Fusing Collection 1 Landsat 7 and 8 Surface Reflectance NDVI

Question

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

Answer 1

I finally have an answer to this question, and I thought I would respond to this post for future reference. I emailed Dr. Roy and he kindly replied that the USGS did not correct any spectral differences between L7 and L8, and that it is still appropriate to apply the regression when fusing L7 and L8 C1 data.