the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 10 May 2022
Measurement report: Structure of the atmospheric boundary layer and its relationship with the land-atmosphere interaction on the Tibetan Plateau
Maoshan Li
Wei Fu
Na Chang
Ming Gong
Pei Xu
Yaoming Ma
Zeyong Hu
Yaoxian Yang
Fanglin Sun
Abstract. There is a deep atmospheric boundary layer on the Tibetan Plateau (TP) that has always been of interest to researchers. The variation in the atmospheric boundary layer under the influence of the southern branch of the westerly wind and that of the Asian monsoon was analyzed using sounding data collected in 2014 and 2019. Then, the hourly high-resolution comprehensive observation data for the land-atmosphere interaction on the TP and the ERA5 reanalysis data were used to study the influence of the atmospheric boundary layer’s structure in Mount Everest, Nyingchi, Nam Co, Nagqu, and Shiquan River regions. The results show that the height of the convective boundary layer observed at the Mount Everest, Nyingchi, Nam Co, Nagqu, and Shiquan River stations on the TP under the influence of the southern branch of the westerly wind was higher than that during the Asian monsoon season. The height of the convective boundary layer in the Shiquan River area was often highest at 20:00. The structure of the boundary layer in the Mount Everest area was often affected by the westerly jets and glacial winds. The inversion layer developed earlier in the Nyingchi area than at the other stations. The height of the boundary layer was positively correlated with the sensible heat flux and negatively correlated with the latent heat flux. The vertical velocity in the atmospheric boundary layer in the Nyingchi area decreased, which may be one of the reasons why the height of the convective boundary layer was lower in this area than at the other stations and humidity inversion often occurred in this area.
Maoshan Li et al.
Status: closed
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RC1: 'Comment on acp-2022-257', Anonymous Referee #1, 01 Jun 2022
This study used the sounding, surface heat flux and reanalysis data to characterize the PBL structures of 5 stations in Tibetan Plateau (TP) under different wind flow conditions (south branch of westerly wind VS summer monsoon).
The major weakness of this study is a lack of physical explanation of the PBL structures from the data analysis. The sounding data analysis presents only a few days to characterize the PBL structure under the influence of monsoon flow, plateau flow, and westerly flow. The results from the limited data analysis are not sufficient. A seasonal and long-term data analysis is required to enhance the validity of this study.
- P3, line 82-84, It is found that the thermal structure of the â¨Plateau Atmospheric boundary layer is abnormal, the development of the convective boundary â¨layer is deep, and the dynamic mechanism of Ekman "suction pump" in the plateau boundary layer. â¨What do you mean “abnormal”? Please explain “suction pump”.
- P3, line 85, why there are extreme values?
- P4, “strengthening period”, unclear description.
- Line 94, why PBL height is high in west and low in east?
- What is the similarities and dissimilarities of this study comparing with the previous studies? What is the importance and unique results from this study?
- Line 142, is PBL height determined by subjective personal inspection?
- Line 157, this study only utilized limited observation data in 2014 and 2019.
- This study only utilized limited sounding observations to characterize the PBL structures. I suggest you expanding the analysis by including the regular sounding observations (twice a day 00 and 12 UTC) for longer period (3 to 5 years) to enhance the representativeness of the results.
- Discussions in session 3 and 4 are very descriptive and lacking in any in-depth interpretation. It’s very difficult to understand the whole discussions. The physics responsible for characterizing the structures are not discussed.
- Line 168, why the low-level interval of radiosonde data is large?
- Line 194-196, how the westerly jet affect inversion stratification?
- Line 199, what is super-insulation layer?
- Line 214, “Stable Boundary Layer” height reaches 1500 m? Isn’t 1500 m too high for a SBL?
- Line 243, why convective BL height reached highest point at hour 20:00?
- Line 284, how did you tell there is formation of valley wind?
- Line 305, how the glacial wind is formed? How to tell there is formation of glacial wind?
- Line 311-314, unclear description.
- Line 346-349, there is apparent bias between observation data and ERA5 data.
- Line 331, “under coordinated action of the westerly wind and monsoon”, unclear description.
- The structure of the presentation needs to be better organized.
- The writing needs to be improved.
- Please remove the general descriptions in the manuscript to enhance the understanding of the importance from this study.
- Sessions 3 and 4 and conclusions of the current form are lengthy and tedious descriptions and must be rewritten to enhance the interest of the reader.
- Some conclusions based on limited data analysis (a single sounding observation) is a major defect and is of little interest to the broader scientific community.
Citation: https://doi.org/10.5194/acp-2022-257-RC1 -
AC1: 'Reply on RC1', Li Maoshan, 02 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-257/acp-2022-257-AC1-supplement.pdf
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AC3: 'Reply on RC1', Li Maoshan, 02 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-257/acp-2022-257-AC3-supplement.pdf
-
RC2: 'Comment on acp-2022-257', Anonymous Referee #2, 12 Jun 2022
The authors studied the boundary layer structure in the Tibetan Plateau on the basis of sounding measurements in 2014 and 2019. However, there is nothing new in this manuscript, and only a few sounding profiles were presented. Most literature cited was published twenty years ago, the authors failed to clarify the motivation for the work presented. The authors tried to understand the different influence of the southern branch of the westerly wind and Asian monsoon, while the large-scale synoptic conditions were not presented and analyzed. Also, the authors mentioned the local terrain wind systems (e.g., westerly jet, glacial wind) in the Result section, while no observational evidences were presented.
