|General comments : |
The article has been deeply rewritten, mainly following the Reviewers’ comments. In particular the analysis is now performed at country level rather than at regional level, which I definitively support. There are also new analyses on CAPE, 2m temperatures and weather regimes. However I’m still puzzled about several points:
- Although the author claims that the agreement between ERA5 and EOBS is “remarkable” (L. 121), I see in Figures 1-2 quite large differences, and not only for Turkey (the color scale doesn’t ease comparison but, e.g., there seems to be around 25-50% difference in all Scandinavia). It seems to me that ERA5 tends to overestimate EOBS.
- All the results of section 4 to explain positive trends in extreme snowfall are based on four countries : Albania (AL), Macedonia (ME), Switzerland (CH) and Turkey (TR). These countries are chosen because they show “the largest positive changes” in maximum snowfall in ERA 5 (L. 173). However according to Figure 4, three of these countries (namely CH, ME, TR) show strong negative trends in EOBS ! Therefore how much confidence can we have in the results for explaining positive trends? Note that the positive trend in ERA5 for Switzerland is in contradiction with several other studies based on snow stations (e.g. Scherrer et al. 2013, Marty and Blanchet, 2012)
- What the author calls “Macedonia” in all the article seems actually to be the Montenegro (which indeed shows a positive trend in both ERA5 and EOBS)
- According to Figure 4, there are only 3 countries with strong positive trends in both ERA5 and EOBS: Bosnia, Montenegro, Albania. All three are located on the eastern flank of the Adriatic Sea. Therefore I suggest focusing on these three countries to attempt explaining positive trends.
- I didn’t understand the results of the weather regime analysis. Whereas AL and ME show similar sea level pressure fields for the maxima, CH and TR show very different fields. Therefore isn’t it inconsistent that for the four countries AR and BLO are found to be by far the most frequent weather regimes during the days of maximum snowfalls?
- L 121 “is remarkable”: as said above it seems to me there are quite large differences for different countries. To ease comparison I suggest 1) using a color scale with larger gradient, 2) showing the ratio ERA5/EOBS.
- Figure 1c: why is part of Turkey missing ?
- L 162 “notably ion the Balkans”: I’d be more moderated on the Balkans because EOBS and ERA5 only agree on 3 countries.
- L 173: “the largest positive changes, namely Albania (AL), Macedonia (ME), Switzerland (CH) and Turkey (TR)”: as already said, among these countries actually ERA and EOBS only agree on AL…
- In all Section 4, don’t you mean Montenegro rather than Macedonia?
- Figure 6 and L. 181-184: the difference are so small that it seems to me to be only sampling variability.
- L 188 “for Switzerland maxima of snowfalls tend to occur in December rather than in January”: Yes, this is in accordance with Klein et al. 2016.
- Figures 7-8-9: the green dots hide where we are supposed to look at. Please consider replacing the dots by the country borders.
- L 207 “and on the Alps for Switzerland”: actually for CH, CAPE is large not only over the Alps, but rather over all eastern Europe.
- L 214-215 “the local temperature difference … is small” : what would be large? For AL the difference is of 3°C. Isn’t it large? For CH: is it red or white? The green dot is about the size of the country so it doesn’t allow us to see the values.
- L 235 “increase of CAPE over the central Med … Switzerland”: I don’t understand this interpretation. According to Figure 9, the maxima in CH are produced by Atlantic flows, so I don’t get the interpretation in terms of Mediterranean CAPE.
- L 245 “technique presented in Faranda et al. 2017”: do you take the same thresholds as therein to produce the classification (98% and 2%)?
- L 245 “five possible regimes” It would be helpful to show the composites of the five classes.
- Figure 10 and L 248 “prevalence of BLO and AR patterns”: as already said, I don’t understand how BLO and AR can prevail for CH and TR whereas Figure 9 shows completely different influences for these countries.
- L 251-254 “this patterns consists … Mediterranean basin”: according to Figure 9, this doesn’t seem to apply to CH.
Typos and clarifications:
- L 147: positive IN Switzerland
- L 185 Figure 6 → Figure 6b
- L 186 date → average date?
- L 207 SwitZerland
Klein, G., Vitasse, Y., Rixen, C. et al. (2016) Shorter snow cover duration since 1970 in the Swiss Alps due to earlier snowmelt more than to later snow onset. Climatic Change 139, 637–649. https://doi.org/10.1007/s10584-016-1806-y
Marty, C., Blanchet, J. (2012) Long-term changes in annual maximum snow depth and snowfall in Switzerland based on extreme value statistics. Climatic Change 111, 705–721. https://doi.org/10.1007/s10584-011-0159-9
Scherrer, Simon & Wüthrich, Christian & Croci-Maspoli, Mischa & Weingartner, Rolf & Appenzeller, Christof (2013). Snow variability in the Swiss Alps 1864–2009. International Journal of Climatology, 33, 10.1002/joc.3653.