Sun-tracking microwave radiometry with dynamic beam modeling for all-weather atmospheric and solar characterization at w-band

In this work, we present an enhanced Sun-tracking microwave radiometry approach for atmospheric and solar characterization at millimeter-wave frequencies, specifically at W-band. Sun-tracking radiometry is a ground-based technique that uses the Sun as a stable natural source to simultaneously estimate the Sun's brightness temperature and the atmospheric optical thickness. We propose a dynamic modeling of the Sun–Earth geometry to account for seasonal variations, achieving a 50% reduction in the standard deviation of the Sun brightness temperature compared to previous studies. For the first time, we quantify the impact of Sun brightness temperature estimation errors on the retrieval of atmospheric attenuation, addressing an open issue previously unassessed in the literature. The analysis relies on a long-term dataset collected over three years in Rome, NY (USA), representing one of the few ground-based databases capable of statistically characterizing atmospheric attenuation in all-weather conditions at K-, Ka-, V-, and W-bands. Results confirm that improvements in Sun brightness temperature estimation do not compromise the precision of atmospheric optical thickness retrievals, validating the robustness and reliability of the enhanced Sun-tracking technique. These findings offer new insights for microwave remote sensing and propagation studies at millimeter wavelengths, supporting next-generation satellite communication and remote sensing systems.