TOC calibration : questions about sources for atmospheric datas and aerosol model

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Hi,

I try to perform optical calibration on Pleiades images taken in last september above Lorient and its bay. About the TOC calibration level, i wondered where to find datas as I cannot have aeronet file to download on my location.

But i would like to have your advice about the website below (the page is just an example) :
https://neo.sci.gsfc.nasa.gov/view.php?datasetId=MODAL2_M_AER_OD
Here, I can download several kind of datas about atmospheric conditions. Of course, dowloaded datas are not very spatially precise, but it seems to provide good daily global datas on my location, for aerosol optical thickness, ozone amount and water vapour. And you could note that ozone amount are in dobson units which must be converted to atm-cm (100 DU ~ 0,100 cm-atm).

And about the aerosol model, a good choice seems to be maritime, for areas located along the coast and the small Island of Groix.

So, my two questions are :

  1. Is this website relevant to get atmospheric datas on a specific location without aeronet file ?
  2. About aerosol models (6S) : What do we mean exactly by maritime model ? Does it depend on salinity ? To how much distance from the coast could we use the maritime model for an area ?

Thanks by advance,
Etienne

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Hi again,

As I have understood. Datas from the website quoted above are just revelant for visulazing purposes. It is not advised to use those datas for scientific works. But we can use the RAW datas which were used for the global maps of the NEO website.

I have listed interresting sources for downloading appropriate raw datas. Please not that a registered account (free) is compulsory for downloading datas from NASA repositories :

On those websites, you can draw a region of interest instead of downloading the entire set of data.

1 Like
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And I would like to let know one thing :

The unit used for Ozone amount seems to be wrongly written. Maybe it is correctly computed with the 6S model but to avoid confusion, we should write atm-cm (0.1 atm-cm = 100 Dobson units) instead of cm-atm.

I would like to have confirmation from experts in climatology and from the developpers.

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Dear @yitianetie,
I think you are right. I will try to talk with an expert at the CNES, and then update the documentation.
Thank you.
Sincerely.
Julien.