the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 08 Feb 2024
Simulating lake ice phenology using a coupled atmosphere-lake model at Lake Nam Co, a typical deep alpine lake on the Tibetan Plateau
Abstract. Simulating the ice phenology of deep alpine lakes is important and challenging in coupled atmosphere-lake models. In this study, the Weather Research and Forecasting (WRF) model, coupled with two lake models, the fresh-water lake model (WRF-FLake) and the default lake model (WRF-Lake), was applied to lake Nam Co, a typical deep alpine lake located in the centre of the Tibetan Plateau, to simulate its lake ice phenology. Due to the large errors in simulating lake ice phenology, related key parameters and parameterizations were improved in the coupled model based on observations and physics-based schemes. By improving the momentum, hydraulic and thermal roughness length parameterizations, both the WRF-FLake and the WRF-Lake models reasonably simulated the lake freeze-up date. By improving the key parameters associated with shortwave radiation transfer process when lake ice exists, both models generally simulated the lake break-up date well. Compared with WRF-Lake without improvements, the coupled model with both revised lake models significantly improved the simulation of lake ice phenology. However, there were still considerable errors in simulating the spatial patterns of freeze-up and break-up dates, implying that significant challenges in simulating the lake ice phenology still exist in representing some important model physics, including lake physics such as grid-scale water circulation, and atmospheric processes such as snowfall and surface snow dynamics. Therefore, this work can provide valuable new implications for advancing lake ice phenology simulations in coupled models and the improved model also has practical application prospects in weather and climate forecasts.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
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- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2023-2455', Anonymous Referee #1, 25 Mar 2024
This paper focuses on the ice phenology of Lake Nam Co a large alpine lake on the Tibetan plateau. Some interesting comparisons between model predicted freeze-up and break-up dates and values derived from MODIS data are presented. Three models are compared in this study two of which have been revised to improve their accuracy compared to the third. These revisions included changes to the momentum, hydraulic and thermal roughness length parameterizations, and refining parameters associated with the transfer of shortwave radiation lake ice is present. The authors present the following conclusions:
“With improvements of momentum, hydraulic and thermal roughness length parameterizations, both the WRF-FLake and the WRF-Lake models reasonably simulated the lake water temperature compared with MODIS and station observations.”
“Water temperature represents the lake energy storage, and therefore, the lake freeze-up date in both models was reasonably simulated compared with MODIS.”
“With revisions of key parameters and improvements of key parameterizations associated with the shortwave radiation transfer both the WRF-FLake and the WRF-Lake models generally simulated the lake break-up date well.”
“Compared with WRF coupled with the unrevised default lake model, the simulation of lake ice phenology was significantly improved by WRF coupled with both the improved lake models.”
I think the authors have presented enough convincing evidence to support these conclusions. However, I think the paper is in need of major revisions prior to publication. I provide some general comments below and numerous detailed comments in the annotated PDF that is attached.
General Comments:
The quality of the writing needs to be improved. I have noted many instances of grammatical errors, poor/awkward wording and unclear/vague wording.
More complete and/or clearer descriptions of some aspects of the methodology are required. For example, a much better description of how the MODIS freeze-up and break-up dates were calculated is needed. Other examples are noted in my detailed comments.
A clearer explanation of how the one-dimensional lake models are implemented for Lake Nam Co is required. I was able to determine that the WRF model had 116 grid points over the lake by reviewing their earlier paper. But it is not clear if the lake models were simulating 116 water columns or not. What is also not clear is why a uniform depth of 40 m was used in the lake models. No information about the actual lake bathymetry is provided and no justification for the use of 40 m is provided. The authors stated that “…a setup with identical depth for all grids can, to some extent, reflects the horizontal energy mixing associated with lake water circulation”. I am quite puzzled by this statement and by others where claims about better simulation of lake energy circulation in the lake are made.
The authors also need to provide some better arguments regarding the significance of their findings. They write the following in the summary section:
“Therefore, the main results and findings of this work can provide a good reference for climate model applications and the improved model also has practical application prospects over the alpine lake covered regions.”
This is a vague and unclear statement. Some more detailed and specific statements regarding the significance and novelty of this study are required.
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AC1: 'Reply on RC1', xu zhou, 23 May 2024
Dear reviewer,
Thank you very much for your concrete comments. Following is a list to list reply. Our reply is in italic font after each list of your comments.
