Impacts of the Indian Summer Monsoon on the Southern Boundary Water Vapor Transport and Precipitation over the Tibetan Plateau
Round 1
Reviewer 1 Report
Ref.: Atmosphere 2022-13-x
Title: Impacts of the Indian Summer Monsoon on the southern boundary water vapor transport and precipitation over the Titian Plateau
In this study, the authors investigated the effects of the Indian summer monsoon (ISM) on the characteristics of water vapor transport across the southern boundary of the TP and its impact on the change of the precipitation over the TP using the ERA5 reanalysis data and CMORPH precipitation products. However, this paper is confined to the superficial comparisons between the ISM months of different intensities but the underlying physical mechanisms still remain vague. I document here several underlying issues, which I feel should be further confirmed in this paper.
Major comments
1. In this paper, the Indian summer monsoon Index (IMI) defined by Wang and Fan (1999) is applied to classify the strong and weak ISM months. I wonder whether the results are sensitive to the definition of the IMI. Have the authors compared the results using other indexes? An even more serious issue here is that the index is suitable for the Southeast Asian – western Pacific monsoon, instead of the ISM.
2. In this paper, the precipitation concentration region (PCR) is defined as the area between 30-32.5°N and 85-90°E. The author should explain the reasons for selecting such an area and whether the results are sensitive to the location.
3. The authors should avoid using superfluous pictures. For example, one single figure is enough to illustrate the information on the Fig. 2 and Fig. 3 and the same with the Fig. 7 and Fig. 11, Fig. 12 and Fig. 15.
4. In line 191–193, the authors mentioned that the PCR precipitation exhibited later diurnal peaks compared with the whole TP, however Fig.4 didn’t show the diurnal cycle of the precipitation in the whole TP during normal ISM months. The authors should specify it.
5. The authors illustrate the diurnal cycle of meridional and zonal water vapor flux transported across different boundaries. I wonder how the values are calculated. The authors should specify the methods.
6. In Fig. 5, the stippling denotes the values exceeding the 90% confidence level. I suggest a higher confidence level (e.g. 95%) and the authors should specify the mothed of assessing the statistical significance (e.g. the Student's t test) in Section 2. Moreover, the caption in Fig.5 describing the confidence level is informal and the captions of Fig. 9 and Fig. 14 haven’t explained the meaning of the stippling. The authors should check the captions.
7. In Fig. 7 and Fig. 11, the captions describing the local time are inconsistent with the left strings of the figures. For example, the caption is '(a) LT08, (b)LT09, (c)LT10, (d)LT17, (e)LT18, and (f)LT19' in Fig. 7, however the left strings in figures are (a) LT06, (b)LT07 and so on, which makes the manuscript confusing. The authors should check it carefully.
8. In line 302–303, the authors mentioned that there was a water vapor transport channel in Bond 9 around 29°N, 82°E. I wonder how the specific latitude and longitude are determined. Could the authors give more information?
9. In line 302–306, the authors mentioned that analysis was based on Fig. 15. However, Fig. 15 didn’t show the results from LT14 to LT18. It is really confusing and the authors should check it carefully.
10. In the conclusion (line 365–373), the authors mentioned that the precipitation in PCR was greater in strong ISM months although less water vapor was transported there. The authors give several possible reasons. By contrast, the precipitation in PCR is weaker in weak ISM months while more water vapor is transported there. Could the authors give some possible reasons?
11. The authors mainly attributed the diurnal cycle of the precipitation to the diurnal cycle of the water vapor flux. I understand that this paper mainly focuses on the contribution of thermodynamic process to the precipitation. However, the dynamic process such as the diurnal cycle of the Tibetan Plateau vortex may also contribute to the precipitation. I suggest that the authors consider it at the discussion part. Some key may help the authors to explain the relevant physical mechanisms more clearly. e.g., Gao, Y.; Yao, X. Impact of Dynamic and Thermal Forcing on the Intensity Evolution of the Vortices over the Tibetan Plateau in Boreal Summer. Journal of Tropical Meteorology. 2020, 26(2): 239-252, https://doi.org/10.46267/j.1006-8775.2020.022.
