During the period 25 OCT 95 through 28 OCT 95, researchers at the Starfire Optical Range (SOR) near Albuquerque, New Mexico observed a complete upper-tropospheric turbulence event which varied in intensity from light to severe over the course of the observation period. The observing instruments included an optical coherence length sensor and an isoplanatic angle sensor developed at the Naval Postgraduate School. Both sensors measure a path integral of optical turbulence. The coherence length device performs a uniform weighting and the isoplanatic angle device performs an altitude z^5/3 weighting. The integrated optical turbulence varied by over one order of magnitude during this period, severely degrading the quality of images propagating through the atmosphere.
The observation period was marked by the passage of a surface cold front, a sub-tropical jet retreating toward the south, and the approach and passage of a polar jet in the upper troposphere. The periods of strongest turbulence appear to occur when observations were made at the horizontal periphery of each jet.
The Navy's Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) was used to generate numerical simulations with very fine horizontal resolution (3 km) and 30 vertical levels to compare the in situ upper-tropospheric turbulence measurements to that generated by the model. Turbulence in COAMPS was generated using the Mellor and Yamada (1982) 2.5 closure scheme for parameterizing mixing length with the Bougeault and Lacarrere (1989) scheme for computing optical turbulence. Comparisons indicate that the current parameterization underestimates turbulent kinetic energy (TKE) in the free atmosphere. Modeling TKE for the upper-troposphere must be revised to generalize parameterizations typically tuned for boundary layers in close proximity to the earth's surface.