I have been recently experiencing a hard time with NDVI values derived for Sentinel-2 scenes Level 2A (processed with Stand-alone Sen2Cor 2.4.0 with topographic correction).
My concern is that NDVI is a way too high than what I would expect for grassland/pasture land cover classes in winter/early-spring in Europe NW. Some areas are getting NDVI >0.9. The image looks ok, but the range is shifted towards the high end. I have been experiencing it for a several Sentinel-2 tiles acquired over Europe.
I am aware of this paper: http://ieeexplore.ieee.org/document/6449317/ and understand that the NDVI values derived from Sentinel-2 are going to be different, but having most of pixels in a high end on the NDVI range (much into the usual saturation levels) hampers imho for example LAI~NDVI modelling .
On the other hand, going through Sentinel-2 related scientific papers, I have never come across any publication that would have tackle this issue. On the contrary, all presented NDVI values sit well within the expected range, with only single observations on the high end (above 0.8).
I am wondering whether anyone has been experiencing similar issues with S2 data (?!).
Thanks for your input and insight.