Light Extinction Coeff.

Question

Hello Chris,

I have three questions.

1- Is the extinction coefficient calculated based on the concentrations of algae, inorganic and detrital particles, and dissolved organic material only for PAR sunlight bandwidth? What about UVA and UVB? In equation 2.2 of CAEDYM science manual v3.3, where can I adjust the Ke values in the .bio file?

2- Can extinction coefficients been updated during the simulation. I know that users can initialize and controls the light extinction using a written subroutine (don't know how yet) but what I am interested in is to have the extinction coefficients as time series input to the model. I would like to change it during the simulation and see their effects. Maybe it is weird to do that but I have some reasons for that.

3- The EXTC output is just for PAR bandwidth? if yes, can we have it for other bandwidths (UVA and UVB) as well?

Thanks,

Mohammad

Answer 1

1) Currently, only PAR is extinction is updated.  The Kep section is just before the nutrient parameters, something like

! Kep (ug chlaL^-1m^-1) : Specific attenuation coefficient                     !
     0.01400            ! Whittington et al 2000 [Stage 1 = 0.0067]             
     0.01400            !                                                       
     0.01400                                                                    
     0.01400                                                                    
     0.01400                                                                    
     0.03300                                                                    
     0.01400  

2) You can use an update bc to modify the extinction coefficient during the simulation

3) Datablock output keywords for this are

PAR_EXTINCTION
NIR_EXTINCTION
UVA_EXTINCTION
UVB_EXTINCTION