Radar and aircraft observations of a layer of strong refractivity turbulence

Frank D. Eaton; Gregory D. Nastrom; Bruce S. Masson; Ila L. Hahn; Kimberley A. McCrae; Scott R. Nowlin; Timothy L. Berkopec

doi:10.1117/12.323944

8 September 1998 Radar and aircraft observations of a layer of strong refractivity turbulence

Frank D. Eaton, Gregory D. Nastrom, Bruce S. Masson, Ila L. Hahn, Kimberley A. McCrae, Scott R. Nowlin, Timothy L. Berkopec

Author Affiliations +

Proceedings Volume 3381, Airborne Laser Advanced Technology; (1998) https://doi.org/10.1117/12.323944
Event: Aerospace/Defense Sensing and Controls, 1998, Orlando, FL, United States

Abstract

The Air Force Research Laboratory at Kirtland Air Force Base examined the characteristics of the refractive index structure parameter (C²_n) within a strong and persistent layer of turbulence using observations obtained from a 49.25 MHz radar and an instrumented C-135E aircraft at the Atmospheric Profiler Research Facility at White Sands Missile Range, NM on January 23, 1997. The aircraft measurements sensed the atmospheric temperature structure parameter (C²_T) with fine-wire aerothermal probes for deriving C²_n while the radar measurements provided C²_n from Bragg scatter at turbulent scales in the clear air. The aircraft results provide horizontal spatial information at the specific altitudes flown while the radar-obtained values show temporal profile information. Flight legs approximately 200 km long were flown along the wind direction at eight different altitudes from 11.01 km to 12.21 km MSL. The turbulent layer and direction of flights were selected from the VHF radar-obtained C²_n and wind measurements prior to take-off. Presentations include a range-height display of the patterns of refractivity turbulence obtained from the aircraft measurements and a range-height display derived from the radar observations corresponding to the aircraft results. Both range-height displays were produced by assuming Taylor's hypothesis and applying the actual wind profile to the time-height data. The evolution and persistency of features is discussed. A statistical evaluation comparing the two different methods of sensing C²_n is presented. Salient features of the aircraft sensors and radar are discussed.

Citation Download Citation

Frank D. Eaton, Gregory D. Nastrom, Bruce S. Masson, Ila L. Hahn, Kimberley A. McCrae, Scott R. Nowlin, and Timothy L. Berkopec "Radar and aircraft observations of a layer of strong refractivity turbulence", Proc. SPIE 3381, Airborne Laser Advanced Technology, (8 September 1998); https://doi.org/10.1117/12.323944

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