The emissivity of sea foam at the microwave frequencies is estimated using a two-stream approximation radiative transfer model. Reference: Y. Xie, F. Weng, X. Han and Y. Han, "Physically Based Simulations of Foam-Covered Ocean Emission at Microwave Frequencies," in IEEE Transactions on Geoscience and Remote Sensing, vol. 63, pp. 1-9, 2025, Art no. 2000109, doi: 10.1109/TGRS.2024.3508662.