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Last modified: Tue Jul 11 20:44:09 2006.
NAME:
abscoef
PURPOSE: (one line)
calculate absorbtion coefficient (in cm^-1)
DESCRIPTION:
CATEGORY:
Spectra
CALLING SEQUENCE:
k = abscoef(lnarr, nabs, nu)
INPUTS:
lnarr - an array of spectral line structures
nabs - number density of absorber (cm^-3)
nu - array of wavenumbers
OPTIONAL INPUT PARAMETERS:
KEYWORD INPUT PARAMETERS:
nolim - set for no restriction of range
(overrides eps, nlorwidth, ndopwidth)
nlorwidth - maximum number of Lorentz widths to calculate line on
ndopwidth - maximum number of Doppler widths to calculate line on
eps - if nlorwidth or ndopwidth not set, calculate nwidths
such that uncalculated taus are < eps and fractional
error in width is < eps
KEYWORD OUTPUT PARAMETERS:
none
OUTPUTS:
k - absorbtion coeff in inverse cm
COMMON BLOCKS:
None
SIDE EFFECTS:
None
RESTRICTIONS:
PROCEDURE:
MODIFICATION HISTORY:
Written 2001 May, by Leslie Young, SwRI
2002 Sept LAY relax selection for nu-nu0 from 500 widths to 1e6 widths.
2004 Nov 16 LAY. Added nlorwidth, ndopwidth
(See spectra/abscoef.pro)
NAME: binedge PURPOSE: (one line) Given a list of bin centers, return the bin edges DESCRIPTION: Given a list of bin centers, return the bin edges CATEGORY: Spectra CALLING SEQUENCE: binedge, x, n, x0, x1, dx INPUTS: x: centers of bins OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: n: length of array x0: lower edge x1: upper edge dx: bin width COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: x has to be monotonically increasing PROCEDURE: Interior bin edges are midway between bin centers. X[0] and X[n-1] are in the middle of their bins MODIFICATION HISTORY: Written Leslie Young, SwRI, Nov 8, 2000 Jan 3 2006. Added doc, moved to layoung/spectra, LAY
(See spectra/binedge.pro)
NAME:
binedge
PURPOSE: (one line)
resample fine (x,y) to coarse (u,v)
DESCRIPTION:
resample fine (x,y) to coarse (u,v)
CATEGORY:
Spectra
CALLING SEQUENCE:
v = resample, x, y, u, DX = dx, DU = du, YERR=yerr, VERR=verr
INPUTS:
x: the dependant variable (1-D array) (centers of fine bins)
y: the unsmoothed independant variable (1-D array) (average of fine bin)
u: the coarser x's (center of coarse bins)
OPTIONAL INPUT PARAMETERS:
none
KEYWORD INPUT PARAMETERS:
DX = width of fine bins. If not passed, the bin edges and widths
are calculated using binedge.
DU = width of coarse bins. If not passed, the bin edges and widths
are calculated using binedge.
