A model has been developed which describes the degradation of visibility due to battlefield aerosols. Emphasis is placed on the diffusion and transport of the aerosols and their effect on visibility degradation at locations remote from the sources. The starting point which we describe here is a simplified approach designed to evaluate the interplay between particle and meteorological components of the model and to obtain an order of magnitude estimate of the potential for visibility degradation due to battlefield aerosols. The one-dimensional meteorological model includes atmospheric turbulence and radiation effects and describes the diurnal development of the planetary boundary layer. The particle model adopts a Monte Carlo approach with 1,000 pseudo-particles (small air parcels containing many aerosol particles) released into the atmospheric conditions generated by the meteorological model. The full solution of this problem will require a meteorological model in three dimensions with a dynamic development of synoptic conditions on the regional scale.

A theoretical model proposed for calculating the space-time deformation of laser pulses due to multiple scattering in particulate media is improved by dropping the small-angle approximation and extending the validity of the model to the description of multiple scattering into a full solid angle. The problem is reduced to the computation of the generalized functions used in the model, carried out through the use of the recursive relations employed in the original model. For the dominant forward scattering, the deviation between the two models is found to be small. The strong dependence of pulse broadening on the angle of observation is emphasized. The results received are confirmed by applying the generalized functions to typical cases of forward scattering.

This paper is an update of a paper of the same title presented to SPIE in 1989. A new perspective of C_n² in low stratus clouds and their associated subcloud regions is developed in this paper. Two environments are still considered, that of a rising parcel and that of the ambient environment, resulting in two vertical profiles of C_n². An extension of Tatarski's formulations is used to characterize the environments, assuming that the turbulent parcels are weakly conservative and passive. Vertical profiles of the mean refractive index, the part of the gradient of the mean refractive index that does not adjust immediately when a parcel is displaced vertically, and C_n² associated with the rising parcel and those associated with the ambient atmosphere are presented for one set of conditions in a stable atmosphere.

In the atmospheric surface boundary layer, traditional optical turbulence models fail to provide environment-specific information. Moreover, new forms proposed for the turbulence spectrum depend on the turbulent inner and outer scales, as well as the refractive index structure parameter profile. Use of these turbulence spectrums to estimate propagation statistics for general linear propagation paths requires knowledge of all three profiles. These profiles exhibit a definite, interrelated vertical structure in the atmospheric surface boundary. Evidence suggests the actual turbulence spectrum should exhibit a "bump" in the region near frequencies associated with the inner scale. Therefore, propagation statistics are likely more sensitive to inner scale than previously expected. Consequently, reasonable estimates of inner scale become necessary to ensure accuracy of models predicting optical turbulence effects on propagation. The optical turbulence model contained in the Electro-Optical Systems Atmospheric Effects Library module IMTURB (imaging through optical turbulence) has been extended to calculate the profile for inner scale. Obukhov similarity is used to predict surface fluxes and gradients, and the Kolmogorov principle of universal equilibrium is employed to estimate dissipation. From dissipation profiles, consistent profiles of turbulent inner and outer scale are predicted, as well as the refractive index structure parameter profile. This comprehensive description of optical turbulence structure, when used with one of the new forms for the turbulence spectrum, will result in more realistic linear propagation statistics for the dry unstable surface boundary.

A scintillation calculation is presented in which the ground intensity is calculated for a satellite transmission through a model atmospheric irregularity of well-defined geometry. Artificial intelligence, in the form of extensive computer generated algebra, has been used to produce a closed form solution whose properties provide new information about the scintillation problem.

Atmospheric turbulence is a major limitation to optical high resolution imaging systems observing through the lower atmosphere. In most conditions, it limits the angular resolution to about one arcsecond, which is the resolution of a small 10 cm telescope operating in the visible. From a theoretical standpoint, its effects on beam propagation can be rather well predicted with the knowledge of atmospheric conditions and the assumption of the Kolmogorov turbulence law. Then, the practical problem turns out to be the characterization of propagation conditions and the compensation of turbulence effects.

The residual image is analyzed to determine a constraint which regularizes the ill-posed least squares image restoration problem. The energy in the residual image is constrained at a level which depends on the noise statistics, image degradation, and restoration method. This constraint is applied individually to different image subregions, to find different regularizations appropriate in each subregion. This defines a spatially variant restoration method, even for a spatially invariant image degradation. Least squares image restoration methods using this constraint are applied to an artificial image which has been degraded by simulated long-exposure atmospheric turbulence and random noise. Quantitative analysis of the restored image shows significant improvement with this constraint, in comparison to the usual constraint on residual energy which depends only on noise statistics.

