Townsend snow loss (via pvlib) + precipitation-aware soiling model using monthly climate inputs (manual-clean option); month-by-month results to support EPC yield estimates and O&M cleaning plans.
Reference used Townsend, T., & Powers, L. (2011). Photovoltaics and snow: An update from two winters of measurements in the Sierra In 37th IEEE Photovoltaic Specialists Conference (pp. 003231–003236). IEEE. https://doi.org/10.1109/PVSC.2011.6186627