the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 22 Nov 2024
Technical note: a Weighing Forest Floor Grid-Lysimeter
Abstract. The forest floor (FF) is dominated by plant litter and its decomposition products, thereby it differs significantly from the mineral soil. Because of its wider range of pore sizes and overall high porosity, it has a large capacity to retain water and thus plays an important role in redistributing water to the mineral soil beneath. Until now most studies have focused on the behaviour of the organic layer when wetted and dried in a laboratory setting. Alternatively, field fresh samples were collected to determine the water storage potential. We present a novel low-cost grid-lysimeter designed specifically for the FF, but also suitable for other organic soil layers. It can continuously measure all water balance components of the FF. The lysimeter detects precipitation with an accuracy of 0.03 mm outperforming most rain gauges. The developed setup allows for further customization of in-situ water quality measurements. This technical note describes the setup of the lysimeter and presents performance metrics from laboratory results and initial field data.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Hydrology and Earth System Sciences.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.- Preprint
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RC1: 'Comment on egusphere-2024-3503', Anonymous Referee #1, 27 Nov 2024
I enjoyed this simple paper describing an innovative way to measure fine-scale fluxes of water in the forest floor. The presentation was generally clear and I can find no fault with the description of the device or the demonstration of its capabilities. I have some suggestions to improve the presentation in a few instances.
"weighted” lysimeter appears several times where "weighing” lysimeter is meant.
L84 what is an SDI-12 sensor?
Sec 2.2.2 many of these comparisons to alternatives are not very helpful, given that they mainly refer to old hardware. An eye to making the description of the device more timeless would improve its long-term utility.
Sec 2.3 I think the precision and resolution of the load cells is more important than accuracy. Please explain how precisely changes in mass can be resolved. Also I am curious about temperature dependence.
L145 a narrow hole may prevent calibration problems with the bucket, but it does degrade the ability of the device to precisely estimate time of infiltration. That is worth mentioning, along with any information you might have to quantify this effect.
L150 can you give some indication of the morphology of the forest floor? Is this a mor humus with a distinct organic-mineral transition, or a mull humus where the transition is indistinct? I don't think this matters much for the description of the device, but it does give some context on what is possible using this measurement technique.
L152 what is garden fleece?
Figure 3 would improve if it included indications of the reference masses
L214 I don't understand this sentence. It sounds like the second thing is a consequence of the first, and that they are not two separate effects.
L218 I don't understand this sentence. Perhaps fumigation is the wrong word?
Figures 4 and 5 would improve if the width of the time bins was specified.
Instead of SCE and SCM, which are difficult to remember, why not "crown edge" and "crown middle" in all figures? There is plenty of room available.
Table 2 what is 16.5.-26.5.?
Throughout the results: in a few places there are explanations for various things like why percept throughfall varied (L241, L267), but these are not reliable conclusions due to low sample size.
Editing:
In general the English was understandable but awkward in many places. A general for wording would help.
L79 L157 "electronics were"
L144 "has to pass through"
L178 is a sentence fragment
L187 "an influence"
L227, L230 commas where periods are required
Citation: https://doi.org/10.5194/egusphere-2024-3503-RC1 -
AC1: 'Response to Reviewer #1', Heinke Paulsen, 31 Jan 2025
We appreciate the helpful comments of the Anonymous Referee #1. All technical corrections will be implemented and the comments are answered below.
I enjoyed this simple paper describing an innovative way to measure fine-scale fluxes of water in the forest floor. The presentation was generally clear and I can find no fault with the description of the device or the demonstration of its capabilities. I have some suggestions to improve the presentation in a few instances. Reply We would like to thank the anonymous referee for his/her interest and the comments on our manuscript.
"weighted” lysimeter appears several times where "weighing” lysimeter is meant. Reply We will change this when revising the paper.
L84 what is an SDI-12 sensor? Reply SDI-12 sensors are common to be used in environmental applications. They use a common digital protocol for interconnection of sensors and dataloggers and are characterized by a low energy consumption. We will add a short explanation.
Sec 2.2.2 many of these comparisons to alternatives are not very helpful, given that they mainly refer to old hardware. An eye to making the description of the device more timeless would improve its long-term utility. Reply In a revised version, we will put more focus on our board, instead of the comparison to old hardware.
Sec 2.3 I think the precision and resolution of the load cells is more important than accuracy. Please explain how precisely changes in mass can be resolved. Also I am curious about temperature dependence. Reply In Sec 3.1 we show, that mass changes of 2 g corresponding to 0.008 mm of precipitation can be detected. By now we found that the temperature dependence addressed in Sec 4 does not derive from the load cells themselves but was caused by inadequate positioning of the lysimeter box and therefore suboptimal force application to the load cell. This caused “weight changes” when the stainless steel box shifted due to thermal expansion.
L145 a narrow hole may prevent calibration problems with the bucket, but it does degrade the ability of the device to precisely estimate time of infiltration. That is worth mentioning, along with any information you might have to quantify this effect. Reply Since we do not detect the timestamp of every single tip but aggregate the number of tips over the measurement interval (e.g. 10 minutes) we already degraded this very precise estimate of infiltration. Usually in this interval all the water will pass the tipping bucket. But of course, this is worth mentioning. We will also add a number of how much water could flow through the MU in an interval of 10 minutes.
L150 can you give some indication of the morphology of the forest floor? Is this a mor humus with a distinct organic-mineral transition, or a mull humus where the transition is indistinct? I don't think this matters much for the description of the device, but it does give some context on what is possible using this measurement technique. Reply It’s a typical Moder. We will add this information.
L152 what is garden fleece? Reply A thin nonwoven fabric that allows water to pass but keeps soil and other particles from draining from the box.
Figure 3 would improve if it included indications of the reference masses Reply We will add this information to the figure.
L214 I don't understand this sentence. It sounds like the second thing is a consequence of the first, and that they are not two separate effects. Reply We will rewrite this sentence to make clear that the retention of infiltration and amount of stored water are two separate points.
L218 I don't understand this sentence. Perhaps fumigation is the wrong word? Reply We will change the wording.
Figures 4 and 5 would improve if the width of the time bins was specified. Reply We will add the specification.
Instead of SCE and SCM, which are difficult to remember, why not "crown edge" and "crown middle" in all figures? There is plenty of room available. Reply We will change the labelling.
Table 2 what is 16.5.-26.5.? Reply It’s the date of the 10- day period, we will remove it.
Throughout the results: in a few places there are explanations for various things like why percept throughfall varied (L241, L267), but these are not reliable conclusions due to low sample size. Reply Of course the presented results in this technical paper are not enough to draw strong conclusions on the processes going on in the forest floor. But we show them to illustrate what conclusions could be drawn from lysimeter data with a higher sample size in the future and that the FFGL is a valuable addition to existing approaches.
Citation: https://doi.org/10.5194/egusphere-2024-3503-AC1
-
AC1: 'Response to Reviewer #1', Heinke Paulsen, 31 Jan 2025
-
RC2: 'Comment on egusphere-2024-3503', Anonymous Referee #2, 20 Dec 2024
The technical note “A Weighing Forest Floor Grid-Lysimeter” by Paulsen and Weiler reports the technical details, performance tests and preliminary analyses of a novel lysimeter that allows estimating the water storage and retention capacity of the forest floor. The technical innovation is highly appreciated, a lot of work must have been gone in the development of the lysimeters. However, the manuscript sometimes is a little hard to follow i.e., when it’s not clear what pointers refer to, some sentences could be rephrased to make them shorter and clearer. I’d like to suggest some edits that might help to improve the manuscript, but please thoroughly edit the entire manuscript to improve the overall readability. Figure captions are often very short and lack important information, maybe you can improve them during revision.
Overall I only identified one critical aspect that is related to the accuracy of load cells. Most (cheaper) load cells suffer from uncertainty with changing temperatures (as the authors also acknowledge) and additionally they have weak long term stability in the measured weight (drift). Did you do any long term reliability testing (ideally with different temperatures) and could you show these results (e.g., in the supplement)? I understand that new measurements and tests might not be an option, so therefore I’d suggest to at least discuss this topic thoroughly and report the metrics provided by the load cell supplier in the manuscript. Maybe a paragraph can be added in the discussion.
L17: induce runoff generation? Should this be “reduce”?
