This study presents a novel and compelling mechanism—the Giant Cloud Condensation Nuclei-enhanced Ice Sublimation Process (GCCN-ISP)—that challenges the traditional Wegener-Bergeron-Findeisen (WBF) paradigm in mixed-phase clouds. The key innovation lies in demonstrating how large CCN can alter the direction of vapor transfer, enabling supercooled droplets to coexist with ice crystals under specific conditions. The theoretical framework, combining Köhler theory with solute effects, is well-constructed and supported by observational data from the AFLUX campaign. The identification of a "balanced diameter" for droplet-ice equilibrium provides a valuable conceptual advance, with potential implications for improving cloud microphysics in climate models. I recommend acceptance after minor revisions, contingent on a more comprehensive discussion of uncertainties and broader impacts.

• The reliance on a single case study (AFLUX campaign) limits the generalizability of GCCN-ISP. Expanding validation to diverse geographic regions (e.g., mid-latitude mixed-phase clouds) and seasons would strengthen the conclusions. Direct measurements of CCN size/composition (e.g., via aerosol mass spectrometers)，if available, can be used to corroborate inferred CCN properties.
• The assumption of pure NaCl CCN (κ=1.4) oversimplifies real-world aerosol diversity. Incorporating mixed CCN types (e.g., organics, sulfates) and non-spherical shapes would enhance realism. Additionally, the model neglects dynamic processes like turbulence and entrainment, which could modulate GCCN-ISP efficiency.
• While the mechanism’s microphysical basis is plausible, its broader climatic impacts (e.g., on cloud radiative forcing or Arctic amplification) remain unquantified. Some words on coupling the framework with large-scale models and further study on the climate effect of this mechanism can be added.
• The study does not explore how GCCN-ISP competes or synergizes with other ice nucleation pathways (e.g., secondary ice production) or collision-coalescence. A discussion of these interactions would contextualize the mechanism’s relative importance
• Controlled laboratory experiments (e.g., cloud chamber studies) are critical to isolate GCCN-ISP under varying temperature, humidity, and CCN conditions. Such experiments could validate the theoretical "balanced diameter" and vapor transfer dynamics .