Landsat 8 Level 2 products. Converting Pan & Thermal bands to spectral reflectance

Question

We have downloaded around 20 Landsat Level 2 Surface Reflectance scenes for our AoI. The processed bands available in the downloaded scenes are, as you people know - Aerosol,B,G,R,NIR,SWIR,Cirrus.

The unprocessed bands - Pan and 2 Thermal bands, we would like to convert those in to surface reflectance as well as we are working on band ratioing, band combinations & PCA.

I've downloaded LaSRC - which USGS uses to convert DN -> surface reflectance - from their github repository https://github.com/USGS-EROS/espa-surface-reflectance. But couldn't able to run it as it requires few dependencies it seems (our's is windows 10 system. But has QGIS, GRASS and few other OSGEO softwares installed).

My questions are,

1) Can't we convert Thermal bands (which will be in the units of kelvin) to surface reflectance ? If we can't, then how to do band rationing and combinations with thermal bands ? (Tried ENVI's Thermal Correction tool. But not working)

2) Converting Pan band to surface reflectance is straight forward i suppose. Though we are going to use Pan for visual enhancement, do we still need to convert those to surface reflectance ?

Answer 1

No, you can not convert Thermal bands (which are in digital number and not Kelvin) to surface reflectance.

In remote sensing, we having a non spoken rule about NOT combining data belonging to different 'domaines'. i.e: Reflectance (Visible & reflective IR), Emission (Thermal), Retrodifusion (microwave).

Converting pan to surface reflectance is not straightforward, because the pan represents the mean value of the entire visible spectrum (and part of the NIR).

Fortunately for you, you don't need to do any of that. Because most pan-sharpening algorithmes do some sort of histogram matching before 'fusing' MS (multispectral) and PAN data.