17 May 2007

Lidar observations of the MLT metal layer and temperatures at

(and with) the Arecibo Observatory

Jonathan FriedmanArecibo Observatory

17 May 2007

17 May 2007

Outline

• Arecibo’s lidars• Results

– Ion-neutral interactions … sporadic layers

– Micrometeors and the metal layer topside

– MLT temperature measurements & solar influence

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

17 May 2007

K lidar Transmitter & Receiver

17 May 2007

Some Results

1. Summary of some past results• Sporadic layers• Temperatures, inversion layers, and Gravity

Wave events2. Ongoing projects

• Metal layer topside and micrometeoroids• Seasonal thermal structure of the Arecibo

mesopause.

17 May 2007

Sporadic layer event during the 1998 Coquí II sounding

rocket campaign

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Tepley et al., 2003

Ca+

e-

K

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Ducted waves and temperature inversions

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Arecibo and SABER inversion measurement

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The Metal Layer Topside: A direct

measure of micrometeor input?

17 May 2007

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Metal Layer Topside

0.1/cc

100/cc10/cc

1/cc

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Metal abundance ratios

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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.

17 May 2007

Example from Kühlungsborn (2/2)

17 May 2007

[K/Na] example for Arecibo

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Comparisons with K

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Seasonal Climatology of the tropical MLT

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Seasonal Climatology and how the mesopause above Arecibo fits into the

global picture

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17 May 2007

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78°N, SpitsbergenHöffner, 2006

Latitude Comparison

35°N, Albuquerque, NM (Starfire)Chu et al., 2005

18°N, Arecibo, PRFriedman and Chu, 2007

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21°N, Maui, HIFriedman and Chu, 2006

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Comparing specific altitudes

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12-tidal oscillationsa work in progress

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January 12-h Analysis

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Including the 24-h tide from GSWM

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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.

17 May 2007

Additional slides

17 May 2007

Tracking Ks layers

17 May 2007

Tracking ion layers