HR: 1400h
AN: SA33A-04    [Abstracts]
TI: Seasonal Variations in the Electron and Ion Auroral Hemispheric Power
AU: * Emery, B A
EM: emery@ucar.edu
AF: HAO/NCAR, 3450 Mitchell Lane, Boulder, CO 80301, United States
AU: Evans, D S
EM: david.s.evans@noaa.gov
AF: SEC/NOAA, 325 Broadway, Boulder, CO 80305, United States
AU: Rich, F J
EM: frederick.rich@hanscom.af.mil
AF: VSBP/AFRL, 29 Randolph Road, Hanscom AFB, MA 01731, United States
AU: Germany, G A
EM: germanyg@cspar.uah.edu
AF: CSPAR/UAH, Technology Hall S131, Huntsville, AL 35899, United States
AU: Coumans, V
EM: v.coumans@ulg.ac.be
AF: LPAP/ University of Liege, Allee du 6 aout, 17, Liege, B-4000, Belgium
AB: Models for electron and ion auroral energy inputs usually ignore seasonal or interhemispheric variations. Our study shows, however, that there are significant seasonal variations in the electron and ion auroral energy inputs, which are opposite from each other. Both seasonal variations are strengthened with higher solar flux. The electron energy inputs are represented by hourly estimates of the electron hemispheric power (Hpe) (1) over 28 years from 24 intercalibrated NOAA and DMSP satellites, and (2) over three years from the UVI imager on the POLAR satellite. The ion hemispheric power (Hpi) was estimated (1) from four NOAA SEM-2 satellites over eight years, and (2) over four seasons in solar maximum from the FUV experiment on IMAGE. The data are split into four-month seasons over the years of measurements. The summer Hpe exceeds the winter Hpe by ~20% for Kp 0, and the winter Hpe exceeds the summer Hpe by ~15% for Kp 3-5 for NOAA/DMSP and POLAR. The four-month average winter Hpe excess over that of the summer varies from 3-5% for all conditions. The interhemispheric advantage of the winter Hpe over the summer Hpe at solstices can be as much as 20% and 50% in solar minimum and maximum, respectively. The summer Hpi is larger than the winter Hpi for all Kp, where the four-month average increase is 18% for solar flux values <130 and 35% (double) for solar flux values >130. The summer to winter Hpi enhancement is similar from IMAGE at ~30%.
DE: 0310 Airglow and aurora
DE: 0358 Thermosphere: energy deposition (3369)
DE: 2162 Solar cycle variations (7536)
DE: 2455 Particle precipitation
DE: 2788 Magnetic storms and substorms (7954)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly