the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 30 Apr 2024
Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem
Abstract. Few studies have investigated the performance of land surface models for semi-arid Mediterranean forests. This study aims to parameterize and test the performance of the Noah-MP land surface model for an eastern Mediterranean ecosystem. To this end, we modeled the water balance components of two conifer species, Pinus brutia, and Cupressus sempervirens, in a plantation forest on the Mediterranean island of Cyprus. The study area has a long-term average annual rainfall of 315 mm. Observations from 4 sap flow and 48 soil moisture sensors, for the period from December 2020 to June 2022, were used for model parameterization. A local sensitivity analysis found that the surface infiltration (REFKDT), hydraulic conductivity (SATDK), and stomatal resistance (RSMIN) parameters had the highest impacts on the soil water balance components and transpiration. The model performed better during the wetter 9-month validation period (379 mm rain) than during the drier 10-month calibration period (175 mm rain). Average soil moisture in the top 60-cm of the soil profile was reasonably well captured for both species (daily NSE > 0.70 for validation). Among the three soil layers, the second layer (20–40 cm) showed better simulation performance during both periods and for both species. The model exhibited limitations in simulating transpiration, particularly during the drier calibration period. Inclusion of a root distribution function in the model, along with the monitoring of soil moisture below the 60-cm soil depth in the field, could improve the accuracy of model simulations in such water-limited ecosystems.
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RC1: 'Comment on hess-2024-107', Anonymous Referee #1, 09 Jul 2024
Dear authors,
The manuscript titled “Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem” aims to parameterize and test the performance of the LSM Noah-MP on an eastern Mediterranean planted forest. The authors monitored the sap flow of two coniferous species and soil moisture over 19 months to achieve the goal. The manuscript reads very well. However, while the presented study is both interesting and timely, some issues need to be addressed before the manuscript can be accepted for publication.
My main concern is about the number of sap flow sensors, only two sap flow sensors per species, which in my opinion is quite small. To overcome this significant limitation, you must make clear that transpiration variability within species in the plantation is sufficiently low. Additionally, concerning tree variability, the standard error for tree dimensions is missing. Providing this information will inform readers about the representativeness of the studied trees within the plantation.
It would be important to have some more information concerning the water use strategies and rooting systems of the studied species, Pinus brutia and Cupressus sempervirens, in the introduction (eventually around lines 40-48), to help results interpretation and subsequent discussion.
The mention of the reported or studied water balance components (transpiration and soil moisture?) in the abstract is advised.
The choice of the parameter designation is not very straightforward (e.g. REFKDT or SATDK), the manuscript would benefit with the use of simpler designations or the name of the parameters
Figure 1: it would be interesting to distinguish between pine and cypress at the site, and eventually identify which trees were used for sap flow
Please consider my specific questions, technical corrections or suggestions on the attached pdf file.
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AC1: 'Reply on RC1', Mohsen Amini Fasakhodi, 29 Jul 2024
Dear Referee,
We appreciate your time for insightful comments and raising these important points. To avoid overlooking your concerns, I bullet them below to better address them one by one.
- My main concern is about the number of sap flow sensors, only two sap flow sensors per species, which in my opinion is quite small. To overcome this significant limitation, you must make clear that transpiration variability within species in the plantation is sufficiently low.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
- Additionally, concerning tree variability, the standard error for tree dimensions is missing. Providing this information will inform readers about the representativeness of the studied trees within the plantation.
We agree that including measures of variability for tree dimensions is essential for demonstrating the representativeness of our study sample. A comprehensive table reporting the mean, and standard deviation for stem diameter for all species, and a table reporting stem diameter, bark thickness, sapwood depth, tree height, and canopy coverage area for all twelve trees (six pine and six cypress) are provided in Djuma et al. (2024). To enhance the clarity of the current manuscript, we will incorporate a concise table summarizing these key tree dimension statistics.
- It would be important to have some more information concerning the water use strategies and rooting systems of the studied species, Pinus brutia and Cupressus sempervirens, in the introduction (eventually around lines 40-48), to help results interpretation and subsequent discussion.
We appreciate the reviewer's suggestion to provide more context on the contrasting water use strategies and root systems of Pinus brutia and Cupressus sempervirens. We agree that this information is crucial for readers to fully grasp the implications of our findings.
In the revised manuscript, we will incorporate a brief discussion around lines 40-48 highlighting the key differences between these species. Specifically, we will note that Pinus brutia, as a drought-tolerant species, typically develops a deep and extensive root system that allows it to access water from deeper soil layers. In contrast, Cupressus sempervirens, while relatively drought-tolerant, tends to have a shallower root system, making it potentially more reliant on surface moisture. We will draw upon relevant studies (e.g., [Rog et al., 2021]) to support these points. This expanded discussion will provide a stronger foundation for interpreting the observed differences in sap flow dynamics between the two species.
- The mention of the reported or studied water balance components (transpiration and soil moistue?) in the abstract is advised.
We agree that specifying the studied water balance components in the abstract will provide readers with a clearer understanding of our research focus. In the revised abstract, we will explicitly state that our study measured both transpiration rates and soil moisture content at various depths.
- The choice of the parameter designation is not very straightforward (e.g. REFKDT or SATDK), the manuscript would benefit with the use of simpler designations or the name of the parameters
We appreciate the reviewer's feedback regarding the clarity of parameter designations. We understand that using abbreviations common in model documentation might pose challenges for readers unfamiliar with NOAHMP and WRF. However, these parameter short names (abbreviations) are used in the model documentation and code. They are also used in other journal articles on the NOAHMP and WRF model. All parameters are also listed with their full description and units in Table 1, so these could be relatively easy to find back for the reader. For the surface infiltration parameter REFKDT, which is a scaling factor, we will add the equation and description in a footnote of Table 1.
- Figure 1: it would be interesting to distinguish between pine and cypress at the site, and eventually identify which trees were used for sap flow
The reviewer makes an excellent point. Clearly distinguishing between pine and cypress trees in Figure 1, and highlighting those used for sap flow measurements, would significantly improve the figure's informativeness. The study site has more than 2300 mixed species trees/shrubs. There are 846 pine and 216 cypress trees, which were planted in random locations in the study site. Eight trees (four pine and four cypress) with stem diameter greater than 8 cm were randomly selected for sap flow monitoring (presented in Djuma et al 2024). In addition to these eight trees, two fenced sites were established, where sap flow sensors were installed on neighboring pine and cypress trees (four trees in total) with additional soil moisture sensors between the trees (used for the current manuscript). We will incorporate this information in the revised manuscripts.