L 19-20: rephrase the sentence: I do not think that these are “ecosystem services” of canopies, but you rather want to state that similar processes occur in canopies & FF, also I’d rephrase the processes: e.g., retention (is important but missing currently), water redistribution (I think this is meant by water infiltration) - > maybe more general: canopies and FF affect the temporal, spatial distribution but also chemical composition of soil water recharge.
L 28: change a to the
L 39: not clear what “true” precipitation is
L 65: remove: “without further securing measures” -> not clear what it means to me.
L 68: into
L 69: remove “later”
L 79: were instead of was
L84: rephrase: the output data from the FFGL are in SDI-12
L 102: I’d say “testing” instead
L 179: make this a correct sentence
L 182: filled instead of loaded
L 185 (& 193): remove “in”
L 201: yield instead of yielding
L 215: () missing
L 220: I’d say “approximately” here
Figure 4: water flux in mm / per time, write out precipitation and drainage in the legend, better call it “cumulative water amounts”
Figure 5: mention in the caption which lysimeter is below the edge (SCE) vs. the middle of the canopy (SCM)
Table 2: it would be good to reiterate the abbreviations in the caption
L263: say “Evaporation”
Figure 6, caption: why are some words capitalized? better call it “cumulative water amounts”, not clear what “measured on the tower” means, say above the canopy?
L 267: remove “up”
L 271: could & could, maybe this sentence can be rephrased
Figure 7: make clear what the two lysimeters are (i.e., mention below the edge (SCE) vs. the middle of the canopy (SCM))
L 276:say with SMT100 sensors, upslope “of” the lysimeter
L 277: how is this 5mm to 10% conversion done?
Figure 8: also here the Figure caption lacks some information
L 285 – 287: The sentence doesn’t make sense to me. i.e., I’d start with “The data include…” but it’s not clear how the lysimeter data include information on climate conditions, canopy structure; “e”vaporation -> now I understand, etc. misses a second dot, still not very clear.
L 291: measurement noise
L 298: of total drainage
L 314: not clear what that means
The “conclusions & outlook” are only an outlook, maybe you can rewrite this
Citation: https://doi.org/10.5194/egusphere-2024-3503-RC2 -
AC2: 'Response to Reviewer #2', Heinke Paulsen, 31 Jan 2025
We appreciate the helpful comments of the Anonymous Referee #2. All technical corrections will be implemented and the comments are answered below.
The technical note “A Weighing Forest Floor Grid-Lysimeter” by Paulsen and Weiler reports the technical details, performance tests and preliminary analyses of a novel lysimeter that allows estimating the water storage and retention capacity of the forest floor. The technical innovation is highly appreciated, a lot of work must have been gone in the development of the lysimeters. However, the manuscript sometimes is a little hard to follow i.e., when it’s not clear what pointers refer to, some sentences could be rephrased to make them shorter and clearer. I’d like to suggest some edits that might help to improve the manuscript, but please thoroughly edit the entire manuscript to improve the overall readability. Figure captions are often very short and lack important information, maybe you can improve them during revision. Reply We will improve the readability during revision and also further clarify and extend the figure captions.
Overall I only identified one critical aspect that is related to the accuracy of load cells. Most (cheaper) load cells suffer from uncertainty with changing temperatures (as the authors also acknowledge) and additionally they have weak long term stability in the measured weight (drift). Did you do any long term reliability testing (ideally with different temperatures) and could you show these results (e.g., in the supplement)? I understand that new measurements and tests might not be an option, so therefore I’d suggest to at least discuss this topic thoroughly and report the metrics provided by the load cell supplier in the manuscript. Maybe a paragraph can be added in the discussion. Reply As mentioned in the Response to Referee #1 by now we found that the temperature dependence addressed in Sec 4 does not derive from the load cells themselves but was caused by inadequate positioning of the lysimeter box and therefore suboptimal force application to the load cell. This caused apparent “weight changes” when the stainless steel box shifted due to thermal expansion. We performed some tests regarding long term reliability (also under different temperatures) and can show them in the supplement. Also, we will change the part in Sec 4, explaining the phenomenon.
L17: induce runoff generation? Should this be “reduce”? Reply Yes, we will change it.
