1. 17 May 2007 Lidar observations of the MLT metal layer and temperatures at (and with) the Arecibo Observatory Jonathan Friedman Arecibo Observatory 17 May 2007

2. Outline Arecibo’s lidars Results –Ion-neutral interactions … sporadic layers –Micrometeors and the metal layer topside –MLT temperature measurements & solar influence

3. 17 May 2007 Arecibo Observatory Lidars Two broadband resonance density lidars (any 2 of Na, Ca, Ca +, Fe) Narrowband K Doppler lidar Four 80-cm diameter cassegrain telescopes, fiber coupled to detectors. Seven independent channels with PMT detectors, APD channels under development. Daylight capability for K lidar being implemented

4. 17 May 2007 K lidar Transmitter & Receiver

5. 17 May 2007 Some Results 1.Summary of some past results Sporadic layers Temperatures, inversion layers, and Gravity Wave events 2.Ongoing projects Metal layer topside and micrometeoroids Seasonal thermal structure of the Arecibo mesopause.

6. 17 May 2007 Sporadic layer event during the 1998 Coquí II sounding rocket campaign

7. 17 May 2007 Tepley et al., 2003 Ca + e-e- K

8. 17 May 2007 Ducted waves and temperature inversions

9. 17 May 2007 Arecibo and SABER inversion measurement

10. 17 May 2007 The Metal Layer Topside: A direct measure of micrometeor input?

11. 17 May 2007 Metal Layer Topside 0.1/cc 100/cc 10/cc 1/cc

12. 17 May 2007 Metal abundance ratios

13. 17 May 2007 An example from Kühlungsborn (1/2) Plotted are ratios of metal atom densities (K/Fe), K/Ca, and Fe/Ca from Kühlungsborn, 27 Oct 97.

14. 17 May 2007 Example from Kühlungsborn (2/2)

15. 17 May 2007 [K/Na] example for Arecibo

16. 17 May 2007 Comparisons with K

17. 17 May 2007 Seasonal Climatology of the tropical MLT

18. 17 May 2007 Seasonal Climatology and how the mesopause above Arecibo fits into the global picture

19. 17 May 2007 78°N, Spitsbergen Höffner, 2006 Latitude Comparison 35°N, Albuquerque, NM (Starfire) Chu et al., 2005 18°N, Arecibo, PR Friedman and Chu, 2007 21°N, Maui, HI Friedman and Chu, 2006

20. 17 May 2007 Comparing specific altitudes

21. 17 May 2007 12-tidal oscillations a work in progress

22. 17 May 2007 January 12-h Analysis

23. 17 May 2007 Including the 24-h tide from GSWM

24. 17 May 2007 Summary Arecibo has multiple resonance lidars to investigate the properties of the mesospheric metal layer The K lidar is a Doppler lidar for temperature measurements. We have studied sporadic layers in conjunction with the ionospheric radar. We work together with visiting instruments to study transient phenomena. We participate in the study of the meteoric input to the atmosphere, and how micrometeoroids may produce the topside. We study thermal structure & oscillations Full daylight capabilities imminent.

25. 17 May 2007 Additional slides

26. 17 May 2007 Tracking K s layers

27. 17 May 2007 Tracking ion layers