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Lidar observations of the MLT metal layer and temperatures at (and with) the Arecibo Observatory. Jonathan Friedman Arecibo Observatory 17 May 2007. Outline. Arecibo’s lidars Results Ion-neutral interactions … sporadic layers Micrometeors and the metal layer topside
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Lidar observations of the MLT metal layer and temperatures at (and with) the Arecibo Observatory Jonathan Friedman Arecibo Observatory 17 May 2007
Outline • Arecibo’s lidars • Results • Ion-neutral interactions … sporadic layers • Micrometeors and the metal layer topside • MLT temperature measurements & solar influence
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
Some Results • Summary of some past results • Sporadic layers • Temperatures, inversion layers, and Gravity Wave events • Ongoing projects • Metal layer topside and micrometeoroids • Seasonal thermal structure of the Arecibo mesopause.
Sporadic layer event during the 1998 Coquí II sounding rocket campaign
Tepley et al., 2003 Ca+ e- K
The Metal Layer Topside: A direct measure of micrometeor input?
Metal Layer Topside 0.1/cc 1/cc 10/cc 100/cc
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.
Seasonal Climatology and how the mesopause above Arecibo fits into the global picture
Latitude Comparison 78°N, Spitsbergen Höffner, 2006 35°N, Albuquerque, NM (Starfire) Chu et al., 2005 21°N, Maui, HI Friedman and Chu, 2006 18°N, Arecibo, PR Friedman and Chu, 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.