AAS 195th Meeting, January 2000
Session 92. Missions: From Stonehenge to HST
Oral, Friday, January 14, 2000, 10:00-11:30am, Centennial IV

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[92.02] Atmospheric Fluctuation Measurements with the Palomar Testbed Interferometer

R. P. Linfield (Infrared Processing and Analysis Center, Caltech), M.M. Colavita (Jet Propulsion Laboratory, Caltech), B. F. Lane (Department of Planetary Sciences, Caltech), PTI Collaboration

Atmospheric turbulence parameters have been derived from the Palomar Testbed Interferometer, using delay line and fringe phase time series from 30~nights in 1998. The most significant result is that the power law slope of the delay structure function is shallower than the three-dimensional Kolmogorov value of~5/3. Measured power law slopes ranged from~1.3 to~1.55. Such sub-Kolmogorov slopes mean that the `seeing' will improve at longer wavelengths faster than the standard \lambda- 0.2 law (\lambda is the wavelength). The variation in the power law slopes from night to night were substantially larger than the variation within individual nights. However, the coherence time often varied by factors of 2--3 within one night.

Time series of measurements from the starlight angle trackers have been used to derive additional information on the turbulence for a few nights in 1999. The angular structure function shows evidence for multiple layers, with different wind velocities (e.g. a dominant layer with a velocity of 2~m/s, and weaker turbulence with velocity \ge 20~m/s).

Parts of this research were performed by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

The author(s) of this abstract have provided an email address for comments about the abstract: RPL@ipac.caltech.edu

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