Logo Aeris
Copyright 2017 CNES-CNRS
GEISA : spectroscopic database



Database Access

       ------------------------

    HOME

     What's new ?

    Graphical tool

    GEISA 2015 (new)

    GEISA 2011

    GEISA 2003
 

  HOME > GEISA-03-Description and Access > Aerosols2003 > LITMS



The aerosol data base from LITMS

(Laboratory for Information Technologies and Mathematical Simulation)








logo FIRST PART : Complex indices of refraction computed aerosol integrated optical properties


Table 1. Complex indices of refraction  m=p-iq of basic aerosol components

Basic aerosol constituent
File(*)
Water (liquid)
h2o.ref
Dust
dust_l.ref
75 % H2SO4
h2so4.ref
Sea salt
ocean.ref
Soot
soot.ref
Volcanic ash
volc_ash.ref
Water-soluble particles
w_s.ref
(*) See headers of data files for format and content description


Table 2. Integrated optical properties(*) (extinction coefficient, single scattering albedo, asymmetry factor) of principal aerosol models

Aerosol model Basic aerosol constituent Volume relative concentration (%) Particle number relative concentration(**)
File
Continental
Dust-Like
Water-Soluble
Soot
70
29
1
2.26278 10-6
9.37437 10-1
6.25607 10-2
s_cont.dat
Urban
Water-Soluble
Soot
Dust-Like
61
22
17
5.88931 10-1
4.11069 10-1
1.64128 10-7
s_urb.dat
Maritime
Ocean
Water-Soluble
95
5
4.29942 10-4
9.99573 10-1
s_mar.dat
Stratospheric
75%  H2SO4
100
1.0
s_h2so4.dat
Volcanic
Volcanic Ash
100
1.0
s_volc.dat
Cloudy 
Water
100
1.0
s_cloud.dat
    (*) See headers of data files for format and content description
    (**) For each aerosol model, the total sum of basic aerosol constituent concentrations has to be equal to 1 (dimensionless)

 
 
Table 3. Integrated optical properties (extinction coefficient, single scattering albedo, asymmetry factor)

Basic aerosol constituent
File(*)
Dust-like particles
s_dust.dat
water-soluble particles
s_w_s.dat
Soot
s_soot.dat
Oceanic
s_oc.dat
(*) See headers of data files for format and content description




logo SECOND PART : Computation of the integrated optical properties of atmospheric aerosols: the AERCOMP FORTRAN code

The FORTRAN code AERCOMP (UNIX version) allows calculations of the above basic aerosol integrated optical properties (see Table 3) for more complex, composite aerosol models with user's selected concentrations of constituents, in the same format as the *.dat files of Tables 2,3.

To download and install this software:

  • click here
  • save rublev.tar file into a directory on the hard disk
  • restore the compressed files with the command tar xvf rublev.tar
  • compile aercomp.f file with a FORTRAN compiler (e.g. f77 aercomp.f -o aercomp) aercomp is the executable in this example

         Description and use of the AERCOMP program.

The aerocomp.f program uses the following files:

  • i_*.dat binary files (Float, 4 bytes) with the optical properties of the 7 basic aerosol constituents listed in Table 2 (column 2) and with values of the phase function at 204 angles (in degres) from the ug_204.dat file. Table 4 summarizes the involved constituents (column 1) and the corresponding i_*.dat files (column 2).

 
Table 4. Basic aerosol constituents and related i_*.dat binary files used by the AEROCOMP code.

Basic aerosol constituent
i_*.dat file
Dust-like
i_dust.dat
Water-soluble
i_w_s.dat
Soot
i_soot.dat
Ocean
i_oc.dat
75% H2SO4
i_h2so4.dat
Volcanic Ash
i_volc.dat
Water (cloud)
i_cloud.dat


The i_*.dat binary files delivered with the AEROCOMP software are 2D arrays (61columns x 210 lines) of real numbers (Float, 4 bytes) stored as disk files. They comprise the following data:

