Dear Janaki,

Maybe you would be able to find your answer in the following USGS link:

https://www.usgs.gov/faqs/how-do-landsat-collection-2-level-2-products-compare-products-collection-1

Check the USGS link below for details:

https://www.usgs.gov/faqs/how-do-landsat-collection-2-level-2-products-compare-products-collection-1

Yousef Bahrami Umer Alvi Richard Gloaguen Thank you very much. and looking for your suggestions on followings

So as per all your suggestions,

C1- Raw data

C2L1- need to do atmospheric corrections

C2L2- atmospherically corrected

Yes, but you can also find ready to use products for C2L2, see link below:

https://www.usgs.gov/landsat-missions/landsat-collection-2-level-2-science-products

Umer Alvi Thanks.

Since L2 data comes in reflectance, can I use them directly for temperature extraction?

Surface refection and surface temperature are different.

For temperature use this :

https://www.usgs.gov/landsat-missions/landsat-collection-2-surface-temperature

when you used a python code familiar with C1L1 and after launch of landsat 9 all the data on C2L2 so you need to update python code for your work.

The science products for Landsat Collection 2 Level-2 Surface Reflectance and Surface Temperature are scene-based, produced using the standard processing method, and can be downloaded directly from EarthExplorer. Landsat 4-5 TM, Landsat 7 ETM+, and Landsat 8-9 OLI/TIRS data acquired from 1982 to present are available as Collection 2 Level-2 products. Level-2 products for Landsat MSS 1-5 data are currently unavailable.

Only on-demand processing (Surface Reflectance, scene-based) or Landsat Collection 1 U.S. Analysis Ready Data (ARD) are available for Level-2 products from Landsat Collection 1. (tile-based). From 1984 to December 31, 2021, when fresh Collection 1 processing concluded, Level-2 items were accessible.

Check out further information via these links..

https://www.usgs.gov/media/files/landsat-8-collection-2-level-2-science-product-guide

https://www.usgs.gov/media/files/landsat-4-7-collection-2-level-2-science-product-guide