6S (Second Simulation of Satellite Signal in the Solar Spectrum)
c**********************************************************************c
c       igeom               geometrical conditions                     c
c               --------------------------------------                 c
c                                                                      c
c                                                                      c
c   you choose your own conditions; igeom=0                            c
c         0     enter solar zenith angle   (in degrees )               c
c                     solar azimuth angle        "                     c
c                     satellite zenith angle     "                     c
c                     satellite azimuth angle    "                     c
c                     month                                            c
c                     day of the month                                 c
c                                                                      c
c   or you select one of the following satellite conditions:igeom=1to7 c
c         1       meteosat observation                                 c
c                 enter month,day,decimal hour (universal time-hh.ddd) c
c                       n. of column,n. of line.(full scale 5000*2500) c
c                                                                      c
c         2       goes east observation                                c
c                 enter month,day,decimal hour (universal time-hh.ddd) c
c                      n. of column,n. of line.(full scale 17000*12000)c
c                                                                      c
c         3       goes west observation                                c
c                 enter month,day,decimal hour (universal time-hh.ddd) c
c                      n. of column,n. of line.(full scale 17000*12000)c
c                                                                      c
c         4       avhrr ( PM noaa )                                    c
c                 enter month,day,decimal hour (universal time-hh.ddd) c
c                       n. of column(1-2048),xlonan,hna                c
c                       give long.(xlonan) and overpass hour (hna) at  c
c                       the ascendant node at equator                  c
c                                                                      c
c         5       avhrr ( AM noaa )                                    c
c                 enter month,day,decimal hour (universal time-hh.ddd) c
c                       n. of column(1-2048),xlonan,hna                c
c                       give long.(xlonan) and overpass hour (hna) at  c
c                       the ascendant node at equator                  c
c                                                                      c
c         6       hrv   ( spot )    * enter month,day,hh.ddd,long.,lat.c
c                                                                      c
c         7       tm    ( landsat ) * enter month,day,hh.ddd,long.,lat.c
c                                                                      c
c                                                                      c
c     note:       for hrv and tm experiments long. and lat. are the    c
c                 coordinates of the scene center.                     c
c                 lat. must be > 0 for north lat., < 0 for south lat.  c
c                 long. must be > 0 for east long., <0 for west long.  c
c                                                                      c
c                 solar and viewing positions are computed             c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c                                                                      c
c                                 / scattered direction                c
c                               /                                      c
c                             /                                        c
c                           / adif                                     c
c    incident   + + + + + + + + + + + + + + +                          c
c    direction                                                         c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c       idatm      atmospheric model                                   c
c                 --------------------                                 c
c                                                                      c
c                                                                      c
c  you select one of the following standard atmosphere: idatm=0 to 6   c
c         0    no gaseous absorption                                   c
c         1    tropical                )                               c
c         2    midlatitude summer      )                               c
c         3    midlatitude winter      )                               c
c         4    subarctic summer        )      from lowtran             c
c         5    subarctic winter        )                               c
c         6    us standard 62          )                               c
c                                                                      c
c  or you define your own atmospheric model idatm=7 or 8               c
c         7    user profile  (radiosonde data on 34 levels)            c
c              enter altitude       (  in km )                         c
c                    pressure       (  in mb )                         c
c                    temperature    (  in k  )                         c
c                    h2o density    (in  g/m3)                         c
c                    o3  density    (in  g/m3)                         c
c                                                                      c
c           for example, altitudes are  from  0 to 25km step of 1km    c