Citation: https://doi.org/10.5194/hess-2024-107-AC1
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AC1: 'Reply on RC1', Mohsen Amini Fasakhodi, 29 Jul 2024
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RC2: 'Comment on hess-2024-107', Anonymous Referee #2, 25 Jul 2024
The manuscript "Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem" presents a study on simulating water balance components in Mediterranean coniferous forests using the Noah-MP land surface model. The methodology, which combines field observations with advanced modeling techniques, is robust and well-documented. Nevertheless, my major concern is that the scientific contribution and broader implications of the study are not fully articulated. The study primarily focuses on calibrating the model using observational data but lacks a clear discussion on the implications of these findings for broader scientific understanding or practical applications. For example,
- The Introduction does not adequately discuss the potential implications of the study’s findings. There is no mention of how the results might contribute to model development or forest management practices. Also, the introduction mentions several studies but does not critically engage with them to highlight what has been done and what remains to be explored. It is not clear how the research gap (I assume it is "no research in the literature has combined field observations with land surface models (LSMs) to estimate water balance components in Mediterranean coniferous forests.") would be relevant for new understanding or methodological advances.
- In the Discussion and Conclusions, while the comparison with previous studies is informative, it lacks depth in explaining why certain differences or similarities occur. For instance, it is still not clear why strong water limitation in your study area might influence these sensitivities differently than in other regions. Still, the broader implications of the sensitivity analysis findings for model calibration, validation, and application are not sufficiently discussed. It would be appreciated to discuss how your results contribute to the understanding of the effects of soil and vegetation parameters on water balance components under different climatic conditions.
- In addition, the study observes better model performance during the wetter validation period compared to the drier calibration period. I suggest that an additional calibration-validation framework can be considered. Specifically, the authors could calibrate the model using data from the wetter period (September 2021 to June 2022) and validate it using data from the drier period (December 2020 to August 2021). By reversing the calibration and validation periods, the study can assess whether the model is robust across different hydrological conditions.
- Last but not least, the study only uses a few site observations, which raises my concerns about the generalizability of the findings. While this may not be the focus of the study, modeling only a single tree may lead to an oversimplified representation of the ecosystem. I recommend discussing the limitations of this approach and suggesting ways to improve the generalizability of future studies.
Overall, while this paper presents a comprehensive study that calibrates the Noah-MP model for Mediterranean coniferous forests, it falls short in articulating the significance and broader impact of its findings. I am not an expert in the specific field, so I cannot definitively judge the paper's actual contribution in its current form. I recommend that the editor assess its suitability for publication.
Citation: https://doi.org/10.5194/hess-2024-107-RC2 -
AC2: 'Reply on RC2', Mohsen Amini Fasakhodi, 30 Jul 2024
Dear Referee,
We appreciate your emphasis on articulating the broader significance of our findings. We agree that while model calibration is a central component of our study, the value lies in how these calibrated models can advance scientific understanding and inform practical applications. We will strengthen the revised manuscript by elaborating on the following implications. To avoid overlooking your concerns, I will number them below to better address them individually.
- The Introduction does not adequately discuss the potential implications of the study’s findings. There is no mention of how the results might contribute to model development or forest management practices. Also, the introduction mentions several studies but does not critically engage with them to highlight what has been done and what remains to be explored. It is not clear how the research gap (I assume it is "no research in the literature has combined field observations with land surface models (LSMs) to estimate water balance components in Mediterranean coniferous forests.") would be relevant for new understanding or methodological advances.
The reviewer raises crucial points about the clarity and depth of our Introduction. We acknowledge the need to more effectively convey the potential implications of our research and to critically engage with existing literature to highlight the knowledge gap our study addresses. In the revised manuscript, we will restructure and enrich the Introduction as follows:
We will go beyond simply stating the absence of combined field observation and LSM studies in Mediterranean coniferous forests. Instead, we will elaborate on the limitations of previous research that relied solely on either field measurements or modeling approaches. For instance, we can highlight how neglecting species-specific physiological responses or relying on generalized model parameters might lead to inaccurate water balance estimations and hinder effective forest management decisions.
We will emphasize that our calibrated model, parameterized with species-specific data, can serve as a benchmark for improving the representation of Mediterranean coniferous forests in regional and global LSMs. This enhanced accuracy is crucial for predicting the impacts of climate change on water resources and forest productivity at broader scales.
We will emphasize that our findings can inform decisions related to species selection, planting density, and irrigation strategies, particularly in the context of increasing drought stress in Mediterranean regions. By providing a more accurate understanding of species-specific water use patterns, our study can contribute to the development of more sustainable forest management practices.
We will go beyond simply citing relevant studies by actively engaging with their findings and limitations. For example, we will discuss how Klein et al. (2014), while providing valuable insights into water use dynamics in a water-limited pine forest, focused on a single species and did not incorporate LSMs. This highlights the novelty of our approach, which combines species-specific data with advanced modeling techniques. Similarly, we will discuss other relevant studies (e.g., those mentioned in lines 50-60) and emphasize how our research builds upon and extends their findings. (Klein, T., Rotenberg, E., Cohen-Hilaleh, E., Raz-Yaseef, N., Tatarinov, F., Preisler, Y., … Yakir, D. (2013)Quantifying transpirable soil water and its relations to tree water use dynamics in a water-limited pine forest. Ecohydrology, 7(2), 409–419. doi:10.1002/eco.1360)
- In the Discussion and Conclusions, while the comparison with previous studies is informative, it lacks depth in explaining why certain differences or similarities occur. For instance, it is still not clear why strong water limitation in your study area might influence these sensitivities differently than in other regions. Still, the broader implications of the sensitivity analysis findings for model calibration, validation, and application are not sufficiently discussed. It would be appreciated to discuss how your results contribute to the understanding of the effects of soil and vegetation parameters on water balance components under different climatic conditions.
