Review of

Extremes of surface snow grains change in East Antarctica and their relationship with meteorological conditions

by Claudio Stefanini and others

General

This paper reports on the temporal and spatial occurrence of extreme snow grain sizes on the interior plateau of East Antarctica, as observed by satellite. Four events are discussed in more detail, but explanations in terms of climatological forcing remain inconclusive. This is an interesting paper; the results are original but the analysis lacks depth and remains descriptive, reducing the impact. The figures are of good quality and the clarity of the writing is sufficient.

Major comments

Title: the title is not clear, please find an alternative (e.g., Extreme changes in East Antarctic snow grain size and their ...)

Section 2.2.2: Even though AR detection is only weakly sensitive to the re-analysis product used, it is still puzzling why not the same re-analyses were used for the AR detection and meteorological analysis. Please comment.

A major concern is the accuracy of ERA5/MERRA over this extreme environment in interior East Antarctica, yet these data form the basis of much of the discussions. Please comment.

Section 2.3: How can the subsurface temperatures be determined using daily average climate forcing (l. 65)? The daily cycle is considerable and important for grain growth, given its nonlinear dependence on temperature.

l. 97: As the definition of an extreme growth event, I expect a growth rate, not an occurrence.

l. 134: The GSI time series show a highly asymmetric seasonal cycle, it almost appears as if the signal is reset each year. It is therefore not surprising that correlations with climate variables are weak. This deserves a brief discussion at this location: how can this be understood from physical processes? How can we be sure that this is not an artifact of the used method and/or satellite data?

The same holds for the connection between grain size and atmospheric rivers: how would they be expected to be physically connected?

l. 171 and following paragraph: The discussion remains very descriptive and potential correlations are discussed mainly in terms of variance explained; it would be more informative to identify physical processes that cause rapid grain growth, and then try to couple these to co-variations with meteorological parameters. See also comment on the seasonal cycle above.

Minor and textual comments

l. 18: insulation -> isolation

l. 21: tropics -> subtropics or mid-latitudes

l. 22: Consider moving this motivation to study grain size to the beginning of the introduction.

l. 39: "high grain size" sounds awkward; suggest finding an alternative.

l. 65: suggest: "and we reprojected them using the Southern polar stereographic projection"

l. 65: mean -> means

l. 107: Please specify what you mean by 'models' here.

Fig. 2: axes labels are missing

l. 198: short -> shorter

l. 232: to the pole -> to the interior

l. 263: the downhill transport of cold air is a katabatic wind

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