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<>Scientific Software in IDL
This page offers IDL routines
addressing a variety of topics. If you have problems or wish to
share a program contact Mark Hervig (m.e.hervig@gats-inc.com).
Radiation and Optics
- Rayleigh scattering and absorption by spheres
- Mie scattering and absorption by spheres
- Molecular scattering according to Rayleigh theory
- Blackbody radiance according to Planck's function
- Refractive index of ice at 100 K temperature
- Refractive index of ice at 163 K temperature
- Refractive index of ice at 266 K temperature
- Refractive index of nitric acid trihydrate (NAT) at 196 K temperature
- Refractive index of nitric acid dihydrate (NAD) at 184 K temperature
- Refractive index of liquid ternary HNO3-H2O-H2SO4 aerosols at wavelengths less than 2 microns
- Refractive index of pure liquid water
- Refractive index of H2SO4-H2O (sulfate) solution at 215 K temperature (program and data file )
- Temperature dependence of the refractive index of a liquid according to Lorentz-Lorenz
- Refractive index of a mixture of two substances according to Maxwell-Garnet
- Refractive index of H2SO4 vs. temperature and composition according to Neidziela et al. [1998]
Thermodynamics
- Equilibrium properties of nitric acid trihydrate (NAT)
- Equilibrium properties of nitric acid dihydrate (NAD)
- Equilibrium properties of nitric acid pentahydrate (NAP)
- Equilibrium properties of sulfuric acid tetrahydrate (SAT)
- Equilibrium properties of liquid ternary HNO3-H2O-H2SO4 aerosols
- Equilibrium properties of ice
- Equilibrium properties of solid CO2
- Saturation water vapor pressure over ice according to Goff-Gratch
- Saturation water vapor pressure over ice according to Marti and Mauersberger
- Saturation water vapor pressure over ice according to Mauersberger and Krankowsky
- Saturation water
vapor
pressure over ice according to Rapp and Thomas [2005]
- Saturation water vapor pressure over liquid water according to Goff-Gratch
- Saturation water vapor pressure over liquid water according to Clegg and Brimblecombe
- Density of liquid H2SO4-H2O, HNO3-H2O, or ternary HNO3-H2O-H2SO4 solutions
- Equilibrium composition of sulfate aerosols (wt.% H2SO4), according to Steele and Hamill, 1981
- Equilibrium composition of sulfate aerosols (wt.% H2SO4), according to Tabazadeh et al., 1997
- Altitude change between two pressure levels using the hydrostatic equation
- Column ozone amount in Dobson units
- Ice density for 93K < T < 273K
Aerosols and Particles
- Functional description of a lognormal size distribution
- The fall velocity of a sphere according to Stokes law
- Compute optical properties of clouds and aerosols
- Compute the change in saturation vapor pressure over an ice sphere (the Kelvin effect)
- The Critical radius of ice particles according to Rapp & Thomas [2006]
- The fall velocity of mesospheric ice particles according to Turco et al. [1982]
The Sun & Earth
- Solar intensity as a function of angular distance from sun center for a sun view from Earth ("Allen curve")
- Solar images with and without refraction at the limb path tangent point for a sun view from Earth orbit
- Solar intensity as a function of wavelength for 0.2 to 196 microns (program, data file)
- Calculate the Earth - Sun distance for a particular date
- Calculate local solar time
- Calculate solar zenith angle
- Earth radius for a given geodetic latitude
Date and Time
- Convert date as yyyymmdd to julian date
- Convert day of year and year to a character date string (e.g., inputing day 172 in year 1994 gives "21-Jun-1994")
- Compute elapsed time from January 1 in a reference year, for a given date and time
- Input YYYYDDD to get numeric month, date, year, and a character date (DDD = day of year)
- Input numeric month, date, and year to get YYYYDDD and character date (e.g., 1993280 is 7-oct-1993)
Geometry
- Great circle distance and heading between two locations
- Relate angular field of view at the spacecraft to linear distance subtended at tangent for a limb view
- Relate linear distance subtended at tangent for a limb view, to angular field of view at the spacecraft
- Calculate path length of the tangent point sample volume for a limb view from space
Math
- Two-point linear interpolation
- Compute a histogram for your
data,
the median value (most frequent), and the mean and std. deviation
- Find all interpolates on a multi-valued function (i.e., find all Y values for a given X on the curve X vs. Y)
- Generate a set of random numbers that has a mean value below a specified limit
- Find the half power points for a curve (e.g., a FOV or RSR curve)
- Generate a uniform logarithmic series of numbers
Meteorology
Working With Data Sets
- Find time-space coincidences between two data sets
- Compute comparison statistics for sets of coincident profiles
- Generate a uniform time series
- Generate an average profile
- Generate a uniform time-height cross section
- Apply a box-car smooth
- See what's inside a NCDF file
- Grid data in one dimension
- Grid data in two dimensions (e.g., lat vs. lon or time vs. height)
Plotting
- Draw a color bar
- Use the HALOE color table: program, file ( right click "save as...")
- Make a latitude vs. longitude color contour map of your data with an Earth projection underneath