In the unstable surface boundary layer, extremes in optical turbulence structure are encountered that seldom occur in astronomical applications. This is especially true when concern is with regions very near the earth's surface. Quantities defining optical turbulence spectrums, e.g. inner scale, outer scale and C_n², exhibit distinct vertical structures that might reasonably be expected to influence path dependent turbulence phenomena. Propagation statistics derived using path-indexed turbulence spectrums requiring profiles for turbulent inner and outer scales in addition to C_n² may differ from those predicted using the Kolmogorov spectrum, even when path dependence on C_n² is included in both cases. To study this problem in an engineering context, the well-known modified von Karman spectrum is used to characterize optical turbulence structure. Because of it's relevance to a wide range of optical turbulence related phenomena, the mutual coherence function is selected as the propagation statistic of interest. To evaluate the mutual coherence function, a weak fluctuation gaussian beam wave model based on direct, high fidelity numerical evaluation of defining integrals is employed. Estimates of the wave structure function and related mutual coherence function are then derived for propagation paths through designated optical turbulence regimes. The vertical structure of optical turbulence is estimated by a model based on similarity theory and the universal equilibrium principle. Behavior of the mutual coherence function for plane and spherical wave propagation may then be examined for near-horizontal linear propagation paths through optical turbulence regimes representing the realistic extremes in structure characteristic of the unstable surface boundary. For purposes of comparison, parallel calculations of the mutual coherence function are performed by extrapolating from commonly employed engineering estimates based on the Kolmogorov spectrum. Differences in the mutual coherence functions derived using these two techniques reflect differences in spectral form, vertical structure in turbulence profiles, and approximations to integral forms typical of engineering applications. Results have significant bearing on the fidelity of standard engineering models employed in the assessment of optical turbulence effects on system design and performance.

Measuring the scintillation of two electromagnetic waves that have propagated over a horizontal path near the earth's surface is tantamount to measuring the turbulent surface fluxes of sensible (H_S) and latent (H_L) heat, if we choose the wavelengths correctly. I call this the two-wavelength method. Here I show how to choose the two wavelengths and how to find the heat fluxes from a scintillation variable, C_n² , the refractive index structure parameter. We optimize the two wavelength method by pairing a short wavelength--one in the visible or infrared regions--with a long wavelength--one in the millimeter or radio regions. With such a two-wavelength combination, H_S and H_L will, typically, have uncertainties of 10-20% when the Bowen ratio, Bo = H_S/H_L, obeys -2.5 < Bo < -0.015 or 0.03 < Bo < 5.

The variance of the unbiased focal-plane estimates of image centroids from a point source is calculated for arbitrary strength of scattering using path-integral results. The Markov approximation and narrow-angular scattering are assumed. The telescope aperture is a circular disk for centroid variance and two identical circular disks for the variance of the difference between two centroids. The atmospheric turbulence described by the Hill spectrum are assumed to be homogeneous along the propagation path. When there are irradiance fluctuations, the variance of the unbiased estimate of image centroids depends on the choice of the origin of the weighting vector. The variance of the centroid of a single image depends on three physical parameters related to the Fresnel scale, inner scale, and strength of scattering. The variance of the separation between two images from two separated telescope apertures depends on the same parameters in addition to the normalized separation of the apertures. The important contributions from propagation distance and spectral wavenumber are identified for the different parameter regimes. The behavior of centroid variances are presented for typical boundary layer conditions and aperture sizes.

The response of fine wire resistance temperature transducer was analyzed including the effects of (i) conductive heat transfer between wire and the supporting prong and (ii) a thermal boundary layer which can form around the prongs especially at low stream velocities. The transfer function H(w) varied substantially with frequency of turbulence and density and velocity of the air stream. The a.c. gain of the sensor was evaluated as a function of altitude (0-30 km) and air stream velocity. Variation in a.c. gain with altitude can lead to a significant error in the measurement of turbulence with (delta)T probes. The error becomes even larger if the velocity of air stream (relative to sensor) becomes very small.

