Hi,
I’m a bit confused about the need or not for thermal noise removal in S1 SLC processing as of 2024. My first SLC processing chain was derived from Mandal et al. (2019), who make no mention of it. My (trusted) colleague says that thermal noise removal is required for S1 scenes pre ~2018, before it was introduced as standard preprocessing step for Level 1 products, and it is no longer required.
However, Wang et al. (2024) indicate that it is required, Filipponi (2019) uses it and border noise removal for GRD processing, and this recent (2023) post uses it.
The Sentinel-1 Product Specification indicates that there is a metadata value saying whether or not it has been performed:
and my S1 SLC data indicates that it has not:
So, for recent (2024) S1 scenes, is thermal noise removal required?
References:
Filipponi, F. (2019). Sentinel-1 GRD Preprocessing Workflow. 3rd International Electronic Conference on Remote Sensing, 11. Sentinel-1 GRD Preprocessing Workflow
Mandal, D., Vaka, D. S., Bhogapurapu, N. R., Vanama, V. S. K., Kumar, V., Rao, Y. S., & Bhattacharya, A. (2019). Sentinel-1 SLC Preprocessing Workflow for Polarimetric Applications: A Generic Practice for Generating Dual-pol Covariance Matrix Elements in SNAP S-1 Toolbox [Preprint]. EARTH SCIENCES. https://doi.org/10.20944/preprints201911.0393.v1
Wang, M., Wang, L., Guo, Y., Cui, Y., Liu, J., Chen, L., Wang, T., & Li, H. (2024). A Comprehensive Evaluation of Dual-Polarimetric Sentinel-1 SAR Data for Monitoring Key Phenological Stages of Winter Wheat. Remote Sensing, 16(10), 1659. A Comprehensive Evaluation of Dual-Polarimetric Sentinel-1 SAR Data for Monitoring Key Phenological Stages of Winter Wheat