The reviewer raises a valid point about the need for a more in-depth analysis of the observed differences and similarities in sensitivity compared to other studies, particularly in the context of our study area's strong water limitation. Additionally, you highlight the importance of elaborating on the broader implications of our sensitivity analysis for model application and understanding the interplay between soil, vegetation, and climate. We agree that our Discussion and Conclusions sections would benefit from a more comprehensive exploration of these aspects. In the revised manuscript, we will:
We will move beyond simply stating differences or similarities with previous studies and delve into the potential reasons behind them. For example, we will critically examine how the strong water limitation in our study area might lead to distinct sensitivities compared to regions with less water stress. This will involve considering factors like plant physiological adaptations, soil water holding capacity, and the timing and magnitude of precipitation events.
We will discuss how identifying the most sensitive parameters can guide future data collection efforts and improve model calibration strategies, particularly in water-limited environments.
We will discuss how the sensitivity of specific parameters might vary across different climatic conditions. This will provide valuable insights for extrapolating our model to other regions and predicting the impacts of climate change on water balance components.
We will explicitly discuss how our results contribute to understanding the complex interplay between soil properties, vegetation characteristics, and climatic factors in shaping water balance components. This will involve synthesizing our findings on parameter sensitivity with existing knowledge of eco-hydrological processes in Mediterranean ecosystems. We will highlight the importance of considering these interactions for accurate model predictions and effective management of water resources in similar environments.
- In addition, the study observes better model performance during the wetter validation period compared to the drier calibration period. I suggest that an additional calibration-validation framework can be considered. Specifically, the authors could calibrate the model using data from the wetter period (September 2021 to June 2022) and validate it using data from the drier period (December 2020 to August 2021). By reversing the calibration and validation periods, the study can assess whether the model is robust across different hydrological conditions.
We appreciate the reviewer's insightful suggestion to assess model robustness across different hydrological conditions by reversing the calibration and validation periods. We acknowledge that the observed difference in model performance between the wetter validation and drier calibration periods warrants further investigation. We will reverse the calibration-validation periods
- Last but not least, the study only uses a few site observations, which raises my concerns about the generalizability of the findings. While this may not be the focus of the study, modeling only a single tree may lead to an oversimplified representation of the ecosystem. I recommend discussing the limitations of this approach and suggesting ways to improve the generalizability of future studies.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
Eventually, We appreciate the reviewer's thorough assessment of our manuscript and acknowledge the importance of clearly articulating the significance and broader implications of our findings. We recognize that our initial submission fell short in this regard, particularly in the Introduction and Discussion sections. However, we are confident that the revisions we have outlined in our detailed responses to each comment will effectively address the reviewer's concerns.
Citation: https://doi.org/10.5194/hess-2024-107-AC2
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AC2: 'Reply on RC2', Mohsen Amini Fasakhodi, 30 Jul 2024
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AC1: 'Reply on RC1', Mohsen Amini Fasakhodi, 29 Jul 2024
Dear Referee,
We appreciate your time for insightful comments and raising these important points. To avoid overlooking your concerns, I bullet them below to better address them one by one.
- My main concern is about the number of sap flow sensors, only two sap flow sensors per species, which in my opinion is quite small. To overcome this significant limitation, you must make clear that transpiration variability within species in the plantation is sufficiently low.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
- Additionally, concerning tree variability, the standard error for tree dimensions is missing. Providing this information will inform readers about the representativeness of the studied trees within the plantation.
We agree that including measures of variability for tree dimensions is essential for demonstrating the representativeness of our study sample. A comprehensive table reporting the mean, and standard deviation for stem diameter for all species, and a table reporting stem diameter, bark thickness, sapwood depth, tree height, and canopy coverage area for all twelve trees (six pine and six cypress) are provided in Djuma et al. (2024). To enhance the clarity of the current manuscript, we will incorporate a concise table summarizing these key tree dimension statistics.
- It would be important to have some more information concerning the water use strategies and rooting systems of the studied species, Pinus brutia and Cupressus sempervirens, in the introduction (eventually around lines 40-48), to help results interpretation and subsequent discussion.
We appreciate the reviewer's suggestion to provide more context on the contrasting water use strategies and root systems of Pinus brutia and Cupressus sempervirens. We agree that this information is crucial for readers to fully grasp the implications of our findings.
In the revised manuscript, we will incorporate a brief discussion around lines 40-48 highlighting the key differences between these species. Specifically, we will note that Pinus brutia, as a drought-tolerant species, typically develops a deep and extensive root system that allows it to access water from deeper soil layers. In contrast, Cupressus sempervirens, while relatively drought-tolerant, tends to have a shallower root system, making it potentially more reliant on surface moisture. We will draw upon relevant studies (e.g., [Rog et al., 2021]) to support these points. This expanded discussion will provide a stronger foundation for interpreting the observed differences in sap flow dynamics between the two species.
- The mention of the reported or studied water balance components (transpiration and soil moistue?) in the abstract is advised.
We agree that specifying the studied water balance components in the abstract will provide readers with a clearer understanding of our research focus. In the revised abstract, we will explicitly state that our study measured both transpiration rates and soil moisture content at various depths.
- The choice of the parameter designation is not very straightforward (e.g. REFKDT or SATDK), the manuscript would benefit with the use of simpler designations or the name of the parameters
We appreciate the reviewer's feedback regarding the clarity of parameter designations. We understand that using abbreviations common in model documentation might pose challenges for readers unfamiliar with NOAHMP and WRF. However, these parameter short names (abbreviations) are used in the model documentation and code. They are also used in other journal articles on the NOAHMP and WRF model. All parameters are also listed with their full description and units in Table 1, so these could be relatively easy to find back for the reader. For the surface infiltration parameter REFKDT, which is a scaling factor, we will add the equation and description in a footnote of Table 1.
- Figure 1: it would be interesting to distinguish between pine and cypress at the site, and eventually identify which trees were used for sap flow
The reviewer makes an excellent point. Clearly distinguishing between pine and cypress trees in Figure 1, and highlighting those used for sap flow measurements, would significantly improve the figure's informativeness. The study site has more than 2300 mixed species trees/shrubs. There are 846 pine and 216 cypress trees, which were planted in random locations in the study site. Eight trees (four pine and four cypress) with stem diameter greater than 8 cm were randomly selected for sap flow monitoring (presented in Djuma et al 2024). In addition to these eight trees, two fenced sites were established, where sap flow sensors were installed on neighboring pine and cypress trees (four trees in total) with additional soil moisture sensors between the trees (used for the current manuscript). We will incorporate this information in the revised manuscripts.
Citation: https://doi.org/10.5194/hess-2024-107-AC1 -
AC2: 'Reply on RC2', Mohsen Amini Fasakhodi, 30 Jul 2024
Dear Referee,
We appreciate your emphasis on articulating the broader significance of our findings. We agree that while model calibration is a central component of our study, the value lies in how these calibrated models can advance scientific understanding and inform practical applications. We will strengthen the revised manuscript by elaborating on the following implications. To avoid overlooking your concerns, I will number them below to better address them individually.
- The Introduction does not adequately discuss the potential implications of the study’s findings. There is no mention of how the results might contribute to model development or forest management practices. Also, the introduction mentions several studies but does not critically engage with them to highlight what has been done and what remains to be explored. It is not clear how the research gap (I assume it is "no research in the literature has combined field observations with land surface models (LSMs) to estimate water balance components in Mediterranean coniferous forests.") would be relevant for new understanding or methodological advances.
The reviewer raises crucial points about the clarity and depth of our Introduction. We acknowledge the need to more effectively convey the potential implications of our research and to critically engage with existing literature to highlight the knowledge gap our study addresses. In the revised manuscript, we will restructure and enrich the Introduction as follows:
We will go beyond simply stating the absence of combined field observation and LSM studies in Mediterranean coniferous forests. Instead, we will elaborate on the limitations of previous research that relied solely on either field measurements or modeling approaches. For instance, we can highlight how neglecting species-specific physiological responses or relying on generalized model parameters might lead to inaccurate water balance estimations and hinder effective forest management decisions.
We will emphasize that our calibrated model, parameterized with species-specific data, can serve as a benchmark for improving the representation of Mediterranean coniferous forests in regional and global LSMs. This enhanced accuracy is crucial for predicting the impacts of climate change on water resources and forest productivity at broader scales.
We will emphasize that our findings can inform decisions related to species selection, planting density, and irrigation strategies, particularly in the context of increasing drought stress in Mediterranean regions. By providing a more accurate understanding of species-specific water use patterns, our study can contribute to the development of more sustainable forest management practices.
We will go beyond simply citing relevant studies by actively engaging with their findings and limitations. For example, we will discuss how Klein et al. (2014), while providing valuable insights into water use dynamics in a water-limited pine forest, focused on a single species and did not incorporate LSMs. This highlights the novelty of our approach, which combines species-specific data with advanced modeling techniques. Similarly, we will discuss other relevant studies (e.g., those mentioned in lines 50-60) and emphasize how our research builds upon and extends their findings. (Klein, T., Rotenberg, E., Cohen-Hilaleh, E., Raz-Yaseef, N., Tatarinov, F., Preisler, Y., … Yakir, D. (2013)Quantifying transpirable soil water and its relations to tree water use dynamics in a water-limited pine forest. Ecohydrology, 7(2), 409–419. doi:10.1002/eco.1360)
- In the Discussion and Conclusions, while the comparison with previous studies is informative, it lacks depth in explaining why certain differences or similarities occur. For instance, it is still not clear why strong water limitation in your study area might influence these sensitivities differently than in other regions. Still, the broader implications of the sensitivity analysis findings for model calibration, validation, and application are not sufficiently discussed. It would be appreciated to discuss how your results contribute to the understanding of the effects of soil and vegetation parameters on water balance components under different climatic conditions.
The reviewer raises a valid point about the need for a more in-depth analysis of the observed differences and similarities in sensitivity compared to other studies, particularly in the context of our study area's strong water limitation. Additionally, you highlight the importance of elaborating on the broader implications of our sensitivity analysis for model application and understanding the interplay between soil, vegetation, and climate. We agree that our Discussion and Conclusions sections would benefit from a more comprehensive exploration of these aspects. In the revised manuscript, we will:
We will move beyond simply stating differences or similarities with previous studies and delve into the potential reasons behind them. For example, we will critically examine how the strong water limitation in our study area might lead to distinct sensitivities compared to regions with less water stress. This will involve considering factors like plant physiological adaptations, soil water holding capacity, and the timing and magnitude of precipitation events.
We will discuss how identifying the most sensitive parameters can guide future data collection efforts and improve model calibration strategies, particularly in water-limited environments.
We will discuss how the sensitivity of specific parameters might vary across different climatic conditions. This will provide valuable insights for extrapolating our model to other regions and predicting the impacts of climate change on water balance components.
We will explicitly discuss how our results contribute to understanding the complex interplay between soil properties, vegetation characteristics, and climatic factors in shaping water balance components. This will involve synthesizing our findings on parameter sensitivity with existing knowledge of eco-hydrological processes in Mediterranean ecosystems. We will highlight the importance of considering these interactions for accurate model predictions and effective management of water resources in similar environments.
- In addition, the study observes better model performance during the wetter validation period compared to the drier calibration period. I suggest that an additional calibration-validation framework can be considered. Specifically, the authors could calibrate the model using data from the wetter period (September 2021 to June 2022) and validate it using data from the drier period (December 2020 to August 2021). By reversing the calibration and validation periods, the study can assess whether the model is robust across different hydrological conditions.
We appreciate the reviewer's insightful suggestion to assess model robustness across different hydrological conditions by reversing the calibration and validation periods. We acknowledge that the observed difference in model performance between the wetter validation and drier calibration periods warrants further investigation. We will reverse the calibration-validation periods
- Last but not least, the study only uses a few site observations, which raises my concerns about the generalizability of the findings. While this may not be the focus of the study, modeling only a single tree may lead to an oversimplified representation of the ecosystem. I recommend discussing the limitations of this approach and suggesting ways to improve the generalizability of future studies.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
Eventually, We appreciate the reviewer's thorough assessment of our manuscript and acknowledge the importance of clearly articulating the significance and broader implications of our findings. We recognize that our initial submission fell short in this regard, particularly in the Introduction and Discussion sections. However, we are confident that the revisions we have outlined in our detailed responses to each comment will effectively address the reviewer's concerns.
Citation: https://doi.org/10.5194/hess-2024-107-AC2
Status: closed
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RC1: 'Comment on hess-2024-107', Anonymous Referee #1, 09 Jul 2024
Dear authors,
The manuscript titled “Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem” aims to parameterize and test the performance of the LSM Noah-MP on an eastern Mediterranean planted forest. The authors monitored the sap flow of two coniferous species and soil moisture over 19 months to achieve the goal. The manuscript reads very well. However, while the presented study is both interesting and timely, some issues need to be addressed before the manuscript can be accepted for publication.
My main concern is about the number of sap flow sensors, only two sap flow sensors per species, which in my opinion is quite small. To overcome this significant limitation, you must make clear that transpiration variability within species in the plantation is sufficiently low. Additionally, concerning tree variability, the standard error for tree dimensions is missing. Providing this information will inform readers about the representativeness of the studied trees within the plantation.
It would be important to have some more information concerning the water use strategies and rooting systems of the studied species, Pinus brutia and Cupressus sempervirens, in the introduction (eventually around lines 40-48), to help results interpretation and subsequent discussion.
The mention of the reported or studied water balance components (transpiration and soil moisture?) in the abstract is advised.
The choice of the parameter designation is not very straightforward (e.g. REFKDT or SATDK), the manuscript would benefit with the use of simpler designations or the name of the parameters
Figure 1: it would be interesting to distinguish between pine and cypress at the site, and eventually identify which trees were used for sap flow
Please consider my specific questions, technical corrections or suggestions on the attached pdf file.
-
AC1: 'Reply on RC1', Mohsen Amini Fasakhodi, 29 Jul 2024
Dear Referee,
We appreciate your time for insightful comments and raising these important points. To avoid overlooking your concerns, I bullet them below to better address them one by one.
- My main concern is about the number of sap flow sensors, only two sap flow sensors per species, which in my opinion is quite small. To overcome this significant limitation, you must make clear that transpiration variability within species in the plantation is sufficiently low.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
- Additionally, concerning tree variability, the standard error for tree dimensions is missing. Providing this information will inform readers about the representativeness of the studied trees within the plantation.
We agree that including measures of variability for tree dimensions is essential for demonstrating the representativeness of our study sample. A comprehensive table reporting the mean, and standard deviation for stem diameter for all species, and a table reporting stem diameter, bark thickness, sapwood depth, tree height, and canopy coverage area for all twelve trees (six pine and six cypress) are provided in Djuma et al. (2024). To enhance the clarity of the current manuscript, we will incorporate a concise table summarizing these key tree dimension statistics.
- It would be important to have some more information concerning the water use strategies and rooting systems of the studied species, Pinus brutia and Cupressus sempervirens, in the introduction (eventually around lines 40-48), to help results interpretation and subsequent discussion.
We appreciate the reviewer's suggestion to provide more context on the contrasting water use strategies and root systems of Pinus brutia and Cupressus sempervirens. We agree that this information is crucial for readers to fully grasp the implications of our findings.
In the revised manuscript, we will incorporate a brief discussion around lines 40-48 highlighting the key differences between these species. Specifically, we will note that Pinus brutia, as a drought-tolerant species, typically develops a deep and extensive root system that allows it to access water from deeper soil layers. In contrast, Cupressus sempervirens, while relatively drought-tolerant, tends to have a shallower root system, making it potentially more reliant on surface moisture. We will draw upon relevant studies (e.g., [Rog et al., 2021]) to support these points. This expanded discussion will provide a stronger foundation for interpreting the observed differences in sap flow dynamics between the two species.
- The mention of the reported or studied water balance components (transpiration and soil moistue?) in the abstract is advised.
We agree that specifying the studied water balance components in the abstract will provide readers with a clearer understanding of our research focus. In the revised abstract, we will explicitly state that our study measured both transpiration rates and soil moisture content at various depths.
- The choice of the parameter designation is not very straightforward (e.g. REFKDT or SATDK), the manuscript would benefit with the use of simpler designations or the name of the parameters
We appreciate the reviewer's feedback regarding the clarity of parameter designations. We understand that using abbreviations common in model documentation might pose challenges for readers unfamiliar with NOAHMP and WRF. However, these parameter short names (abbreviations) are used in the model documentation and code. They are also used in other journal articles on the NOAHMP and WRF model. All parameters are also listed with their full description and units in Table 1, so these could be relatively easy to find back for the reader. For the surface infiltration parameter REFKDT, which is a scaling factor, we will add the equation and description in a footnote of Table 1.
- Figure 1: it would be interesting to distinguish between pine and cypress at the site, and eventually identify which trees were used for sap flow
The reviewer makes an excellent point. Clearly distinguishing between pine and cypress trees in Figure 1, and highlighting those used for sap flow measurements, would significantly improve the figure's informativeness. The study site has more than 2300 mixed species trees/shrubs. There are 846 pine and 216 cypress trees, which were planted in random locations in the study site. Eight trees (four pine and four cypress) with stem diameter greater than 8 cm were randomly selected for sap flow monitoring (presented in Djuma et al 2024). In addition to these eight trees, two fenced sites were established, where sap flow sensors were installed on neighboring pine and cypress trees (four trees in total) with additional soil moisture sensors between the trees (used for the current manuscript). We will incorporate this information in the revised manuscripts.
Citation: https://doi.org/10.5194/hess-2024-107-AC1
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AC1: 'Reply on RC1', Mohsen Amini Fasakhodi, 29 Jul 2024
-
RC2: 'Comment on hess-2024-107', Anonymous Referee #2, 25 Jul 2024
The manuscript "Modeling water balance components of conifer species using the Noah-MP model in an eastern Mediterranean ecosystem" presents a study on simulating water balance components in Mediterranean coniferous forests using the Noah-MP land surface model. The methodology, which combines field observations with advanced modeling techniques, is robust and well-documented. Nevertheless, my major concern is that the scientific contribution and broader implications of the study are not fully articulated. The study primarily focuses on calibrating the model using observational data but lacks a clear discussion on the implications of these findings for broader scientific understanding or practical applications. For example,
- The Introduction does not adequately discuss the potential implications of the study’s findings. There is no mention of how the results might contribute to model development or forest management practices. Also, the introduction mentions several studies but does not critically engage with them to highlight what has been done and what remains to be explored. It is not clear how the research gap (I assume it is "no research in the literature has combined field observations with land surface models (LSMs) to estimate water balance components in Mediterranean coniferous forests.") would be relevant for new understanding or methodological advances.
- In the Discussion and Conclusions, while the comparison with previous studies is informative, it lacks depth in explaining why certain differences or similarities occur. For instance, it is still not clear why strong water limitation in your study area might influence these sensitivities differently than in other regions. Still, the broader implications of the sensitivity analysis findings for model calibration, validation, and application are not sufficiently discussed. It would be appreciated to discuss how your results contribute to the understanding of the effects of soil and vegetation parameters on water balance components under different climatic conditions.
- In addition, the study observes better model performance during the wetter validation period compared to the drier calibration period. I suggest that an additional calibration-validation framework can be considered. Specifically, the authors could calibrate the model using data from the wetter period (September 2021 to June 2022) and validate it using data from the drier period (December 2020 to August 2021). By reversing the calibration and validation periods, the study can assess whether the model is robust across different hydrological conditions.
- Last but not least, the study only uses a few site observations, which raises my concerns about the generalizability of the findings. While this may not be the focus of the study, modeling only a single tree may lead to an oversimplified representation of the ecosystem. I recommend discussing the limitations of this approach and suggesting ways to improve the generalizability of future studies.
Overall, while this paper presents a comprehensive study that calibrates the Noah-MP model for Mediterranean coniferous forests, it falls short in articulating the significance and broader impact of its findings. I am not an expert in the specific field, so I cannot definitively judge the paper's actual contribution in its current form. I recommend that the editor assess its suitability for publication.
Citation: https://doi.org/10.5194/hess-2024-107-RC2 -
AC2: 'Reply on RC2', Mohsen Amini Fasakhodi, 30 Jul 2024
Dear Referee,
We appreciate your emphasis on articulating the broader significance of our findings. We agree that while model calibration is a central component of our study, the value lies in how these calibrated models can advance scientific understanding and inform practical applications. We will strengthen the revised manuscript by elaborating on the following implications. To avoid overlooking your concerns, I will number them below to better address them individually.
- The Introduction does not adequately discuss the potential implications of the study’s findings. There is no mention of how the results might contribute to model development or forest management practices. Also, the introduction mentions several studies but does not critically engage with them to highlight what has been done and what remains to be explored. It is not clear how the research gap (I assume it is "no research in the literature has combined field observations with land surface models (LSMs) to estimate water balance components in Mediterranean coniferous forests.") would be relevant for new understanding or methodological advances.
The reviewer raises crucial points about the clarity and depth of our Introduction. We acknowledge the need to more effectively convey the potential implications of our research and to critically engage with existing literature to highlight the knowledge gap our study addresses. In the revised manuscript, we will restructure and enrich the Introduction as follows:
We will go beyond simply stating the absence of combined field observation and LSM studies in Mediterranean coniferous forests. Instead, we will elaborate on the limitations of previous research that relied solely on either field measurements or modeling approaches. For instance, we can highlight how neglecting species-specific physiological responses or relying on generalized model parameters might lead to inaccurate water balance estimations and hinder effective forest management decisions.
We will emphasize that our calibrated model, parameterized with species-specific data, can serve as a benchmark for improving the representation of Mediterranean coniferous forests in regional and global LSMs. This enhanced accuracy is crucial for predicting the impacts of climate change on water resources and forest productivity at broader scales.
We will emphasize that our findings can inform decisions related to species selection, planting density, and irrigation strategies, particularly in the context of increasing drought stress in Mediterranean regions. By providing a more accurate understanding of species-specific water use patterns, our study can contribute to the development of more sustainable forest management practices.
We will go beyond simply citing relevant studies by actively engaging with their findings and limitations. For example, we will discuss how Klein et al. (2014), while providing valuable insights into water use dynamics in a water-limited pine forest, focused on a single species and did not incorporate LSMs. This highlights the novelty of our approach, which combines species-specific data with advanced modeling techniques. Similarly, we will discuss other relevant studies (e.g., those mentioned in lines 50-60) and emphasize how our research builds upon and extends their findings. (Klein, T., Rotenberg, E., Cohen-Hilaleh, E., Raz-Yaseef, N., Tatarinov, F., Preisler, Y., … Yakir, D. (2013)Quantifying transpirable soil water and its relations to tree water use dynamics in a water-limited pine forest. Ecohydrology, 7(2), 409–419. doi:10.1002/eco.1360)
- In the Discussion and Conclusions, while the comparison with previous studies is informative, it lacks depth in explaining why certain differences or similarities occur. For instance, it is still not clear why strong water limitation in your study area might influence these sensitivities differently than in other regions. Still, the broader implications of the sensitivity analysis findings for model calibration, validation, and application are not sufficiently discussed. It would be appreciated to discuss how your results contribute to the understanding of the effects of soil and vegetation parameters on water balance components under different climatic conditions.
The reviewer raises a valid point about the need for a more in-depth analysis of the observed differences and similarities in sensitivity compared to other studies, particularly in the context of our study area's strong water limitation. Additionally, you highlight the importance of elaborating on the broader implications of our sensitivity analysis for model application and understanding the interplay between soil, vegetation, and climate. We agree that our Discussion and Conclusions sections would benefit from a more comprehensive exploration of these aspects. In the revised manuscript, we will:
We will move beyond simply stating differences or similarities with previous studies and delve into the potential reasons behind them. For example, we will critically examine how the strong water limitation in our study area might lead to distinct sensitivities compared to regions with less water stress. This will involve considering factors like plant physiological adaptations, soil water holding capacity, and the timing and magnitude of precipitation events.
We will discuss how identifying the most sensitive parameters can guide future data collection efforts and improve model calibration strategies, particularly in water-limited environments.
We will discuss how the sensitivity of specific parameters might vary across different climatic conditions. This will provide valuable insights for extrapolating our model to other regions and predicting the impacts of climate change on water balance components.
