Hi,
It’s great to see HLS being available on SentinelHub! I’m interested in tracking NDVI for an AOI and I was wondering how comparable the results are with NDVI from Sentinel-2 L2A.
The inputs to HLS are Sentinel-2 L1C and Landsat 8/9 (both of top-of-atmosphere reflectance), whereas Sentinel-2 L2A is of bottom-of-atmosphere reflectance. According to HLS documentation, atmospheric correlation is applied to both inputs:
A series of radiometric and geometric corrections are applied to convert data to surface reflectance, adjust for BRDF differences, and adjust for spectral bandpass differences.
“convert to surface reflectance” → Does it mean that HLS is in fact of bottom-of-atmosphere reflectance?
Apologies in advance if this question is more suitable to HLS authors (USGS) but I thought I could get a quicker response here 🙂