c                        from 25 to 50km step of 5km                   c
c                        and two values at 70km and 100km              c
c                        so you have 34*5 values to input.             c
c         8    enter water vapor and ozone contents                    c
c                 uw  (in  g/cm2 )                                     c
c                 uo3 (in  cm-atm)                                     c
c                 profil is taken from us62                            c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c                                                                      c
c       iaer       aerosol model(type)                                 c
c                  --------------                                      c
c                                                                      c
c                                                                      c
c  you select one of the following standard aerosol models:            c
c         0  no aerosols                                               c
c         1  continental model  )                                      c
c         2  maritime model     )  according to sra models             c
c         3  urban model        )                                      c
c         5  shettle model for background desert aerosol               c
c         6  biomass burning                                           c
c         7  stratospheric model                                       c
c                                                                      c
c  or you define your own model using basic components: iaer=4         c
c         4 enter the volumic percentage of each component             c
c                 c(1) = volumic % of dust-like                        c
c                 c(2) = volumic % of water-soluble                    c
c                 c(3) = volumic % of oceanic                          c
c                 c(4) = volumic % of soot                             c
c                   between 0 to 1                                     c
c                                                                      c
c  or you define your own model using size distribution function:      c 
c         8  Multimodal Log Normal distribution (up to 4 modes)        c
c         9  Modified gamma  distribution                              c
c        10  Junge Power-Law distribution                              c
c                                                                      c
c  or you define a model using sun-photometer measurements:            c
c        11  Sun Photometer  distribution (50 values max)              c
c             you have to enter:  r and d V / d (logr)                 c
c                  where r is the radius (in micron) and V the volume  c
c                  and d V / d (logr) in (cm3/cm2/micron)              c
c             and then you have to enter: nr and ni for each wavelengthc
c                  where nr and ni are respectively the real and       c
c                  imaginary part of the refractive index              c
c                                                                      c
c  or you can use results computed and previously saved                c
c        12  Reading of data previously saved into FILE                c
c             you have to enter the identification name FILE in the    c
c             next line of inputs.                                     c
c                                                                      c
c                                                                      c
c  iaerp and FILE  aerosol model(type)-Printing of results             c
c                  ---------------------------------------             c
c                                                                      c
c For iaer=8,9,10,and 11:                                              c
c    results from the MIE subroutine may be saved into the file        c
c    FILE.mie (Extinction and scattering coefficients, single          c
c    scattering albedo, Asymmetry parameter, phase function at         c
c    predefined wavelengths) and then can be re-used with the          c 
c    option iaer=12 where FILE is an identification name you           c
c    have to enter.                                                    c
c                                                                      c
c    So, if you select iaer=8,9,10,or 11, next line following the      c
c    requested inputs by the options 8,9,10, or 11 you have to enter   c
c    iaerp                                                             c
c                                                                      c
c        iaerp=0    results will not be saved                          c
c        iaerp=1    results will be saved into the file FILE.mie       c
c                    next line enter FILE                              c
c                                                                      c
c                                                                      c
c   example for iaer and iaerp                                         c
c 8                      Multimodal Log-Normale distribution selected  c
c 0.0001 100.0 3         Rmin, Rmax, 3 components                      c
c 0.5000 2.99 1.66E-7    Rmean, Sigma, percentage density-1st componentc
c 1.53 1.53 1.53 1.53 1.53 1.53 1.52 1.40 1.22 1.27  nr-10 wavelengths c 
c .008 .008 .008 .008 .008 .008 .008 .008 .009 .011  ni-10 wavelengths c
c 0.0050 2.99 0.5945     Rmean, Sigma, percentage density-2nd componentc
c 1.53 1.53 1.53 1.53 1.53 1.53 1.52 1.51 1.42 1.452 nr-10 wavelengths c
c .005 .005 .005 .005 .006 .007 .012 .023 .010 .004  ni-10 wavelengths c
c 0.0118 2.00 0.4055     Rmean, Sigma, percentage density-3rd componentc