This paper focuses on the ice phenology of Lake Nam Co a large alpine lake on the Tibetan plateau. Some interesting comparisons between model predicted freeze-up and break-up dates and values derived from MODIS data are presented. Three models are compared in this study two of which have been revised to improve their accuracy compared to the third. These revisions included changes to the momentum, hydraulic and thermal roughness length parameterizations, and refining parameters associated with the transfer of shortwave radiation lake ice is present. The authors present the following conclusions:
“With improvements of momentum, hydraulic and thermal roughness length parameterizations, both the WRF-FLake and the WRF-Lake models reasonably simulated the lake water temperature compared with MODIS and station observations.”
“Water temperature represents the lake energy storage, and therefore, the lake freeze-up date in both models was reasonably simulated compared with MODIS.”
“With revisions of key parameters and improvements of key parameterizations associated with the shortwave radiation transfer both the WRF-FLake and the WRF-Lake models generally simulated the lake break-up date well.”
“Compared with WRF coupled with the unrevised default lake model, the simulation of lake ice phenology was significantly improved by WRF coupled with both the improved lake models.”
I think the authors have presented enough convincing evidence to support these conclusions. However, I think the paper is in need of major revisions prior to publication. I provide some general comments below and numerous detailed comments in the annotated PDF that is attached.
General Comments:
The quality of the writing needs to be improved. I have noted many instances of grammatical errors, poor/awkward wording and unclear/vague wording.
More complete and/or clearer descriptions of some aspects of the methodology are required. For example, a much better description of how the MODIS freeze-up and break-up dates were calculated is needed. Other examples are noted in my detailed comments.Response: We will carefully refine the writing and description of methodology in the revised version.
A clearer explanation of how the one-dimensional lake models are implemented for Lake Nam Co is required.
Response: the lake model is driven by atmospheric forcing including air temperature, pressure, humidity, wind, short wave and long wave radiation, precipitation and reference height (height of first atmospheric layer). The lake models feedback momentum, sensible heat and latent heat fluxes. The above will be added in the revised version.
I was able to determine that the WRF model had 116 grid points over the lake by reviewing their earlier paper. But it is not clear if the lake models were simulating 116 water columns or not.
Response: It is the same, also 116 water columns, this information will be added in the revised version.What is also not clear is why a uniform depth of 40 m was used in the lake models.
No information about the actual lake bathymetry is provided and no justification for the use of 40 m is provided.Response: A uniform depth is a general way for treating lakes in climate models. 40m is based on previous studies with field observation and used in the study of La et al., (2016). It is calculated by the total water storage divide lake area. The total water storage is based on Zhang et al., (2016).This will be added in the revised version.
Actual lake bathymetry has been provided in previous studies. E.g. Huang et al., (2019). We will provide a short description about the lake bathymetry, and cite these references.References
Huang, A.N., Lazhu, Wang, J.B., Dai, Y.J., Yang, K., Wei, N., Wen, L.J., Wu, Y., Zhu, X.Y., Zhang, X.D. and Cai, S.X. 2019. Evaluating and Improving the Performance of Three 1-D Lake Models in a Large Deep Lake of the Central Tibetan Plateau. J Geophys Res-Atmos 124(6), 3143-3167.
La, Z., Yang, K., Wang, J.B., Lei, Y.B., Chen, Y.Y., Zhu, L.P., Ding, B.H. and Qin, J. 2016. Quantifying evaporation and its decadal change for Lake Nam Co, central Tibetan Plateau. J Geophys Res-Atmos 121(13), 7578-7591.
Zhang, B., Wu, Y., Zhu, L., Wang, J., Li, J. and Chen, D. 2011. Estimation and trend detection of water storage at Nam Co Lake, central Tibetan Plateau. J Hydrol 405(1), 161-170.The authors stated that “…a setup with identical depth for all grids can, to some extent, reflects the horizontal energy mixing associated with lake water circulation”. I am quite puzzled by this statement and by others where claims about better simulation of lake energy circulation in the lake are made.
Response: Currently, we did not find some work to exactly support such a statement. Thus, after a discussion with the coauthors, we think that better to delete it, to avoid misleading the readers.
The authors also need to provide some better arguments regarding the significance of their findings. They write the following in the summary section:
“Therefore, the main results and findings of this work can provide a good reference for climate model applications and the improved model also has practical application prospects over the alpine lake covered regions.”
This is a vague and unclear statement. Some more detailed and specific statements regarding the significance and novelty of this study are required.Response: we were supposed that this statement is supported by the previous part of the paragraph. To be more specific, it will be changed to ‘Therefore, we expected that the main results and findings of this work can provide a good reference when simulating lake ice phenology by climate models, especially for the alpine lake.’ in the revised version.
Citation: https://doi.org/10.5194/egusphere-2023-2455-AC1
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AC1: 'Reply on RC1', xu zhou, 23 May 2024
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RC2: 'Comment on egusphere-2023-2455', Laura Rontu, 14 Apr 2024
Simulating lake ice phenology using a coupled atmosphere-lake
model at Lake Nam Co, a typical deep alpine lake on the Tibetan
Plateau
Xu Zhou, Binbin Wang, Xiaogang Ma, Zhu La, and Kun YangThis is an interesting study about ice evolution on a large Tibetan Plateau lake Nam Co, that is located in high alpine conditions at 4500 m above the sea level. The article will be interesting for NWP model and lake parametrization developers.
Weather Research and Forecast model WRF coupled to three different settings of lake models was used. The results were compared with in-situ lake water temperature and MODIS satellite observations. The results and discussions largely agree with those of similar studies over Northern European and Canadian lakes. Unfortunately, the authors seem to be unaware about them, at least those studies are not mentioned in the large list of references.
I would suggest a (minor) revision to improve the presentation of the models and results. It would be good for the authors to carefully check the language and concepts used in manuscript - there are inaccuracies, sometimes misleading formulations, inconsistencies. As a non-native speaker of English I have only randomly pointed out some instances where it was not evident what the authors mean with their sentences.
Some detailed comments can be found in the annotated pdf of the manuscript.
-
AC2: 'Reply on RC2', xu zhou, 23 May 2024
Dear Laura Rontu,
We thank you for taking time to review our work. Following is a list to list reply. Our reply is in italic font after each list of your comments.
This is an interesting study about ice evolution on a large Tibetan Plateau lake Nam Co, that is located in high alpine conditions at 4500 m above the sea level. The article will be interesting for NWP model and lake parametrization developers.
Weather Research and Forecast model WRF coupled to three different settings of lake models was used. The results were compared with in-situ lake water temperature and MODIS satellite observations. The results and discussions largely agree with those of similar studies over Northern European and Canadian lakes. Unfortunately, the authors seem to be unaware about them, at least those studies are not mentioned in the large list of references.Response: Indeed, we search only the papers focusing the alpine lake at the preparing stage. We will refer to the work over Northern European and Canadian lakes, in the revised version.
I would suggest a (minor) revision to improve the presentation of the models and results. It would be good for the authors to carefully check the language and concepts used in manuscript - there are inaccuracies, sometimes misleading formulations, inconsistencies. As a non-native speaker of English I have only randomly pointed out some instances where it was not evident what the authors mean with their sentences.
Some detailed comments can be found in the annotated pdf of the manuscript.Response: Thank you very much for the thorough comments, these details will be addressed in the revised version. Additionally, we will specifically refine the writing, and looking for a professional scientific editing service before submitting the revised version.
Citation: https://doi.org/10.5194/egusphere-2023-2455-AC2
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AC2: 'Reply on RC2', xu zhou, 23 May 2024
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2023-2455', Anonymous Referee #1, 25 Mar 2024
This paper focuses on the ice phenology of Lake Nam Co a large alpine lake on the Tibetan plateau. Some interesting comparisons between model predicted freeze-up and break-up dates and values derived from MODIS data are presented. Three models are compared in this study two of which have been revised to improve their accuracy compared to the third. These revisions included changes to the momentum, hydraulic and thermal roughness length parameterizations, and refining parameters associated with the transfer of shortwave radiation lake ice is present. The authors present the following conclusions:
“With improvements of momentum, hydraulic and thermal roughness length parameterizations, both the WRF-FLake and the WRF-Lake models reasonably simulated the lake water temperature compared with MODIS and station observations.”
“Water temperature represents the lake energy storage, and therefore, the lake freeze-up date in both models was reasonably simulated compared with MODIS.”
“With revisions of key parameters and improvements of key parameterizations associated with the shortwave radiation transfer both the WRF-FLake and the WRF-Lake models generally simulated the lake break-up date well.”
“Compared with WRF coupled with the unrevised default lake model, the simulation of lake ice phenology was significantly improved by WRF coupled with both the improved lake models.”
I think the authors have presented enough convincing evidence to support these conclusions. However, I think the paper is in need of major revisions prior to publication. I provide some general comments below and numerous detailed comments in the annotated PDF that is attached.
General Comments:
The quality of the writing needs to be improved. I have noted many instances of grammatical errors, poor/awkward wording and unclear/vague wording.