L 19-20: rephrase the sentence: I do not think that these are “ecosystem services” of canopies, but you rather want to state that similar processes occur in canopies & FF, also I’d rephrase the processes: e.g., retention (is important but missing currently), water redistribution (I think this is meant by water infiltration) - > maybe more general: canopies and FF affect the temporal, spatial distribution but also chemical composition of soil water recharge. Reply This is a good objection. We will adapt the phrase.
L 39: not clear what “true” precipitation is Reply It’s the exact amount of water reaching the surface. Other measurements like rain gauges are affected by e.g. wind and therefore have a higher error. We will clarify what we mean by “true”.
L 65: remove: “without further securing measures” -> not clear what it means to me. Reply We will remove it.
L84: rephrase: the output data from the FFGL are in SDI-12 Reply We will rephrase the sentence according to Referee #1 to make it more understandable.
Figure 4: water flux in mm / per time, write out precipitation and drainage in the legend, better call it “cumulative water amounts” & Figure 5: mention in the caption which lysimeter is below the edge (SCE) vs. the middle of the canopy (SCM) &. Figure 7: make clear what the two lysimeters are (i.e., mention below the edge (SCE) vs. the middle of the canopy (SCM)) & Figure 8: also here the Figure caption lacks some information Reply We will change the labelling in the figures and reduce abbreviations and make more clear captions.
Table 2: it would be good to reiterate the abbreviations in the caption Reply We will do that.
Figure 6, caption: why are some words capitalized? better call it “cumulative water amounts”, not clear what “measured on the tower” means, say above the canopy? Reply We will change that.
L 271: could & could, maybe this sentence can be rephrased Reply We will rephrase the sentence.
L 277: how is this 5mm to 10% conversion done? Reply When the amount of stored water rises from 0 to 5 mm the soil moisture rises from 15% to 25%.
L 285 – 287: The sentence doesn’t make sense to me. i.e., I’d start with “The data include…” but it’s not clear how the lysimeter data include information on climate conditions, canopy structure; “e”vaporation -> now I understand, etc. misses a second dot, still not very clear. Reply We will rephrase the sentence to: Evaporation, retention, and storage processes are assessed in actual field conditions, while environmental factors like climatic conditions, pre-wetness, canopy structure, litter composition, soil structure, etc. stay incorporated.
L 314: not clear what that means Reply We will rephrase this sentence so that it becomes clearer that in future measurements we will include specific calibrations for each TB and not use the one tipping volume of 2.1 for all the TBs.
The “conclusions & outlook” are only an outlook, maybe you can rewrite this Reply We will rewrite this part putting some more conclusion into it.
Citation: https://doi.org/10.5194/egusphere-2024-3503-AC2
-
AC2: 'Response to Reviewer #2', Heinke Paulsen, 31 Jan 2025
Status: closed
-
RC1: 'Comment on egusphere-2024-3503', Anonymous Referee #1, 27 Nov 2024
I enjoyed this simple paper describing an innovative way to measure fine-scale fluxes of water in the forest floor. The presentation was generally clear and I can find no fault with the description of the device or the demonstration of its capabilities. I have some suggestions to improve the presentation in a few instances.
"weighted” lysimeter appears several times where "weighing” lysimeter is meant.
L84 what is an SDI-12 sensor?
Sec 2.2.2 many of these comparisons to alternatives are not very helpful, given that they mainly refer to old hardware. An eye to making the description of the device more timeless would improve its long-term utility.
Sec 2.3 I think the precision and resolution of the load cells is more important than accuracy. Please explain how precisely changes in mass can be resolved. Also I am curious about temperature dependence.
L145 a narrow hole may prevent calibration problems with the bucket, but it does degrade the ability of the device to precisely estimate time of infiltration. That is worth mentioning, along with any information you might have to quantify this effect.
L150 can you give some indication of the morphology of the forest floor? Is this a mor humus with a distinct organic-mineral transition, or a mull humus where the transition is indistinct? I don't think this matters much for the description of the device, but it does give some context on what is possible using this measurement technique.
L152 what is garden fleece?
Figure 3 would improve if it included indications of the reference masses
L214 I don't understand this sentence. It sounds like the second thing is a consequence of the first, and that they are not two separate effects.
L218 I don't understand this sentence. Perhaps fumigation is the wrong word?
Figures 4 and 5 would improve if the width of the time bins was specified.
Instead of SCE and SCM, which are difficult to remember, why not "crown edge" and "crown middle" in all figures? There is plenty of room available.
Table 2 what is 16.5.-26.5.?
Throughout the results: in a few places there are explanations for various things like why percept throughfall varied (L241, L267), but these are not reliable conclusions due to low sample size.
Editing:
In general the English was understandable but awkward in many places. A general for wording would help.
L79 L157 "electronics were"
L144 "has to pass through"
L178 is a sentence fragment
L187 "an influence"
L227, L230 commas where periods are required
Citation: https://doi.org/10.5194/egusphere-2024-3503-RC1 -
AC1: 'Response to Reviewer #1', Heinke Paulsen, 31 Jan 2025
We appreciate the helpful comments of the Anonymous Referee #1. All technical corrections will be implemented and the comments are answered below.
I enjoyed this simple paper describing an innovative way to measure fine-scale fluxes of water in the forest floor. The presentation was generally clear and I can find no fault with the description of the device or the demonstration of its capabilities. I have some suggestions to improve the presentation in a few instances. Reply We would like to thank the anonymous referee for his/her interest and the comments on our manuscript.
"weighted” lysimeter appears several times where "weighing” lysimeter is meant. Reply We will change this when revising the paper.
L84 what is an SDI-12 sensor? Reply SDI-12 sensors are common to be used in environmental applications. They use a common digital protocol for interconnection of sensors and dataloggers and are characterized by a low energy consumption. We will add a short explanation.
Sec 2.2.2 many of these comparisons to alternatives are not very helpful, given that they mainly refer to old hardware. An eye to making the description of the device more timeless would improve its long-term utility. Reply In a revised version, we will put more focus on our board, instead of the comparison to old hardware.
Sec 2.3 I think the precision and resolution of the load cells is more important than accuracy. Please explain how precisely changes in mass can be resolved. Also I am curious about temperature dependence. Reply In Sec 3.1 we show, that mass changes of 2 g corresponding to 0.008 mm of precipitation can be detected. By now we found that the temperature dependence addressed in Sec 4 does not derive from the load cells themselves but was caused by inadequate positioning of the lysimeter box and therefore suboptimal force application to the load cell. This caused “weight changes” when the stainless steel box shifted due to thermal expansion.
L145 a narrow hole may prevent calibration problems with the bucket, but it does degrade the ability of the device to precisely estimate time of infiltration. That is worth mentioning, along with any information you might have to quantify this effect. Reply Since we do not detect the timestamp of every single tip but aggregate the number of tips over the measurement interval (e.g. 10 minutes) we already degraded this very precise estimate of infiltration. Usually in this interval all the water will pass the tipping bucket. But of course, this is worth mentioning. We will also add a number of how much water could flow through the MU in an interval of 10 minutes.
L150 can you give some indication of the morphology of the forest floor? Is this a mor humus with a distinct organic-mineral transition, or a mull humus where the transition is indistinct? I don't think this matters much for the description of the device, but it does give some context on what is possible using this measurement technique. Reply It’s a typical Moder. We will add this information.
L152 what is garden fleece? Reply A thin nonwoven fabric that allows water to pass but keeps soil and other particles from draining from the box.
Figure 3 would improve if it included indications of the reference masses Reply We will add this information to the figure.
L214 I don't understand this sentence. It sounds like the second thing is a consequence of the first, and that they are not two separate effects. Reply We will rewrite this sentence to make clear that the retention of infiltration and amount of stored water are two separate points.
L218 I don't understand this sentence. Perhaps fumigation is the wrong word? Reply We will change the wording.
Figures 4 and 5 would improve if the width of the time bins was specified. Reply We will add the specification.
Instead of SCE and SCM, which are difficult to remember, why not "crown edge" and "crown middle" in all figures? There is plenty of room available. Reply We will change the labelling.
Table 2 what is 16.5.-26.5.? Reply It’s the date of the 10- day period, we will remove it.
Throughout the results: in a few places there are explanations for various things like why percept throughfall varied (L241, L267), but these are not reliable conclusions due to low sample size. Reply Of course the presented results in this technical paper are not enough to draw strong conclusions on the processes going on in the forest floor. But we show them to illustrate what conclusions could be drawn from lysimeter data with a higher sample size in the future and that the FFGL is a valuable addition to existing approaches.
