HR: 0800h
AN: SM51B-1297    [Abstracts]
TI: A colourful auroral substorm
AU: * Partamies, N
EM: noora@phys.ucalgary.ca
AF: University of Calgary, 2500 University Drive N.W., Calgary, AB T2N 1N4 Canada
AU: Syrjaesuo, M
EM: mikko@phys.ucalgary.ca
AF: University of Calgary, 2500 University Drive N.W., Calgary, AB T2N 1N4 Canada
AU: Donovan, E
EM: eric@phys.ucalgary.ca
AF: University of Calgary, 2500 University Drive N.W., Calgary, AB T2N 1N4 Canada
AB: The prototype of an auroral colour camera named RAINBOW, was run in Longyearbyen, Svalbard, during a Finnish optical and EISCAT campaign in February, 2004. Instead of narrow band-pass filters and greyscale images, this imager records colour images of the aurora using four wideband channels (a colour CCD) with the field-of-view of about 150 degrees. In this study, we show the results of fitting the four RAINBOW channels (cyan-magenta, cyan-green, yellow-magenta, yellow-green) to reconstruct the traditionally filtered auroral wavelengths: green (557.7nm), red (630.0nm) and blue (427.8nm) as simultaneously recorded by the Meridian Scanning Photometer (MSP) at the same station. This fit is qualitatively extremely good and almost linear throughout the data. Due to wide-band colour channels of the Rainbow camera, the background illumination has a significant effect on the data. During low signal levels (only background or faint aurora) the reconstruction errors are larger. In studying the auroral evolution during substorms, there is no difference whether MSP or Rainbow data is used. As an example of physically useful information extracted from the colour auroral images, we show the location of the poleward boundary of red emission, which is widely used as a proxy for the boundary of the polar cap. The data for this study were captured on 21st Feb, 2004. The time period of interest includes a substorm sequence, which is examined using colour auroral images and data from the MSP.
UR: http://www.phys.ucalgary.ca/~mikko/Rainbow/
DE: 2407 Auroral ionosphere (2704)
DE: 2494 Instruments and techniques
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005