We will explicitly discuss how our results contribute to understanding the complex interplay between soil properties, vegetation characteristics, and climatic factors in shaping water balance components. This will involve synthesizing our findings on parameter sensitivity with existing knowledge of eco-hydrological processes in Mediterranean ecosystems. We will highlight the importance of considering these interactions for accurate model predictions and effective management of water resources in similar environments.
- In addition, the study observes better model performance during the wetter validation period compared to the drier calibration period. I suggest that an additional calibration-validation framework can be considered. Specifically, the authors could calibrate the model using data from the wetter period (September 2021 to June 2022) and validate it using data from the drier period (December 2020 to August 2021). By reversing the calibration and validation periods, the study can assess whether the model is robust across different hydrological conditions.
We appreciate the reviewer's insightful suggestion to assess model robustness across different hydrological conditions by reversing the calibration and validation periods. We acknowledge that the observed difference in model performance between the wetter validation and drier calibration periods warrants further investigation. We will reverse the calibration-validation periods
- Last but not least, the study only uses a few site observations, which raises my concerns about the generalizability of the findings. While this may not be the focus of the study, modeling only a single tree may lead to an oversimplified representation of the ecosystem. I recommend discussing the limitations of this approach and suggesting ways to improve the generalizability of future studies.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
Eventually, We appreciate the reviewer's thorough assessment of our manuscript and acknowledge the importance of clearly articulating the significance and broader implications of our findings. We recognize that our initial submission fell short in this regard, particularly in the Introduction and Discussion sections. However, we are confident that the revisions we have outlined in our detailed responses to each comment will effectively address the reviewer's concerns.
Citation: https://doi.org/10.5194/hess-2024-107-AC2
-
AC2: 'Reply on RC2', Mohsen Amini Fasakhodi, 30 Jul 2024
-
AC1: 'Reply on RC1', Mohsen Amini Fasakhodi, 29 Jul 2024
Dear Referee,
We appreciate your time for insightful comments and raising these important points. To avoid overlooking your concerns, I bullet them below to better address them one by one.
- My main concern is about the number of sap flow sensors, only two sap flow sensors per species, which in my opinion is quite small. To overcome this significant limitation, you must make clear that transpiration variability within species in the plantation is sufficiently low.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
- Additionally, concerning tree variability, the standard error for tree dimensions is missing. Providing this information will inform readers about the representativeness of the studied trees within the plantation.
We agree that including measures of variability for tree dimensions is essential for demonstrating the representativeness of our study sample. A comprehensive table reporting the mean, and standard deviation for stem diameter for all species, and a table reporting stem diameter, bark thickness, sapwood depth, tree height, and canopy coverage area for all twelve trees (six pine and six cypress) are provided in Djuma et al. (2024). To enhance the clarity of the current manuscript, we will incorporate a concise table summarizing these key tree dimension statistics.
- It would be important to have some more information concerning the water use strategies and rooting systems of the studied species, Pinus brutia and Cupressus sempervirens, in the introduction (eventually around lines 40-48), to help results interpretation and subsequent discussion.
We appreciate the reviewer's suggestion to provide more context on the contrasting water use strategies and root systems of Pinus brutia and Cupressus sempervirens. We agree that this information is crucial for readers to fully grasp the implications of our findings.
In the revised manuscript, we will incorporate a brief discussion around lines 40-48 highlighting the key differences between these species. Specifically, we will note that Pinus brutia, as a drought-tolerant species, typically develops a deep and extensive root system that allows it to access water from deeper soil layers. In contrast, Cupressus sempervirens, while relatively drought-tolerant, tends to have a shallower root system, making it potentially more reliant on surface moisture. We will draw upon relevant studies (e.g., [Rog et al., 2021]) to support these points. This expanded discussion will provide a stronger foundation for interpreting the observed differences in sap flow dynamics between the two species.
- The mention of the reported or studied water balance components (transpiration and soil moistue?) in the abstract is advised.
We agree that specifying the studied water balance components in the abstract will provide readers with a clearer understanding of our research focus. In the revised abstract, we will explicitly state that our study measured both transpiration rates and soil moisture content at various depths.
- The choice of the parameter designation is not very straightforward (e.g. REFKDT or SATDK), the manuscript would benefit with the use of simpler designations or the name of the parameters
We appreciate the reviewer's feedback regarding the clarity of parameter designations. We understand that using abbreviations common in model documentation might pose challenges for readers unfamiliar with NOAHMP and WRF. However, these parameter short names (abbreviations) are used in the model documentation and code. They are also used in other journal articles on the NOAHMP and WRF model. All parameters are also listed with their full description and units in Table 1, so these could be relatively easy to find back for the reader. For the surface infiltration parameter REFKDT, which is a scaling factor, we will add the equation and description in a footnote of Table 1.
- Figure 1: it would be interesting to distinguish between pine and cypress at the site, and eventually identify which trees were used for sap flow
The reviewer makes an excellent point. Clearly distinguishing between pine and cypress trees in Figure 1, and highlighting those used for sap flow measurements, would significantly improve the figure's informativeness. The study site has more than 2300 mixed species trees/shrubs. There are 846 pine and 216 cypress trees, which were planted in random locations in the study site. Eight trees (four pine and four cypress) with stem diameter greater than 8 cm were randomly selected for sap flow monitoring (presented in Djuma et al 2024). In addition to these eight trees, two fenced sites were established, where sap flow sensors were installed on neighboring pine and cypress trees (four trees in total) with additional soil moisture sensors between the trees (used for the current manuscript). We will incorporate this information in the revised manuscripts.
Citation: https://doi.org/10.5194/hess-2024-107-AC1 -
AC2: 'Reply on RC2', Mohsen Amini Fasakhodi, 30 Jul 2024
Dear Referee,
We appreciate your emphasis on articulating the broader significance of our findings. We agree that while model calibration is a central component of our study, the value lies in how these calibrated models can advance scientific understanding and inform practical applications. We will strengthen the revised manuscript by elaborating on the following implications. To avoid overlooking your concerns, I will number them below to better address them individually.
- The Introduction does not adequately discuss the potential implications of the study’s findings. There is no mention of how the results might contribute to model development or forest management practices. Also, the introduction mentions several studies but does not critically engage with them to highlight what has been done and what remains to be explored. It is not clear how the research gap (I assume it is "no research in the literature has combined field observations with land surface models (LSMs) to estimate water balance components in Mediterranean coniferous forests.") would be relevant for new understanding or methodological advances.
