HR: 11:55h
AN: SA41C-07    [PDF]
TI: Simultaneous Observations of Neutral Ca and K Metallic Layers from Arecibo and the Possible Influence of Micrometeoroids on Sporadic Layers
AU: * Raizada, S
EM: shikha@naic.edu
AF: Arecibo Observatory, HC-03 Box 53995, Arecibo, PR 00612 United States
AU: Tepley, C A
EM: craig@naic.edu
AF: Arecibo Observatory, HC-03 Box 53995, Arecibo, PR 00612 United States
AU: Janches, D
EM: diego@naic.edu
AF: Arecibo Observatory, HC-03 Box 53995, Arecibo, PR 00612 United States
AU: Friedman, J S
EM: jonathan@naic.edu
AF: Arecibo Observatory, HC-03 Box 53995, Arecibo, PR 00612 United States
AU: Zhou, Q H
EM: zhouq@muohio.edu
AF: Miami University, Manufacturing and Mechanical Engineering Department, Oxford, OH 45056 United States
AU: Mathews, J D
EM: jdmathews@psu.edu
AF: Pennsylvania State University, Communications and Space Sciences Laboratory, University Park, PA 16802 United States
AB: We present a few cases of simultaneous lidar observations of neutral Ca and K metallic layers from Arecibo. During several nights, sudden enhancements in both metals were seen in the early morning hours and we tried to correlate this with the occurrence of meteor showers. Our observations show that the sporadic layers were strong during the weak Lyrids showers in June, as compared with those that occurred during the presence of fast meteor showers like the Eta-Aquarids and the Perseids. The occurrence of early morning sporadic layers appears to be consistent with the increase in meteor activity during that period, which has been reported earlier in the literature. Thus, we investigated the seasonal variations observed in sporadic micrometeoroids using the Arecibo Observatory radar operated in the meteor mode. This study revealed an increase in the sporadic activity of micrometeoroids in June, which may be partly responsible for the occurrence of strong neutral layers seen during early morning hours in the summer. Apart from this, we will discuss the different characteristics of Ca and K layers observed at Arecibo and relate them to the mesospheric chemistry.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 3360 Remote sensing
DE: 6245 Meteors
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting