The study evaluates two planetary boundary layer (PBL) schemes in WRF in the North Sea. Both are compatible with the Fitch wind farm parameterization. For validation, high-resolution measurements of a research aircraft and the FINO1 mast measurements are used. The study finds that the optimal PBL scheme varies with the location, quantity of interest, and error metric. 

In contrast to what the title suggests, not only the PBL scheme is varied, but also the TKE advection within WRF is activated and deactivated, and the sensitivity of the results to the TKE factor within the WFP by Fitch et al. is investigated. Due to the many different aspects being studied, as well as the two parameters, different error matrices, and two locations, the results section is rather clouded, and it is difficult to extract the main message. On the other hand, it shows how complex the situation is and that a simple answer to the question of the "optimal" scheme is impossible to give. I think this in itself is an important conclusion and therefore I recommend publishing this article, after some revisions. 

Major comments

(1) The authors put a lot of effort into investigating this single case study of (mainly) 2 hours (although some FINO1 analysis stretches over the period of 1 day). This imminently raises the question of how transferable those results are to other meteorological conditions (and sites). While the conclusions state that "Subsequent investigations could explore other case studies to provide perspective into the generalizability of the results across other sites." the author also critically highlights from previous literature that "Conclusions drawn from these validation studies may also be influenced by site-specific or meteorological conditions." Thus, the discussion on the generalizability should be extended to highlight why it is worth spending so much effort on just 2 hours.

(2) The study mainly compares the two PBL schemes, the 3DPBL and the MYNN scheme, in a wind farm context. Thus, along with a short introduction to the WFP by Fitch et al., it should also provide some introduction to the two schemes and the difference between those to extend the too brief description that is given in the introduction (line 72-81). This will also aid the interpretation of the results. 

(3) Validation of atmospheric stability: Stability is an important parameter for analyzing the results. However, while it is discussed thoroughly from the simulations, the profiles are not validated with the measurements in the lower part of the atmosphere. Both the FINO measurements and the profiles flown by the aircraft could be used to evaluate the simulations in the lower part of the PBL.

(4) The appendix is too long and not only adds supporting information but presents new findings, e.g., regarding the effect of TKE advection. I suggest moving the section on the TKE advection to the main text, while some plots can probably be kept in the appendix (or removed completely) to limit the size of the main text. Furthermore, some additional figures can be removed if they do not add any new information. This would make the Appendix much more accessible, as now it is flooded with figures.

Specific comments

- Line 47: Other (newer) references should be mentioned

- Line 59: Add citation for EWP

- Table 1: "Select" -> "Selected"

- Section 2.2 Provide a tabular overview of the WRF settings to provide a better overview for the readers. Also, consider publishing the namelist settings on Zenodo for reproducibility.

- Line 131: Which WRF version is used precisely?

- Line 157: Consider repeating, "The results from the other runs are analyzed in the Appendix."

- Line 205: Consider removing "also"

- Figure 4: Why are not all curves labeled? This might be useful for other researchers. 

- Figure 8: Why is the Mean (solid line) sometimes above the single realizations (as shown by the symbols)? Or does "Mean" mean something else here?

- Figure 14 / 15 captions: Put the analyzed quantity at the beginning of the caption to easier see the difference between those two figures:  Error metric box plot for aircraft observations collected at 250 m for wind speed / TKE.

- Line 408: add space between "(2023)," and "Optis"

- Figure A1 caption: Use also abbreviations as documented in table 4 in the caption

- Figure B10-B13: See comment regarding figure 14/15

- Line 632: "..wind speeds - to - outperform ... " add "to" here?