More complete and/or clearer descriptions of some aspects of the methodology are required. For example, a much better description of how the MODIS freeze-up and break-up dates were calculated is needed. Other examples are noted in my detailed comments.
A clearer explanation of how the one-dimensional lake models are implemented for Lake Nam Co is required. I was able to determine that the WRF model had 116 grid points over the lake by reviewing their earlier paper. But it is not clear if the lake models were simulating 116 water columns or not. What is also not clear is why a uniform depth of 40 m was used in the lake models. No information about the actual lake bathymetry is provided and no justification for the use of 40 m is provided. The authors stated that “…a setup with identical depth for all grids can, to some extent, reflects the horizontal energy mixing associated with lake water circulation”. I am quite puzzled by this statement and by others where claims about better simulation of lake energy circulation in the lake are made.
The authors also need to provide some better arguments regarding the significance of their findings. They write the following in the summary section:
“Therefore, the main results and findings of this work can provide a good reference for climate model applications and the improved model also has practical application prospects over the alpine lake covered regions.”
This is a vague and unclear statement. Some more detailed and specific statements regarding the significance and novelty of this study are required.
-
AC1: 'Reply on RC1', xu zhou, 23 May 2024
Dear reviewer,
Thank you very much for your concrete comments. Following is a list to list reply. Our reply is in italic font after each list of your comments.
This paper focuses on the ice phenology of Lake Nam Co a large alpine lake on the Tibetan plateau. Some interesting comparisons between model predicted freeze-up and break-up dates and values derived from MODIS data are presented. Three models are compared in this study two of which have been revised to improve their accuracy compared to the third. These revisions included changes to the momentum, hydraulic and thermal roughness length parameterizations, and refining parameters associated with the transfer of shortwave radiation lake ice is present. The authors present the following conclusions:
“With improvements of momentum, hydraulic and thermal roughness length parameterizations, both the WRF-FLake and the WRF-Lake models reasonably simulated the lake water temperature compared with MODIS and station observations.”
“Water temperature represents the lake energy storage, and therefore, the lake freeze-up date in both models was reasonably simulated compared with MODIS.”
“With revisions of key parameters and improvements of key parameterizations associated with the shortwave radiation transfer both the WRF-FLake and the WRF-Lake models generally simulated the lake break-up date well.”
“Compared with WRF coupled with the unrevised default lake model, the simulation of lake ice phenology was significantly improved by WRF coupled with both the improved lake models.”
I think the authors have presented enough convincing evidence to support these conclusions. However, I think the paper is in need of major revisions prior to publication. I provide some general comments below and numerous detailed comments in the annotated PDF that is attached.
General Comments:
The quality of the writing needs to be improved. I have noted many instances of grammatical errors, poor/awkward wording and unclear/vague wording.
More complete and/or clearer descriptions of some aspects of the methodology are required. For example, a much better description of how the MODIS freeze-up and break-up dates were calculated is needed. Other examples are noted in my detailed comments.Response: We will carefully refine the writing and description of methodology in the revised version.
A clearer explanation of how the one-dimensional lake models are implemented for Lake Nam Co is required.
Response: the lake model is driven by atmospheric forcing including air temperature, pressure, humidity, wind, short wave and long wave radiation, precipitation and reference height (height of first atmospheric layer). The lake models feedback momentum, sensible heat and latent heat fluxes. The above will be added in the revised version.
I was able to determine that the WRF model had 116 grid points over the lake by reviewing their earlier paper. But it is not clear if the lake models were simulating 116 water columns or not.
Response: It is the same, also 116 water columns, this information will be added in the revised version.What is also not clear is why a uniform depth of 40 m was used in the lake models.
No information about the actual lake bathymetry is provided and no justification for the use of 40 m is provided.Response: A uniform depth is a general way for treating lakes in climate models. 40m is based on previous studies with field observation and used in the study of La et al., (2016). It is calculated by the total water storage divide lake area. The total water storage is based on Zhang et al., (2016).This will be added in the revised version.
Actual lake bathymetry has been provided in previous studies. E.g. Huang et al., (2019). We will provide a short description about the lake bathymetry, and cite these references.References
Huang, A.N., Lazhu, Wang, J.B., Dai, Y.J., Yang, K., Wei, N., Wen, L.J., Wu, Y., Zhu, X.Y., Zhang, X.D. and Cai, S.X. 2019. Evaluating and Improving the Performance of Three 1-D Lake Models in a Large Deep Lake of the Central Tibetan Plateau. J Geophys Res-Atmos 124(6), 3143-3167.
