|In the revised version of the manuscript, Zhang et al. appropriately considered the comments of the reviewers. I was happy to see that the authors added a discussion of possible pressure effects on ice crystal growth. |
From my point of view, the manuscript is now suited for publication in ACP. Below, there are just a few suggestions for technical corrections (I refer to the line numbering in the annotated manuscript that was attached to the reply to the reviewers):
- P3, L3: Also Hoose and Möhler (2012, Figs. 1 and 2) provide a neat overview of heterogeneous freezing modes and the freezing activity of various aerosol types.
- P6, L12: '...mixed-phase clouds is similar....'
- P7, L1: '...10 dBZ variation....'
- P8, L16-L17: '...CTT, clouds with a larger LWP have a geometrically...'
- P8, L18: '...and to grow larger....' ; '....clouds with larger LWP also have larger ice growth rates...'
Dust is likely a main contributor to the observed seasonal variability of ice formation. Recently, however, also a discussion was started about the potential role of biogenic INP ( Hoose and Möhler, 2012; Hader et al., 2014; Augustin-Bauditz et al., 2016; Dreischmeier et al., 2017). The authors could consider this aspect in their discussion by adding a single sentence that also biological activity is much higher in the northern hemisphere because of the larger land mass, which would in addition also agree to the observed seasonality in ice formation efficiency reported by the authors.
Augustin-Bauditz, S., Wex, H., Denjean, C., Hartmann, S., Schneider, J., Schmidt, S., Ebert, M., and Stratmann, F.: Laboratory-generated mixtures of mineral dust particles with biological substances: characterization of the particle mixing state and immersion freezing behavior, Atmos. Chem. Phys., 16, 5531-5543, https://doi.org/10.5194/acp-16-5531-2016, 2016.
Dreischmeier K, Budke C, Wiehemeier L, Kottke T, Koop T. Boreal pollen contain ice-nucleating as well as ice-binding ‘antifreeze’ polysaccharides. Scientific Reports. 2017;7: 41890.
Hader, J. D., Wright, T. P. & Petters, M. D. Contribution of pollen to atmospheric ice nuclei concentrations. Atmos. Chem. Phys. 14, 5433–5449 (2014).
Hoose, C. and Möhler, O.: Heterogeneous ice nucleation on atmospheric aerosols: a review of results from laboratory experiments, Atmos. Chem. Phys., 12, 9817-9854, https://doi.org/10.5194/acp-12-9817-2012, 2012.