Variability of slant-path turbulence parameters and inner scale effects

A six-year data set of refractive index structure parameter (Cn2) results from VHF radar observations at White Sands Missile Range, NM is used to calculate slant path values of the transverse coherence length (ro), the isoplanatic angle, and the Rytov variance. The calculations were for a spherical wave condition, a wavelength of 1 micrometers , four different elevation angles, two path lengths, and platform, such as an aircraft, at 12.5 km MSL. Over 281,000 radar-derived profiles sampled at three minute intervals with 150-m height resolution were used for the calculations. The approach, an 'onion skin' model, assumes horizontal stationarity over each entire propagation path and is consistent with Taylor's hypothesis. Refractivity turbulent effects are greatly reduced as the elevation angle increase, a pronounced seasonal effect is seen consistent with climatological variables and gravity wave activity, and interactions of enhanced turbulence in the tropopause region is evaluated. An evaluation of inner scale on the calculations is discussed. Results of a two region model understood in terms of upward propagating gravity waves that are launched by strong winds over complex terrain are shown.