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Precipitation and total power consumption in the ionosphere: Global MHD simulation results compared with Polar and SNOE observations

Authors :
M. Palmroth
P. Janhunen
G. Germany
D. Lummerzheim
K. Liou
D. N. Baker
C. Barth
A. T. Weatherwax
J. Watermann
Finnish Meteorological Institute (FMI)
Department of Physical Sciences [Helsinki]
University of Helsinki
University of Alabama in Huntsville (UAH)
Geophysical Institute [Fairbanks]
University of Alaska [Fairbanks] (UAF)
Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)
Laboratory for Atmospheric and Space Physics [Boulder] (LASP)
University of Colorado [Boulder]
Siena College
Okayama University
Danish Meteorological Institute (DMI)
EGU, Publication
Source :
Annales Geophysicae, Vol 24, Pp 861-872 (2006), ResearcherID, Annales Geophysicae, Annales Geophysicae, European Geosciences Union, 2006, 24 (3), pp.861-872, Annales Geophysicae, Vol 24, Iss 3, Pp 861-872 (2006)
Publication Year :
2018

Abstract

We compare the ionospheric electron precipitation morphology and power from a global MHD simulation (GUMICS-4) with direct measurements of auroral energy flux during a pair of substorms on 28-29 March 1998. The electron precipitation power is computed directly from global images of auroral light observed by the Polar satellite ultraviolet imager (UVI). Independent of the Polar UVI measurements, the electron precipitation energy is determined from SNOE satellite observations on the thermospheric nitric oxide (NO) density. We find that the GUMICS-4 simulation reproduces the spatial variation of the global aurora rather reliably in the sense that the onset of the substorm is shown in GUMICS-4 simulation as enhanced precipitation in the right location at the right time. The total integrated precipitation power in the GUMICS-4 simulation is in quantitative agreement with the observations during quiet times, i.e., before the two substorm intensifications. We find that during active times the GUMICS-4 integrated precipitation is a factor of 5 lower than the observations indicate. However, we also find factor of 2-3 differences in the precipitation power among the three different UVI processing methods tested here. The findings of this paper are used to complete an earlier objective, in which the total ionospheric power deposition in the simulation is forecasted from a mathematical expression, which is a function of solar wind density, velocity and magnetic field. We find that during this event, the correlation coefficient between the outcome of the forecasting expression and the simulation results is 0.83. During the event, the simulation result on the total ionospheric power deposition agrees with observations (correlation coefficient 0.8) and the AE index (0.85).

Details

Language :
English
ISSN :
14320576 and 09927689
Database :
OpenAIRE
Journal :
Annales Geophysicae, Vol 24, Pp 861-872 (2006), ResearcherID, Annales Geophysicae, Annales Geophysicae, European Geosciences Union, 2006, 24 (3), pp.861-872, Annales Geophysicae, Vol 24, Iss 3, Pp 861-872 (2006)
Accession number :
edsair.doi.dedup.....b634e512920ab43ad63b8c85bfc23333