HR: 0800h
AN: SA21A-0335    [Abstracts]
TI: Some Prominent Temporal Variations in the Metal Layers in the Upper Atmosphere.
AU: * Grebowsky, J M
EM: joseph.m.grebowsky@nasa.gov
AF: Goddard Space Flight Center, Code 695 Greenbelt Road, Greenbelt, MD 20771 United States
AU: Aikin, A C
EM: aikin@comcast.net
AF: The Catholic University of America, 200 Hannon Hall, Washington, DC 20064 United States
AU: Correira, J
EM: 17correira@cua.edu
AF: The Catholic University of America, 200 Hannon Hall, Washington, DC 20064 United States
AB: Using resonant radiation in the 237-300 nm range measured by the nadir viewing Global Ozone Measuring Experiment (GOME) UV/VIS spectrometer on the ERS-2 satellite, temporal changes in the vertical column contents of the most dominant meteoric metal species Mg$^{+}$, Mg, Fe$^{+}$, Fe and Si have been analyzed in November, encompassing Leonid meteor shower period. Several years of data are available for analysis. ERS-2 orbits the Earth 14 times per day at 795 km in a sun synchronous orbit with an equatorial crossing time of 10:30 AM. For this study data were restricted to the latitude zone of 10$^{o}$N to 30$^{o}$N, straddling the declination of the shower radiant. The presence of a Leonid shower effect in the studied measurements is not clear cut in 1996. During one of the visible shower periods associated with the 1996 Leonid, there appears to be an ion-neutral composition change associated with one of the showers - i.e., the ion content increases during the maximum of the shower activity and it precedes an enhancement of the neutral species. However during the entire month there are many similar enhancements unassociated with the shower. Also, it is found that there are longitudinal effects in the measurements, most notably in the measured neutral Si, which is observed to have surprisingly high vertical contents. A detailed comparison is made between the variations observed in 2000 and ground-based observations of the shower activity - this was a particularly well-surveyed event.
DE: 5717 Impact phenomena
DE: 6245 Meteors
DE: 2419 Ion chemistry and composition (0335)
DE: 2423 Ionization mechanisms
DE: 0340 Middle atmosphere--composition and chemistry
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting