Please see my comments in the attached file.

In their article titled “Assessing Soil and Potential Air Temperature Coupling Using PALM-4U: Implications for Idealized Scenarios,” the authors aim to answer the important question of how underground temperature extremes impact atmospheric temperatures. More specifically, the authors formulate the following three research questions:

• How to depict a realistic but idealized domain in PALM-4U?
• Do heat or cold extremes in the soil modify potential air temperatures?
• What parameters affect these modifications?

The authors are moving in a new direction by investigating the effect of subsurface temperature extremes on air temperatures (and not vice-versa). In the introduction, the authors succinctly address the relevance of this novel perspective. With its interdisciplinary view of the interactions between multiple spheres of the Earth system, this research is of interest to the scientific community and beyond, making it a suitable contribution to ESD. The authors present a well-written and concise manuscript in most parts and provide a good introduction to the general relevance of the topic as well as typical approaches and limitations in understanding and implementing a thermal coupling of the subsurface and the atmosphere.

However, I find the manuscript difficult to follow for the following reasons: First, the introduction provides a good overview of the relevance and state of knowledge, but it seems decoupled from the rest of the manuscript. For example, I assume the choice of boundary conditions is self-evident to the authors, but it may not be to every interested reader. In that way, a brief explanation of boundary conditions used in temperature simulation at interfaces (e.g., in atmospheric research) would help the reader understand the choice of boundary conditions, their pros and cons, and why they were considered for the investigation.

Second, there is a very detailed presentation/explanation and interpretation (rather than discussion) of the obtained results. My impression is that the authors focus on these highly detailed results, but the general evaluation of the model performance/suitability is not prominently discussed and/or limited to the plausibility check of the results. Therefore, the question arises of how the results and model performance can be evaluated and checked. Can available datasets or data from experiments be used to validate the results?

The very technical nature and a high degree of detailed explanation of the results make it difficult to follow the common theme and line of argumentation and really understand the work's contribution and novelty – also regarding the accuracy of the results and validity beyond the model domain. The guidance of the reader is missing or at least not apparent to me. Hence, I encourage the authors to revise the manuscript accordingly (moderate to major revision required).

Minor comments include:

Lines 20-27: Check the syntax for suitability in a scientific journal

Line 41: How relevant is the impact of an individual construction? The accumulation is probably relevant, and the examples given appear somewhat random.

Line 46: Delete “However”

Line 64: Please specify “near surface atmosphere”

Line 87: What about heat transport via percolating water? Should be addressed.

Line 158 and others: Is “right side” the best terminology to refer to the orientation in the model?

Line 197: You mention Fig. 2 and then Fig.5. Should Fig. 5 then be renamed as Fig. 3?