A technique is presented for simultaneous measurement of both the transverse coherence length, r₀, and the isoplanatic angle, (theta)₀, over coincident paths using a CCD array detection system. The theoretical basis for the measurements is discussed, and results of an extended test using this measurement technique are presented. These results substantiate the independence of the stellar image motion and image intensity fluctuations arising from atmospheric turbulence. Possible applications of this technique to atmospheric propagation studies are also discussed.

The paper describes a method of calculating the point spread and modulation transfer functions for imaging through aerosol media. The method is based on the image solution of a point source determined with the multiscattering propagation model of Bissonnette (1988). Results are presented that illustrate the effects of particle size, extinction coefficient and geometry. Comparisons with measurements show good consistency but no systematic validation is performed because the available image and aerosol data are not sufficiently documented or outside the range of validity of the propagation model. The calculated modulation transfer functions are applicable to image enhancement algorithms and could potentially be inverted to provide information on particle sizes.

A microphysics model was used to simulate vertical profiles of drop size distributions in very low stratus clouds and their associated subcloud regions. Drop size distribution profiles produced by the model for two different sets of atmospheric conditions specified at a reference level are presented. These profiles were compared with those reported by other authors and found to yield characteristics generally consistent with the measured values.

A model is presented for simulating very low stratus clouds and their associated subcloud regions. This model includes droplet growth, mass balance of total water, thermodynamics, similarity, and parcel ascent. The model requires only limited user input: some conventional meteorological values at a reference height (2 m above ground level) and some parameter values and other specifications. Input values for a visibility parameter and relative humidity are used to define the parameters of a bimodal lognormal dropsize distribution at the reference height. Drop size distributions are simulated and plotted for cases for which relative humidity at the reference height is 95 and 98 percent. Backscatter, absorption, and total extinction coefficients are calculated using Mie efficiency factors with simulated drop size distributions and plotted as functions of height for wavelengths of 0.55, 0.625, 1.06, 3.8, 4.0, and 10.6 micrometers.

The sensitivity of high energy laser propagation at 1.06 micrometers to an existing volcanic aerosol layer in the stratosphere has been studied by analyzing far field calculations performed with the WJSA four dimensional (three space plus time) Wave Optics Code with Adaptive Optics (OMEGA). The LOWTRAN moderate aged volcanic, high fresh volcanic, and extreme fresh volcanic models have been considered.

Aircraft measurements of trace gases and atmospheric aerosols were performed over the central United States during four research field periods in 1988 as a part of the Central U.S. RADM Test and Assessment Intensives (CURTAIN). Aerosol size distributions were measured at six altitudes between 700 and 3200 m above sea level over the size range 0.1-32 micrometers, using two Particle Measuring Systems (PMS) probes; an active scattering aerosol spectrometer probe (ASASP) and a forward scattering spectrometer probe (FSSP), mounted on the wings of the NOAA King Air research aircraft. The FSSP data were first corrected using a scheme which accounts for the effects of the probe's electronic response time and nonuniformity in the laser beam intensity profile on the measured aerosol size spectra. Vertical profiles of the average aerosol concentration show seasonal characteristics, with maximum concentrations during summer and minimum concentrations during winter. In summer, the aerosol number concentration in the fme. particle mode is rather constant about 2,000 cm^-3 up to about 1900 m asl level. Number concentration of the soil. derived aerosols in the coarse-particle mode is maximized during spring. The measured aerosol number size distributions exhibit typically bimodal distributions for both boundary layer and free tropospheric aerosols. Each measured number size distribution is approximated with a sum of two lognormal distributions using a lognormal fitting routine. The aerosol size distribution data measured in the boundary layer and in the free troposphere are compared with the LOWTRAN 'Rural' aerosol model and Tropospheric aerosol model, respectively.

Aerosols are difficult to measure and model in the atmosphere because of their complex variability in space and time. Lidar systems offer excellent capabilities for studying atmospheric aerosols because of their ability to remotely monitor large volumes of the atmosphere from a single site with very high spatial and temporal resolution. This paper presents an overview of current lidar applications for aerosol measurements. The present status of such work is summarized and the advantages and limitations of lidar are discussed.

Backscatter lidar systems are widely applied for remote measurements relating to atmospheric physics and environmental protection. One application is the observation of the dispersion of aerosol plumes close to the surface. Plumes from smoke stacks, industrial complexes and power stations are included in the problem. To evaluate various dispersion theories, many artificial plumes were observed with backscatter lidars installed in a van.

