Speaker
Description
The Soil Moisture and Ocean Salinity (SMOS) mission was launched almost sixteen years ago as part of the Earth Explorers ESA missions. It generates full polarimetric brightness temperature images in the L-band at 1.4 GHz with an integration time of 1.2 s. As the Sun appears in most images as the strongest source of contamination, data are processed with a Sun removal algorithm. This signal can be used to monitor the Sun's activity and to generate a high time-resolution solar flux timeseries. The evolution of the SMOS solar flux is strongly correlated and in good agreement with the radio-telescope measurements, showcasing a peculiar signature compared to other alternatives. Similarly, the correlation between the SMOS solar flux and other solar activity proxies, including the MgII index and the International Sunspot Number, is assessed. Both the correlation with the different frequency solar flux measurements and the solar proxies are evaluated from the start of the mission up until 2025 and then analyzed with a focus on the XXV Solar cycle only. SMOS data show a remarkable stability over time and are not affected by relevant seasonal biases, and provide almost continuous monitoring without the need for intercalibration, recalibration over solar minima, and atmospheric corrections. The SMOS data offers a valuable resource for both long-term tracking of the solar activity and short-term analysis, which can be used to detect solar radio burst events characterized with full polarimetric measurements. Data quality is expected to further improve over time thanks to new and better processors planned to be operational in 2026.
