Please see attached comments in PDF format. 

The manuscript discusses Rayleigh-Bénard type measurements conducted in the Pi chamber, addressing higher-order statistics of temperature fluctuations, including second- and third-order moments and spectra. Evaluating the measurement capabilities of the Pi chamber for this Rayleigh-Benard helps make us aware of the capabilities and limitations of measurements that can be performed with the Pi chamber. I find this aspect of the study helpful and valuable for the community. Unfortunately, this is not well presented in the manuscript. The experimental results are compared with direct numerical simulations of the same system, showing good overall agreement. However, why the simulations do not show symmetry around the mid-plane is not discussed, which should be there unless asymmetries in the setup are also modelled. 

The overall impression is that the manuscript lacks rigorous scientific analysis/discussion (see points below), making it unsuitable for publication in this form. 

Limitations of the manuscript are:

(i) The manuscript has incorrect analysis and discussions on some of the data. In particular, some of the 3-minute measurement data is misinterpreted. It should be noted that this data is not statistically converged. 

(ii) The conclusion and abstract need to indicate more of the limitations of the presented measurements. 

(iii) Line 26 states some limitations, but this needs to be mentioned more in the data discussion to explain certain observations. 

(iv) See a list of incorrect/inconsistent analyses and statements in the manuscript. 

-- Figure 3: Unclear what is learned from this figure. 

-- Line 28: Suggest you do measurements in the boundary layer, which is incorrect. Boundary layer thickness is well below 1 cm for Ra=1e9, so the sentence should be removed.

-- Line 52: Fan et al not relevant 

-- Line 55: Olsthoorn, 2023 not relevant

-- Line 71: Brown and Ahlers's most famous model on LSC is not cited, and not all given references are relevant. 

-- Line 77: See Annu. Rev. Fluid Mech. 2010. 42:335–64

-- Line 143: Deteremination --> Determination

-- Line 155-156: Why are no differences observed near the top plate? Roughness should still affect the flow. 

-- Line 172: "All these effects are beyond the scope of this investigation, but the raw measurements give clear evidence of changing oscillations near both plates." --> This statement is incorrect. The fluctuations shown in Figure 4 cannot be compared to the LSC measured as performed in the RB community. 

-- Scatter in these figures indicates that longer measurement data would be required. Performing measurements longer than 19 minutes would reduce fluctuations in statistical data.

-- Figure A1 and Figure A2: Temporal comparison between experiments and simulations is misleading as no one-to-one comparison of the same flow state is performed. 

-- line 195 and further: Discussion incorrect as the data are not converged. This data is not converged, and that discussion is meaningless. The 19-minute-long measurements do not show such an increase. 

-- line 211: Indeed 3, minute measurements are too short. 

-- Figure 7: Vertical variability of the LSC period with respect to --> LSC is the coherent large scale flow structure in the cell, so it should not vertically vary. The discussion should be adjusted accordingly. 

-- Provide details on how Pearson correlation coefficients are calculated.

-- Line 252: "relatively small variability of PSD slopes." --> The variations in the slopes are very large. Scaling exponents vary by as much as 20 to 30%. This severely limits how much one can learn from this data. That is recognized in line 254 ("Our analysis provides no clear answer,")

-- line 257-291: What main point do you want to explain to the reader?

-- line 339: It should be discussed that both measurement times are too short, especially the 3-minute data, which even leads to misleading discussions in the manuscript. 

-- line 341: How this improves our understanding of atmospheric flow is not discussed.

-- line 368: Scheel et al. is a numerical study with no theory on heat transport. 

-- Figure 11: Why is DNS not symmetric around the mid-plane?

-- Appendix B: "and display greater symmetry compared" --> Incorrect. Normalising the temperature difference between the plates does not affect symmetry around the midplane. 

-- Figure C1: What does it mean that velocity in the centre is always positive? Is this a velocity magnitude?

-- Figure C2: What are all the numbers in the legend?

-- Figure D1: The data are visibly deviating from the presented lines. Difficult to see how this corresponds to Pearson correlation coefficients of -1.