Yerr = errors for y (the original fine values)
KEYWORD OUTPUT PARAMETERS:
Verr = errors for v (the calculated coarse values)
OUTPUTS:
Return v, the y's averaged over bins du wide
COMMON BLOCKS:
None
SIDE EFFECTS:
RESTRICTIONS:
x and u have to be monotonically increasing
PROCEDURE:
MODIFICATION HISTORY:
Written Leslie Young, SwRI, Nov 8, 2000
Jan 3 2006. Added doc, moved to layoung/spectra, LAY
(See spectra/resample.pro)
NAME: changept_specline PURPOSE: (one line) Change the strength and pressure/doppler widths to reflect a new temperature & pressure DESCRIPTION: Given a spectral line structure and a temperature, update the strength, air-broadened half-width, and doppler width. CATEGORY: Spectra CALLING SEQUENCE: changept_specline, ln, p, t INPUTS: ln - the spectral line structure to be changed p - the new pressure (microbar) t - the new temperature for the line (K) OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: None COMMON BLOCKS: None SIDE EFFECTS: Changes the following fields in ln: s intensity in cm^-1/(molecule cm^-2) gamma_air air-broadened halfwidth (HWHM) in cm^-1 at specified pressure p pressure for gamma_air t temperature for s, gamma_air, and gamma_self dopw doppler width (Goody&Yung definition), cm^-1 RESTRICTIONS: 1. Only works for molecules 1-7 (H2O, CO2, O3, N2O, CO, CH4, O2) 2. Assumes the partition function (Q) varies as temperature to some power (c.f.. Steve Lord's ATRAN program), rather than using the full polynomial expressions of select96. 3. Does not change gamma, the self-braodened halfwidth. PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI 29 May 2001 LAY. Added call to qoft
(See spectra/changept_specline.pro)
NAME: changept_specline_array PURPOSE: (one line) Change an array of lines to reflect a new temperature & pressure DESCRIPTION: Given a spectral line structure and a temperature, update the strength, air-broadened half-width, and doppler width. CATEGORY: Spectra CALLING SEQUENCE: changept_specline_array, ln, p, t INPUTS: lna - an array of spectral line structures to be changed p - the new pressure (microbar) t - the new temperature for the line (K) OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: None COMMON BLOCKS: None SIDE EFFECTS: Changes the following fields in the elements of lna: s intensity in cm^-1/(molecule cm^-2) gamma_air air-broadened halfwidth (HWHM) in cm^-1 at specified pressure p pressure for gamma_air t temperature for s, gamma_air, and gamma_self dopw doppler width (Goody&Yung definition), cm^-1 RESTRICTIONS: 1. Only works for molecules 1-7 (H2O, CO2, O3, N2O, CO, CH4, O2) 2. Assumes the partition function (Q) varies as temperature to some power (c.f.. Steve Lord's ATRAN program), rather than using the full polynomial expressions of select96. 3. Does not change gamma, the self-braodened halfwidth. See changept_specline PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/changept_specline_array.pro)
NAME: changet_specline PURPOSE: (one line) Change the strength and pressure/doppler widths to reflect a new temperature DESCRIPTION: Given a spectral line structure and a temperature, update the strength, air-broadened half-width, and doppler width. CATEGORY: Spectra CALLING SEQUENCE: changet_specline, ln, t INPUTS: ln - the spectral line structure to be changed t - the new temperature for the line OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: None COMMON BLOCKS: None SIDE EFFECTS: Changes the following fields in ln: s intensity in cm^-1/(molecule cm^-2) gamma_air air-broadened halfwidth (HWHM) in cm^-1 at specified pressure t temperature for s, gamma_air, and gamma_self dopw doppler width (Goody&Yung definition), cm^-1 RESTRICTIONS: 1. Only works for molecules 1-7 (H2O, CO2, O3, N2O, CO, CH4, O2) 2. Assumes the partition function (Q) varies as temperature to some power (c.f.. Steve Lord's ATRAN program), rather than using the full polynomial expressions of select96. ------ NOW IT DOES. LAY 29 May 2001 3. Does not change gamma, the self-braodened halfwidth. PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI 29 May 2001 LAY. Added call to qoft 22 Mar 2005 LAY. Changed rad calculation to call expm1
(See spectra/changet_specline.pro)
NAME: changet_specline_array PURPOSE: (one line) Change an array of lines to reflect a new temperature DESCRIPTION: Given a spectral line structure and a temperature, update the strength, air-broadened half-width, and doppler width. CATEGORY: Spectra CALLING SEQUENCE: changet_specline_array, lna, t INPUTS: lna - an array of spectral line structures to be changed t - the new temperature for the line OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: None COMMON BLOCKS: None SIDE EFFECTS: Changes the following fields in the elements of lna: s intensity in cm^-1/(molecule cm^-2) gamma_air air-broadened halfwidth (HWHM) in cm^-1 at specified pressure t temperature for s, gamma_air, and gamma_self dopw doppler width (Goody&Yung definition), cm^-1 RESTRICTIONS: 1. Only works for molecules 1-7 (H2O, CO2, O3, N2O, CO, CH4, O2) 2. Assumes the partition function (Q) varies as temperature to some power (c.f.. Steve Lord's ATRAN program), rather than using the full polynomial expressions of select96. ------ NOW IT DOES. LAY 29 May 2001 3. Does not change gamma, the self-braodened halfwidth. See changet_specline PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/changet_specline_array.pro)
NAME:
corr_k
PURPOSE: (one line)
calculate correlated-k coefficients
DESCRIPTION:
CATEGORY:
Spectra
CALLING SEQUENCE:
corr_k, kin, k, dk, f, dg, g, kmin=kmin, kmax=kmax, dlnk=dlnk, weight=weight
INPUTS:
kin - absorbtion coefficient in cm^-1 or cross section in cm^2
KEYWORD INPUT PARAMETERS:
kmin - minimum k to tabulate. Default = min(kin)
kmax - maximum k to tabulate. Default = max(kin)
dlnk - spacing between k's. k[i+1] = k[i] * exp(dlnk). Default = 0.1
weight - relative weighting for kin, same length as kin.
