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Peer review report 2 On “Observational Study on Complementary relationship between pan evaporation and actual evapotranspiration and its variation with pan type”
Agricultural and Forest Meteorology 217 (2016) 190–191
Contents lists available at ScienceDirect
Agricultural and Forest Meteorology journal homepage: www.elsevier.com/locate/agrformet
Peer Review Report
Peer review report 2 On “Observational Study on Complementary relationship between pan evaporation and actual evapotranspiration and its variation with pan type”
Original Submission
Minor comments
Recommendation
Line 51, the reference [Cong et al., 2009] and [Yang and Yang, 2012] should be cited. Line 57, [Yang and Yang, 2012] revealed that the main causes for change were deceasing wind speed in most parts of China, and it should be cited.
Major Revision
Comments to Author Based on the observations from a flux tower in the arid region of northwest China, this manuscript evaluated the complementary relationship between actual evapotranspiration and pan evaporations from different pans, and then found out that intensity of the non-uniformity is the main factor affecting the asymmetry of the complementary relationship and the coefficient b has a linear relationship with the pan evaporation intensity index (pan evaporation / reference crop evapotranspiration). It is very interesting, and helps to further understanding the complementary relationship. Also it is well-written. However, I have one major concern. Line 510-531, the authors revealed a linear relationship between b and IE, and presumed that b = 3.476 under the condition IE =1. In fact, the authors defined IE = pan evaporation / reference crop evapotranspiration (The reference crop evapotranspiration is defined as the evapotranspiration from short green grass); hence pan evaporation is also larger than reference crop evapotranspiration when the pan area tends to infinite. Consequently, the statement that “When evaporation surface area continues to expand and IE falls to 1, the water surface evaporation and the potential evaporation will be equal (such as lake, or large-scale water surface) (line 517-519)” is incorrect. To avoid the theoretical predicament, I therefore suggest that the pan evaporation intensity index should be defined as pan evaporation / potential evaporation (free water evaporation, estimated by Penmen equation). In that case, the condition IE = 1 means the pan with infinite area, “such as lake or large-scale water surface”; and b maybe tend to 1. Therefore, I recommend major revision, and I think that it can become an excellent paper.
DOI of published article: http://dx.doi.org/10.1016/j.agrformet.2016.03.002. http://dx.doi.org/10.1016/j.agrformet.2016.11.022 0168-1923/
References Cong, Z. T., D. W. Yang, and G. H. Ni (2009), Does evaporation paradox exist in China? HYDROL EARTH SYST SC, 13(3), 357-366. Yang, H. B., and D. W. Yang (2012), Climatic factors influencing changing pan evaporation across China from 1961 to 2001, J HYDROL, 414, 184-193. Revision 1 Recommendation Minor revision Comments to Author This manuscript (MS) is much improved; well done to the authors, and also thanks for a comprehensive response letter. Your MS is now realising its potential to make a very solid contribution to the international understanding of how rates of pan evaporation (Epan - as an observation atmospheric evaporative demand (AED)) can be used to understand how these changes will impact the rate of actual evapotranspiration (ETa) via the complementary theory. The MS reports a well conducted experiment that will be of interest to many readers of Agricultural and Forest Meteorology (AgForMet). I would like to see the following issues resolved/considered thus allowing me to recommend acceptance to AgForMet; I hope that the authors rise to the challenge. Ultimately this has the potential to be a very good and very influential AgForMet paper. 1) Main concern: my opinion, as expressed last time in my comment #7, is that the MS would be much (I mean MUCH) improved if the Results section and the Discussion section were separated. To me, combining these sections means the relevance back to the topics raised in the Introduction section is not as optimal as it could
Peer Review Report / Agricultural and Forest Meteorology 217 (2016) 190–191
