Dear authors,

Thank you for your revised manuscript and your rebuttal letter. I have carefully read the revised version and find it suitable for publication after minor (but many) revisions as outlined below. Please implement these changes carefully and provide a justification where you disagree with my suggestions. To speed up the further process, please also provide a highlighted version of the revised manuscript so your changes can better be tracked.

Kind regards,
Stephan Gruber

Title: Weichselian permafrost depth in the Netherlands: an uncertainty and sensitivity analysis (the Po Basin would also be lowland Europe...)

MAJOR COMMENTS
Why is the “fully frozen front” the relevant metric (P6L13)? I have several issues with this: (a) no justification is given, (b) down to -40ºC you will not find ‘fully’ frozen soil/rock and thus this only exists in your current parameterization – with all the inherent arbitrariness, (c) one would assume that the presence of any amount of ice would be relevant as this begins to affect hydraulic permeability and material structure. If you have a good reason to stick to ‘fully frozen’, please justify this well. If not, I suggest to us the definition of permafrost (<0ºC) as this is (a) conservative and (b) provides a definite distinction of ground that can/cannot have ice. See next comment.

You give a valid permafrost definition, and at the same time you use a conflicting and arbitrary definition of -0.25ºC as an indicator (P6L16, P13L8–10, P16L14, P17L31). This is arbitrary and confusing.

Distinguish the description of material freezing behaviour and the parameterization used in your numberc scheme (P6L2/3 shows lack of understanding, as your liquidus/solidus parameterization of freezing may be interpreted of representing pore diameter and surface effects).

P4L25–28: Please reformulate to clarify that (a) you describe the behavior of your parameterization (in reality there will be unfrozen water below you solidus) and (b) that this describes the behavior of water in a porous medium (a mixture of substances and not a pure material), correspondingly the term used should be ‘thaw’ rather then ‘melt’.


MINOR COMMENTS
P1L14: “It thus is important to determine…”
P1L21: “…, snow cover, surface temperature gradients…”
P1L24: “…, would be 120–200 m at the 2 [sigma] level. In any case, simulated permafrost does not…”
P1L27: Delete last sentence.
P2L1: “Northern hemisphere permafrost is presently …”
P2L5: “Today, the lowlands of northwestern Europe are free of permafrost.”
P2L7: “…permafrost conditions during the last glacial maximum …”
P2L29: “… affected during permafrost conditions,…”
P2L33: “It is thus important to …”
P3L6: “…and geothermal heat flux.”
P3L18: “… analogous to the last glacial (Weichselian).”
P3L21: “… geothermal heat flux.”
P3L23: “…geological disposal, is taken a few steps further.”
P3L26: “… possible adverse effects from the presence of permafrost.”
P4L1: “…the sub-surface of the …”
P4L7: W/(m K)
P4L14: “…medium, thawing cannot…”
P5L12: “In case of phase change…”
P5L15: Use original reference, not Mottaghy and Rath.
P5L28: “COMSOL Multiphysics, Earth Science Module”
P6L11: radioactive waste, not radwaste
P6L21: “…surface conditions, mostly air temperature …”
P6L23: “(geology)”
P6L27: “…force the permafrost model…”
P7L2: “250 m x 250 m”
P7L5: same with units of km here
P7L25: “…porosity is influenced…”
P7L33: This is a heading
P8L2: “…stage 5) are based…”
P10L22–27 Delete
P11L5: “…uncertainty: uncertainty…”
P11L6: “…conceptual models; uncertainty…”
P11L10: “…are seldom known …”
P13L14: “…late Pleniglacial).”
P15L16: thawing
P15L22: thaw
P16L7: “…low temperature…”
P17L23: Delete: “based on natural …ice-wedge casts.” It is OK to call for research but why prescribe how it should be done?
P18L11–13: Delete: “However in order to…the country.” This recommendation is very general and not a specific result of your investigation.

Please check you references for consistency with respect to capitalization and quotation marks.

Dear authors,

thank you for your rebuttal and your revised manuscript. Please check you text again, thoroughly, and resubmit.

In you rebuttal you write "We therefore agree to use the 0°C isotherm as the permafrost indicator" and still I find the old concept inconsistently interspersed in your manuscript, e.g., P15L26: "The best estimate permafrost depth values of 140-180 m (50% ice and 50% water)" or P17L7: "indicates that the permafrost front (50% ice and 50% water) would".

Kind regards,
Stephan Gruber

Thank you for ironing out the remaining mixup between 0ºC and 50/50 methods.

Kind regards,
Stephan Gruber