You may download here climatologies for :

PAR : the photosynthetically available radiation

K PAR : the mean attenuation coefficient for PAR

PAR B : the bottom irradiance (i.e. on the sea floor of the coastal zone)

N.B. : these data are also available at

To Calculate a P-function

follow steps 1 to 4

- step 1 : Select region among Arctic, NonPolar, Antarctic

- step 2 : Select a subregion of the selected region by north, south, east, west and name

- step 3 : Do the calculations and wait for them to finish before going to step 4

- step 4 : Download the P-function and optionally plot it

Select region

Select subregion

longitudes from -180° to 180°, latitudes from -90° to 90°
south and north initial values are adapted to the selected region


Consider that the calculation time ranges from one minute to several tens of minutes ... depending on the selected region

when the calculations are complete, the file containing the tabulated P-function will be available for download

you can follow the progress of the calculations on the progress bar that will appear at the bottom right of this window when you click on the GO! button


wait for the calculations to be finished before downloading and plotting