c 1.75 1.75 1.75 1.75 1.75 1.75 1.75 1.77 1.81 1.90  nr-10 wavelengths c
c .46  .45  .45  .44  .43  .43  .43  .46  .50  .57   ni-10 wavelengths c
c 1                      Results will be saved into FILE.mie           c
c URBAN-WCP112           Identification of the output file called FILE c
c                    -> results will be saved into URBAN-WCP112.mie    c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c              aerosol model (concentration)                           c
c              ----------------------------                            c
c                                                                      c
c                                                                      c
c  v             if you have an estimate of the meteorological         c
c                parameter: the visibility v, enter directly the       c
c                value of v in km (the aerosol optical depth will      c
c                be computed from a standard aerosol profile)          c
c                                                                      c
c  v=0, taer55   if you have an estimate of aerosol optical depth ,    c
c                enter v=0 for the visibility and enter the aerosol    c
c                optical depth at 550                                  c
c                                                                      c
c  v=-1          warning:  if iaer=0, enter v=-1                       c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c xps is the parameter to express the  altitude of target              c
c                                                                      c
c                                                                      c
c                  xps >=0. means the target is at the sea level       c
c                                                                      c
c                  xps <0. means you know the altitude of the target   c
c                        expressed in km and you put that value as xps c
c                                                                      c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c                                                                      c
c  xpp is the parameter to express the sensor altitude                 c
c                                                                      c
c         xpp= -1000  means that the sensor is a board a satellite     c
c         xpp=     0  means that the sensor is at the ground level     c
c                                                                      c
c                                                                      c
c     for aircraft simulations                                         c
c    -100< xpp <0  means you know the altitude of the sensor expressed c
c                  in kilometers units                                 c
C     this altitude is relative to the target altitude                 c
c                                                                      c
c     for aircraft simulations only, you have to give                  c
c	puw,po3   (water vapor content,ozone content between the       c
c                  aircraft and the surface)                           c
c	taerp     (the aerosol optical thickness at 550nm between the  c
c                  aircraft and the surface)                           c
c    if these data are not available, enter negative values for all    c
c    of them, puw,po3 will then be interpolated from the us62 standard c
C    profile according to the values at ground level. Taerp will be    c
c    computed according to a 2km exponential profile for aerosol.      c
c**********************************************************************c
c**********************************************************************c
c      iwave input of the spectral conditions                          c
c            --------------------------------                          c
c                                                                      c
c  you choose to define your own spectral conditions: iwave=-1,0 or 1  c
c                   (three user s conditions )                         c
c        -2  enter wlinf, wlsup, the filter function will be equal to 1c
c            over the whole band (as iwave=0) but step by step output  c
c            will be printed                                           c
c        -1  enter wl (monochr. cond,  gaseous absorption is included) c
c                                                                      c
c         0  enter wlinf, wlsup. the filter function will be equal to 1c
c            over the whole band.                                      c
c                                                                      c
c         1  enter wlinf, wlsup and user's filter function s(lambda)   c
c                          ( by step of 0.0025 micrometer).            c
c                                                                      c
c                                                                      c
c   or you select one of the following satellite spectral band         c
c   with indication in brackets of the band limits used in the code :  c
c                                                iwave=2 to 60         c
c         2  vis band of meteosat     ( 0.350-1.110 )                  c
c         3  vis band of goes east    ( 0.490-0.900 )                  c
c         4  vis band of goes west    ( 0.490-0.900 )                  c
c         5  1st band of avhrr(noaa6) ( 0.550-0.750 )                  c
c         6  2nd      "               ( 0.690-1.120 )                  c
c         7  1st band of avhrr(noaa7) ( 0.500-0.800 )                  c
c         8  2nd      "               ( 0.640-1.170 )                  c
c         9  1st band of avhrr(noaa8) ( 0.540-1.010 )                  c
c        10  2nd      "               ( 0.680-1.120 )                  c
