This section contains functions for use in atmospheric modeling. There are functions which generate profiles of the refractive index structure constant, Cn2, and absorption and scattering coefficients, temperature, density and other parameters.
Name 
Description 
Returns the value of the AFGLAMOS night turbulence profile given altitude above sea level in meters.  
Returns model data for absorption and scattering coefficients, and temperature as a function of altitude h for a given wavelength and atmospheric condition. Models were developed for 0 km to 11 km altitude, but can be extended to higher altitudes. COIL analysis was performed for 1.31521 microns wavelength (see reference below).  
Return model data interpolated from Atmospheric InfraRed Sounder (AIRS) measurements.  
Returns the value of the apparent gravity profile given altitude above sea level in meters and latitude. This function will generate the slight changes in gravity with altitude. It is valid from the surface to 86 km above mean sea level.  
Currently supported models:
 
Computes the average values of the input model over the specified phase screen slabs. Can be used with any model type.  
Maps input altitudes in the interval [hInt(1),hInt(2)] into altitudes in the interval [hhInt(1) hhInt(2)] before calling the atmospheric model 'BaseModel' with altitude hh given parameters p1,...,pN. Intended to facilitate using atmospheric models in the earth's boundary layer where certain altitudes should be referenced to ground level, and other altitudes should be referenced to sea level. Generally, hInt(2) = hhInt(2) = boundarylayer altitude limit. However, code will accept other inputs and use them accordingly. Altitudes in interval hInt are set according to: hh = hhInt(1)+(diff(hhInt)/diff(hInt)).*(hhInt(1)); Input altitudes less than hInt(1) are set to hhInt(1).  
Returns value of the Bufton wind model for input altitude h. This model was originally used for wind profiles from the Maui Space Surveillance Site on Haleakala and as such, the altitude corresponding to z = 0 is 3048 meters above MSL when using the default values for vg, hpk, hscale, and vt  see reference 2 below.  
Function to change parameters of an existing Atm structure. Any of the allowed atmospheric models from AtmStruct can be changed, in addition to geometry, number of screens, maximum altitude, turbulence multiplier alpha when a Cn2 model is present, and wavelength in extinction models. For a change in wavelength to work properly, a wavelength string must be the third input to the model function. Additionally, multipliers of other profiles can be specified with the input 'alpha[model]' for the parameter name. To change turbulence multiplier, specify either 'alphaCn2' or 'alpha.'  
Returns the value of the CLEAR1 night turbulence profile given altitude above sea level in meters. CLEAR1 night is only defined from 1230 m to 30 km altitude, however, this function will return values for altitudes lower than 1230 m and higher than 30 km. The values below 1230 m are an extrapolation of the model form between 1230 m and 2130 m. The values above 30 km are an extrapolation of the model form between 10.34 km and 30 km.  
Clear 2 Night turbulence profile. Profile is based on data taken above White Sands Missile Range. Databased profile function is defined for 1230 m <= h <= 30 km. Ground level of model is h = 1216 m, and for numerical convenience we define Cn2 below 1230 m to be equal to the model value at 1230 m. For h > 30 km, returned values are an extrapolation of the databased function.  
Value of Clear2 wind model.  
Converts a dew point temperature to a relative humidity given the air temperature.  
Returns the value of the DLRmodified HufnagelValley (5/7) turbulence profile given altitude above sea level in meters  
Computes Cn2 using AFIT's dynamic piecewise model based on AIRS maritime observations.  
Returns the dynamic viscosity as a function of temperature.  
Compute the refractive index modulus for a given lambda based on work published by Owen.  
Calculates pathnormalized phase screen positions and thicknesses for equal strength phase screens. This function first calculates the plane wave coherence length, $r_0^{5/3}$, and divides by Nscreens so that each segment will have the same strength. This function discretizes the calculation by breaking the path into n segments per meter and integrating $C_n^2$ to reach the desired strength per phase screen. If Atm.MaxAlt is not infinite, output screen positions are over the path where altitude is less than Atm.MaxAlt as assumed by AtmStruct.  
This function runs FASCODE and return a structure that has the output. The output includes the trans. and extinction coefficient. FASCODE is not distributed with ATMTools. The user must obtain a version of FASCODE and install in ATMTools/OTT/FASCODE.  
