HR: 15:30h
AN: SA14A-01    [Abstracts]
TI: Direct and Indirect Thermospheric Heating Sources
AU: * Knipp, D J
EM: delores.knipp@usafa.af.mil
AF: US Air Force Academy , Department of Physics Suite 2A25 Fairchild Hall, USAF Academy, CO 80840 United States
AU: Tobiska, W K
EM: ktobiska@spacenvironment.net
AF: Space Environment Technologies, 1676 Palisades Dr, Pacific Palisades, CA 90272 United States
AU: Emery, B
EM: emergy@ucar.edu
AF: High Altitude Observatory, NCAR,, 3150 Mitchell Lane, Boulder, CO 80301 United States
AB: Solar variability is often cast in terms of radiative emission and the associated long-term climate response; however, growing societal reliance on technology is creating more interest in day-to-day solar variability. This variability is associated with both solar radiative and solar wind emissions. In this paper we explore the combined effects of radiative and solar wind fluctuations at Earth. The fluctuations in radiative and geomagnetic power create an extended interval of solar maximum for the upper atmosphere. We use a trio of empirical models to estimate, over the last three solar cycles, the relative contributions of solar extreme ultraviolet (UV) power, Joule power, and particle kinetic power to the Earth's upper atmosphere energy budget. Daily power values are derived from three source models. The SOLAR2000 solar irradiance specification model provides estimates of the daily extreme and far UV solar power input. Geomagnetic power is derived from a combination of satellite-estimated particle precipitation power and an empirical model of Joule power from hemispherically-integrated estimates of high-latitude energy deposition. During the interval 1975 to 2004, the average daily contributions were: particles--36 GW, Joule--95 GW and solar--464 GW for a total of 595 GW. Solar wind-driven geomagnetic power provided 22% of the total global upper atmospheric energy. In the top 15 power events, geomagnetic power contributed two-thirds of the total power budget. In each of these events, Joule power alone exceeded solar power. With rising activity, Joule power becomes the most variable element of solar-upper- atmosphere interactions. This variability has significant implications for satellite drag, pointing accuracy and collision avoidance.
DE: 0358 Thermosphere--energy deposition
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 7537 Solar and stellar variability
DE: 7538 Solar irradiance
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly