Daytime r_0 evaluated from vertical microthermal measurements

Abstract

The usefulness of parameter r(0) for describing the effect of atmospheric turbulence on wavefront distortion sensitive optical systems has been widely discussed. In this paper we present in situ daytime r(0) measurements (5500 A, Zenith propagation) obtained from balloon-borne microthermal radiosondes. We find that the parameter r(0) is log normal distributed at various levels aloft and that r(0) follows a power law in the 100-10,000-m range. Comparing our results with nighttime ground based observations we conclude that local turbulence prevails in determining image quality.

Site testing in summer at Dome C, Antarctica

“…First, a monitoring of the turbulence parameters in the visible (seeing r 0 , isoplanatic angle θ 0 , outer scale L 0 , and coherence time τ 0 ) with a GSM experiment (Ziad et al 2000) specially designed to work in polar winter conditions. In addition to this monitoring, it was proposed to launch balloons equipped with microthermal sensors to measure the vertical profile of the refractive index structure constant C 2 n (h) (Barletti et al 1977). Is was predicted that 50 to 60 balloons would be regularly launched during the polar winter.…”

Optical turbulence modeling in the boundary layer and free atmosphere using instrumented meteorological balloons

“…These in situ experiments are very useful tools for investigating astronomical seeing without using large telescopes. The same technique has been extensively used by Barletti et al (1974Barletti et al ( , 1977 during the J.O.S.O. site testing campaign.…”

Aircraft measurements on vertical changes in aerosol parameters - Remote sensing with detection of upwelling radiance from an atmosphere-ocean surface system.

“…Here we assumed k=0.0069 for aerosols in the urban atmosphere, summarizing other investigators' values (e.g., GRAMS et al, 1974;TOON and POLLACK, 1976;BARLETTI et al, 1977), and the real part index was chosen as the parameter retrieved from the measurement.…”