This is a straightforward and thorough study which compares a series of model simulations to observations of a mixed-phase cloud to determine what changes are necessary to the microphysics scheme in order to reproduce the observed microphysical structure of the cloud. While I think that the discussion at times becomes tedious and the results could be presented more concisely, I can find no fundamental problems with the methodology or the interpretation of the results. The main takeaways of the paper are a number of recommendations to modelers for accurately representing SIP processes in Arctic clouds which I believe could be useful for the modeling community. Below are mainly suggestions for improvement and a few questions about minor points that were unclear.

Abstract: Just a suggestion for revision. Currently the abstract is about 2/3 preamble and 1/3 about the study. I would recommend putting more emphasis on the results of the study and less emphasis on the preamble. 

Lines 73-80: I think that a more direct statement of this study's objective would be useful for framing the paper.  I didn't have a clear sense for where the paper was going after reading the introduction.

Line 130: I initially thought that Eq. 1 could be found in the given citation. Then, five lines down, Eq 1 appears awkwardly without context. I recommend moving Eq. 1 to appear immediately after it is mentioned, as is typically done with equations.

Line 190-191: If CCNC is 9/cc for updrafts, downdrafts, and negligible, then is this simply a 1-moment version of the scheme? And if not, then what activation scheme is used if not Cohard and Pinty?

Table 1: Does the CCN type really matter, particularly for MYadap? 

Line 387: "The overview over in which ..." ... please clarify.