Jwtype

WTYPE

This parameter selects amongst a set of coefficients that define the double exponential profile for shortwave radiation absorption calculated by Paulson and Simpson's (1977) fit to the data of Jerlov (1976)

WTYPE values 1 through 5 correspond to Jerlov's classification of water types I, IA, IB, II and III, respectively.

The model for the downward flux of solar radiation is:

$Q_{down}(z)=Q_{sw}(r{\mbox{ }}\exp(z/\mu _{1})+(1-r){\mbox{ }}\exp(z/\mu _{2}))$

where Q_sw is the downward shortwave radiation at the sea surface. This parameterization is implemented in lmd_swfrac.F if called for. Downward shortwave data (or an analytical value) is required as input.

The parameters of this simple optical model are described and set in mod_scalars.F:

   lmd_mu1     Reciprocal of the absorption coefficient for solar
               wavelength band 1 as a function of the Jerlov
               water type. Units are meters.
   lmd_mu2     Reciprocal of the absorption coefficient for solar
               wavelength band 2 as a function of the Jerlov
               water type. Units are meters.
   lmd_r1      Fraction of total radiance for wavelength band 1 as
               a function of the Jerlov water type.

The values are:

    Jerlov water type :  I       IA      IB      II      III
               WTYPE     1       2       3       4       5
   
     lmd_mu1           0.35 ,  0.6  ,  1.0  ,  1.5  ,  1.4  
     lmd_mu2          23.0  , 20.0  , 17.0  , 14.0  ,  7.9  
     lmd_r1            0.58 ,  0.62 ,  0.67 ,  0.77 ,  0.78