  • The first line contains ordered numbers from 1 to 61;
  • The second line (i.e. the records number from 62 to 122) contains the values of 61 irregular spaced wavelengths from 0.2 to 40 micrometers;
  • The third line contains the extinction coefficients, in km-1, for a particle number concentration N=1 particle per cm3, at the wavelengths given in line two;
  • The fourth line contains the single scattering albedo values at the above mentioned wavelengths;
  • The fifth line contains the asymmetry factors at the above mentioned wavelengths;
  • The sixth line contains the normalization factors at the above mentioned wavelengths;
  • The remaining 204 lines from 7 to 210 contain the phase function values at the above mentioned 61 wavelengths and at 204 angles (irregulary spaced from 0 to 180 degrees) stored in the ug_204.dat file: e.g. line 7 contains the phase function values at the first angle value of the ug_204.dat file (0 degree), line 8 contains the phase function values at 0.02 degrees (second value of the ug_204.dat file), etc...
The detailed description and the explicit formulas for the above listed (see Table 2) optical parameters can be found in Rublev, 1994
  • inp_comp.dat file: control parameters file to be set up by the user.
  • lm_sh.dat file: file with wavelengths (in micrometers) used for calculations of the basic aerosol constituents integrated optical properties according to the Mie theory. The user should not change this file!
  • ug_204.dat file: file with the angles values (in degrees) used for calculation of the phase function of the basic aerosol constituents. The user should not change this file!
The inp_comp.dat file delivered with this software package as an example, allows the computations of  integral optical characteristics of the continental aerosol model given in Table 2, storing them into the s_cont1.dat (ASCII) and i_cont1.dat (binary) files. The control parameters file inp_comp.dat contains N+1 blocs, where N is the number of the basic aerosol constituents (Nmax=7) in an aerosol of interest.
The s_cont1.dat file contains the same integrated optical properties (extinction coefficient, single scattering albedo, asymmetry factor, and normalization factor)and has the same format as the *.dat files from Table 3.
The i_cont1.dat file has the same binary format as the above mentioned the i_*.dat files (only it corresponds to 2D array with 13 columns and 187 lines- see parameters in Table 5).
The user should set up the parameters of an aerosol of interest filling up the fields of the inp_comp.dat file  and then run the executable aercomp. Note that the binary file i_cont1.dat can be used as an input file for aercomp.f program in order to compose more complex aerosol models.
Table 5, given as an example,  describes the inp_comp.dat file corresponding to an aerosol mixture including three basic constituents: i.e., dust-like, water-soluble, and soot particles, with the respective particles number concentrations (in particles per cm3): 2.26278 10-6, 0.937437, and 0.0625607. In column 1 are the input and output parameters for computations. Column 2 gives  identification of column 1 data in the aercomp.f program, and column 3 describes column 1 data.
The  integrated optical parameters will be computed at the wavelengths and at the angles stored in the lm_exam.dat and ug_181.dat files respectively. Note, that the wavelength and angle values stored in these files have to be within the same interval (i.e. from 0.2 to 40 microns for wavelengths and from 0 to 180 degrees for angles) as those of the lm_sh.dat and ug_204.dat files respectively. The program uses a linear interpolation algorithm to calculate the integrated optical properties at the wavelengths and angles stored in the lm_exam.dat and ug_181.dat files.
 
Table 5. Example of the inp_comp.dat file delivered with this software package(*)

3                      n_comp      -  NUMBER OF BASIC AEROSOL CONSTITUENTS
13                 n_m0      -  NUMBER OF WAVELENGTHS TO BE USED IN CALCULATIONS(**)
lm_exam.dat   name_m0    -  FILE FOR SELECTED WAVELENGTHS
181                  n_ug0          -  TOTAL NUMBER OF SELECTED ANGULAR MESH POINTS(***)
ug_181.dat      name_ug0  -  FILE WITH ANGULAR MESH POINTS
s_cont1.dat     s_dat           - OUTPUT FILE FOR EXTINCTION COEFFICIENTS
i_cont1.dat      i_dat           - OUTPUT FILE FOR PHASE FUNCTION
********************************************************************************************************
61                   n_m       -  NUMBER OF WAVELENGTHS TO BE USED IN CALCULATIONS
i_dust.dat     nc_ind    - INPUT FILE FOR BASIC AEROSOL CONSTITUENT PARAMETERS
2.26278E-6       si                -  PARTICLE NUMBER CONCENTRATION (particle cm-3)
lm_sh.dat            name_m    - FILE OF WAVELENGTHS
204                    n_ug           -  TOTAL NUMBER OF ANGULAR MESH POINTS
ug_204.dat         name_ug    -  FILE OF ANGULAR MESH POINTS
********************************************************************************************************
61                   n_m         -  NUMBER OF WAVELENGTHS TO BE USED IN CALCULATIONS
i_w_s.dat     nc_ind    -  INPUT FILE FOR BASIC AEROSOL CONSTITUENT PARAMETERS
0.937437           si                 -  PARTICLE NUMBER CONCENTRATION (particle cm-3)
lm_sh.dat            name_m      - FILE OF WAVELENGTHS
204                     n_ug           -  TOTAL NUMBER OF ANGULAR MESH POINTS
ug_204.dat          name_ug     -  FILE OF THE ANGULAR MESH POINTS
********************************************************************************************************
61                    n_m        - NUMBER OF WAVELENGTHS TO BE USED IN CALCULATIONS
i_soot.dat      nc_ind   - INPUT FILE FOR BASIC AEROSOL CONSTITUENT PARAMETERS 
0.0625607          si               -  PARTICLE NUMBER CONCENTRATION (particle cm-3)
lm_sh.dat             name_m   - FILE OF WAVELENGTHS
204                      n_ug          -  TOTAL NUMBER OF ANGULAR MESH POINTS
ug_204.dat           name_ug   -  FILE OF THE ANGULAR MESH POINTS
******************************************************************************************************
    (*) Parameters in italic can be changed by the user for own calculations. Parameters in bold should not be changed!
    (**) The parameter n_m0 should be less or equal to the total number of records in the lm_exam.dat file.
    (***) The parameter n_ug0 should be less or equal to the total number of records in the ug_181.dat file.