MERIS Case 2 regional processor. V1.6

Hi, There are few questions regarding MERIS Case 2 regional processor. V1.6 algorithms :-

  1. Does the above processor use the following atmospheric correction, if no can you please provide the proper link for the atm. correction paper:-
    "__Alternative Atmospheric Correction procedure for Case 2 Water Remote Sensing using MERIS (ATBD V.1.0)Author: Ronald Doerffer (27/05/2011)

  2. To confirm" R Doerffer & H. Schiller (2007) The MERIS Case-2 water algorithm " is the paper for the scientific documentation of the algorithm?

  3. I want to try the Ruddick’s “Atmospheric correction of SeaWifs imagery for turbid coastal and inland waters (2000)” refelectance data as an input in the C2R algorithm instead of its own atmospheric correction reflectance data: Is it possible to do so?

These are at the moment the latest papers. New ones are currently written.
The following is a paper which is briefly describes the evolution:

3.At the moment, it is not possible to use a different AC as input.

Thanks for your reply. Can the CR2CC be applied in any other platform other than SNAP or BEAM?

No, it is implemented only for SNAP.

Marco, I read the paper, the C2RCC serves my purpose. Is it available in SNAP 5?

With original C2R I was having over-estimation of CDOM (which I calculated from an empirical relationship between backscatter and Non-Algal particle, which was taken out of the yellow substance value to obtain CDOM ). I am applying the C2R algorithm in a region where is highly dominated by sediments such that a minor change in the slope of NAP can alter the CDOM slope, giving an overestimated result.

It is not in SNAP 5. It will be in SNAP 6 and is already available in the preview (below the SNAP 5 download).

Thanks Marco…I will test my data with the CR2CC in a place where it is highly dominated by sediments.

I am planning to compare the C2R v. 1.6 with C2RCC. At first instance, I am observing some major differences in their products, especially the TSM product is hell and heaven different for a MERIS FRS scene in the near-shore area. Also, the C2RCC gives scattering coefficient value whereas the C2R gives backscattering value.

For C2RCC I am observing that there is parameter SALINITY ( salinity of the scene). I am dealing with estuarine and near-shore data with offshore component also, so there the salinity gradient of the scene varies. Does this processor require mean salinity of the scene. As there is a specific salinity for the plume, estuarine, coastal, and offshore area; will the mean salinity affect the processing.?

If I remember correctly the salinity has only a slight influence on the results. So it is not too bad to use a mean value for one scene. You have to try with different values and see how it influences your results.

Hi Marco,

I have been applying the C2RCC algorithm on the MERIS FRS images. Sadly the near-shore zone and the entire estuarine zone is getting masked by “R_tosa_OOS”: The input spectrum to the atmospheric correction neural net was out of the scope of the training range and the inversion is likely to be wrong. Please find attached the processed FRS images of 19th July 2010: iop_gelb (Nelson-Hayes River: Southwest Hudson Bay, Canada). These are the region of very high sediment concentration. The same applies for other dates also. Thus this is preventing me to use this algorithm as my zone of interest: the estuary and coast is masked. I was expecting this algorithm was better adapted for coastal region with extreme values, but the previous C2R v 1.6 is algorithm is producing pretty decent result. Though my question might be a bit vague, but is there any solution to it at this moment.

Hi Marco,

Can you please confirm the aYS (443 nm) product of C2R V 1.6 algorithm exclusively gives the absorption of CDOM and not the Colour Detrital matter (CDOM+Detritus).


In C2RCC, have you switched to the C2X nets? They are intended for the usage in areas with extreme conditions.

If you like the old C2R processor and use MERIS data you might like the CoastColour on-demand processing service too.

Yes, I can confirm this. It is only CDOM respectively gelbstoff.