General Comments:

This study presents comprehensive analyses of water vapor, temperature and cloud measurements made during the StratoClim field campaign, which was completed in the summer of 2017. The main goal of the study is to understand the complicated role of convection in the water vapor budget over the Asian summer monsoon region in the upper troposphere and lower stratosphere. The authors seemed to have performed such a thorough analyses of all the available in-situ, satellites measurements and a trajectory model to shed bright light on this subject. It is fascinating to learn that overshooting convection indeed play two roles, both hydrating and dehydrating. I have three general, rather minor comments that I would like to make. First, even though the focus of this study is the Asian summer monsoon, it is important to remind us that the North American monsoon also plays role in the lower stratospheric water vapor budget. There are some parts of the text that needs to be clarified (see the first specific comment below). Second, I would like to see some statements about uncertainties in the trajectory model results. Can we trust 100% of the result? How sensitive is the result to the input variables or dynamical fields? Third, the figures in the manuscript and the supplement material are outstanding and yet complex. Some figures are probably too complex. I had hard time understanding Figure 1, in particular, as it contains so many variables and colors. It would be helpful to revisit the figures and improve if there is time.

Specific Comments:

This study focuses only on the Asian summer monsoon. There also exists the North American summer monsoon, which is one of the wettest regions and one of the primary contributors to the water vapor maximum in the lower stratosphere. I think it is fair to treat the Asian summer monsoon as one of the contributors instead of the only contributor. I have listed a couple of examples as a way of accomplishing this without making significant changes below.

Examples

P1, L21 – ‘the wettest region’ can be replaced by ‘one of the wettest regions’

P1, L30 – ‘water vapour enhancements’ can be replaced by ‘water vapour measurements during the campaign’

P2, L40 – ‘the primary contributor’ could be replace by ‘one of the primary contributors’

P2, L57-60 – It would be helpful to add a sentence summarizing the findings, e.g., is the degree of convective impact different? Or do the source regions differ in different studies?

P3, L82 – ‘in the other flights’ could be replaced by ‘the rest of the flights’

P3, L86-87 –Do Stroh et al. (2021) include the description of the instruments as well?

P3, L91 – ‘and then substantially’ could be replaced by ‘and substantially’.

P3, L107 – Does ‘under UTLS conditions’ mean low temperature and low humidity?

P4, L126 – Here, ‘They’ refers to Singer et al. (2021)?

P4, L136-137 – Here, ‘distribution’ could be replaced by ‘distributions’ on both sentences.

P5, L153 – The meaning of ‘evenly distributed’ is unclear. Also, there is a newer version of MLS H₂O (v5), which became available more than a year ago. It is also known that MLS H₂O (v4.2) has drift issues in the stratosphere.

P5, section 2.3 – I think this section provides useful information. It would be helpful to add a sentence explaining the purpose of this section here.

P5, L178 – It is unclear why the thermal approach to TTL definition is only suitable for this study. Is this related to the fact that water vapor is sensitive to vertical structure of temperature?

P5, L185-186 – It would be useful to include references for the hydration vs. dehydration processes in the TTL.

P6, L197 – Are there any references for HIMAWARI-8 could be cited here?

P6, L207 – Would ‘a specific version of product based on the version 2018.1’ be the same as ‘version 2018.1’?

P6, L211 – Is ‘100 hPa’ an arbitrary threshold or based on a statistical analysis?

P6, L219 – How is the 2017 Asian monsoon season characterized as a stable anticyclone? Compared to 10-year climatology or compared to previous three years? Some statistics might be helpful here.

Comments for Fig. 1

Fig. 1a - It is not easy to tell from Fig. 1a. In Fig. 1a, the water vapor contours can be smoothed (1-2-1 smoothing) or one can use bigger grid boxes to show smooth contours. Also, what do black colors mean in Fig. 1a? I think the wind vectors can be improved here as well (likewise in Fig. 5). For instance, one can put wind vectors every 2.5 degree latitude instead of 5.

Fig. 1b – I think the AMA boundary looks rather too broad here. Adding more contours or choose a smaller threshold of Montgomery stream function might work better.

P7, L241 – Is Brunamonti et al. (2018) also based on summer of 2017?

P7, L247 – I would recommend using a quantitative adjective than ‘striking’ here, e.g., ‘large’ variability.

P7, L261 – Do ‘those’ refer to the high RHi values?

P7, L263 – It would be helpful to add an explanation about ‘Lagrangian temperature history’ here.

P7, L274- Is ‘14%’ higher or lower than any statistics or expectations?

Comments for Fig. 4

It would be useful to add approximate altitude for Figs. 4a and 4b. Also, in Fig. 4b, high delta D exists as high as 420K potential temperature surface.

P9, Section 4.2 – I am wondering is there a way to quantify the uncertainty in the derived convective age. Is it sensitive to the type of cloud top data and also meteorological fields?

P10, L340 – Does ‘mixing ratio enhancement’ mean the actual water vapor mixing ratios or only the increased amount of water vapor?

P10, L350 – Fig. 6a,b could be replaced by Figs. 6a and 6b

P10, L350 – Does ‘at this level’ mean local CPT?