Citation: https://doi.org/10.5194/egusphere-2024-3503-AC1
-
AC1: 'Response to Reviewer #1', Heinke Paulsen, 31 Jan 2025
-
RC2: 'Comment on egusphere-2024-3503', Anonymous Referee #2, 20 Dec 2024
The technical note “A Weighing Forest Floor Grid-Lysimeter” by Paulsen and Weiler reports the technical details, performance tests and preliminary analyses of a novel lysimeter that allows estimating the water storage and retention capacity of the forest floor. The technical innovation is highly appreciated, a lot of work must have been gone in the development of the lysimeters. However, the manuscript sometimes is a little hard to follow i.e., when it’s not clear what pointers refer to, some sentences could be rephrased to make them shorter and clearer. I’d like to suggest some edits that might help to improve the manuscript, but please thoroughly edit the entire manuscript to improve the overall readability. Figure captions are often very short and lack important information, maybe you can improve them during revision.
Overall I only identified one critical aspect that is related to the accuracy of load cells. Most (cheaper) load cells suffer from uncertainty with changing temperatures (as the authors also acknowledge) and additionally they have weak long term stability in the measured weight (drift). Did you do any long term reliability testing (ideally with different temperatures) and could you show these results (e.g., in the supplement)? I understand that new measurements and tests might not be an option, so therefore I’d suggest to at least discuss this topic thoroughly and report the metrics provided by the load cell supplier in the manuscript. Maybe a paragraph can be added in the discussion.
L17: induce runoff generation? Should this be “reduce”?
L 19-20: rephrase the sentence: I do not think that these are “ecosystem services” of canopies, but you rather want to state that similar processes occur in canopies & FF, also I’d rephrase the processes: e.g., retention (is important but missing currently), water redistribution (I think this is meant by water infiltration) - > maybe more general: canopies and FF affect the temporal, spatial distribution but also chemical composition of soil water recharge.
L 28: change a to the
L 39: not clear what “true” precipitation is
L 65: remove: “without further securing measures” -> not clear what it means to me.
L 68: into
L 69: remove “later”
L 79: were instead of was
L84: rephrase: the output data from the FFGL are in SDI-12
L 102: I’d say “testing” instead
L 179: make this a correct sentence
L 182: filled instead of loaded
L 185 (& 193): remove “in”
L 201: yield instead of yielding
L 215: () missing
L 220: I’d say “approximately” here
Figure 4: water flux in mm / per time, write out precipitation and drainage in the legend, better call it “cumulative water amounts”
Figure 5: mention in the caption which lysimeter is below the edge (SCE) vs. the middle of the canopy (SCM)
Table 2: it would be good to reiterate the abbreviations in the caption
L263: say “Evaporation”
Figure 6, caption: why are some words capitalized? better call it “cumulative water amounts”, not clear what “measured on the tower” means, say above the canopy?
L 267: remove “up”
L 271: could & could, maybe this sentence can be rephrased
Figure 7: make clear what the two lysimeters are (i.e., mention below the edge (SCE) vs. the middle of the canopy (SCM))
L 276:say with SMT100 sensors, upslope “of” the lysimeter
L 277: how is this 5mm to 10% conversion done?
Figure 8: also here the Figure caption lacks some information
L 285 – 287: The sentence doesn’t make sense to me. i.e., I’d start with “The data include…” but it’s not clear how the lysimeter data include information on climate conditions, canopy structure; “e”vaporation -> now I understand, etc. misses a second dot, still not very clear.
L 291: measurement noise
L 298: of total drainage
L 314: not clear what that means
The “conclusions & outlook” are only an outlook, maybe you can rewrite this
Citation: https://doi.org/10.5194/egusphere-2024-3503-RC2 -
AC2: 'Response to Reviewer #2', Heinke Paulsen, 31 Jan 2025
We appreciate the helpful comments of the Anonymous Referee #2. All technical corrections will be implemented and the comments are answered below.
The technical note “A Weighing Forest Floor Grid-Lysimeter” by Paulsen and Weiler reports the technical details, performance tests and preliminary analyses of a novel lysimeter that allows estimating the water storage and retention capacity of the forest floor. The technical innovation is highly appreciated, a lot of work must have been gone in the development of the lysimeters. However, the manuscript sometimes is a little hard to follow i.e., when it’s not clear what pointers refer to, some sentences could be rephrased to make them shorter and clearer. I’d like to suggest some edits that might help to improve the manuscript, but please thoroughly edit the entire manuscript to improve the overall readability. Figure captions are often very short and lack important information, maybe you can improve them during revision. Reply We will improve the readability during revision and also further clarify and extend the figure captions.
Overall I only identified one critical aspect that is related to the accuracy of load cells. Most (cheaper) load cells suffer from uncertainty with changing temperatures (as the authors also acknowledge) and additionally they have weak long term stability in the measured weight (drift). Did you do any long term reliability testing (ideally with different temperatures) and could you show these results (e.g., in the supplement)? I understand that new measurements and tests might not be an option, so therefore I’d suggest to at least discuss this topic thoroughly and report the metrics provided by the load cell supplier in the manuscript. Maybe a paragraph can be added in the discussion. Reply As mentioned in the Response to Referee #1 by now we found that the temperature dependence addressed in Sec 4 does not derive from the load cells themselves but was caused by inadequate positioning of the lysimeter box and therefore suboptimal force application to the load cell. This caused apparent “weight changes” when the stainless steel box shifted due to thermal expansion. We performed some tests regarding long term reliability (also under different temperatures) and can show them in the supplement. Also, we will change the part in Sec 4, explaining the phenomenon.
L17: induce runoff generation? Should this be “reduce”? Reply Yes, we will change it.
L 19-20: rephrase the sentence: I do not think that these are “ecosystem services” of canopies, but you rather want to state that similar processes occur in canopies & FF, also I’d rephrase the processes: e.g., retention (is important but missing currently), water redistribution (I think this is meant by water infiltration) - > maybe more general: canopies and FF affect the temporal, spatial distribution but also chemical composition of soil water recharge. Reply This is a good objection. We will adapt the phrase.
L 39: not clear what “true” precipitation is Reply It’s the exact amount of water reaching the surface. Other measurements like rain gauges are affected by e.g. wind and therefore have a higher error. We will clarify what we mean by “true”.
L 65: remove: “without further securing measures” -> not clear what it means to me. Reply We will remove it.
L84: rephrase: the output data from the FFGL are in SDI-12 Reply We will rephrase the sentence according to Referee #1 to make it more understandable.
Figure 4: water flux in mm / per time, write out precipitation and drainage in the legend, better call it “cumulative water amounts” & Figure 5: mention in the caption which lysimeter is below the edge (SCE) vs. the middle of the canopy (SCM) &. Figure 7: make clear what the two lysimeters are (i.e., mention below the edge (SCE) vs. the middle of the canopy (SCM)) & Figure 8: also here the Figure caption lacks some information Reply We will change the labelling in the figures and reduce abbreviations and make more clear captions.
Table 2: it would be good to reiterate the abbreviations in the caption Reply We will do that.
Figure 6, caption: why are some words capitalized? better call it “cumulative water amounts”, not clear what “measured on the tower” means, say above the canopy? Reply We will change that.
L 271: could & could, maybe this sentence can be rephrased Reply We will rephrase the sentence.
L 277: how is this 5mm to 10% conversion done? Reply When the amount of stored water rises from 0 to 5 mm the soil moisture rises from 15% to 25%.
L 285 – 287: The sentence doesn’t make sense to me. i.e., I’d start with “The data include…” but it’s not clear how the lysimeter data include information on climate conditions, canopy structure; “e”vaporation -> now I understand, etc. misses a second dot, still not very clear. Reply We will rephrase the sentence to: Evaporation, retention, and storage processes are assessed in actual field conditions, while environmental factors like climatic conditions, pre-wetness, canopy structure, litter composition, soil structure, etc. stay incorporated.
L 314: not clear what that means Reply We will rephrase this sentence so that it becomes clearer that in future measurements we will include specific calibrations for each TB and not use the one tipping volume of 2.1 for all the TBs.
The “conclusions & outlook” are only an outlook, maybe you can rewrite this Reply We will rewrite this part putting some more conclusion into it.
Citation: https://doi.org/10.5194/egusphere-2024-3503-AC2
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AC2: 'Response to Reviewer #2', Heinke Paulsen, 31 Jan 2025
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