Jwtype

Jwtype

Jwtype

Jerlov water type: an integer value from 1 to 5.

option =

routine = mod_mixing.F

keyword = WTYPE

input = roms.in

---

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 (roms.in) 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:

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

where $Q_{s}w$ 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 in the block headed "Water clarity parameters":

   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:

    WTYPE                1       2       3       4       5
    Jerlov water type :  I       IA      IB      II     III
    
     lmd_mu1            0.35 ,  0.60 ,  1.00 ,  1.50 ,  1.40  
     lmd_mu2           23.00 , 20.00 , 17.00 , 14.00 ,  7.90  
     lmd_r1             0.58 ,  0.62 ,  0.67 ,  0.77 ,  0.78