Examples:
1. Unevenly tabulated kin. weight = bin widths.
2. Rapid computation of tranmission times a solar spectrum.
weight = solar spectrum.
3. Weighting by instrumental smoothing function.
KEYWORD OUTPUT PARAMETERS:
none
OUTPUTS:
k - correlated-k in same units as kin
dk - width of k bins, in same units as kin
f - frequency distribution, in inverse the units of kin
g - culmulative distribution, unitless, 0 to 1
dg - culmulative distribution bin, unitless
COMMON BLOCKS:
None
SIDE EFFECTS:
None
RESTRICTIONS:
PROCEDURE:
Following Lacis and Oinis 1991, "A description of the correlated k
distribution method for modeling nongray gaseous absorption,
thermal emission, and multiple scattering in vertically inhomogenous
atmospheres." JGR 96, 9027-9063.
The goal is to calculate the average transmission as a
function u, where u is path length (for k in cm^-1) or column density
(for k in cm^2).
The continuous equation is
/k=inf
T(u) = | exp(-u*kin(nu)) (1/(nu1-nu0) ) dnu
/k=0
or, for weighted k's
/k=inf
T(u) = | exp(-u*kin(nu)) w(nu) dnu
/k=0
where the integral of w over the frequency range is 1.
Discretely, this is
T(u) = total( exp(-u*kin) * w )
f - frequency distribution (units are inverse the units of k)
or cm for k in cm^-1, cm^-2 for k in cm^2).
f(k) dk is the fraction of relevent frequency interval
for which the absorption is between k and k+dk.
The continuous and discrete equations are
/k=inf
T(u) = | f(k) exp(-u*k) dk
/k=0
T(u) = total( f * exp(-k * u) * dk )
g - culmulative distribution (unitless)
g(k) is the fraction of relevent frequency interval
for which the absorption is less than k.
The continuous and discrete equations are
/g=1
T(u) = | exp(-u*k) dg
/g=0
T(u) = total( exp(-k * u) * dg )
EXAMPLE: UNWEIGHTED
corr_k, kin, k, dk, f, dg, g
total( exp(-kin*u) ) should equal
total( exp( -k*u) * dg)
EXAMPLE: WEIGHTED
corr_k, kin, k, dk, f, dg, g, weight = w
total( exp(-kin*u) * w)/total(w) should equal
total( exp( -k*u)*dg)
MODIFICATION HISTORY:
2005 Feb 17 Leslie Young SwRI
2005 Mar 29 LAY Added documentation, moved to $idl/spectra,
removed tests, changed name to avoid conflicts
(See spectra/corr_k.pro)
NAME: dopwidth PURPOSE: (one line) Calculate the doppler width of a spectral line DESCRIPTION: The doppler width follows the Goody and Yung definition CATEGORY: Spectra CALLING SEQUENCE: dopw = dopwidth(nu0, t, mu) INPUTS: nu0 - wavenumber of the line in cm^-1 t - temperature (K) mu - molecular weight (g/mole) OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: doppler width in cm^-1 COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: Note that if nu0 is in other units (e.g. nm), the returned width will be in those same units. PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/dopwidth.pro)
NAME: mk_nuwgt PURPOSE: (one line) make a list of inverse cm (and optionally, weights) DESCRIPTION: pick nu's appropriate for the temperature CATEGORY: Spectra CALLING SEQUENCE: nuarr = mk_nuwgt(lnarr, nuwgt) INPUTS: lnarr - an array of spectral line structures to be changed OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: nu - array of wavenumbers (inverse cm) nuwgt - array of wavenumber weights (inverse cm) COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: None PROCEDURE: MODIFICATION HISTORY: Written 2001 May, by Leslie Young, SwRI
(See spectra/mk_nuwgt.pro)
