4.3 Comparison of Two Medium Energy Electron Data Sets in WACCM

Tuesday, 9 January 2018: 11:00 AM
Salon J (Hilton) (Austin, Texas)
Josh Pettit, Univ. of Colorado Boulder, Boulder, CO; and C. Randall, E. D. Peck, D. R. Marsh, C. Bardeen, and X. Fang

Precipitation into the atmosphere of protons and electrons from the Sun and radiation belts often leads to changes in chemistry and temperature throughout the middle and upper atmosphere. Solar protons have been studied thoroughly over the past few decades, and their effects are fairly well understood. Effects of precipitating electrons are less well understood, and uncertainties are largest for electrons with energies greater than ~30 keV. These electrons are underrepresented in modeling studies today, primarily because valid measurements of their precipitating spectral energy flux are lacking. Observations from the Polar Orbiting Environmental Satellites (POES) Medium Energy Proton and Electron Detectors (MEPED) constitute perhaps the best data set for determining the precipitating flux of electrons with energies between about 30 keV and 1 MeV. The MEPED data have known deficiencies, however, such as contaminating protons in the electron energy channels, poor spectral resolution, and insufficient coverage of the bounce loss cone. Several studies have been conducted to address these issues and produce precipitating electron data sets for use in atmospheric models. This presentation describes simulations from the Whole Atmosphere Community Climate Model (WACCM) that incorporated estimates of the differential spectrum of precipitating electron flux derived from POES measurements and based on the work of Peck et al. [2015]. These results are compared to results from WACCM simulations that rely on a parameterization of the precipitating electron flux based on the POES electron counts. Both simulations are run from 1 Jan 2004 to 1 June 2004, a time period during which significant energetic electron precipitation occurred. Comparisons between the WACCM results and satellite observations of temperature, odd nitrogen, hydroxyl, and ozone are presented.
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