Sentinel 2A BOA Reflectance to BOA Radiance

I am trying to convert Sentinel L1C level data (TOA Reflectance) to BOA Radiance.

To do this I was able to use Sen2Cor to transform TOA to BOA Reflectance, but I cant transform the reflectance to radiance in the generated product using the (Optical/Reflectance to Radiance).
I get the error “Please specify the solar irradiance”

If I try to convect the L1C TOA Reflectance to Radiance I have no problems.

Any ideas of what I am doing wrong or how to proceed?

The processor only considers S2 L1C, that’s why it doesn’t work with S2 L2A data.
For which application do you want BOA radiances? I Haven’t heard this before.

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Thank you for your reply, that makes sense.
The reason for wanting atmospheric corrected radiance values is to be able to apply Lyzenga water column correction for seagrass mapping.

I am sorry, i forgot to ask.

is there a way of transforming reflectance to radiance in S2 L2A products?

Are you talking about water leaving radiance? Because then what you need is the atmospherically corrected data (or reflectance).

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Oh, thank you about that.
I was under the impression that Lyzenga could only be applied to radiance data, but I also found a paper that used atmospherically corrected reflectance.

Thanks a lot!

Could you please share with us the name of the paper? I am also doing the same research for seagrass using sentinel-2 data and it could be handy if it is not in my list.
Thank you.

This is the paper:

Thalib, M. S., Nurdin, N., & Aris, A. (2018, June). The Ability of Lyzenga’s Algorithm for Seagrass Mapping using Sentinel-2A Imagery on Small Island, Spermonde Archipelago, Indonesia. In IOP Conference Series: Earth and Environmental Science (Vol. 165, No. 1, p. 012028). IOP Publishing.

Hope it helps!

Working with sentinel-2 and seagrass classification I am trying to find out if the L2A products provided by open hub copernicus are “ready to use” products. By saying “ready to use” I mean further corrections that must be applied to work with underwater materials. Except from water column correction which is another topic, am I satisfied with L2A products or I must apply further correction? As I have understood and already have been said, L2A products are atmospherically corrected and BOA reflectance images.

Hello Marios @msgouros

Yes. L2A (and L1C) are ‘operational’ (i.e. distributed) products. They are ready to use. More interesting things - such as DOP or SDB, or seagrass mapping, are for the User community to perform.



S2 MPC Operations Manager

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Thank you for clarifying this one. As I see it I must concentrate on shallow water column correction and apply afterwards a classification.