NAME: mk_nuwgt_low PURPOSE: (one line) make a list of inverse cm (and optionally, weights) (lowlevel) DESCRIPTION: pick nu's appropriate for the temperature CATEGORY: Spectra CALLING SEQUENCE: nuarr = mk_nuwgt_low(nu0arr, dopwarr, nx, ndopw, s, ng, dnuarr) INPUTS: nu0arr - array of line centers (may be scalar) dopwarr - array of doppler widths (same length as nu0arr) nx - number of points in all other grids ndopw - number of doppler widths in the core s - scale of spacing between grids (must be >1 ) ng - number of grids OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: nu - array of wavenumbers (inverse cm) dnuarr - if present, array of wavenumber weights (inverse cm) COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: None PROCEDURE: MODIFICATION HISTORY: Written 2001 May, by Leslie Young, SwRI Modified 2004 Jun 27, LAY, based on Meadows&Crisp 1996
(See spectra/mk_nuwgt_low.pro)
NAME: molec_weight PURPOSE: (one line) Return the molecular weight, given the molecule and isotope index used by HITRAN DESCRIPTION: CATEGORY: Spectra CALLING SEQUENCE: w = molec_weight(mol, iso) INPUTS: mol - molecule index (e.g., 1 for H2O) iso - isotope index (e.g., 1 for 1H 16O 1H) OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: atomic weight (g/mole, e.g., 18. for molec_weight(1,1) ) COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: None PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/molec_weight.pro)
NAME:
new_specline
PURPOSE: (one line)
Create an empty spectral line structure
DESCRIPTION:
mol molecule index
iso isotope index
nu0 frequency in cm^-1
s intensity in cm^-1/(molecule cm^-2)
r2 transition probability squared in Debye^2
gamma_air air-broadened halfwidth (HWHM) in cm^-1 at specified pressure
gamma_self self-broadened halfwidth (HWHM) in cm^-1 at specified pressure
E_lower lower state energy in cm^-1
n coef. of temperature dependence of air-broadened halfwidth
delta air-broadened pressure shift of the line transition in cm^-1/atm
v_upper upper state global quanta index
v_lower lower state global quanta index
Q_upper upper state global quanta index
Q_lower lower state global quanta index
ier accuracy indices for frequency, intensity,
and air-broadened halfwidth
iref indices for table of references corresponding to
frequency, intensity, and air-broadened halfwidth
t temperature for s, gamma_air, and gamma_self
p pressure in microbar, for air-broadened half-width
dopw doppler width (Goody&Yung definition), cm^-1
temperature, etc of original source
t_orig
p_orig
s_orig
gamma_air_orig ; air-broadened halfwidth (HWHM) in cm/atm
gamma_self_orig
CATEGORY:
Spectra
CALLING SEQUENCE:
specline = new_specline()
INPUTS:
None
OPTIONAL INPUT PARAMETERS:
none
KEYWORD INPUT PARAMETERS:
none
KEYWORD OUTPUT PARAMETERS:
none
OUTPUTS:
empty spectral line structure
COMMON BLOCKS:
None
SIDE EFFECTS:
RESTRICTIONS:
Tailored for HITRAN
PROCEDURE:
MODIFICATION HISTORY:
Written 2000 October, by Leslie Young, SwRI
2005 March LAY changed floats to doubles
(See spectra/new_specline.pro)
NAME: ok_specline PURPOSE: (one line) Return true if a spectral line matches criteria DESCRIPTION: CATEGORY: Spectra CALLING SEQUENCE: ok_specline, ln, mol, iso, v_upper, v_lower, min_nu0, max_nu0, min_s INPUTS: ln - the spectral line structure to be tested mol - index of molecule (or 0 for any) iso - index of isotope (or 0 for any) v_upper - upper vibrational quantum number, or 0 for any v_lower - lower vibrational quantum number, or 0 for any min_nu0 - minimum wavenumber of the transition, or 0 for any max_nu0 - maximum wavenumber of the transition, or 0 for any min_s- minimum strength of the transition, or 0 for any OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: true for match, false for no match COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: None PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/ok_specline.pro)