A study of the LOWTRAN 6 radiance models shows how atmospheric profile layering could improve near-horizon radiance predictions. The LOWTRAN 6 program is used to predict atmospheric path radiance, which is then compared with two sets of measurements made over the Mediterranean Sea. LOWTRAN 6 radiance predictions are made for two atmospheric profiles including radiosonde data. The "zero-order" and the "conservative" scattering models are also examined.

Measurements of 8 to 12 micrometers near-horizon sky radiances and meteorological parameters over the ocean near San Diego, California were used to evaluate the sky radiance algorithm of LOWTRAN 6. Discrepancies in measured and calculated sky radiances previously attributed to the neglect of multiple scattering effects of aerosols can be overcome by introducing additional low-level layers in the calculations of LOWTRAN 6. A comparison between radiance calculations using the single scattering, additive-layer approach and those using a multiple scattering version of LOWTRAN raises questions about the applicability of the multiple scattering approach in the far infrared region.

An understanding of how broad-band transmittance is affected by the atmosphere is crucial to accurately predicting how broad-band sensors such as FLIRs will perform. This is particularly true for sensors required to function in an environment where countermeasures such as smokes/obscurants have been used to limit sensor performance. A common method of estimating the attenuation capabilities of smokes/obscurants released in the atmosphere to defeat broad-band sensors is to use a band averaged extinction coefficient with concentration length values in the Beer-Bouguer transmission law. This approach ignores the effects of source spectra, sensor response, and normal atmospheric attenuation, and can lead to results for band averages of the relative transmittance that are significantly different from those obtained using the source spectra, sensor response, and normal atmospheric transmission. In this paper we discuss the differences that occur in predicting relative transmittance as a function of concentration length using band-averaged mass extinction coefficients or computing the band-averaged transmittance as a function of source spectra. Two examples are provided to illustrate the differences in results. The first example is applicable to 8- to l4-um band transmission through natural fogs. The second example considers 3- to 5-um transmission through phosphorus smoke produced at 17% and 90% relative humidity. The results show major differences in the prediction of concentration length values by the two methods when the relative transmittance falls below about 20%.

A review of the experimental results obtained in the laboratory regarding the characterization of the phenomena limiting the propagation of laser beams through the atmosphere is presented. It identifies in particular the thermo-mechanical effects created on isolated particles - vaporization, deformation, shattering, ejection - as well as the determination of the threshold values in terms of intensity and energy density required to initiate optical breakdown on aerosols and presents a real site experiment outside the laboratory situation for special meteorological conditions (determination of the breakdown thresholds and transmission balances).

The aerosol attenuation of a near-ultraviolet laser radiation propagating through a simulated and controlled medium is investigated experimentally. Radiation from an excimer laser in an air-sea interaction simulation tunnel is utilized. Attention is focused on the measurement of aerosol profiles as a function of the X-axis above the water surface, water density in air, mean wind velocity in the tunnel, the difference between air and water temperature corresponding to various fog densities as well as the differential measurements of the total attenuation of the ultraviolet radiation passing through the medium. Examples of KrF and XeF transmittances for various granulometric distributions of water droplets are presented along with relationships between measured transmittances and liquid volume per unit air volume.

Model SENSAT (Sensor-Atmosphere-Target) is a tool for evaluating the radiometric system performance of passive optical sensors. In combination with the LOWTRAN-7 code the model can be employed in the spectral range 0.20-28 microns. The model is capable of treating up to three homogeneous objects in the sensor's instantaneous field of view. It calculates the emitted/reflected radiance contribution of each object at the sensor, the SNR, the brightness temperature (IR sensors), and derived quantities such as the detector signal, and associated quantized (A/D converted) digital numbers. Special features include the multiple path option (sun-earth-target-sensor), a noise model for quantum detectors, a spectral band optimization, and a multi-band sensor option, which processes a sequence of contiguous spectral bands (e.g. high resolution spectrometer). Besides the system performance prediction the model can also be employed to process images of spaceborne/airborne optical sensors by performing the atmospheric correction and calculating ground reflectance images.

