14th International EISCAT Workshop, Tromsø, Norway, 3-7 August 2009

Empirical distributions of EISCAT electron densities and other retrieved parameters, with applications to improved statistical analysis methods

C.-F. Enell1, A. Kero1, J. P. Vierinen1, Th.Ulich1, E. Turunen2, I. Häggström2, M. Friedrich3

1Sodankylä Geophysical Observatory, Sodankylä, Finland,
2EISCAT Scientific Association, Kiruna, Sweden,
3University of Graz, Graz, Austria


Analysed data from more than one solar cycle of measurements with the present EISCAT VHF and UHF systems are readily available online through the EISCAT MADRIGAL database. Parameters available include electron density, ion temperature, and ion-electron temperature ratio profiles, retrieved using the standard GUISDAP analysis package. We here determine empirical distributions of these fitted parameters representative of different typical conditions, correcting for known error sources such as the presence of negative ions in the lower D region.

These distributions are applicable as prior distributions in the refined statistical analysis methods which are under continuous development at Sodankylä Geophysical Observatory. As a test case we reanalyse EISCAT VHF data from the Hotel Payload (HotPay) 2 rocket campaign which took place in January-February 2008. During the HotPay2 campaign a very quiet period was followed by several days of persistent auroral precipitation, making it a "schoolbook-like" test case.