Spatial-scale dependence of aerosol indirect effects over land in eastern China: a comparative analysis

Liu, Yuqin; Lin, Tao; Zhang, Jiahua; Wang, Fu; Lin, Meixia; Chen, Yuan; Huang, Yiyi; Geng, Hongkai; Cao, Xin; de Leeuw, Gerrit

doi:10.5194/acp-26-6351-2026

Articles | Volume 26, issue 9

https://doi.org/10.5194/acp-26-6351-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-26-6351-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 9

Research article

|

12 May 2026

Research article |

| 12 May 2026

Spatial-scale dependence of aerosol indirect effects over land in eastern China: a comparative analysis

Yuqin Liu, Tao Lin, Jiahua Zhang, Fu Wang, Meixia Lin, Yuan Chen, Yiyi Huang, Hongkai Geng, Xin Cao, and Gerrit de Leeuw

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Final revised paper (published on 12 May 2026)
Preprint (discussion started on 10 Oct 2025)

Interactive discussion

Status: closed

RC1:
'Comment on egusphere-2025-3157', Anonymous Referee #2, 02 Nov 2025

The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3157/egusphere-2025-3157-RC1-supplement.pdf

Citation: https://doi.org/10.5194/egusphere-2025-3157-RC1
- AC1: 'Reply on RC1', Yuqin Liu, 03 Feb 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3157/egusphere-2025-3157-AC1-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-3157-AC1
RC2:
'Comment on egusphere-2025-3157', yong zha, 17 Nov 2025

General comments
Using aerosol and cloud parameter data derived from MODIS and CALIPSO satellite observations over the land areas of eastern China, this study systematically investigated the regulatory role of liquid water path (LWP) in cloud droplet effective radius (CER), and the interaction between aerosol optical depth (AOD) and cloud properties during Period 1 (2008–2014) and Period 2 (2015–2022). This manuscript is well planned and written, and I think that the analysis of data is well conducted. However, in my opinion, the current version of the manuscript has some problems which need to be addressed before the work can be considered suitable for publication.

Comments (1): Discussion: This study explores the responses of two cloud parameters (CER and Nd) to AOD and the sensitivity of these responses to scales, but lacks an in-depth analysis of the differences and correlations between the two parameters' responses to AOD. It would be helpful if the authors make comparisons between them.
Comments (2): Discussion: This study conducts a comparative analysis using two periods with different atmospheric pollution concentrations. Although AOD exerts a significant impact on cloud parameters, the role of meteorological conditions cannot be overlooked. Therefore, when comparing the differences in cloud parameters' responses to aerosols between different periods, explanations of meteorological conditions should be incorporated.
Comments (3): Abstract: It would greatly enhance the abstract (as well as the conclusion section) if the authors could emphasize the overall significance and potential implications of this study at the abstract’s conclusion.
Comments (4): It would be beneficial to include a figure or table illustrating the availability of satellite retrievals across the analyzed domain. Additionally, the sample size should be reported for all figures presented in the study.

Comments (5): There are a number of statements that I could not understand. I cannot list them all here, but I will list some under Specific Comments. I think editing for English grammar and style would help with readability a great deal.

Specific comments
Comments: (1) Page 1, Line 31: change “significantly…weaker of aerosol” to “significant...weaker aerosol…”

Comments: (2) Page 5, Line 144: Please replace them with more recent literature citations.

Comments: (3) Page 6, Line 149: change “30–40 N and 112–122 E” to “30°–40°N and 112°–122°E”

Comments: (4) Page 6, Line 154: change “LT” to “Local time”

Comments: (5) Page 6, Line 159-160: The selection of AOD values greater than 1.5 requires literature support.

Comments: (6) Page 6, Line 161: CDR appears in multiple places throughout the manuscript and should be corrected.

Comments: (7) The clarity of Figure 7 in the manuscript needs to be improved.

Comments: (8): Explanations should be provided for the abnormal values of S_CER and S_Nd (which do not conform to general conditions) under the larger buffer zones in the figures.

Comments: (9): The usage of “period” and “P” when referring to the two different periods in the manuscript should be consistent.

Comments: (10) Page 11, Line 268: delete ‘.’

Comments: (11) Lines 288, 294, and many others: Present tense is used where past tense should be (are vs. were, is vs. was). When describing what was done and what was found, the past tense should be used.

Comments: (12) Lines 295, It is necessary to supplement the findings of Liu et al. (2021).

Comments: (13) Lines 308-311, The “Towmey effect” is mentioned in multiple places throughout the manuscript; it should be simplified when referenced for the second time.

Comments: (14) Lines 316, change “much stronger” to “much more strongly”

Comments: (15) Lines 322-323, It is necessary to clarify why this definition is adopted.

Comments: (16) Lines 327, change “decreases” to “also decreases”

Comments: (17) Lines 362, change “cloud-aerosol” to “aerosol-cloud”

Comments: (18) Lines 378,392,419, change “Supplement” to “Appendices”

Comments: (19) Lines 409, The expression suffers from ambiguous reference.

Comments: (20) Lines 431, The descriptions of “regime” and “phase” in the manuscript need to be consistent.

Comments: (21) Lines 449, The logical expression of the sentence is unclear.

Comments: (22) Lines 450-453, It is necessary to add supplementary literature to support this point.

