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The networks of HF coherent backscatter radars known as SuperDARN measure ionospheric LOS Doppler velocities over a large portion of the northern and southern hemispheres [Greenwald et al., 1995]. The northern component of SuperDARN has recently been augmented with two new radars in British Columbia, Canada and Kodiak Island, Alaska. The additional radars extend the coverage of the network to include western North America (see Figure 1 and Table 1). This study focuses on a particular period during which SuperDARN measurements were available over a region of the northern hemisphere that extended over $\sim$18 hours of magnetic local time (MLT) or nearly 3/4 of the high latitude ionosphere.

Figure 1: Locations and fields of view of the eight operating SuperDARN HF radars in the northern hemisphere. Flags indicate the primary source of support of each radar. Radar identification letters are defined in Table 1.

Table 1: SuperDARN Radars Operating in the Northern Hemisphere
Radar ID Location Affiliation Lat.$^\circ$N Lon.$^\circ$E Operational
CUTLASS$^{\rm a}$ /Finland F Hankasalmi, Finland University of Leicester 62.32 26.61 April 1995
CUTLASS$^{\rm a}$ /Iceland E Pykkvibær, Iceland University of Leicester 63.77 -20.54 Dec. 1995
Iceland West W Stokkseyri, Iceland CNRS$^{\rm b}$ 63.86 -20.02 Oct. 1994
Goose Bay G Labrador, Canada JHU/APL$^{\rm c}$ 53.32 -60.46 June 1983
Kapuskasing K Ontario, Canada JHU/APL$^{\rm c}$ 49.39 -83.32 Sept. 1993
Saskatoon T Saskatchewan, Canada University of Saskatoon 52.16 -106.53 Sept. 1993
Prince George B British Columbia, Canada University of Saskatoon 53.98 -122.59 Mar. 2000
Kodiak A Kodiak Island, Alaska UAF$^{\rm d}$ 57.62 -152.19 Jan. 2000
$^{\rm a}$ Co-operative United Kingdom Twin Located Auroral Sounding System.
$^{\rm b}$ Centre National de la Recherche Scientifique.
$^{\rm c}$ Johns Hopkins University Applied Physics Labratory.
$^{\rm d}$ University of Alaska, Fairbanks.

In order to demonstrate that definitive global solutions of $\Phi$ are now possible with direct measurements of convection, we show that given sufficient coverage, as in the case for the period selected, the solution of $\Phi$ is insensitive to the selection of statistical model data. The fitting technique, further explained in the the text, used to construct a global solution of $\Phi$ over the region >50$^\circ\Lambda$, is applied to the SuperDARN data in combination with a wide variety of statistical model patterns. The lack of any significant differences in the resulting solutions of $\Phi$ demonstrate that $\Phi$ and hence, $\Phi_{\sf PC}$, are largely constrained by the measurements alone.

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Next: Example of Fitting Technique Up: Electrostatic potential patterns in Previous: Background

Simon Shepherd 2000-07-13