c        11  1st band of avhrr(noaa9) ( 0.530-0.810 )                  c
c        12  2nd      "               ( 0.680-1.170 )                  c
c        13  1st band of avhrr(noaa10 ( 0.530-0.780 )                  c
c        14  2nd      "               ( 0.600-1.190 )                  c
c        15  1st band of avhrr(noaa11 ( 0.540-0.820 )                  c
c        16  2nd      "               ( 0.600-1.120 )                  c
c        17  1st band of hrv1(spot1)  ( 0.470-0.650 )                  c
c        18  2nd      "               ( 0.600-0.720 )                  c
c        19  3rd      "               ( 0.730-0.930 )                  c
c        20  pan      "               ( 0.470-0.790 )                  c
c        21  1st band of hrv2(spot1)  ( 0.470-0.650 )                  c
c        22  2nd      "               ( 0.590-0.730 )                  c
c        23  3rd      "               ( 0.740-0.940 )                  c
c        24  pan      "               ( 0.470-0.790 )                  c
c        25  1st band of tm(landsat5) ( 0.430-0.560 )                  c
c        26  2nd      "               ( 0.500-0.650 )                  c
c        27  3rd      "               ( 0.580-0.740 )                  c
c        28  4th      "               ( 0.730-0.950 )                  c
c        29  5th      "               ( 1.5025-1.890 )                 c
c        30  7th      "               ( 1.950-2.410 )                  c
c        31  1st band of mss(landsat5)( 0.475-0.640 )                  c
c        32  2nd      "               ( 0.580-0.750 )                  c
c        33  3rd      "               ( 0.655-0.855 )                  c
c        34  4th      "               ( 0.785-1.100 )                  c
c        35  1st band of MAS (ER2)    ( 0.5025-0.5875)                 c
c        36  2nd      "               ( 0.6075-0.7000)                 c
c        37  3rd      "               ( 0.8300-0.9125)                 c
c        38  4th      "               ( 0.9000-0.9975)                 c
c        39  5th      "               ( 1.8200-1.9575)                 c
c        40  6th      "               ( 2.0950-2.1925)                 c
c        41  7th      "               ( 3.5800-3.8700)                 c
c        42  MODIS   band 1           ( 0.6100-0.6850)                 c
c        43  MODIS   band 2           ( 0.8200-0.9025)                 c
c        44  MODIS   band 3           ( 0.4500-0.4825)                 c
c        45  MODIS   band 4           ( 0.5400-0.5700)                 c
c        46  MODIS   band 5           ( 1.2150-1.2700)                 c
c        47  MODIS   band 6           ( 1.6000-1.6650)                 c
c        48  MODIS   band 7           ( 2.0575-2.1825)                 c
c        49  1st band of avhrr(noaa12 ( 0.500-1.000 )                  c
c        50  2nd      "               ( 0.650-1.120 )                  c
c        51  1st band of avhrr(noaa14 ( 0.500-1.110 )                  c
c        52  2nd      "               ( 0.680-1.100 )                  c
c        53  POLDER  band 1           ( 0.4125-0.4775)                 c
c        54  POLDER  band 2 (non polar( 0.4100-0.5225)                 c
c        55  POLDER  band 3 (non polar( 0.5325-0.5950)                 c
c        56  POLDER  band 4   P1      ( 0.6300-0.7025)                 c
c        57  POLDER  band 5 (non polar( 0.7450-0.7800)                 c
c        58  POLDER  band 6 (non polar( 0.7000-0.8300)                 c
c        59  POLDER  band 7   P1      ( 0.8100-0.9200)                 c
c        60  POLDER  band 8 (non polar( 0.8650-0.9400)                 c
c  note: wl has to be in micrometer                                    c
c**********************************************************************c
c**********************************************************************c
c here, we first compute an equivalent wavelenght which is the input   c
c value for monochromatic conditions or the integrated value for a     c
c filter functionr (call equivwl) then, the atmospheric properties are c
c computed for that wavelength (call discom then call specinterp)      c
c molecular optical thickness is computed too (call odrayl). lastly    c
c the successive order of scattering code is called three times.       c
c first for a sun at thetas with the scattering properties of aerosols c
c and molecules, second with a pure molecular atmosphere, then with thec
c actual atmosphere for a sun at thetav. the iso code allows us to     c
c compute the scattering transmissions and the spherical albedo. all   c
c these computations are performed for checking the accuracy of the    c
c analytical expressions and in addition for computing the averaged    c
c directional reflectances                                             c
c**********************************************************************c
c*********************************************************************c
c     inhomo        ground reflectance (type)                          c
c                   ------------------                                 c
c                                                                      c
c  you consider an homogeneous surface:                                c
c     enter - inhomo=0                                                 c
c                you may consider directional surface  effects         c
c                  idirec=0 (no directional effect)                    c
c                          you have to specify the surface reflectance:c
c                          igroun  (see note1) which is uniform and    c
c                          lambertian                                  c
c                  idirec=1 ( directional effect)                      c
c                          you have to specify the brdf of the surface c