be. The wider implications of your results do not shine as much as they could by having a separate Discussion section. 2) L15, do you mean “collected globally”? This is not clear and needs to be improved. This is the first sentence of your abstract and you have one chance to make a good first impression. Or are you wanting to talk about studies that seek to relate Epan trends / processes with ETa trends / processes? 3) L16, this and numerous other small annotated comments (small in isolation, yet collectively they will make a large difference to your MS) are provided, you should go thru these carefully to improve your MS. 4) L50, I think you also wish to refer to McVicar et al (2012) Ecohydrology paper here, it is Figure 1 of this paper that you wish to refer readers to. 5) L61, I think you mean relative humidity, as opposed to specific humidity or absolute humidity, and you should always explicitly mention which humidity so a reader does not have to guess. 6) L66, you may wish to know about the following that is soon be published. ˜ Zhang, Y.Q., Pena-Arancibia, J.L., McVicar, T.R., Chiew, F.H.S, Vaze, J., Liu, C.M., Lu, X.J., Zheng, H.X., Wang, Y.P., Liu, Y.Y., Miralles, D.G. and Pan, M. (2015). Multi-decadal trends in terrestrial evapotranspiration and its components. Nature Scientific Reports. 5, 19124, doi:10.1038/srep19124 7) Key concern: L195, a short objective-based literature review table would really help here. That is review other papers, and your contribution, relative the objectives of your paper. Doing this should make it more apparent to readers (and reviewers) what the new contribution of your MS is. If you feel the newness is not being highlighted enough this may suggest that your objective is too ‘chunky’ and that you may need more granularity by providing 2-3 objectives so you can better highlight what your new contribution is to the international scientific effort. This table can also be used in the Discussion section, to place your findings back into the
191
broader context and to effectively and efficiently allow you to give back to the wider scientific community. For example of objective-specific tabular literature reviews, please see Table 1 of the following papers. Jarihani, A.A., et al (2015) Where does all the water go? Partitioning water transmission losses in a data-sparse, multichannel and low-gradient dryland river system using modelling and remote sensing. Journal of Hydrology. 529(3), 1511-1529, doi:10.1016/j.jhydrol.2015.08.030 Jarihani, A.A., et al (2015) Satellite-derived digital elevation model (DEM) selection, preparation and correction for hydrodynamic modelling in large, low gradient and datasparse catchments. Journal of Hydrology. 524, 489-506, doi:10.1016/j.jhydrol.2015.02.049 8) L230, what happened to the site albedo? 9) Good luck making your revisions, the resultant manuscript should be suitable for me to recommend publication in AgForMet, and there are elements of your manuscript that I would already like to cite - this is a good sign; well done. Revision 2 Recommendation Accept Comments to Author No comments. Hanbo Yang (Ph.D.) Tsinghua University, Qinghuayuan 1, Beijing 100084, China Available online 30 November 2016
Contents lists available at ScienceDirect
Agricultural and Forest Meteorology journal homepage: www.elsevier.com/locate/agrformet
Peer Review Report
Peer review report 2 On “Observational Study on Complementary relationship between pan evaporation and actual evapotranspiration and its variation with pan type”
Original Submission
Minor comments
Recommendation
Line 51, the reference [Cong et al., 2009] and [Yang and Yang, 2012] should be cited. Line 57, [Yang and Yang, 2012] revealed that the main causes for change were deceasing wind speed in most parts of China, and it should be cited.
Major Revision
Comments to Author Based on the observations from a flux tower in the arid region of northwest China, this manuscript evaluated the complementary relationship between actual evapotranspiration and pan evaporations from different pans, and then found out that intensity of the non-uniformity is the main factor affecting the asymmetry of the complementary relationship and the coefficient b has a linear relationship with the pan evaporation intensity index (pan evaporation / reference crop evapotranspiration). It is very interesting, and helps to further understanding the complementary relationship. Also it is well-written. However, I have one major concern. Line 510-531, the authors revealed a linear relationship between b and IE, and presumed that b = 3.476 under the condition IE =1. In fact, the authors defined IE = pan evaporation / reference crop evapotranspiration (The reference crop evapotranspiration is defined as the evapotranspiration from short green grass); hence pan evaporation is also larger than reference crop evapotranspiration when the pan area tends to infinite. Consequently, the statement that “When evaporation surface area continues to expand and IE falls to 1, the water surface evaporation and the potential evaporation will be equal (such as lake, or large-scale water surface) (line 517-519)” is incorrect. To avoid the theoretical predicament, I therefore suggest that the pan evaporation intensity index should be defined as pan evaporation / potential evaporation (free water evaporation, estimated by Penmen equation). In that case, the condition IE = 1 means the pan with infinite area, “such as lake or large-scale water surface”; and b maybe tend to 1. Therefore, I recommend major revision, and I think that it can become an excellent paper.
