosphere was made at Sondre Stromfjord, Greenland as part of a CEDAR high latitude campaign. Our objective was to observe the low altitude signature of the cusp during southward IMF but under fairly quiet ionospheric conditions (Kp=2). The HiLat satellite measured in-situ particle precipitation, field-aligned currents and velocity shears in the dayside cusp/cleft, while the VHF beacon on board showed large phase scintillation and saturated intensity scintillation. The phase spectral index was fairly shallow indicating that large power spectral density was present up to scales on the order of 100m. During the spacecraft overflight, the radar was scanning close to the F-region projection of the satellite track. It is the object of this paper to compare the radar measured thermal density, Ti and Te features in the F-region with topside density and velocity structures and particle precipitation characteristics measured in-situ by the satellite at 830 km. The precipitating electron flux measured by HiLat was also input to an ionospheric chemistry model that calculates electron density and temperature profiles for different exospheric temperatures. The modeling results show that most of the features of the radar data may be explained in terms of cleft precipitation, consequent higher exospheric temperatures and enhanced convection.
KeywordsTotal Electron Content Solar Zenith Angle Vertical Total Electron Content Amplitude Scintillation Phase Scintillation
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