La, Z., Yang, K., Wang, J.B., Lei, Y.B., Chen, Y.Y., Zhu, L.P., Ding, B.H. and Qin, J. 2016. Quantifying evaporation and its decadal change for Lake Nam Co, central Tibetan Plateau. J Geophys Res-Atmos 121(13), 7578-7591.
Zhang, B., Wu, Y., Zhu, L., Wang, J., Li, J. and Chen, D. 2011. Estimation and trend detection of water storage at Nam Co Lake, central Tibetan Plateau. J Hydrol 405(1), 161-170.The authors stated that “…a setup with identical depth for all grids can, to some extent, reflects the horizontal energy mixing associated with lake water circulation”. I am quite puzzled by this statement and by others where claims about better simulation of lake energy circulation in the lake are made.
Response: Currently, we did not find some work to exactly support such a statement. Thus, after a discussion with the coauthors, we think that better to delete it, to avoid misleading the readers.
The authors also need to provide some better arguments regarding the significance of their findings. They write the following in the summary section:
“Therefore, the main results and findings of this work can provide a good reference for climate model applications and the improved model also has practical application prospects over the alpine lake covered regions.”
This is a vague and unclear statement. Some more detailed and specific statements regarding the significance and novelty of this study are required.Response: we were supposed that this statement is supported by the previous part of the paragraph. To be more specific, it will be changed to ‘Therefore, we expected that the main results and findings of this work can provide a good reference when simulating lake ice phenology by climate models, especially for the alpine lake.’ in the revised version.
Citation: https://doi.org/10.5194/egusphere-2023-2455-AC1
-
AC1: 'Reply on RC1', xu zhou, 23 May 2024
-
RC2: 'Comment on egusphere-2023-2455', Laura Rontu, 14 Apr 2024
Simulating lake ice phenology using a coupled atmosphere-lake
model at Lake Nam Co, a typical deep alpine lake on the Tibetan
Plateau
Xu Zhou, Binbin Wang, Xiaogang Ma, Zhu La, and Kun YangThis is an interesting study about ice evolution on a large Tibetan Plateau lake Nam Co, that is located in high alpine conditions at 4500 m above the sea level. The article will be interesting for NWP model and lake parametrization developers.
Weather Research and Forecast model WRF coupled to three different settings of lake models was used. The results were compared with in-situ lake water temperature and MODIS satellite observations. The results and discussions largely agree with those of similar studies over Northern European and Canadian lakes. Unfortunately, the authors seem to be unaware about them, at least those studies are not mentioned in the large list of references.
I would suggest a (minor) revision to improve the presentation of the models and results. It would be good for the authors to carefully check the language and concepts used in manuscript - there are inaccuracies, sometimes misleading formulations, inconsistencies. As a non-native speaker of English I have only randomly pointed out some instances where it was not evident what the authors mean with their sentences.
Some detailed comments can be found in the annotated pdf of the manuscript.
-
AC2: 'Reply on RC2', xu zhou, 23 May 2024
Dear Laura Rontu,
We thank you for taking time to review our work. Following is a list to list reply. Our reply is in italic font after each list of your comments.
This is an interesting study about ice evolution on a large Tibetan Plateau lake Nam Co, that is located in high alpine conditions at 4500 m above the sea level. The article will be interesting for NWP model and lake parametrization developers.
Weather Research and Forecast model WRF coupled to three different settings of lake models was used. The results were compared with in-situ lake water temperature and MODIS satellite observations. The results and discussions largely agree with those of similar studies over Northern European and Canadian lakes. Unfortunately, the authors seem to be unaware about them, at least those studies are not mentioned in the large list of references.Response: Indeed, we search only the papers focusing the alpine lake at the preparing stage. We will refer to the work over Northern European and Canadian lakes, in the revised version.
I would suggest a (minor) revision to improve the presentation of the models and results. It would be good for the authors to carefully check the language and concepts used in manuscript - there are inaccuracies, sometimes misleading formulations, inconsistencies. As a non-native speaker of English I have only randomly pointed out some instances where it was not evident what the authors mean with their sentences.
Some detailed comments can be found in the annotated pdf of the manuscript.Response: Thank you very much for the thorough comments, these details will be addressed in the revised version. Additionally, we will specifically refine the writing, and looking for a professional scientific editing service before submitting the revised version.
Citation: https://doi.org/10.5194/egusphere-2023-2455-AC2
-
AC2: 'Reply on RC2', xu zhou, 23 May 2024
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Binbin Wang
Xiaogang Ma
Zhu La
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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