Specific comments
1. P2 Line 61: 'appearing' instead of 'appears'.
2. P2 Line 70: 'dominated' instead of 'dominates'
3. P2 Line 88: 'Possibilities' instead of 'Possible'
4. P3 Line 98: 'the' instead of 'The'
5. P4 Line 135 equation (2): The unit of the IVT is wrong and there should be a minus sign on the right-hand side of the equation. Velocity should be expressed as the vector notation, instead of the scalar notation.
6. P4 Line 148: 'divided' instead of 'dived'
7. P4 Line 149: '3000 m' instead of '3000m'
8. P4 Line 154: 'altitude (m)' instead of 'altitude(m)'
9. P4 Line 156: How to understand the '26.5' in the brackets? It is confusing.
10. P5 Line 172: The authors should mention that the 'LT' refers to the local time to avoid confusion.
11. P6 Line 180: 'shading' instead of 'contour'
12. P6 Line 181: 'kg·m-1·s-1' instead of 'm·s-1'
13. P6 Line 190: 'southeastern TP' instead of 'southeastern of the TP'
14. P6 Line 196: 'Figure 6a' instead of 'Figure 6b'
15. P6 Line 198: The authors should specify that the analysis is based on Fig. 6b.
16. P8 Fig.6: The authors illustrated the meridional and zonal water vapor flux transported across Bond 7 in Fig. 6, however they didn’t analyze them in Section 3.1.
17. P8 Line 225: 'shading' instead of 'contour'
18. P9 Line 247: 'Figure 10a' instead of 'Figure 11a'
19. P12 Line 311: The authors should specify which figure the analysis is based on.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Please see the attached comment.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Water vapor transport plays a significant role in maintaining the water cycle over the TP. This study investigates the characteristics of water vapor transport across TP southern boundaries and its impacts on TP precipitation during the ISM. Although there are many previous studies on water vapor and water vapor transport over the TP, most of them as mentioned above are mainly based on monthly or longer time scales. This study firstly focuses on daily and sub-daily variations of water vapor transported into the TP under the influence of the ISM, which is important for us to understand water vapor transport at a short time scale. I suggest the manuscript should be accepted after minor revision.
Specifical comments:
1. Line 16: why don't you name they as boundary 1, 2, 3, 4? what is your classification basis?
2. Line 51: I want to know how to define the boundary? There is a well-defined geographical boundary of Tibetan Plateau described by National Tibetan Plateau Data Center (http://data.tpdc.ac.cn/zh-hans/data/61701a2b-31e5-41bf-b0a3-607c2a9bd3b3/) or by Zhang et al, 2001 (https://doi.org/10.3974/geodp.2021.04.04. CSTR:20146.14.2021.04.04)
3. Line 61: what is the effect of "intense surface sensible heating"?
4. Line 63: please describe specifically "second kind".
5. Line 64-65: How does surface heating influence vapor transportation? I think Tibetan monsoon is also an important dynamic.
6. Line 97: Why choose ERA5 rather than NCEP/NCAR. Can you explain it?
7. Line 156: It is difficult to identify the number in Figure 1.
8. Line 167: Please define the LT.
9. Line 175: I think it is necessary to mark these boundaries in the Figure 2.
10. Line 191: please mark the location of the Siling Co and Zhari Namco in Figure 3.
Other comments see attached annotated file.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Ref.: Atmosphere 2022-13-x
Title: Impacts of the Indian Summer Monsoon on the southern boundary water vapor transport and precipitation over the Titian Plateau
This paper has been well revised and I recommend acceptance of it for publication in the Atmosphere after the following minor comments are addressed.
Author Response
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Author Response File: Author Response.pdf
