I’m quite confused by now with the Top-Of-Atmosphere (TOA) Reflectance in the Sentinel 2 Level 1C Products.
When I work with the Toolboxes in SNAP and read data out from a mask, for example, I get values between 0 to 1 for the reflectance ( I know that values above 1 are possible (explanation here), but it didn’t happen for my products. I use only cloud-free images over the Weddell sea in the antarctic area.)
On the other hand, I work with the JPG-2000 Files for the Sentinel 2, which are also Level 1C products, and they need to be divided by 10000 to have the same reflectance values.
I created threshold for different ice categories and I want to compare the results to spectral albedos, because I only use data from Band 4. But I’m not sure about how and if I can compare them. So if somebody have some ideas or does the same, it would be nice to know it.
SNAP uses the QUANTIFICATION_VALUE in the metadata to display the values in decimal values between 0 and 1. In order to save space for raster storage, the original data (J2000) is stored as full integers.
Yeah, I know. This is the reason why you need to divide the values from the JPG 2000 files with the QUANTIFICATION_VALUE, which is 10000. I thought I wrote this in my question, but yours is way more clear.
No, not solved jet. Sorry, if it wasn’t clear. The reflectance in the Level 1C Product is a TOA Reflectance, but I want to know if I can get a spectral albedo value out of this information. And the reflectance is kinda connected to one wavelength, because I only use Band 4.
I’m not sure I’m getting this, but wouldn’t it be logical to use the L2A (BOA) product? That would give you a closer representation of what is happening on ground.
It would be better when I worked with this files at the beginning. But at this moment it is kind of too late for this work.
And I don’t know how good these products are in the Antarctic area.
Sorry, maybe I misunderstood…