The accuracy of using the spectral width boundary measured in off-meridional SuperDARN HF radar beams as a proxy for the open-closed field line boundary
Chisham, G.; Freeman, M.P.; Sotirelis, T.; Greenwald, R.A.. 2005 The accuracy of using the spectral width boundary measured in off-meridional SuperDARN HF radar beams as a proxy for the open-closed field line boundary. Annales Geophysicae, 23 (7). 2599-2604. SRef-ID: 1432-0576/ag/2005-23-2599Full text not available from this repository.
Determining reliable proxies for the ionospheric signature of the open-closed field line boundary (OCB) is crucial for making accurate measurements of magnetic reconnection. This study compares the latitudes of spectral width boundaries (SWBs) measured by different beams of the Goose Bay radar of the Super Dual Auroral Radar Network (SuperDARN), with the latitudes of OCBs determined using the low-altitude Defense Meteorological Satellite Program (DMSP) spacecraft, in order to determine whether the accuracy of the SWB as a proxy for the ionospheric projection of the OCB depends on the line-of-sight direction of the radar beam. The latitudes of SWBs and OCBs were identified using automated algorithms applied to 5 years (1997–2001) of data measured in the 1000–1400 magnetic local time (MLT) range. Six different Goose Bay radar beams were used, ranging from those aligned in the geomagnetic meridional direction to those aligned in an almost zonal direction. The results show that the SWB is a good proxy for the OCB in near-meridionally-aligned beams but becomes progressively more unreliable for beams greater than 4 beams away from the meridional direction. We propose that SWBs are identified at latitudes lower than the OCB in the off-meridional beams due to the presence of high spectral width values that result from changes in the orientation of the beams with respect to the gradient in the large-scale ionospheric convection pattern.
|Identification Number/DOI:||SRef-ID: 1432-0576/ag/2005-23-2599|
|Programmes:||BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Magnetic Reconnection, Substorms and their Consequences|
|Additional Keywords:||Ionosphere, Plasma convection, Magnetospheric physics|
|NORA Subject Terms:||Atmospheric Sciences
|Date made live:||20 Dec 2007 11:22|
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