The reviewer raises crucial points about the clarity and depth of our Introduction. We acknowledge the need to more effectively convey the potential implications of our research and to critically engage with existing literature to highlight the knowledge gap our study addresses. In the revised manuscript, we will restructure and enrich the Introduction as follows:
We will go beyond simply stating the absence of combined field observation and LSM studies in Mediterranean coniferous forests. Instead, we will elaborate on the limitations of previous research that relied solely on either field measurements or modeling approaches. For instance, we can highlight how neglecting species-specific physiological responses or relying on generalized model parameters might lead to inaccurate water balance estimations and hinder effective forest management decisions.
We will emphasize that our calibrated model, parameterized with species-specific data, can serve as a benchmark for improving the representation of Mediterranean coniferous forests in regional and global LSMs. This enhanced accuracy is crucial for predicting the impacts of climate change on water resources and forest productivity at broader scales.
We will emphasize that our findings can inform decisions related to species selection, planting density, and irrigation strategies, particularly in the context of increasing drought stress in Mediterranean regions. By providing a more accurate understanding of species-specific water use patterns, our study can contribute to the development of more sustainable forest management practices.
We will go beyond simply citing relevant studies by actively engaging with their findings and limitations. For example, we will discuss how Klein et al. (2014), while providing valuable insights into water use dynamics in a water-limited pine forest, focused on a single species and did not incorporate LSMs. This highlights the novelty of our approach, which combines species-specific data with advanced modeling techniques. Similarly, we will discuss other relevant studies (e.g., those mentioned in lines 50-60) and emphasize how our research builds upon and extends their findings. (Klein, T., Rotenberg, E., Cohen-Hilaleh, E., Raz-Yaseef, N., Tatarinov, F., Preisler, Y., … Yakir, D. (2013)Quantifying transpirable soil water and its relations to tree water use dynamics in a water-limited pine forest. Ecohydrology, 7(2), 409–419. doi:10.1002/eco.1360)
- In the Discussion and Conclusions, while the comparison with previous studies is informative, it lacks depth in explaining why certain differences or similarities occur. For instance, it is still not clear why strong water limitation in your study area might influence these sensitivities differently than in other regions. Still, the broader implications of the sensitivity analysis findings for model calibration, validation, and application are not sufficiently discussed. It would be appreciated to discuss how your results contribute to the understanding of the effects of soil and vegetation parameters on water balance components under different climatic conditions.
The reviewer raises a valid point about the need for a more in-depth analysis of the observed differences and similarities in sensitivity compared to other studies, particularly in the context of our study area's strong water limitation. Additionally, you highlight the importance of elaborating on the broader implications of our sensitivity analysis for model application and understanding the interplay between soil, vegetation, and climate. We agree that our Discussion and Conclusions sections would benefit from a more comprehensive exploration of these aspects. In the revised manuscript, we will:
We will move beyond simply stating differences or similarities with previous studies and delve into the potential reasons behind them. For example, we will critically examine how the strong water limitation in our study area might lead to distinct sensitivities compared to regions with less water stress. This will involve considering factors like plant physiological adaptations, soil water holding capacity, and the timing and magnitude of precipitation events.
We will discuss how identifying the most sensitive parameters can guide future data collection efforts and improve model calibration strategies, particularly in water-limited environments.
We will discuss how the sensitivity of specific parameters might vary across different climatic conditions. This will provide valuable insights for extrapolating our model to other regions and predicting the impacts of climate change on water balance components.
We will explicitly discuss how our results contribute to understanding the complex interplay between soil properties, vegetation characteristics, and climatic factors in shaping water balance components. This will involve synthesizing our findings on parameter sensitivity with existing knowledge of eco-hydrological processes in Mediterranean ecosystems. We will highlight the importance of considering these interactions for accurate model predictions and effective management of water resources in similar environments.
- In addition, the study observes better model performance during the wetter validation period compared to the drier calibration period. I suggest that an additional calibration-validation framework can be considered. Specifically, the authors could calibrate the model using data from the wetter period (September 2021 to June 2022) and validate it using data from the drier period (December 2020 to August 2021). By reversing the calibration and validation periods, the study can assess whether the model is robust across different hydrological conditions.
We appreciate the reviewer's insightful suggestion to assess model robustness across different hydrological conditions by reversing the calibration and validation periods. We acknowledge that the observed difference in model performance between the wetter validation and drier calibration periods warrants further investigation. We will reverse the calibration-validation periods
- Last but not least, the study only uses a few site observations, which raises my concerns about the generalizability of the findings. While this may not be the focus of the study, modeling only a single tree may lead to an oversimplified representation of the ecosystem. I recommend discussing the limitations of this approach and suggesting ways to improve the generalizability of future studies.
We appreciate the reviewer's concern regarding the number of sap flow sensors used in this study. While we acknowledge that using data from only two sensors per species might seem limited, we carefully selected these four sensors (two on pine and two on cypress) to represent trees with biometrics and sap flow patterns characteristic of the broader population within the plantation. To demonstrate the low variability of transpiration within species at our study site, we draw upon a more extensive dataset collected from 12 sap flow sensors (six on pine and six on cypress). All the observational data of the 12 sap flow sensors were used for another manuscript (resubmitted, under second revision:Djuma et al., (2024).), where the main objective is to quantify the transpiration of these trees with observational data. We will use the data presented by Djuma et al. (2024) to show that the selected 4 trees in the current manuscript are representative of all 12 sap flow monitored trees. “Djuma, H., Bruggeman, A., Eliades, M., & Zoumides, C. (In review, 2024) Water use of drought-tolerant coniferous trees (Pinus brutia and Cupressus sempervirens) in a semi-arid environment. Ecohydrology.”
Eventually, We appreciate the reviewer's thorough assessment of our manuscript and acknowledge the importance of clearly articulating the significance and broader implications of our findings. We recognize that our initial submission fell short in this regard, particularly in the Introduction and Discussion sections. However, we are confident that the revisions we have outlined in our detailed responses to each comment will effectively address the reviewer's concerns.
Citation: https://doi.org/10.5194/hess-2024-107-AC2
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