NAME: rd_band PURPOSE: (one line) Read a molecular band from a HITRAN file DESCRIPTION: CATEGORY: Spectra CALLING SEQUENCE: rd_band, fn, mol, iso, v_upper, v_lower INPUTS: fn - the filename of a HITRAN molecular file. mol - index of molecule (or 0 for any) iso - index of isotope (or 0 for any) v_upper - upper vibrational quantum number, or 0 for any v_lower - lower vibrational quantum number, or 0 for any OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: Returns an array of spectral line structures COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: This doesn't use the main HITRAN file, but the files in the by_molec directory PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/rd_band.pro)
NAME: rd_next PURPOSE: (one line) Read the next line from an open HITRAN file that satisfies criteria DESCRIPTION: CATEGORY: Spectra CALLING SEQUENCE: rd_next, fp, ln, mol, iso, v_upper, v_lower, min_nu0, max_nu0, min_s INPUTS: ln - the spectral line structure to be filled in fp - a file pointer to an open HITRAN file. mol - index of molecule (or 0 for any) iso - index of isotope (or 0 for any) v_upper - upper vibrational quantum number, or 0 for any v_lower - lower vibrational quantum number, or 0 for any min_nu0 - minimum wavenumber of the transition, or 0 for any max_nu0 - maximum wavenumber of the transition, or 0 for any min_s- minimum strength of the transition, or 0 for any OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: Fills the spectral line, ln COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: ln must be defined before calling. PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/rd_next.pro)
NAME: rd_specline_hitran PURPOSE: (one line) Read the next line from an open HITRAN file, and fill a spectral line structure DESCRIPTION: CATEGORY: Spectra CALLING SEQUENCE: rd_specline_hitran, file_pointer, spectral_line INPUTS: file_pointer - a file pointer to an open HITRAN file. spectral_line - a previously defined spectral line structure OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: Fills the spectral line, spectral_line COMMON BLOCKS: None SIDE EFFECTS: RESTRICTIONS: spectral_line must be defined before calling. PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/rd_specline_hitran.pro)
NAME: spectrademo PURPOSE: (one line) Demonstrate the use of the spectra library DESCRIPTION: A heavily-commented proceedure to show how to use the spectral library CATEGORY: Spectra CALLING SEQUENCE: spectrademo INPUTS: none OPTIONAL INPUT PARAMETERS: none KEYWORD INPUT PARAMETERS: none KEYWORD OUTPUT PARAMETERS: none OUTPUTS: None. COMMON BLOCKS: None. SIDE EFFECTS: Prints and plots RESTRICTIONS: PROCEDURE: MODIFICATION HISTORY: Written 2000 October, by Leslie Young, SwRI
(See spectra/spectrademo.pro)
NAME:
spectralib
PURPOSE: (one line)
Add non-standard system variable for use with spectra library
DESCRIPTION:
Add the following:
!hitrandir - the directory containing the HITRAN databases
CATEGORY:
Spectra
CALLING SEQUENCE:
spectralib
INPUTS:
none
OPTIONAL INPUT PARAMETERS:
none
KEYWORD INPUT PARAMETERS:
none
KEYWORD OUTPUT PARAMETERS:
none
OUTPUTS:
None.
COMMON BLOCKS:
None.
SIDE EFFECTS:
Defines the system variables using defsysv
RESTRICTIONS:
PROCEDURE:
MODIFICATION HISTORY:
Written 2000 April, by Leslie Young, SwRI
Added to "layoung" library 2000 October, by Leslie Young, SwRI
(See spectra/spectralib.pro)