Dear Wajdi,

Your question is too generic, because there may be many solutions (or none) depending on your requirements... Please specify the following constraints on your project:

- What is the area of interest?

- What spatial resolution do you actually need?

- What is the period of interest?

- What accuracy do you require?

- What is your budget?

For historical data over a long period (e.g., 20+ years), explore the suitability of the ASTER instrument:

https://terra.nasa.gov/about/terra-instruments/aster

If your project is more concerned about the future, follow the developments of companies that are currently investing in the development of new sensors, or even new constellations of satellites operating in the thermal infrared range, such as

https://constellr.space/

Lastly, if you want really very high spatial resolution data over a small site, consider mounting an appropriate thermal camera on a drone or a low-flying airplane: those solutions will continue to deliver much higher spatial resolution than satellites, at least for the foreseeable future, although there are other constraints to that approach too.

I hope this may help you. Good luck in your investigations, Michel.

As far I know Landsat 60m thermal bans are the freely available ones.

https://www.azooptics.com/Article.aspx?ArticleID=1105

https://doi.org/10.1080/04353676.1985.11880153

https://doi.org/10.1109/DT.2019.8813438

Dear Wajdi Belkhiria . The GeoEye-1 satellite has high resolution imaging system. See the link: https://en.m.wikipedia.org/wiki/Satellite_imagery

Kindly see also the following useful link: https://blog.maxar.com/earth-intelligence/2020/introducing-15-cm-hd-the-highest-clarity-from-commercial-satellite-imagery

Also check please the following useful link: https://www.fis.uni-bonn.de/en/recherchetools/infobox/professionals/resolution/temporal-resolution

Wajdi Belkhiria ECOSTRESS onboard the International Space Station (ISS) is another freely available thermal infrared (TIR) sensor providing imagery at 70 m spatial resolution. Apart from the freely available, conventionally used TIR imagery from Landsat (60-120m), MODIS (1 km), Sentinel-3 (1 km), ASTER (90m) that were already mentioned, there are some commercial Thermal satellite startups working on creating "small-sat constellations with thermal imaging sensors". Follow the links for more information:

• https://ecostress.jpl.nasa.gov/instrument
• https://chrieke.medium.com/thermal-imaging-with-satellites-34f381856dd1

Dear Wajdi,

I've been dealing with Landsat-8 and MODIS products for the last months. Both are satisfying, but they have some inherent disadvantages in terms of temporal (Landsat-8, restricted to daytime data) and spatial (MODIS, 1km) resulutions. I use both and try to extract their best!

I'm looking forward to work with ASTER TIR data, but I still don't know if it has daytime and nighttime information... It would be nice if you'd share your findings with regard to this topic!

Best!