Modes of Auroral Precipitation Variability: Empirical Orthogonal Analysis of DMSP SSUSI LBH Emission

Abstract:

Being able to understand aurorae provides great insight into the electrodynamics behind the interactions of the magnetosphere and ionosphere with the solar wind. Recognizing that auroral ionospheric conductance is an important missing link toward understanding these interactions, our goal is to make a better use of the wider spatial coverage of FUV imagers in assimilative mapping of auroral ionospheric conductance by taking advantage of the relationship between LBH emissions with two auroral parameters that describe conductance: incident electron characteristic energy and flux. Dominant modes of the variability of these auroral parameters are modeled using empirical orthogonal function analysis of LBHL observations from the Defense Meteorological System Program (DMSP) Special Sensor Ultraviolet Spectrographic Imagers (SSUSI) instruments. Temporal changes of these modes are analyzed for their relationship to changes of geomagnetic indices and solar wind parameters to help us better understand these modes geophysically. DMSP Special Sensor J (SSJ) auroral particle precipitation data are also used for validation. This paper presents a case study for the week surrounding the February 20, 2014 storm event.