HR: 0830h
AN: SA51B-0513    [PDF]
TI: Observation and Modeling of Mesospheric Potassium Over Arecibo Observatory
AU: * Delgado, R
EM: rubendelgado71@comcast.net
AF: Department of Chemistry University of Puerto Rico, P.O. Box 23346 University Station, San Juan, PR 00936 United States
AU: Weiner, B R
EM: brad@adam.uprr.pr
AF: Department of Chemistry University of Puerto Rico, P.O. Box 23346 University Station, San Juan, PR 00936 United States
AU: Plane, J M
EM: j.plane@uea.ac.uk
AF: School of Enviromental Sciences, University of East Anglia, Norwich, NR47TJ United Kingdom
AU: Friedman, J S
EM: jonathan@naic.edu
AF: National Astronomy and Ionosphere Center/Arecibo Observatory, HC3Box 53995, Arecibo, PR 00612 United States
AB: Nighttime observations of the atmospheric potassium layer were performed at the Arecibo Observatory using lidar to determine the seasonal variation in the concentration of the potassium metal atom layer. The K layer shows nightly and seasonal variation; the nightly variation was due to the presence of sporadic layers. The seasonal variability is less in the layer width, while the column abundance exhibits a semiannual variation. To understand the seasonal behavior of the K layer a one dimensional model has been developed. The model includes a meteoric deposition, vertical transport through eddy diffusion, and a full chemical scheme. To identify molecular reservoirs and sinks for the K atom, ab initio calculations were performed to estimate the thermochemistry. Rate constants for the reaction between the metal bicarbonate and atomic H, as well as ion-molecule reactions, were obtained by considering detailed balance mechanism and transition state theory. Reactions KO+ + N2, K+xO2 + O, K+xO2 + N2, and KHCO3 + H can be considered as routes that may cycle species, which can play a role as major sinks of potassium ion or neutrals in the mesospheric cycle. These studies of the metal layer contribute to a better understanding of chemical and dynamical changes that affect atmospheric composition.
DE: 0317 Chemical kinetic and photochemical properties
DE: 0335 Ion chemistry of the atmosphere (2419, 2427)
DE: 0340 Middle atmosphere--composition and chemistry
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting