HR: 1330h
AN: SA12B-1088    [PDF]
TI: An Evaluation of the Charge Exchange Equilibrium Technique to Derive [H]/[O]
AU: Gonzalez, S A
AF: Arecibo Observatory, HC3 BOX 53995, Arecibo, PR 00612 United States
AU: * Waldrop, L S
AF: Arecibo Observatory, HC3 BOX 53995, Arecibo, PR 00612 United States
AU: Vargas, C
AF: Arecibo Observatory, HC3 BOX 53995, Arecibo, PR 00612 United States
AU: Nicolls, M J
AF: Cornell University, Dept. of Electrical and Computer Engineering 318 Rhodes Hall, Ithaca, NY 14853 United States
- AB: Quantification of neutral species densities in the upper thermosphere and lower exosphere using ground-based remote sensing remains a difficult problem. One method to derive [H]/[O] utilizes the O on H$^+$ charge exchange equilibrium equation (CEE) with incoherent scatter radar (ISR) observations of [H$^+$] and [O$^+$]. The CEE technique has been historically hamstrung by the requirement of very high precision measurements of minor constituents in the region where the equilibrium condition holds, and is not violated by H escape, near and just above the F-region peak. By taking advantage of the precise values of [H$^+$], [O$^+$], and T$_{\mathrm{i}}$ now available by consequence of the multiple ion spectral fitting at Arecibo, an investigation into the usefulness of the CEE condition for neutral density determination is now possible. More than 50 days of Arecibo topside ISR measurements are used to derive [H]/[O] at and above the F-region peak, and a statistical comparison with MSIS derived estimates is performed to evaluate the CEE technique. Local time, seasonal, and solar cycle trends are examined. Finally, the differences between the two estimates of [H]/[O] are also characterized.
DE: 0335 Ion chemistry of the atmosphere (2419, 2427)
DE: 0355 Thermosphere--composition and chemistry
DE: 2419 Ion chemistry and composition (0335)
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2481 Topside ionosphere
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting