Unusually High LST Values (69–79°C) from Landsat 8 Using SCP in QGIS

[TaomeiziZhou]

Recently, I’ve been working with the Semi-Automatic Classification Plugin (SCP) in QGIS to retrieve land surface temperature (LST) from Landsat 8 OLI/TIRS Collection 2 Level 2 data.

However, I’ve encountered an issue. The result I obtained showed an unusually high LST range, from 69.3°C to 79.9°C in the Reading area on 30 July 2024 (cloud cover < 10%). I’ve already checked the weather conditions for that day, and it was not considered a heatwave or an unusually hot period. Therefore, I’m unsure what might have caused this abnormal result.

I would be very grateful for any insights or suggestions you could offer!

[semiautomaticgit]

Hello @TaomeiziZhou , the values are quite high indeed.
There could be many causes, from landscape characteristics to sensor failure.
I'd start by comparing the temperature from an image acquired very near in time, or in the same month of a previous year.
Also, you may try to manually convert the Landsat band to temperature using the coefficients in the metadata file and performing a raster calculation.

[TaomeiziZhou]

Many thanks for your reply and help! I had previously calculated the data from June to August for 2020–2023, and the results were all relatively high. I will try the second method. I'm truly grateful!!