Generates absorption and scattering coefficients as well as temperature and pressure using the Global Aerosol Data Set (GADS) and LEEDR/ExPERT meteorological data. It will generate the proper structure for use in LEEDRAtmos based on the provided inputs.  
Returns the value of the Greenwood turbulence profile given altitude above sea level in meters.  
Returns the value of the HufnagelValley turbulence profile given altitude above sea level in meters. Defaults to HV (5/7) if v and A are not passed. Can also compute and use v and A if wavelength, r0, and theta0 are provided.  
Returns the value of the HufnagelValley (5/7) turbulence profile given altitude above sea level in meters.  
Function for computing inner scale as a function of altitude using a physical model.  
Generates model data at specified altitudes, h, based on precomputed LEEDR data generated using the buildLEEDRAtmos function.  
Generates model data at specified altitudes (AGL), h, based on precomputed LEEDR Wx Cube data generated using the buildLEEDRWxCube function. To convert between MSL (used by SHaRE and ATMTools) and AGL, use TerrainAtm (requires DTED data from http://earthexplorer.usgs.gov/  see bilLoad). If the weather cube was generated using buildLEEDRWxCube, there is an option to also generate the terrain elevation data for the cube (provided the DTED data is available). If DTEDdir is true or if DTEDdir specifies a directory with the necessary DTED data, terrain elevation data will be computed if it doesn't already exist and elevation.h5 file... more  
Returns $y = A*{base}^{(h/B)}$, to be used for generic altitudedependent, logarithmicallydecreasing atmospheric models with surface value A and scale height B.  
General LUT function for extrapolating atmospheric data. The specified Matlab data file must contain a vector Altitude and a vector for the desired data.  
Maui 3 Turbulence profile as defined in standard literature. This is the most recent (vintage Feb 2003) model for propagation above Maui's Mt. Haleakala. It is considered more correct than the old AFGL AMOS model for matching median propagation quantities. Maui 3 has been designated the official Mauisite model for the Active Track program. Databased profile values are defined for h > 3050 m. Ground level is h = 3038 m, and for numerical convenience we define Cn2 below 3050m to be equal to Cn2(3050m).  
Computes Mie scattering and extinction efficiencies; asymmetry factor; forward and backscatter amplitude; scattering amplitudes vs. scattering angle for incident polarization parallel and perpendicular to the plane of scattering; coefficients in the Legendre polynomial expansions of either the unpolarized phase function or the polarized phase matrix; some quantities needed in polarized radiative transfer; and information about whether or not a resonance has been hit. This MATLAB code is a transcription of the original FORTRAN code by Wiscombe (see references). Where possible, vectorization has been implemented. MOST input and internal variables and names have been preserved. NOTE : S1, S2, SFORW, SBACK,... more  
Returns model data for absorption and scattering coefficients as a function of altitude h for a given wavelength and atmospheric condition determined by parameters used in MODTRAN and FASCODE. Lookup table data is from 0 to 50 km altitude (Returns zero for altitudes outside the available data). See inputs for list of supported wavelengths.  
Returns the value of the Modified HufnagelValley turbulence profile given altitude above sea level in meters  
This function runs MODTRAN and returns a structure that has the output. The output includes the molecular and aerosol extinction coefficients. MODTRAN is not distributed with ATMTools. The user must obtain MODTRAN separately from Spectral Sciences, Inc (www.spectral.com/) and install in ATMTools/OTT/MODTRAN.  
Bulk model for computing surfacelayer scaling parameters, and the refractive index structure parameter from mean values of meteorological quantities measured near the ocean surface. The wind speed, air temperature and air humidity must be measured between 1 and 50 m above the ocean surface. The model will still run if either the pressure or pressure measurement height inputs are bad (data_flag <= 3). In such cases the pressure is defaulted to 1013.25 mb and the pressure measurement height is defaulted to 10 m. The model will not run if any other inputs besides the pressure and/or pressure measurement height are... more  
Generates absorption and scattering coefficients as well as temperature and pressure using the LEEDR oceanic database and the Advanced Navy Aerosol Model (ANAM) or the Navy Aerosol Model (NAM). It will generate the proper structure for use in LEEDRAtmos based on the provided inputs.  
Function for computing outer scale as a function of altitude. Specifying OuterScale(h) is the same as OuterScale(h,'Physical').  
