I'm fusing L7 & L8 surface reflectance into an NDVI time-series. I'm using the method described in Roy et al. 2016 to convert L7 NDVI to L8 NDVI using a simple regression equation found in table 3:
OLI = 0.0235 + 0.9723 * ETM+
However, this method was developed pre-Collection1, and I've heard that perhaps with collection 1 data I no longer need to adjust ETM+. I've looked at the collection 1 description and I don't see any mention of this issue. https://www.usgs.gov/land-resources/nli/landsat/landsat-collection-1?qt-science_support_page_related_con=1#qt-science_support_page_related_con
Do I still need to apply the correction specified in Roy et al. 2016 or can I fuse the NDVI values with no correction?
Roy et al. 2016. Characterization of Landsat-7 to Landsat-8 reflective wavelength and normalized difference vegetation index continuity. Remote Sensing of Environment