OVATION: Oval variation, assessment, tracking, intensity, and online nowcasting

Abstract. The location of the auroral oval and the intensity of the auroral precipitation within it are basic elements in any adequate characterization of the state of the magnetosphere. Yet despite the many ground-based and spacecraft-borne instruments monitoring various aspects of auroral behavior, there are no clear and consistent answers available to those wishing to locate the auroral oval or to quantify its intensity. The purpose of OVATION is to create a tool which does so. OVATION is useful both for archival purposes and for space weather nowcasting. The long-running DMSP particle data set, which covers both hemispheres, and has operated since the early 1980s, and which will continue to operate well into the next decade, is chosen as a calibration standard. Other data sets, including global images from Polar UVI, SuperDARN boundaries, and meridian scanning photometer images, are cross-calibrated to the DMSP standard. Each incorporated instrument has its average offset from the DMSP standard determined as a function of MLT, along with the standard deviations. The various data can, therefore, be combined in a meaningful manner, with the weight attached to a given boundary measurement varying inversely with the variance (square of the standard deviation). OVATION currently spans from December 1983 through the present, including real-time data. Participation of additional experimenters is highly welcomed. The only prerequisites are a willingness to conduct the prescribed cross-calibration procedure, and to make the data available online. The real-time auroral oval location can be found here: http://sd-www.jhuapl.edu/Aurora/ovation live/northdisplay.html.

Key words. Magnetospheric physics (auroral phenomena; energetic particles, precipitating; magnetosphere – ionosphere interactions)