Earthdata Forum

Hi there,

This is Md Rony Golder, PhD student of Curtin University. I am writing to you to know that---

Is NASA MODIS Aqua Chl-a algorithm (global image, l3 data) applicable for the Southern Ocean?

The literature says that We still say that NASA satellite algorithms under-estimate chlorophyll in the Southern Ocean. What is your point of view on this statement?

I am waiting for your reply.

Quite the loaded question

The Southern Ocean is big and most of it is quite far from civilization. This makes obtaining in situ validation data a challenge to say the least. As a result, the spatial and temporal sampling is rather skewed and probably not applicable to the entire Southern Ocean. That said, a (relatively) recent publication suggests that our data are quite applicable and validate well in the Southern Ocean: https://doi.org/10.3390/rs11151793
They report a difference between fluorometric and HPLC-derived estimates, the later comparing well with our satellite estimates. They posit that the fluorometrically-derived in situ chlorophyll concentrations are overestimated due to an overlap of the chlorophyll-a and chlorophyll-c emission spectra (so, it's the in situ data that are overestimated, not the satellite data underestimating chlorophyll).

Sean

Thank you so much for your reply.