Smoke and dust clouds are often more easily detected than the sources producing the clouds. Long range detection depends on the cloud's size and contrast against its background. However, a cloud can sometimes be detected, even in low average contrast conditions, if it significantly masks the apparent clutter of its background or if it provides sufficiently different clutter itself. This paper investigates a basic cloud detection method that includes both cloud contrast and background clutter. It is assumed that the sensor minimum resolvable contrast (or thermal temperature difference) as a function of spatial frequencies is known. This is used to define a detection threshold. We consider contrast in mean intensity, changes in the width of the background intensity histogram, changes in edge strength, and comparison of spatial frequency content as methods to detect the cloud relative to its background. Methods are examined using measured and simulated images.

Understanding the general statistical characteristics and the distribution of target-like features in thermal background imagery is an important part of solving the automatic target recognition (ATR) problem. An alternative approach to test site and scene characterization, based on thermal background image metrics, is described and demonstrated. A database of forward looking infrared (FLIR) imagery, and meteorological and terrain data was systematically obtained from three continental U.S. (CONUS) test sites. Image metrics, relevant to ATR performance, were computed on all imagery. It was deonstrated that temporal variations in these metrics could be predicted (r² >= 0.79) using current meteorological conditions and a time history of solar loading measurements. Scene-to-scene differences in the texture metrics at a single test site could be predicted (r² >= 0.78) based on gross scene content attributes. The applications and limitations of this approach and procedure are discussed.

A scheme for validating turbulence phase screen generators will be considered. The method does not in general depend on the algorithm used for generating phase screens, nor on the spectrum which describes the turbulence, although these must be specified in order to obtain numerical results. The "correctness", or validation of a generator can be defined in various ways. Of particular significance is that the screens be generated with the proper Zernike modes, and this is the validation criterion taken here. The Zernike modes are of interest because they represent classical optical aberrations, such as tilt and focus.

New analytical models of the spatial power spectra of temperature fluctuations and refractive-index fluctuations in the atmospheric boundary layer, showing the characteristic "bump" just prior to the dissipation ranges, have recently been developed as a modification of the standard Tatarski model. Using this new model for the power spectrum of the refractive index, new expressions are developed for the phase structure function of an optical wave propagating through atmospheric turbulence. The effects of this new phase structure function on the phase coherence length, and hence on Fried's seeing parameter r₀ for the critical diameter of a telescope, are also examined.

The Applied Physics Laboratory has developed a physical optics electromagnetic propagation computer code at radar frequencies that features long path length representation of atmospheric waveguides or ducts. Thus, an accurate tropospheric absorption model, emphasizing water vapor and oxygen effects, is required for a realistic code. The HITRAN database now provides a comprehensive characterization of spectral lines from 0 to 10 cm^-1. A theoretical local line shape is used with this database, which improves the traditional models. Also, a new semiempirical water vapor continuum model has been developed based on the theoretical work of Birnbaum and the most recent experimental data. The result is an improved model for low-altitude, long path calculations of atmospheric absorption at radar and millimeter wavelengths.

Advancements in short wavelength lasers has renewed the interest in molecular extinction in the 1.0 to 2.0 micrometer region. In recent programs sponsored by three agencies: Lincoln Laboratory, the U.S. Army Strategic Defense Command, and the Atmospheric Sciences Laboratory, OptiMetrics has refined molecular parameters in this spectral region for use with both ground level and slant atmospheric paths.

For the past twelve years, a coordinated tri-service effort has been underway in the United States Department of Defense to provide an atmospheric effects assessment capability for existing and planned electro-optical (E0) systems. This paper reviews the exploratory development effort in the US Navy. A key responsibility for the Navy was the development of marine aerosol models. An initial model, the Navy Aerosol Model (NAN), was developed, tested, and transitioned into LOWTRAN 6. A more comprehensive model, the Navy Oceanic Vertical Aerosol Model (NOVAM), has been formulated and is presently undergoing comprehensive evaluation and testing. Marine aerosols and their extinction properties are only one important factor in EO systems performance assessment. For many EO systems applications, an accurate knowledge of marine background radiances is required in addition to considering the effects of the intervening atmosphere. Accordingly, a capability was developed to estimate the apparent sea surface radiance for different sea states and meteorological conditions. Also, an empirical relationship was developed which directly relates apparent mean sea temperature to calculated mean sky temperature. In situ measurements of relevant environmental parameters are essential for real-time EO systems performance assessment. Direct measurement of slant path extinction would be most desirable. This motivated a careful investigation of lidar (light detection and ranging) techniques including improvements to single-ended lidar profile inversion algorithms and development of new lidar techniques such as double-ended and dual-angle configurations. It was concluded that single-ended, single frequency lidars can not be used to infer slant path extinction with an accuracy necessary to make meaningful performance assessments. Other lidar configurations may find limited application in model validation and research efforts. No technique has emerged yet which could be considered ready for shipboard implementation. A shipboard real-time performance assessment system was developed and named PREOS (Performance and Range for EO Systems). PREOS has been incorporated into the Navy's Tactical Environmental Support System (TESS). The present version of PREOS is a first step in accomplishing the complex task of real-time systems performance assessment. Improved target and background models are under development and will be incorporated into TESS when tested and validated. A reliable assessment capability can be used to develop Tactical Decision Aids (TDAs). TDAs permit optimum selection or combination of sensors and estimation of a ship's own vulnerability against hostile systems.

