Abstract
We report on the first simultaneous observations of Ca and K metallic layers using the low-latitude lidar systems located at the Arecibo Observatory in Puerto Rico (18.35°N, 66.75°W). We often observe sudden increases in both Ca and K densities during early morning hours on nights where meteor showers take place. During these periods, the Ca/K abundance ratio varied between 2 and 3. On occasion, differences were observed in Ca and K layers, which relate to differences in the chemistry of the two metals. It is known that metallic layers display distinct seasonal variations, but chemistry alone cannot explain the measured differences. Thus, we examined whether or not the seasonal distribution of micrometeoroids, derived from meteor observations using the Arecibo 430 MHz radar, can account for the dissimilar metallic observations. We found that the deposition flux of micrometeoroids, with particle sizes ranging between 0.5 and 100 μm, increased by a factor of two during the summer as compared with the winter, suggesting a seasonal variation of their sporadic activity. In addition, our data support the idea that differential ablation leads to a depletion of Ca atoms in the mesosphere.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 595-606 |
| Number of pages | 12 |
| Journal | Journal of Atmospheric and Solar-Terrestrial Physics |
| Volume | 66 |
| Issue number | 6-9 |
| DOIs | |
| State | Published - Apr 1 2004 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Geophysics
- Atmospheric Science
- Space and Planetary Science
Cite this
}
Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity. / Raizada, S.; Tepley, C. A.; Janches, D.; Friedman, J. S.; Zhou, Q.; Mathews, John David.
In: Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 66, No. 6-9, 01.04.2004, p. 595-606.Research output: Contribution to journal › Article
TY - JOUR
T1 - Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity
AU - Raizada, S.
AU - Tepley, C. A.
AU - Janches, D.
AU - Friedman, J. S.
AU - Zhou, Q.
AU - Mathews, John David
PY - 2004/4/1
Y1 - 2004/4/1
N2 - We report on the first simultaneous observations of Ca and K metallic layers using the low-latitude lidar systems located at the Arecibo Observatory in Puerto Rico (18.35°N, 66.75°W). We often observe sudden increases in both Ca and K densities during early morning hours on nights where meteor showers take place. During these periods, the Ca/K abundance ratio varied between 2 and 3. On occasion, differences were observed in Ca and K layers, which relate to differences in the chemistry of the two metals. It is known that metallic layers display distinct seasonal variations, but chemistry alone cannot explain the measured differences. Thus, we examined whether or not the seasonal distribution of micrometeoroids, derived from meteor observations using the Arecibo 430 MHz radar, can account for the dissimilar metallic observations. We found that the deposition flux of micrometeoroids, with particle sizes ranging between 0.5 and 100 μm, increased by a factor of two during the summer as compared with the winter, suggesting a seasonal variation of their sporadic activity. In addition, our data support the idea that differential ablation leads to a depletion of Ca atoms in the mesosphere.
AB - We report on the first simultaneous observations of Ca and K metallic layers using the low-latitude lidar systems located at the Arecibo Observatory in Puerto Rico (18.35°N, 66.75°W). We often observe sudden increases in both Ca and K densities during early morning hours on nights where meteor showers take place. During these periods, the Ca/K abundance ratio varied between 2 and 3. On occasion, differences were observed in Ca and K layers, which relate to differences in the chemistry of the two metals. It is known that metallic layers display distinct seasonal variations, but chemistry alone cannot explain the measured differences. Thus, we examined whether or not the seasonal distribution of micrometeoroids, derived from meteor observations using the Arecibo 430 MHz radar, can account for the dissimilar metallic observations. We found that the deposition flux of micrometeoroids, with particle sizes ranging between 0.5 and 100 μm, increased by a factor of two during the summer as compared with the winter, suggesting a seasonal variation of their sporadic activity. In addition, our data support the idea that differential ablation leads to a depletion of Ca atoms in the mesosphere.
UR - http://www.scopus.com/inward/record.url?scp=2442710125&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2442710125&partnerID=8YFLogxK
U2 - 10.1016/j.jastp.2004.01.030
DO - 10.1016/j.jastp.2004.01.030
M3 - Article
AN - SCOPUS:2442710125
VL - 66
SP - 595
EP - 606
JO - Journal of Atmospheric and Solar-Terrestrial Physics
JF - Journal of Atmospheric and Solar-Terrestrial Physics
SN - 1364-6826
IS - 6-9
ER -