c                           for the actual solar illumination you  are c
c                           considering as well as the brdf for a sun  c
c                           which would be at an angle thetav, in      c
c                           addition you have to give the surface      c
c                           albedo (spherical albedo). you can also    c
c                           select one of the selected model from the  c
c                           ibrdf value (see note2). 3 reflectances    c
c                           are computed, robar,robarp and robard      c
c                                                                      c
c  you consider a non uniform surface, the surface is considered as a  c
c            circular target with a reflectance roc and of radius r    c
c            (expressed in km) within an environment of reflectance    c
c            roe                                                       c
c     enter - inhomo=1, then                                           c
c             igrou1,igrou2,rad                                        c
c                  - the target reflectance :igrou1  (see note1)       c
c                  - the envir. reflectance :igrou2  (see note1)       c
c                  - the target radius in km                           c
c                                                                      c
c                                                                      c
c                            ****tree****                              c
c                                                                      c
c                               inhomo                                 c
c                             /          \                             c
c                            /            \                            c
c                           /              \                           c
c                          /                \                          c
c                 ------- 0 -------       -----1 -----                 c
c                        /               /   \       \                 c
c                    idirec             /     \       \                c
c                    /  \              /       \       \               c
c                   /    \            /         \       \              c
c                  /      \       igrou1       igrou2    rad           c
c                 0        1        roc          roe     f(r)          c
c                /          \                                          c
c               /            \                                         c
c           igroun          ibrdf                                      c
c        (roc = roe)        (roc)                                      c
c                           (robar)                                    c
c                           (robarp)                                   c
c                           (robard)                                   c
c                                                                      c
c                   ground reflectance (spectral variation)            c
c                   ---------------------------------------            c
c note1: values of the reflectance selected by igroun,igrou1 or igrou2 c
c        may correspond to the following cases,                        c
c         0  constant value of ro (or roc,or roe) whatever the wavelen c
c            gth. you enter this constant value of ro (or roc or roe). c
c        -1  you have to enter the value of ro (or roc,or roe) by step c
c            of 0.0025 micron from wlinf to wlsup (if you have used thec
c            satellite bands,see implicit values for these limits).    c
c         1  mean spectral value of green vegetation                   c
c         2  mean spectral value of clear water                        c
c         3  mean spectral value of sand                               c
c         4  mean spectral value of lake water                         c
c                                                                      c
c                       ground reflectance (brdf)                      c
c                       -------------------------                      c
c note2: values of the directional reflectance is assumed spectrally   c
c        independent, so you have to specify, the brdf at the          c
c        wavelength for monochromatic condition of the mean value      c
c        over the spectral band                                        c
c         0  you have to enter the value of ro for sun at thetas by    c
c            step of 10 degrees for zenith view  angles (from 0 to 80  c
c            and the value for 85) and by step of 30 degrees for       c
c            azimuth view angles from 0 to 360 degrees, you have to do c
c            same for a sun which would be at thetav. in addition, the c
c            spherical albedo of the surface has to be specified ,as   c
C            well as the observed reflectance in the selected geometry c
c           rodir(sun zenith,view zenith, relative azimuth).	       c
c		 						       c
c        you also may select one of the following models               c
c         1  hapke model                                               c
c             the parameters are: om,af,s0,h                           c
c                    om= albedo                                        c
c                    af=assymetry parameter for the phase function     c
c                    s0=amplitude of hot spot                          c
c                    h=width of the hot spot                           c
c                                                                      c
c         2  verstraete et al. model                                   c
c             the parameters are:                                      c
