Thank you very much for your review. We appreciate your comments and will do our best to incorporate them into the revised manuscript. Especially the notes on discussing the equations in the post-processing will improve the understandability of the manuscript. We will also add a sentence explaining the logger unit and the connection in more detail.

See below answers to your edits.

I carefully read the Manuscript entitled "Brief communication: Testing a portable Bullard-type temperature lance confirms highly spatially heterogeneous sediment temperatures under shallow water bodies in the Arctic" by Miesner et al.

Good manuscript, good technical paper.

I have a couple of minor edits :

Line 17 : I would slighlty increase the complexity of the sentence, by adding a reference or an example on microbial activity in lakes. Otherwise I would remove it, since you do it good for methane emissions.

Agree. Will adopt this in revision.

Line 18 : "methane gas emission". I would remove gas, since methane is a gas in these external condition

Agree

Line 18-20: Are we looking at the thermal regime here, or finally the vertical temperature spatial variability ? Unsure we are looking at time series to quantify the regime here.

Thanks for pointing out this ambiguity. We are talking about the thermal regime here, in what would be desirable (knowledge of the spatial and temporal variability of sub-lake sediment temperatures). The temperature lance can be easily used to measure the spatial variability and this is what we show in the paper. With repeat measurements at different times, one could also use the device to cover temporal variability but that is indeed not part of this paper.

Line 26 : "Lister (1970)'s ?" 

Yes and no. This type of heat flow probe is called Lister type (or violin-bow type) after Lister (1970), which we cite in line 27. 

Line 30 : Should be "(Dziadek et al. 2021)" 

Yes

Line 51-52 : You use the 24 bit resolution ?

Yes

Line 54 : " the outside environment 1". You meant Figure 1 I suppose, otherwise your fig is not called.

Yes, thank you for catching this. 

Line 59 : " urethane-potting compound to protect the electronics." I would add that this electrical insulating linner has a lower heat conductivity than all the rest of the assembly. Even if it seems obvious.

We will add a half-sentence in the revision. 

Line 65 :" 0.02 K Threshold", might be good to keep the Celsius unit here since you are mentionning all your variable in C ?

I always use degree C for temperatures and Kelvin for temperature differences, but we agree taht it is less confusing to stick with degree C for all. We will adopt this is the review.

Part 2.1 - 2.2 :

- If you could add a small sentence explaining how you communicate with the probe (No need to be extremely exhaustive). Is it based on Ethernet connection (?), bluetooth, wifi ? Or you simply set them up prior to field deployment ? If so, how/what is the communication protocol ? IN Figure 1-b) we see the logger unit, is it a computer ?

- If you could add a small description about the power supply/battery. On figure 1-b), I think we see an external power supply ?

Thanks for pointing out that this is not adequately explained. We will add a clarifying sentence in part 2.1

-Line 90-93. Could you try to define only one side of the equation. It is difficult to follow, since sometime you are describing the RHS of the equation with "f" and in some other part you are describing alpha. Maybe only focus on the RHS directly stating that f(x), is actually f(x,alpha), and then your paragraph is ok to follow.

We agree that this paragraph is rather hard to follow. We will rewrite this to make it more clear what is happening in the review. 

Line 134 : Sensor accuracy of 0.01 K. Again, unsure this is good to mix Kelvin and Celsius.

Figure 2 : I would re-draw the legend, to clearly see that the shade of blue mimics depth. A simple colorbar should do the job ? As you did for fig 3 ?

Thanks for this suggestion. We will try this in the review. 

Line 183-187, might need to be moved to the part 3, since you are really discussing your data in regards with the literature.

Thank you for this suggestion, we will move part of this dicussion to the results part in review.

Thank you very much for your review and your valuable comments. We will carefully rephrase paragraphs and add information where you indicated we were a bit too short on details. We will add a paragraph discussing how we estimate the penetration depth of the lance. We will also add more detail to the description of the technical details of the PCBs. 

See below for direct comments on your edits.

This study presents the development of a portable Bullard-type temperature lance, and its application to capture spatially heterogeneous sediment temperatures under shallow water bodies in the Arctic. I enjoyed reading the manuscript. I think the work is relevant and of interest for the community, and adequate to be presented as a brief communication article. I only have some minor comments here below.

L.6: The meaning of “overlooked” is not clear (to me at least). Do the authors mean that a single shallow measurement of water temperature would have failed in detecting the presence of bottom-fast ice zone. Please consider rephrasing for improving clarity.

That is exactly what we mean, we will rephrase in review.

L.8: Consider rephrasing with “The portion of land covered with lakes is …”

Will do.

L.13 and 14: if “slows” and “refreezes” refer to “can”, remove the “s” at the end.

They refer to the presence of bottom-fast ice.

L.18, L.30 and likely other places: The reference should be in parenthesis. 

Thanks for catching this. Adopted.

L.16: the “to” before “better” can be removed.

Assuming this is line 19, yes, adopted.

L.49: Please consider providing more information about the PCB boards and the connectors, including if the sensors are mounted on a single long board or if boards are connected together (and if yes, how). Also consider providing information on how the SubConn connector is linked to the PCB.

All connections between nodes and between the uppermost node and the SubConn connector are soldered. We will clarify this in the text during review.

L.58: please consider describing how the accelerometers work, and adding later in the text, any findings that may be of interest for the reader. With regard to discussion of accelerometer and PCB connectors, here is a study that may be of interest:

Wielandt, S.; Uhlemann, S.; Fiolleau, S.; Dafflon, B. Low-Power, Flexible Sensor Arrays with Solderless Board-to-Board Connectors for Monitoring Soil Deformation and Temperature. Sensors 2022, 22, 2814. https://doi.org/10.3390/s22072814

Thank you for the literature  suggestion. In the current iteration of the device, we really only used the accelerometer to see if the lance is upright when pushing it into the sediment.

L.96: “desired” sounds weird to me. If I understand correctly, the equation 2 is solved to estimate the in-situ temperature. Please consider clarifying which parameter is estimated vs assumed to be known. And consider adding a sentence in the results to explain their impact on the estimated values shown on the figure 2b.

Desired does sound a bit weird. We will rephrase this and make it more clear in the review.

L.108: “water depth greater than the 4.6m where we measured”. Was the bottom of the probe in water and not in sediment? it does not look like to be the case based on Figure 3. Please improve clarity (sorry if I missed something).

That sentence is indeed badly phrased. The lance was completely in the sediment. At that location the water was 4.6m deep. The maximum lake depth however, is greater than that. 

L.115: Consider adding some discussion about the uncertainty in estimating the lake depth. In Figure 3, is the 0 on the y-axis defined based on a change in the temperature profile ? or is that depth defined based on resistance when pushing the probe when entering the lake bed ?

This is a great comment and we will add some text on this. The 0 on the y-Axis is based on a mixture of change in the temperature profile in the final data and an estimate made in the field with independent water depth measurements (with a CTD).

L.153 and L.182: consider using Celsius only.

I always use degree C for temperatures and Kelvin for differences, but I will adopt this in the review to avoid confusion.

L.161: upper meter

Yes, thank you.

L.161: “than even the measurements” is not clear to me. Do the authors mean the deepest measurement in the lake ? please improve accordingly.

Yes, will rephrase in the review.

L.189: consider adding “show” before “a higher spatial heterogeneity”.

Adopted.