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Optical effects of thermal structure in the lower atmosphere
1CSIRO Division of Physics, National Standards Laboratory, Sydney, Australia.
Applied Optics
|January 9, 2010
Summary
Stable atmospheric conditions with minimal temperature fluctuations correlate with excellent optical seeing. These quiescent periods are linked to low wind speeds and specific wind-path angles, crucial for astronomical observations.
Area of Science:
- Atmospheric physics
- Optical astronomy
- Turbulence research
Background:
- Atmospheric convective plumes and temperature fluctuations affect optical observations.
- Good optical seeing is intermittently observed in the lower atmosphere.
Purpose of the Study:
- To investigate the correlation between atmospheric temperature fluctuations and optical seeing.
- To identify conditions conducive to periods of good optical seeing.
Main Methods:
- Optical path experiments measuring image dancing and temperature fluctuations.
- Analysis of correlation sensitivity to azimuthal wind-path angles.
- Determination of critical wind speed for temperature-quiescent periods.
Main Results:
- A strong correlation exists between low air-temperature fluctuation periods and good optical seeing.
- Optical seeing quality is dependent on the azimuthal angle between wind direction and the optical path.
- Temperature-quiescent periods require wind speeds below a critical value and show wind-aligned thermal structures.
Conclusions:
- Periods of stable atmospheric thermal structure significantly enhance optical seeing.
- Understanding these atmospheric conditions is vital for improving astronomical observation quality.
- Experimental findings align with direct atmospheric measurements.
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