“…Where satellite measurements generally struggle to determine robustly the thermodynamic phase of clouds with tops between the homogeneous freezing and melting temperatures, polarimetric detection of a cloudbow is a virtually unambiguous indication of liquid drops at the tops of clouds (Riedi et al, 2010, van Diedenhoven, Cairns, et al, 2012). For ice‐topped clouds, multiangle polarimetry allows inference of crystal shape (Baum et al, 2011; van Diedenhoven, Fridlind, et al, 2012; van Diedenhoven, 2018; van Diedenhoven et al, 2020), which may be especially valuable for evaluation of microphysical models predicting ice shape characteristics (e.g., Harrington et al, 2013; Hashino & Tripoli, 2007; Jensen et al, 2017). Furthermore, the inferred ice shape constrains the ice optical model used for retrievals of ice cloud optical thickness and effective radius from shortwave infrared measurements (van Diedenhoven et al, 2014; van Diedenhoven et al, 2020), reducing uncertainties.…”