c                there is three lines of parameters:                   c
c                              line 1 (choice of options)              c
c                              line 2 (structural parameters)          c
c                              line 3 (optical parameters)             c
c                line 1:  opt3 opt4 opt5                               c
c                    opt1=1 parametrized model (see verstraete et al., c
c                           JGR, 95, 11755-11765, 1990)                c
c                    opt2=1 reflectance factor (see pinty et al., JGR, c
c                           95, 11767-11775, 1990)                     c
c                    opt3=0 for given values of kappa (see struc below)c
c                         1 for goudriaan's parameterization of kappa  c
c                         2 for dickinson et al's correction to        c
c                           goudriaan's parameterization of kappa (see c
c                           dickinson et al., agricultural and forest  c
c                           meteorology, 52, 109-131, 1990)            c
c                       ---see the manual for complete references----  c
c                    opt4=0 for isotropic phase function               c
c                         1 for heyney and greensteins' phase function c
c                         2 for legendre polynomial phase function     c 
c                    opt5=0 for single scattering only                 c
c                         1 for dickinson et al. parameterization of   c
c                           multiple scattering                        c
c                line 2:  str1 str2 str3 str4                          c
c                    str1='leaf area density', in m2 m-3               c
c                    str2=radius of the sun flecks on the scatterer (m)c
c                    str3=leaf orientation parameter:                  c
c                         if opt3=0 then str3=kappa1                   c
c                         if opt3=1 or 2  then str3=chil               c
c                    str4=leaf orientation parameter (continued):      c
c                         if opt3=0 then str4=kappa2                   c
c                         if opt3=1 or 2 then str4 is not used         c
c                line 3:  optics1 optics2 optics3                      c
c                    optics1=single scattering albedo, n/d value       c
c                            between 0.0 and 1.0                       c
c                    optics2= phase function parameter:                c
c                         if opt4=0 then this input is not used        c
c                         if opt4=1 then asymmetry factor, n/d value   c
c                                   between -1.0and 1.0                c
c                         if opt4=2 then first coefficient of legendre c
c                                   polynomial                         c
c                    optics3=second coefficient of legendre polynomial c
c                            (if opt4=2)                               c
c                                                                      c
c         3  Roujean et al. model                                      c
c             the parameters are: k0,k1,k2                             c
c                 k0=albedo.                                           c
c                 k1=geometric parameter for hot spot effect           c
c                 k2=geometric parameter for hot spot effect           c
c                                                                      c
c         4  walthall et al. model                                     c
c             the parameters are: a,ap,b,c                             c    
c                 a=term in square ts*tv                               c
c                 ap=term in square ts*ts+tv*tv                        c
c                 b=term in ts*tv*cos(phi) (limacon de pascal)         c
c                 c=albedo                                             c
c                                                                      c
c         5  minnaert model                                            c
c             the parameters are: par1,par2                            c
c                                                                      c
c         6  Ocean                                                     c
c             the parameter are: pws,phi_wind,xsal,pcl                 c
c                 pws=wind speed (in m/s)                              c
c                 phi_wind=azim. of the wind (in degres)               c
c                 xsal=salinity (in ppt) xsal=34.3ppt if xsal<0        c
c                 pcl=pigment concentration (in mg/m3)                 c
c                                                                      c
c         7  Iaquinta and Pinty model                                  c
c             the parameters are:                                      c
c                there is 3 lines of parameters:                       c
c                          line 1: choice of option (pild,pihs)        c
c                          line 2: structural parameters (pxLt,pc)     c
c                          line 3: optical parameters (pRl,pTl,pRs)    c
c                Line 1: pild,pihs                                     c
c                    pild=1  planophile leaf distribution              c 
c                    pild=2  erectophile leaf distribution             c 
c                    pild=3  plagiophile leaf distribution             c 
c                    pild=4  extremophile leaf distribution            c 
c                    pild=5  uniform leaf distribution                 c 
c                                                                      c 
c                    pihs=0  no hot spot                               c 
