General comments

Thank you for the opportunity to review this very interesting work that examines how variations in stochastic signals resulting from micro cone penetration in snow can be used to discern snow type/microstructure.

Field data is compared with laboratory data to enable characteristic signals to be identified and variation in two noise types (diffusive and jump) is particularly examined to suggest snow microstructure behaviour and thus snow type/composition. This work relies on the assumption that the SMP penetration process is analogous to Brownian motion.

I found it a very interesting paper and I recommend it for publication. Below I make a few specific comments and numerous technical observations which the authors may wish to consider. 

Specific comments

My primary comment is that you may wish to consider altering the title/context/frame of your paper. I say this because McCallum has written many papers on Cone Penetration Testing (CPT) in polar snow, some of which examine microstructure assessment using CPT. You may wish to briefly comment on these works in your introduction, or you may wish to refer to your work as ‘micro’ cone penetration testing, just to differentiate between the large body of McCallum’s large-scale (36.7 mm penetrometer) work and the body of work that you discuss here, primarily pertaining to the SMP, Johnson and Schneebeli’s work etc. I am happy with whatever you chose to do; but, if you keep it as cone penetration tests, you probably should mention McCallum’s work…

The rest of my comments are essentially of a technical nature.

Technical observations 

Please re-examine your tense throughout the document. You start off in past tense but this alters; please review and amend.

Now by line #, for your consideration please:

3 “more and more” etc. please re-phase/tighten this sentence.

5 delete “employing”

8 replace allows with enables

11 probably less-dense not lighter; keep terminology consistent.

13 single: how do you discern/confirm this? Perhaps reword.

14 Perhaps: with micro cone penetration tests.

24 Perhaps: supposedly

26 can be resolved

40 Reference re. important applications?

41 to some of the most…

47 delete “the” in the fluid

49 what are micro-events? Please better explain.

53 shot noise? correct?

57 Please reword this last sentence; perhaps: Via this advanced analysis, we seek more detailed snow characterisation from micro cone penetration test resistance data.

59 Delete “the” Sect. 3

63 explains the equations?

64/5 note that although the drive is constant the actual penetration rate may not be.

75 fix “as of the”

77 probably just Friedrich () and Rinn () (instead of semi-colon).

85 do you mean: small depth interval (z)? Also “similar”

91 probably: Such a jump-diffusion dynamic…

107 Wick’s theorem: reference?

114 where here we use…

117 do you mean: small depth interval (z)?

122 perhaps state: “; this is the same as Eq. 2 but…”

128 perhaps “is considered instantaneous”.

129 Please spell out OU and SDE in Fig. 2 caption.

129 Please use drift-jump and jump consistently so as not to cause confusion.

134 Rephrase “as above”; this is unclear.

136 “which is a zero-one…”

137/138 etc. “process were generated”; please change tense to past throughout.

139/140 “Left, a pure…, middle, … and right, …”

141 negligibly

142 “Dots” in Fig. 3 caption

143 process, another parameter that we considered was…

144 proof evidence? Perhaps: to validate our method, based on the KM coefficient…; then. comma after “Eq. 8”; “were chosen”

146 “as the previous example”

152 Probably: Firstly, small snow samples whose microstructure was fully characterised… were used to test… Secondly,… we analysed one… and provided… 

156 Fig. 4 caption; final sentence: Sub-samples shown are …

158 tested

159 Reference for snow types; the samples were prepared.

160 Temperature of sintering? Microstructure was captured.

161 test was conducted

162 on sample preparation..

163 Main sample properties are summarised in Table 1 and the measured hardness profiles…

167 focussed on the fluctuations of the hardness profiles. Each profile was first detrended.

173 divided

174 were separated

175 We estimated the KM coefficients of each sample…; how?

179 data were determined

180 was determined

181 “…0, and the higher order KM…”

182 This indicates the presence…

186 normalizaton, the fixed…

187 length scale is given

189 Figure 5 caption:  Setup of micro cone penetration test; The samples were placed in the cylindrical sample holder…; Is “Kistler 9207” the type of force sensor?

Figure 6 caption. The wording here is unclear: “have smallest trend and fluctuation force”; are you using all these terms consistently? In the next sentence you talk of size not force? Please re-examine…

Figure 7 caption. …for better visualisation.

197 Perhaps: Results are summarized in Table 2; we discuss these in Sect. 4.

198 Perhaps: Hardness of Field Data or Application to Field Snow Data?

200 The measurements were also performed with a SMP, but the tip had a different sensitivity of…what was it?? Spatial sampling was again…

Figure 8 caption. Please reword last sentence; it is difficult to understand.

203 methods was irrelevant, as we subsequently show… that in principle, the… really snow data, and that…

Figure 9 caption. “< 2; we focus our statistical…”

206 therefore, we used…

207 profile was separated… and detrending was performed on each window… 0.6 mm, formalised with…deviation as in our previous analysis of laboratory data.

Figure 10 caption. parameters were determined… are also plotted to enable better comparison (right column); they are shifted… reference to the local characteristic snow types from laboratory measurements, 

212 for better comparison

213 Interpretation of these results will be discussed next.

217 “it is found that sufficient large particle”?? Please reword. “In our interpretation,…”

218 perhaps: “in the immediate surroundings of the SMP, in addition to the pushing aside…” 

219 Delete However; Perhaps: The jump noise may represent (or be representative of) the bond-breaking events occurring directly at the tip of the SMP…

221 perhaps: it is clear that snow type morphology, shown in Fig. 4, is essential for effective stochastic analysis as outlined herein.

223 We started…

230 “R’, and can be approximated…”

249 our earlier discussion,

252 “bigger ice structures”: consider rewording/clarifying this sentence: ”thicker grain necks?

255 “allows”? perhaps: enables differentiation between…

257 perhaps: “With reference to the local characteristic snow types from the laboratory measurements (), we see dynamics that suggest mixtures of different snow types within this depth segment.

261 “the developed methodology appears… in the field, but further quantitative evaluation is required.”

264 allows differentiation of

268 the denser structures typical of DH and…

270 Delete: “we have to remember that”

273 Perhaps: Finally, we would… of a complex material, snow, by a…

276 Perhaps: types, complementing existing methods.

cf attachement