A systems analysis approach is presented for an infrared and radar system operating from the same platform in the atmosphere. Expressions for the radar one way attenuation coefficient are used for the performance degradation calculations. Similar expressions are derived for the atmospheric absorption for the infrared system using the Aggregate method. The transmittances for a four component species model are calculated for the platform line of sight oriented upward, horizontal, and downward from the zenith. Comparisons of the method with field measurements at sea level and at 30 km and with the LOWTRAN method are made.

The light intensity of a laser beam which has propagated through the atmosphere will be irregular due to inhomogeneities in the atmosphere. Thus the intensity falling on a target is higher on some target areas and lower in others leading to damaged areas randomly distributed over the illuminated area. This study predicts the average area, A, of a single damaged area using a mathematical treatment, focusing largely on the concepts of two dimensional level crossings and excursion areas. After developing a solution for A for arbitrary probability density function (pdf), a solution for gamma distributed intensity is developed. This solution is then applied to several models for the spectral distribution of the intensity, including graphs illustrating the results. To reduce the problem to a manageable task, several assumptions and approximations are made. First, the pdf for the intensity is assumed to be the gamma distribution. This gamma distribution is applicable for the intensity of a gaussian field, a sum of gaussian fields, and therefore thermal light'. Second, the covariance function of the intensity is assumed to be isotropic. Furthermore, the intensity required to damage an area, I_crit, is assumed to be sufficiently high so that the probability of a damaged area containing an island of undamaged area is small. Although this assumption makes the calculated results approximate, these results become a better approximation for larger values of I_crit. Lastly, the variations in intensity are assumed to be spacially ergodic.

The uncontrolled thermal currents present in a beam expander can significantly degrade optical performance. Incident laser radiation on mirrors and their supporting structures insures that temperature differences will be present. These temperature differences within the beam path can induce significant optical distortions. Optical performance can be improved with active conditioning of the beam path. This report describes several aspects of active beam path conditioning: boundary layer control on mirrors, thermal conditioning of beam expander cavities and coude paths, and thermal control of vacuum and exit window configurations. Design concepts for each of these components are discussed. Beam path conditioning systems that combine these components are presented and recommendations given. Finally, a summary of current capabilities in beam path conditioning systems is made with recommendations for future work.

Observations are presented displaying the evolution of transparent inhomogeneities in the natural atmosphere. All results are for horizontal paths in the first few meters above ground level. Measurements were taken using both a schlieren optical system capable of sensing fine scale gradients of refractive index and an optical system sensing the fine structure of intensity scintillation over various path lengths. Laser sources were utilized for both systems, and a full description of the two optical systems is included. The schlieren system employs two high quality 10-in-diameter mirrors to produce the illuminated working section. Trade-offs between this and other schlieren optical system configurations are discussed. The intensity scintillation measurements were taken with a collimated laser beam projected on a target board. System characteristics including the CCD camera, sampled frame rates, exposure times, and data processing are discussed. The central problem addressed in this study is to identify the conditions when G. Taylor's "frozen turbulence" hypothesis is justified. The optically derived results are compared to results from previous studies using tower, aircraft, and tethered balloon measurements. Analyses presented include histograms, three-dimensional displays, contour maps of features, and frame subtraction schemes. Simultaneous measurements of integrated path and point measurements of the refractive index structure parameter (C_n²), and wind , are included in the results.