c                    pihs=1  hot spot                                  c 
c                Line 2: pxLt,pc                                       c
c                    pxLt=Leaf area index [1.,15.]                     c 
c                    pc=Hot spot parameter: 2*r*Lambda [0.,2.]         c
c                Line 3: pRl,pTl,pRs                                   c
c                    pRl=Leaf reflectance  [0.,0.99]                   c 
c                    pTl=Leaf transmitance [0.,0.99]                   c 
c                    pRs=Soil albedo       [0.,0.99]                   c 
c                         NB: pRl+PTl <0.99                            c 
c                                                                      c
c         8  Rahman et al. model                                       c
c             the parameters are: rho0,af,xk                           c
c                 rho0=Intensity of the reflectance of the surface     c
c                      cover, N/D value greater or equal to 0          c
c                 af=Asymmetry factor, N/D value between -1.0 and 1.0  c
c                 xk=Structural parameter of the medium                c
c         9   Kuusk's multispectral CR model                           c
c             Reference:                                               c
c             Kuusk A. A multispectral canopy reflectance model.       c
c             Remote Sens. Environ., 1994, 50:75-82                    c
c                                                                      c
c                                                                      c
c             the parameters are:                                      c
c                                                                      c
c     line 1: structural parameters (ul,eps,thm,sl)                    c
c     line 2: optical parameters (cAB,cW,N,cn,s1)                      c
c                                                                      c
c             ul=LAI                                                   c
c             eps,thm - LAD parameters                                 c
c             sl      - relative leaf size                             c
c             cAB     - chlorophyll content, ug/cm^2                   c
c             cW      - leaf water equivalent thickness                c
c             N       - the effective number of elementary layers      c
c                       inside a leaf                                  c
c             cn      - the ratio of refractive indices of the leaf    c
c                       surface wax and internal material              c
c             s1      - the weight of the 1st Price function for the   c
c                       soil reflectance                               c
c**********************************************************************c
c**********************************************************************c
c                                                                      c
c       rapp    that input parameter allows to activate atmospheric    c
c               correction mode                                        c
c                                                                      c
c               if rapp <-1. no atmospheric correction is performed    c
c                                                                      c
c               if rapp >0. :  the code retrieve the value of the      c
c               surface reflectance (rog) that will produce a radiance c
c               equal to rapp [w/m2/str/mic] in the atmospheric        c
c               conditions described by user before                    c
c                                                                      c
c               if -1.<rapp<0. : the code retrieve the value of the    c
c               surface reflectance (rog) value that will produce a    c
c               'reflectance' (radiance*pi/(mus*es)) equal to -rapp    c
c               where mus is the cosine of solar zenith angle,         c
c               es is the solar constant integrated upon the           c
c               filter response and taking account for earth-solar     c
c               distance, es is in [w/m2/sr/mic].                      c
c                                                                      c
c**********************************************************************c
c**********************************************************************c
c                                                                      c
c                     example of input cards                           c
c                                                                      c
c 4                            (avhrr observation)                     c
c 7 6 10.1  600  0.0  10.0     (month,day,htu,cn,longan,han)           c
c 8                            (user's   model)                        c
c 3.0   0.35                   ( uh2o(g/cm2) ,uo3(cm-atm) )            c
c 4                            (aerosols model)                        c
c 0.25  0.25  0.25  0.25       ( % of:dust-like,water-sol,oceanic,soot)c
c 23.0                         (visibility (km) )                      c
c -0.5                         (target at 0.5km high)                  c
c -1000                        (sensor aboard a satellite)             c
c 6                            (avhrr 2 (noaa 8) band)                 c
c 1                            (ground type,i.e. non homogeneous)      c
c 2    1    0.50               (target,env.,radius(km) )               c
c -0.10                        (atmospheric correction mode for a TOA  c
c                                   reflectance equal to 0.10)         c
c                                                                      c
c**********************************************************************c