Citation: https://doi.org/10.5194/acp-2022-257-RC2 -
AC2: 'Reply on RC2', Li Maoshan, 02 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-257/acp-2022-257-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Li Maoshan, 02 Aug 2022
Status: closed
-
RC1: 'Comment on acp-2022-257', Anonymous Referee #1, 01 Jun 2022
This study used the sounding, surface heat flux and reanalysis data to characterize the PBL structures of 5 stations in Tibetan Plateau (TP) under different wind flow conditions (south branch of westerly wind VS summer monsoon).
The major weakness of this study is a lack of physical explanation of the PBL structures from the data analysis. The sounding data analysis presents only a few days to characterize the PBL structure under the influence of monsoon flow, plateau flow, and westerly flow. The results from the limited data analysis are not sufficient. A seasonal and long-term data analysis is required to enhance the validity of this study.
- P3, line 82-84, It is found that the thermal structure of the â¨Plateau Atmospheric boundary layer is abnormal, the development of the convective boundary â¨layer is deep, and the dynamic mechanism of Ekman "suction pump" in the plateau boundary layer. â¨What do you mean “abnormal”? Please explain “suction pump”.
- P3, line 85, why there are extreme values?
- P4, “strengthening period”, unclear description.
- Line 94, why PBL height is high in west and low in east?
- What is the similarities and dissimilarities of this study comparing with the previous studies? What is the importance and unique results from this study?
- Line 142, is PBL height determined by subjective personal inspection?
- Line 157, this study only utilized limited observation data in 2014 and 2019.
- This study only utilized limited sounding observations to characterize the PBL structures. I suggest you expanding the analysis by including the regular sounding observations (twice a day 00 and 12 UTC) for longer period (3 to 5 years) to enhance the representativeness of the results.
- Discussions in session 3 and 4 are very descriptive and lacking in any in-depth interpretation. It’s very difficult to understand the whole discussions. The physics responsible for characterizing the structures are not discussed.
- Line 168, why the low-level interval of radiosonde data is large?
- Line 194-196, how the westerly jet affect inversion stratification?
- Line 199, what is super-insulation layer?
- Line 214, “Stable Boundary Layer” height reaches 1500 m? Isn’t 1500 m too high for a SBL?
- Line 243, why convective BL height reached highest point at hour 20:00?
- Line 284, how did you tell there is formation of valley wind?
- Line 305, how the glacial wind is formed? How to tell there is formation of glacial wind?
- Line 311-314, unclear description.
- Line 346-349, there is apparent bias between observation data and ERA5 data.
- Line 331, “under coordinated action of the westerly wind and monsoon”, unclear description.
- The structure of the presentation needs to be better organized.
- The writing needs to be improved.
- Please remove the general descriptions in the manuscript to enhance the understanding of the importance from this study.
- Sessions 3 and 4 and conclusions of the current form are lengthy and tedious descriptions and must be rewritten to enhance the interest of the reader.
- Some conclusions based on limited data analysis (a single sounding observation) is a major defect and is of little interest to the broader scientific community.
Citation: https://doi.org/10.5194/acp-2022-257-RC1 -
AC1: 'Reply on RC1', Li Maoshan, 02 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-257/acp-2022-257-AC1-supplement.pdf
-
AC3: 'Reply on RC1', Li Maoshan, 02 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-257/acp-2022-257-AC3-supplement.pdf
-
RC2: 'Comment on acp-2022-257', Anonymous Referee #2, 12 Jun 2022
The authors studied the boundary layer structure in the Tibetan Plateau on the basis of sounding measurements in 2014 and 2019. However, there is nothing new in this manuscript, and only a few sounding profiles were presented. Most literature cited was published twenty years ago, the authors failed to clarify the motivation for the work presented. The authors tried to understand the different influence of the southern branch of the westerly wind and Asian monsoon, while the large-scale synoptic conditions were not presented and analyzed. Also, the authors mentioned the local terrain wind systems (e.g., westerly jet, glacial wind) in the Result section, while no observational evidences were presented.
Citation: https://doi.org/10.5194/acp-2022-257-RC2 -
AC2: 'Reply on RC2', Li Maoshan, 02 Aug 2022
The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-257/acp-2022-257-AC2-supplement.pdf
-
AC2: 'Reply on RC2', Li Maoshan, 02 Aug 2022
Maoshan Li et al.
Data sets
Radiosonde observation data of stations on the Tibetan Plateau in 2014 Li, M. https://data.tpdc.ac.cn/zh-hans/data/70edaec5-8418-44cd-afc4-fb089f7bf413/
A long-term dataset of integrated land-atmosphere interaction observations on the Tibetan Plateau (2005-2016) Ma, Y. https://doi.org/10.11888/Meteoro.tpdc.270910
Maoshan Li et al.
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