HR: 0800h
AN: SA31A-1111    [Abstracts]
TI: Characteristics of the mesospheric layers observed using resonance lidars from Arecibo
AU: * Raizada, S
EM: raizada@iap-kborn.de
AF: Leibniz-institut fur Atmospharen Physik, Shloss Strasse 6, Kuehlungsborn, 18225 Germany
AU: Tepley, C A
EM: craig@naic.edu
AF: Arecibo Observatory/Cornell Univ., HC-03, Box 53995, Arecibo, PR 00612 Puerto Rico
AU: Friedman, J
EM: jonathan@naic.edu
AF: Arecibo Observatory/Cornell Univ., HC-03, Box 53995, Arecibo, PR 00612 Puerto Rico
AU: Aponte, N
EM: naponte@naic.edu
AF: Arecibo Observatory/Cornell Univ., HC-03, Box 53995, Arecibo, PR 00612 Puerto Rico
AU: Gonzalez, S
EM: sixto@naic.edu
AF: Arecibo Observatory/Cornell Univ., HC-03, Box 53995, Arecibo, PR 00612 Puerto Rico
AU: Sulzer, M
EM: msulzer@naic.edu
AF: Arecibo Observatory/Cornell Univ., HC-03, Box 53995, Arecibo, PR 00612 Puerto Rico
AB: The resonance lidar at the Arecibo Observatory has been used for simultaneous observations of Na and Fe metallic layers. Such measurements are extremely useful for studying the characteristics of the sporadic layers, which are the regions of enhanced atomic densities as compared to the background layer. Na being alkali like metal behaves very differently from the heavy metal and so the coincident measurements can provide better insight about the two metallic layers. Earlier observations of the annual variation of the Fe metallic layer have revealed the latitudinal variations of the various parameters of the Fe layer at a low latitude station like Arecibo are very different from that observed from a mid latitude site. This paper will present some interesting simultaneous measurements of the Na and Fe layer from Arecibo made in February and March, 2004. On the night of 18 March 2004, we observed `C' type sporadic Na layers (Na$_{S}$) between 92 to 98 km altitude regions. This event occurred around 22:30 hours lasting for about one hour. This was followed by two more events that were less intensive than the first one with a half hour interval between them. However, there is an indication of very weak layers in the case of the Fe during such strong Na$_{S}$. This appears to be very different from the sporadic activity observed at high latitudes where the occurrence frequency for Fe$_{S}$ is more than that observed in the case of Na. This will be compared with the sporadic E layers.
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0335 Ion chemistry of the atmosphere (2419, 2427)
DE: 0355 Thermosphere--composition and chemistry
DE: 0399 General or miscellaneous
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting