From the Finnish Meteorological Institute :
A new paper has recently been published, detailing recent updates and validation of the operational Level-3 Freeze-Thaw product. The latter exploits the sensibility of L-band brightness temperatures to changes between frozen and thawed state.
The latest reprocessed version (3.02), freely accessible via both the ESA SMOS online dissemination service and the FMI dissemination server, features several key improvements :
- Enhanced temporal filtering through Kalman-based noise reduction
- Updated reference conditions
- Refined use of auxiliary data
Validation against in situ data from the International Soil Moisture Network and comparison with ERA5-Land soil temperature data demonstrates the product’s robustness in identifying the day of first freezing – a critical parameter for greenhouse gaz emissions studies.
Comparaison of freezing Day Of Year (2010-2024) from SMOS Freeze-Thaw product and ERA5-Land .