Speaker
Ingmar Sandberg
(NOA)
Description
Activity: Engineering Support Tools
Contractor(s): IASA
Technical Officer: Piers Jiggens
In the scope of the ESA SEPEM (Solar Energetic Particle Environment Modelling) project, in order to produce models of the solar proton environment, the data available needed to be processed and a new data set produced upon which statistical models could be run to produce long-term predictions of the environment. This calibration was done in a consistent way by scaling monitor data (which did not saturate) with science data (which had a better energy response) using a straight-line regression. Such cross-calibration is an essential step in reducing data uncertainties for SEP modelling activities.
The calibration fits performed contained a good deal of scatter and the output SPE (solar particle event) fluence spectra were not entirely consistent with spectral forms published in literature. This was certainly due to the simplistic assumptions applied in the cross-calibration.
In the SEPCALIB project the underlying data was re-assessed and one profoundly important instrument response error was uncovered affecting the data of the scientific instrument to which the data was being cross-calibrated. Furthermore, it was found that to cross-calibrate the dataset that the most important factor is the determination of the energy that corresponds to the radiation monitor measurements rather than to determine and apply a scaling factor to "correct" the fluxes. The results presented have been very well received by experts working with SEP measurements particularly those responsible for the radiation monitor datasets being cross-calibrated.
