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/egusphere-2025-3157

Preprints

https://doi.org/10.5194/egusphere-2025-3157

Preprints

10 Oct 2025

| 10 Oct 2025

Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

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

Abstract. Regulatory effects of liquid water path (LWP) on cloud droplet effective radius (CER) and the interaction between aerosol optical depth (AOD) and cloud properties were systematically investigated. MODIS and CALIOP observed aerosols and clouds over eastern China in two periods: 2008–2014 (period 1) and 2015–2022 (period 2). The results show two distinct regimes of the variation of CER with LWP: a rapid growth regime (LWP < 55/50 g/m²) and a decreasing regime (LWP = 55–135/50–100 g/m²) (thresholds vary by period). The sensitivity of CER to AOD (S_CER) shows a negative correlation, and the S_CER in the LWP regime 2 shows larger than that in LWP regime 1. Here, the spatial scale is described by buffer size and study area. Overall, |S_CER| decreases with increasing spatial scale. The optimal buffer sizes show notable variations in the range from 6°×6° to 10°×10°: increasing as study areas increase in period 2, but decreasing in period 1 for LWP regime 2. Compared with period 1, |S_CER| in period 2 exhibits significantly decreases, reflecting the weaker of aerosol-cloud interactions for declining aerosol concentrations. Additionally, the sensitivity of N_d (cloud droplet number concentration) to AOD (S_Nd) shows a positive correlation, with S_Nd decreases as spatial scale increases. The optimal buffer sizes show larger in the 8°×8° and 10°×10° regions than that in the 4°×4° and 6°×6° areas. This study reveals the scale-dependence of aerosol-cloud interactions.

Received: 02 Jul 2025 – Discussion started: 10 Oct 2025

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.

Download & links

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

Status: open (until 21 Nov 2025)

Post a comment Subscribe to comment alert

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

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
Reply

Citation: https://doi.org/10.5194/egusphere-2025-3157-RC1
RC2: 'Comment on egusphere-2025-3157', yong zha, 17 Nov 2025 reply

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.

Reply

Citation: https://doi.org/10.5194/egusphere-2025-3157-RC2

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

Viewed

Total article views: 165 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
127	27	11	165	7	8

HTML: 127
PDF: 27
XML: 11
Total: 165
BibTeX: 7
EndNote: 8

Views and downloads (calculated since 10 Oct 2025)

Month	HTML	PDF	XML	Total
Oct 2025	100	18	7	125
Nov 2025	27	9	4	40

Cumulative views and downloads (calculated since 10 Oct 2025)

Month	HTML	PDF	XML	Total
Oct 2025	100	18	7	125
Nov 2025	27	9	4	40

Viewed (geographical distribution)

Total article views: 163 (including HTML, PDF, and XML) Thereof 163 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 19 Nov 2025

Short summary

This study reveals how air pollution affects cloud properties in eastern China using satellite data from 2008–2022. We find CER/LWP relationship exhibits three phases, 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°.


Total:	0
HTML:	0
PDF:	0
XML:	0