Citation: https://doi.org/10.5194/egusphere-2025-3157-RC2
- AC2: 'Reply on RC2', Yuqin Liu, 03 Feb 2026
  
  The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3157/egusphere-2025-3157-AC2-supplement.pdf
  
  Citation: https://doi.org/10.5194/egusphere-2025-3157-AC2

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

AR by Yuqin Liu on behalf of the Authors (03 Feb 2026) Author's response

EF by Svenja Lange (06 Feb 2026)

EF by Svenja Lange (09 Feb 2026) Manuscript Author's tracked changes

ED: Referee Nomination & Report Request started (18 Feb 2026) by Stelios Kazadzis

RR by Anonymous Referee #3 (10 Apr 2026)

Suggestions for revision or reasons for rejection

Review of egusphere-2025-3157

This study investigates how the aerosol indirect effect varies with spatial scale and liquid water path. It analyzes the sensitivity of cloud microphysics during two distinct periods with different aerosol loading (high and decreased AOD) over eastern China. This is a very relevant topic and helps us understand how aerosol loading modulates the scale dependence of aerosol indirect effects.

The manuscript is quite clear and scientifically relevant. However, there are some issues with the presentation and discussion that, in my opinion, should be addressed before publication.

The manuscript aims to:

-Reveal patterns of aerosol indirect effects across spatial scales
-Assess the regulatory role of LWP in aerosol-cloud interactions over land in eastern China

In the abstract, two distinct regimes of effective radius variation with liquid water path are presented. Later in the manuscript, however, three regimes are discussed and presented in the conclusions.

The authors present interesting relationships that they discuss could be used as a basis for improving aerosol-cloud parameterization schemes in climate models, but do not demonstrate how these findings translate into model improvements.

As it stands, the connection between the observational analysis and its application in climate models are largely qualitative. If the authors aim to link their main results to aerosol-cloud modeling, it would be helpful to clarify how these findings could be incorporated into parameterization schemes, for example in activation, autoconversion, or in representing the transition from regional-scale effects to model grid scales.

The authors mention similar statements several times throughout the manuscript:

Lines 36-38 - “This study reveals the scale-dependence of aerosol-cloud interactions, providing critical observational support for optimizing climate model parameterization schemes.”

Lines 155-156 - “how the aerosol indirect effect depends on observational spatial scales in eastern China is of great significance for developing parameterization schemes that align with the regional characteristics of aci.”

Lines 173-174 - “The study aims to reveal the patterns of the sensitivity of aerosol indirect effects to spatial scales, provides support for optimizing parameterization schemes and accurate assessment of regional aerosol effects.”

Lines 384-385: “This approach enabled the determination of the optimal buffer size for aerosol indirect effects as function of the size of the study area, ultimately leading to the development of a parameterization scheme for aerosol indirect effects for observations with different spatial resolution and different sizes of the study area over eastern China.”

Line 690- 692: “Such advancements provide actionable insights for refining parameterization schemes in climate models, thereby enhancing their predictive reliability.“

Lines 730-733: “The scale-dependent attenuation of both sensitivities and their modulation by LWP indicate that quantifying aerosol indirect effects requires full consideration of spatial scales and the key role of liquid water, providing observational basis for optimizing climate model parameterization schemes.”

Lines 774-777: These findings not only deepen our understanding of aerosol indirect effects but also provide an important observational basis for improving aerosol-cloud parameterization schemes in climate models. The results emphasize that both the phased characteristics of LWP and spatial scale effects must be considered when assessing aerosol indirect effects.

Minor/technical comments

Line 187-188 – The term aerosol-cloud interactions (aci) is defined earlier (Line 45), but the manuscript later alternates with “cloud-aerosol interactions” and “cloud-aerosol coupling”. For clarity and conceptual consistency, it would be preferable to use consistent terminology (aci) throughout.

Line 346 – You may consider rewriting the list as:

(10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 150, 160, 180, 200, 250, and 300 km)

Line 366 – consider simplifying to: from 10 to 300 km

Line 402 – I would suggest being cautious with the use of the term “pristine”. It may be more appropriate to use a term such as “relatively cleaner”.

Lines 727-733 You may consider briefly incorporating the main points from Section 4.3.3 into the conclusions, rather than introducing them as a separate section

Line 554 & 565 - aerosol- cloud interactions -> aci

Lines 602-624 - During revision, the authors may consider splitting longer sentences into two or three simpler ones to improve readability.

Line 648 – Please define what is meant by “LWP-stratified”. It appears to refer to the binning of LWP described in Lines 424-425, but this is not clearly stated.

Section 3.3 – This section could be slightly shortened to improve readability. It would also be helpful to clarify how increasing the spatial domain may mix cleaner and more polluted conditions, potentially reducing regime contrast and affecting the derived SNd sensitivities.

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ED: Publish subject to minor revisions (review by editor) (11 Apr 2026) by Stelios Kazadzis

AR by Yuqin Liu on behalf of the Authors (19 Apr 2026) Author's response Author's tracked changes

EF by Polina Shvedko (22 Apr 2026) Manuscript

ED: Publish as is (26 Apr 2026) by Stelios Kazadzis

AR by Yuqin Liu on behalf of the Authors (28 Apr 2026)

Short summary

This study reveals how air pollution affects cloud properties in eastern China using satellite data from 2008–2022. We find CER/LWP (cloud droplet effective radius/liquid water path) relationship exhibits three regimes, modulated by aerosol concentration. The Twomey effect is confirmed, and its sensitivity shows significant spatial-scale dependence. Surprisingly, cleaner air after 2015 make clouds less sensitive to pollution's effects. The optimal buffer sizes show notable variations for the study area in the range from 6°×6° to 10°×10°.