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The default plot is in geographic coordinates. Because the auroral oval is influenced mainly by the Earth's magnetic field, it is possible to select magnetic coordinates (Altitude Adjusted Corrected Geomagnetic Coordinates) instead. In magnetic coordinates, the sun is always toward the top of the plot, and local dawn is to the right.
The time resolution can be adjusted by changing the "Time Interval" parameter, set by default to 45 minutes. Only data within the 45 minutes PRIOR to the specified time are incorporated in the default setting. Although higher time resolution is possible by shortening this interval, the accuracy may decline, at least when using DMSP data as the major source. Previous work has demonstrated that superior results are obtained by using a longer time interval to obtain at least a 3-point fit to the oval [Sotirelis et al., 1998], even for elapsed times as long as an hour. The trouble with single point measurements is that they must assume the oval is a circle, and assume its center position. Neither assumption is very reliable. Of course the advantage of including additional (non-DMSP) data sets is the possibility of obtaining higher time resolution multi-point auroral oval positions.
The default mode plots the auroral oval position in the northern hemisphere only. The user can switch to plotting the southern hemisphere position. Only DMSP data is available for plotting the southern hemisphere oval position.
The "previous" and "next" buttons move ahead to the nearest appropriate update based on the time interval selected and the availability of data. If no updated oval positions are available for 6 days, an error message is generated.
Selecting the "precipitation model" replaces the solid color (yellow) oval with the Sotirelis and Newell [2000] Boundary-oriented precipitation model, giving the statistical intensity of oval precipitation at various locations. At present, the intensity is parameterized only by the b2i index, although the shape is fitted to the observed boundary positions. Future versions will include the sampled precipitation intensities along the DMSP trajectories to further adjust the model.