An evaluation of range accuracy in the Super Dual Auroral Radar Network over‐the‐horizon HF radar systems

T K Yeoman,T B Jones,A J Stocker,D M Wright

doi:10.1029/2000rs002558

Abstract

The Super Dual Auroral Radar Network (SuperDARN) of over‐the‐horizon HF radars forms a powerful diagnostic of large‐scale ionospheric and magnetospheric dynamics in the Northern and Southern Hemispheres. Currently, the ground location of the HF radar returns is routinely determined by a simple range‐finding algorithm, which takes no account of the prevailing HF propagation conditions. This is in spite of the fact that both direct E and F region backscatter and 1½‐hop E and F region backscatter are commonly used in geophysical interpretation of the data. Here HF radar backscatter which has been artificially induced by the high‐power RF facility (ionospheric heater) operated by the European Incoherent Scatter Scientific Association at Tromsø is used to provide a range calibration for the SuperDARN radars. The known ground range, the measured radar slant range, and the group path calculated by a ray‐tracing simulation are compared. The standard algorithm for backscatter ground range location is found to be accurate to within 16 km and 60 km for direct and 1½‐hop backscatter, respectively.

Highlights

The SuperDual AuroralRadarNetwork (SuperDARN) of over-the-horizonHF radars formsa powerfuldiagnosticof large-scaleionospheriacndmagnetospherdicynamicsin the NorthernandSouthernHemispheres.Currently,the groundlocationof theHF radarreturnsis routinelydeterminedby a simplerange-findingalgorithmw, hichtakesno accounot f theprevailing HF propagationconditions.Thisis in spiteof thefactthatbothdirectE andF regionbackscatter and11/2-hoEp andF regionbackscattearrecommonlyusedin geophysicainl terpretatioonf the data
Introduction propagationat the speedof light from the radar siteto a target at a given altitude above the Earth and takes The SuperDARN network [Greenwald et al, 1995] no direct account of the prevailing HF propagation currentlyconsistsof eight over-the-horizonHF radarsin conditions [Baker et al, 1986]
The radar systemsrely on the using the straightline approximation. These studies refraction of the HF radiation both in order to achieve suggesteadgreemenbtetweenthegroundrangeandradar orthogonalityto theEarth'smagneticfield, a requirement rangewithin-15 km overa l/2-hoppath. for scatteringoff the ionosphericirregularities, which Early studieswith HF radarseither usedHF radardata alone or combined HF radar data with data from form the targetsfor suchradar systems,and to achieve backscatterfrom the longer ranges,which require over- instrumentssuchas groundmagnetometersw, hichhad a the-horizonoperations

Summary

Ground Location

Norway [Rietveldet al., 1993], is capableof generating artificial field-alignedirregularitiesusinghigh-powerHF. HF radars observe pulsed waves with CUTLASS and the Heater (SP-UK-OUCH; ionosphericflows in the cusp region, which are the Wright and Yeoman [1999]) experiment. In this response to this transient reconnection at the experimenthe CUTLASS radarsrun in a high-temporalmagnetopause [e.g. Pinnock et al, 1993, 1995; resolution and high-spatial-resolution mode, with. Thusbothradarsproduce accurateevaluationof radar range,in a situationwhere data with a temporalresolutionof 6 s Both run in a the radarbackscattemr ay be either1/2hop or 11/2hop high-spatial-resolutiomn ode,with eachradarhaving. Artificial targetsresultin very high returnedbackscatter powerin comparisonto naturallyoccurringirregularities This allows a short integration time to be run on the radar,providinghighertime resolutionthanis normally.

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