Open AccessSeasonal, Kp, solar wind, and solar flux variations in long‐term single‐pass satellite estimates of electron and ion auroral hemispheric power
Author(s) -
Emery Barbara A.,
Coumans Valérie,
Evans David S.,
Germany Glynn A.,
Greer M. Sue,
Holeman Ernest,
KadinskyCade Katharine,
Rich Frederick J.,
Xu Weibin
Publication year - 2008
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007ja012866
Subject(s) - solstice , environmental science , atmospheric sciences , earth's magnetic field , satellite , electron precipitation , solar wind , defense meteorological satellite program , precipitation , interplanetary magnetic field , flux (metallurgy) , physics , climatology , meteorology , magnetic field , magnetosphere , geology , astronomy , latitude , quantum mechanics , materials science , metallurgy
Electron auroral energy flux is characterized by electron hemispheric power (Hpe) estimated since 1978 from National Oceanic and Atmospheric Administration (NOAA) and Defense Meteorological Satellite Program (DMSP) satellites after the estimates were corrected for instrumental problems and adjusted to a common baseline. Similarly, intersatellite adjusted ion hemispheric power (Hpi) estimates come from one MetOp and four NOAA satellites beginning in 1998. The hemispheric power (Hp) estimates are very crude, coming from single satellite passes referenced to 10 global activity levels, where the Hpi estimates are the difference between the total and the electron Hp (Hpi = Hpt‐Hpe). However, hourly averaged NOAA/DMSP Hpe and Hpi estimates correlate well with hourly Polar Ultraviolet Imager (UVI) Hpt and Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE) far ultraviolet (FUV) Hpe and Hpi estimates. Hpe winter values were larger than summer values ∼65% of the time (when geomagnetic activity was moderate or higher), and Hpe were larger in the summer ∼35% of the time (typically for low geomagnetic activity). Hpe was ∼40% larger at winter solstice than summer solstice for the largest Hp from mostly nightside increases, and Hpe was ∼35% larger in summer than winter for the smallest Hp owing to dayside auroral enhancements. Ion precipitation differed from electron precipitation because it was almost always larger in summer than winter. Hpe and Hpi increased with Kp, solar wind speed (Vsw), and negative Interplanetary Magnetic Field (IMF) B z , similar to previous studies. Hpi also increased strongly with positive B z . For quiet conditions, Hpe increased with increasing 10.7‐cm solar flux (Sa), while Hpi increased with Sa up to Sa ∼115 for all conditions.