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I'm doing a temporal analysis of NDVI and temperature over 17 years, necessitating data from Landsat 5,7, & 8. I'm interested in using level-2 Landsat data available from https://espa.cr.usgs.gov/ordering/new/. I would be able to directly download NDVI as well as brightness temperature, which would save me a lot of time. However, the USGS is explicit that the algorithm used to calculate surface reflectance for Landsat 8 is not the same as the algorithm used for previous satellites.

https://landsat.usgs.gov/landsat-surface-reflectance-high-level-data-products

My question is: are the level-2 products from Landsat-8 comparable on an apples-to-apples basis with Landsat 5 or 7 level-2 products, or does this kind of comparison require some sort of adjustment to the data? I haven't been able to find an answer to this question online.

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    I asked the USGS this question and got this response. I'm not really sure what to make of this: "They use different algorithms, yes. That doesn't mean the datasets are completely incompatible. It means you may need to provide additional information in your study." – user5858 Mar 14 '17 at 21:00
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    not much help here, but trying to do some classifications between L8, L7 and L5 images I found out some older images may (not neccessarily) be shifted by a range of kilometers. be sure to check that, it is caused by not using GCPs when calibrating older images (link: landsat.usgs.gov/landsat-processing-details). This info may be related - if you check whether your image was originally L1T or L1GT etc, it is possible your Surface Reflectance derived product has same characteristics - from what I know it can't be repaired, they just eg. didn't have some GCPs back then. – adamczi Apr 3 '17 at 21:13
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Yes, you do need to correct Landsat 8 imagery to compare it against Landsat 5 and 7. The data between the three satellites are not directly comparable in their raw form.

This paper compares Landsat 7 to Landsat 8:

Roy, D.p., et al. “Characterization of Landsat-7 to Landsat-8 Reflective Wavelength and Normalized Difference Vegetation Index Continuity.” Remote Sensing of Environment, vol. 185, 2016, pp. 57–70., doi:10.1016/j.rse.2015.12.024.

For instance, from the paper, to compare Landsat 8 NDVI with Landsat 7 NDVI you need to apply the following correction to the Landsat 8 NDVI:

L7NDVI = 0.0029+0.9589*L8NDVI

Further, this paper shows that Landsat 7 NDVI is about 2.5% higher than Landsat 5 NDVI:

Teillet, P M, et al. “Landsat-7 ETM+ and Landsat-5 TM Cross-Calibration Based on Tandem Data Sets.” Remote Sensing of Environment, vol. 78, no. 1-2, 2000, pp. 39–54., doi:10.4095/219729.

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  • Careful, this may not be the case for the "analysis ready" products. The USGS applies a dynamic range correction to the imagery to correct for wavelength variation. This has been a common correction since the deployment of ETM+7. I had not seen any published correction for cross calibration of dynamic ranges for OLI. You can use Roy et al (2016) band corrections for ETM but not TM5. I guess you could correct TM5 to ETM then to OLI using these coefficients. I just wish they would have developed their coefficient globally. – Jeffrey Evans Jul 27 '20 at 21:28

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