P10, L359 – Here, ‘such an amount’ could be replaced by ‘such high amount’. I am also wondering what is the mechanism that enables the convective plume preserve high water vapor for 5 days.

P11, L373 – ‘intersecting a large convective system’ – It looks like the trajectories lie between the large convective system and the group of small cells to the west.

Comments for Fig. 7c

I assume temperature means potential temperature in Fig. 7c. Also, it is hard to locate 140 or 160% RHi in this figure as explained in the text.

P11, L389 – Does ‘across’ mean from below to above the CPT?

P11, L393 – It would be helpful to give the time marks for the presence of subvisible cirrus clouds in Fig. 8a.

Comments for Fig. 9a

Fonts for T1-B7 could be bigger.

P12, L435 – Instead of ‘around the CPT’, near or close to might be more accurate.

P13, L448 – Does ‘there is typically no more than one case’ apply to all the cases referred above?

P13, L454 – In this sentence, the meanings of ‘over these regions’ and ‘in the summer monsoon anticyclones’ are not clear. Are those referring to the North American monsoons?

P13, L467 – ‘around the tropopause’ could be replaced by ‘near the tropopause’.

P14, L483 – This sentence could be split into two -> introduction. However,…

P14, L505 – It would be helpful to add a sentence about what the authors think the future direction or need is in terms of field studies related to StratoClim.

General comments:

This is a very good paper that should be published.

The authors present the results of StratoClim 2017 flight campaigns over South Asia, satellite dataset analysis, and Lagrangian calculations to investigate the processes by which convection affects water vapour concentrations in the upper levels of the Asian Monsoon anticyclone.

The paper first identifies that the flights took place in two regimes consistent with earlier publications, which differ by the thermodynamic role of convection on local temperatures and hence water vapour concentrations.

The paper then studies the history of anomalously wet air parcels that were observed above the cold-point tropopause, which are shown to have originated from convective injection.

The results provide two contrasting examples of in situ cloud processes on convectively injected water vapour.

I have enjoyed reading this paper, I am very impressed with the narrative that navigates a number of complicated processes with very concise figures.

In my opinion some aspects could be clarified, detailed in specific comments below.

There are also some technical corrections below which are mainly typos/clarifications.

Specific comments:

L291 Please provide a reference in support of this statement.

L303 What number of convective clouds are identified in each case? It is too hard for the reader to integrate by eye the proportion of convective hits over the wet parcels for each flight. e.g. From Fig S3, F1, F5 and F6 appear to have very few wet parcels exceeding 1 standard deviation. I am surprised they appear to have identified as many convective cloud intercepts as other flights. Also, I presume F8 isn't shown in Fig 5 for this reason (no wet parcels along the flight track) but it should be explained somewhere.

L310and L317 Reading is made harder by occasional forward references in the early results sections, particularly L310 and L317. Please reconsider the use of forward references. I would suggest mentioning the convention of labelling hydration events when you point to Supplementary Fig. S4 near L306, rather than referencing forward, since that is where the reader is currently expected to look if they want to see individual moist features.

L330 This sentence is hard to follow. Can the text please specify the flight paths being referred to? Does it mean the paths taken by F1-F7? Or is it referring to F1,F2,and F4 being over Nepal? Perhaps I misunderstand, but F3 seems an obvious exception to the flights F1-4 during the warm/wet period. I am not sure that the argument about intercepts in space can be separated from the impact of time differences.

L343 I found the shift of terminology from 'period' to 'regime' unclear. This is first use of the word regime even though it refers back to section 3 where 'period' is used (and section 3 heading uses 'mode'). Suggest rephrase introduction of the word regime here, or a more consistent terminology introduced in Section 3.

L364 A2 must also be displaced horizontally, which is not shown in Fig 6. How extensive is that? Is it conceivable that such a body of air remained intact after 5 days? You could test this by calculating a series of back trajectories released from vertical and horizontal positions between A2 and B2. Or perhaps more precisely, forward trajectories, allowing for ice settling, from the suspected original convective event for B2. This is a point of interest, I do not expect any revision for this.

L467 It would be of general help to the reader to provide the summary with more backward references to specific results. In particular at L467, a reference to the analysis supporting this conclusion of a drastic drop of water vapour. It might be interpreted that all of Section 1 is relevant, but Fig 1 seems to be the key result for this sentence. It's also important so that a reader does not mix up this convectively-modulated temperature effect from convective lofting processes.

Technical corrections:

L221 typo 'shown'

L335 'at' seems unnecessary. Remove?

L367 The bibliography is missing Kim and Alexander 2015. A quick glance finds Muller and Peter 1992 also missing. Please double-check your bibliography is complete.

Fig1 Figs 1c and 1d are in the reverse order compared to the text in the caption and main body. Correct the text or the figure order.

Fig5 F5 appears to be incorrectly labelled as F4. Please correct.

Fig5 Refers to a hydrated feature C2 but is not mentioned. Please clarify. Is this associated with the ice cloud identified in Fig 6? Or is it meant to be hydrated feature A3 (as the colouring suggests)?

FigS4 The hydrated feature for flight 5 is marked A7. I think it is meant to be A5?