After harmonizing and making all the radiometric corrections, I still get that Landsat 8 shows a wrong increase in vegetation intensity. Anybody with a similar problem that may have found a solution?
Yes, Landsat 5 and Landsat 8 data are generally compatible with each other. Both satellites are part of the Landsat program and have similar imaging capabilities, although there are some differences in sensor characteristics and data processing methods. While Landsat 5 was operational until 2013 and used the Thematic Mapper (TM) sensor, Landsat 8, launched in 2013, carries the Operational Land Imager (OLI) sensor. Despite these differences, efforts are made to ensure data continuity and compatibility between different Landsat missions, allowing for consistent analysis and comparison of imagery collected over time. However, it's always a good practice to verify compatibility based on specific analysis requirements and any potential differences in data characteristics.
Possibly due to different sensors which have different radiometric resolutions.
I have a couple of questions and comments:
1. Which data set did you down load and work with (C2L2 or C2L1 or ?). This determines the level of processing the data had before you down loaded them. This is related to what radiometric corrections have been done; sun elevation and atmospheric corrections are especially important.
2. Once you down loaded the data, did you apply the scaling factors (multiplicative and additive factors) before because this will affect the values that are generated for the NDVI and other indexes. If not, this will make a difference. Also, make sure you apply the correct scaling factors.
Pat
Ofcourse except for band 6 of landsat-5 (120m resolution) & band 8 of landsat-8 (15m resolution).
Therefore, the reason of the problem will be due to incorrect combination of band 8 (15m) with other bands b/c it is sharper thsn others that need panchromatic fusion/pan-sharpening than normal layer stacking of other bands (30m).
Additionally, I recommend you to read land use land cover changes and its causes at Hangar Watershed, Ethiopia from the following link for clarification:
https://www.researchgate.net/profile/Abdata-Wakjira-Galata