Computes displacement of 2 beams (designated beam 1 and beam 2) along propagation path based upon the input displacement type 'DispType' and accompanying parameters. Specified separations should be thought of as applied to beam 2, and reported displacement vector is from beam 1 to beam 2. That is, if vector r1 locates beam 1 and r2 locates beam 2, then r1 + d = r2.  
Download AIRS data, save to HDF file and optionally process and save to a MAT file. Data can also be downloaded from http://mirador.gsfc.nasa.gov/. Using this function to download data requires functions that are not distributed with ATMTools.  
Returns a random Cn2 profile based on the input Cn2 model, baseModel, with the values specified by fixParam constrained to be equal to the computed values from the baseModel profile.  
Given an altitude vector h this function computes the refractive index and the derivative of the refractive index at the heights specified in the h vector for the particular lambda provided.  
Reverses the input atmosphere and geometry making the target position and velocity the platform position and velocity and vice versa.  
Returns the value of the SLC daytime turbulence profile given altitude above sea level in meters  
Returns the value of the SLC nighttime turbulence profile given altitude above sea level in meters  
Returns an atmospheric modeling (Atm) structure containing Cn2 modeling data with 10 path segments for specified conditions. Based upon differentialtilt turbulence profiler measurements made Sep 2004 at Starfire Optical Range, Kirtland AFB, NM for propagation from SOR to the "2 mile" test site. Atm structure will have Atm.Cn2 values for the specified conditions, and Atm.Cn2Eval = 'NoEval'. Also returns the ECF geometry structure for specified path as an optional second output.  
Starfire Optical Range (SOR) wind profile as a function of altitude and time of year.  
Returns the speed of sound as a function of temperature. It is also possible to input a G structure or an Atm structure to evaluate the speed of sound at various altitudes. The temperature at these altitudes is assumed to be modeled by US_Standard76, unless otherwise specified by Atm.TempEval.  
This function returns the value of an atmospheric model evaluated for screen altitude above ground level. Must have the necessary DTED files downloaded for bilLoad.  
Returns the value of a uniform (constant) model over a propagation path given input ModelValue for an arbitrary atmospheric characteristic. UniformAtm is a function of altitude h to work with ATMTools framework, and returns a vector Model of size(h). However, the value returned is constant with respect to altitude variation. May be used to represent any atmospheric characteristic that does not vary over a propagation path.  
Returns the value of a uniform (constant) Cn2 value over a propagation path given an input value C0, or given a specified atmospheric parameter, its value, and the wavelength, range, and (if applicable) the set of discrete turbulence phase screens for which the parameter value was calculated. UniformCn2 is a function of altitude h to work with ATMTools framework, and returns a Cn2 vector the size(h), but the Cn2 value returned is constant with respect to altitude variation.  
This function calculates the Temperature, Pressure, or Density at given altitudes.  
Converts velocity in the target TP coordinate frame defined in a plane perpendicular to the propagation to an LLA velocity based on the platform and target locations. Can specify an alternate vector for projection of the zenith onto the plane perpendicular to the propagation, upDir, for an arbitrary rotation of the TP coordinate frame. One can also specify that the platform be used as the basis for the TP coordinate frame. This option should be used if the user wants to analyze the reverse geometry but does not want to change the relationship between TP/XY and the propagation direction.  
Returns an atmospheric modeling (Atm) structure containing Cn2 modeling data with 10 path segments for specified conditions. Based upon differentialtilt turbulence profiler measurements made MayAug at White Sands Missile Range for propagation between North Oscura Peak (NOP) and the Beck test site. Atm structure will have Atm.Cn2 values for the specified conditions, and Atm.Cn2Eval = 'NoEval'. Also returns the ECF geometry structure for specified path as an optional second output. Range of dates to be used and range of hours on those dates can be specified. Nature of the output is determined by input OutputType (see options below)  
Returns the value of the WSMR turbulence profile given altitude above ground level in meters. If input altitude is specified as meters above sea level, the ground altitude can optionally be specified. The model identified as '80%WorstSpring' is the 80th percentile worst Cn2 for springtime measurements collected between 10001400 local time at WSMR.  
Returns the value of the White Sands Missile Range wind profile.  
Returns the value of the White Sands Missile Range wind heading profile. 
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