VALIDATION OF UARS PARTICLE ENVIRONMENT MONITOR ELECTRON-ENERGY DEPOSITION

One of the primary goals of the particle environment monitor (PEM) on the Upper Atmosphere Research Satellite is the determination of the so lar and magnetospheric particle energy inputs to the upper and middle atmosphere. This is accomplished by measuring the incident particle sp ectra and computing energy deposition and ionization rates as function s of altitude. The particle spectral measurements are made by detector s covering the energy range 5 eV to 5 MeV for electrons and 5 eV to 15 0 MeV for protons. An X ray camera provides global-scale images and en ergy spectra of similar to 3 to 100 keV bremsstrahlung X rays produced by electrons incident on the atmosphere. Thus PEM measures particles which lose their energy in an atmospheric region extending from the th ermosphere down to similar to 50 km, with the altitude of associated b remsstrahlung X rays reaching similar to 25-km levels. PEM validation documented in this report has involved an assessment of the data quali ty of each PEM component instrument, intercalibration of individual in struments, and validation of the computations of the rates of electron energy deposition into the atmosphere. The energy deposition rate cal culations are validated against existing energy deposition codes over the complete energy range of PEM measurements.