DOI of published article: http://dx.doi.org/10.1016/j.agrformet.2016.03.002. http://dx.doi.org/10.1016/j.agrformet.2016.11.022 0168-1923/
References Cong, Z. T., D. W. Yang, and G. H. Ni (2009), Does evaporation paradox exist in China? HYDROL EARTH SYST SC, 13(3), 357-366. Yang, H. B., and D. W. Yang (2012), Climatic factors influencing changing pan evaporation across China from 1961 to 2001, J HYDROL, 414, 184-193. Revision 1 Recommendation Minor revision Comments to Author This manuscript (MS) is much improved; well done to the authors, and also thanks for a comprehensive response letter. Your MS is now realising its potential to make a very solid contribution to the international understanding of how rates of pan evaporation (Epan - as an observation atmospheric evaporative demand (AED)) can be used to understand how these changes will impact the rate of actual evapotranspiration (ETa) via the complementary theory. The MS reports a well conducted experiment that will be of interest to many readers of Agricultural and Forest Meteorology (AgForMet). I would like to see the following issues resolved/considered thus allowing me to recommend acceptance to AgForMet; I hope that the authors rise to the challenge. Ultimately this has the potential to be a very good and very influential AgForMet paper. 1) Main concern: my opinion, as expressed last time in my comment #7, is that the MS would be much (I mean MUCH) improved if the Results section and the Discussion section were separated. To me, combining these sections means the relevance back to the topics raised in the Introduction section is not as optimal as it could
Peer Review Report / Agricultural and Forest Meteorology 217 (2016) 190–191
be. The wider implications of your results do not shine as much as they could by having a separate Discussion section. 2) L15, do you mean “collected globally”? This is not clear and needs to be improved. This is the first sentence of your abstract and you have one chance to make a good first impression. Or are you wanting to talk about studies that seek to relate Epan trends / processes with ETa trends / processes? 3) L16, this and numerous other small annotated comments (small in isolation, yet collectively they will make a large difference to your MS) are provided, you should go thru these carefully to improve your MS. 4) L50, I think you also wish to refer to McVicar et al (2012) Ecohydrology paper here, it is Figure 1 of this paper that you wish to refer readers to. 5) L61, I think you mean relative humidity, as opposed to specific humidity or absolute humidity, and you should always explicitly mention which humidity so a reader does not have to guess. 6) L66, you may wish to know about the following that is soon be published. ˜ Zhang, Y.Q., Pena-Arancibia, J.L., McVicar, T.R., Chiew, F.H.S, Vaze, J., Liu, C.M., Lu, X.J., Zheng, H.X., Wang, Y.P., Liu, Y.Y., Miralles, D.G. and Pan, M. (2015). Multi-decadal trends in terrestrial evapotranspiration and its components. Nature Scientific Reports. 5, 19124, doi:10.1038/srep19124 7) Key concern: L195, a short objective-based literature review table would really help here. That is review other papers, and your contribution, relative the objectives of your paper. Doing this should make it more apparent to readers (and reviewers) what the new contribution of your MS is. If you feel the newness is not being highlighted enough this may suggest that your objective is too ‘chunky’ and that you may need more granularity by providing 2-3 objectives so you can better highlight what your new contribution is to the international scientific effort. This table can also be used in the Discussion section, to place your findings back into the
191
broader context and to effectively and efficiently allow you to give back to the wider scientific community. For example of objective-specific tabular literature reviews, please see Table 1 of the following papers. Jarihani, A.A., et al (2015) Where does all the water go? Partitioning water transmission losses in a data-sparse, multichannel and low-gradient dryland river system using modelling and remote sensing. Journal of Hydrology. 529(3), 1511-1529, doi:10.1016/j.jhydrol.2015.08.030 Jarihani, A.A., et al (2015) Satellite-derived digital elevation model (DEM) selection, preparation and correction for hydrodynamic modelling in large, low gradient and datasparse catchments. Journal of Hydrology. 524, 489-506, doi:10.1016/j.jhydrol.2015.02.049 8) L230, what happened to the site albedo? 9) Good luck making your revisions, the resultant manuscript should be suitable for me to recommend publication in AgForMet, and there are elements of your manuscript that I would already like to cite - this is a good sign; well done. Revision 2 Recommendation Accept Comments to Author No comments. Hanbo Yang (Ph.D.) Tsinghua University, Qinghuayuan 1, Beijing 100084, China Available online 30 November 2016