the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 30 Sep 2024
Measurement report: Aircraft observations of aerosol and microphysical quantities of stratocumulus in autumn over Guangxi Province, China: Diurnal variation, vertical distribution and aerosol-cloud relationship
Abstract. Aerosols and clouds play important roles in the global climate system, and aerosol-cloud interactions have a significant impact on the radiation balance, water cycle, and energy cycle of the earth-atmosphere system. To understand the effect of aerosols on the vertical distribution of stratocumulus microphysical quantities in southwest China, the daily variation characteristics and formation mechanism of the vertical profiles of stratocumulus microphysical characteristics in this region were described by using the data of 9 cloud-crossing aircraft observations over Guangxi from October 10 to November 3, 2020. The influence of aerosol number concentration on cloud microphysical quantity was analyzed by combining the source of air mass and individual cases. Aerosol number concentration (Na) and cloud droplet concentration (Nc) both decreased gradually with the increase of altitude below 1500m, and did not change with the height between 1500 m and 3300 m. The inversion layer at the top of the boundary layer (PBL) hindered the increase in the cloud droplet particle size. The lower layer of the stratocumulus cloud in Guangxi was mainly small particle-size cloud droplet (effective diameter of cloud droplet, Ed<15 μm), and the middle and upper layer cloud droplet was large particle-size cloud droplet (Ed>20 μm). The vertical distribution of cloud microphysical quantity had apparent diurnal variation. When aerosols in the boundary layer were transported to the upper air (14:00 to 20:00), the number of cloud droplets (Nc) in the lower layer decreased, and the small particle-size cloud droplets (Ed <20 μm) in the middle layer and upper layer increased. When aerosols were transported to the boundary layer (10:00 to 13:00), the number of small particle-size cloud droplets in the lower layer of the cloud increased. The characteristics of cloud microphysical quantity were also affected by the source of air mass and the boundary layer. Under the influence of land air mass or in the boundary layer, the aerosol number concentration (Na) and Nc were high, and the cloud droplet number concentration spectrum was unimodal. Na and Nc were low under the influence of marine air mass or above the boundary layer, and the cloud droplet number concentration spectrum was bimodal. The relationship between stratocumulus and aerosol in this region is consistent with the Twomey effect. Ed and Na remain negatively correlated in different liquid water content ranges, and FIE ranged from 0.07 to 0.58.
- Preprint
(2489 KB) - Metadata XML
- BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2024-2756', Anonymous Referee #1, 26 Oct 2024
The comment was uploaded in the form of a supplement: https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2756/egusphere-2024-2756-RC1-supplement.pdf
-
CC1: 'Comment on egusphere-2024-2756', Liang YUAN, 31 Oct 2024
Aircraft observation is the most important way to directly obtain the cloud microphysical characteristics. However, due to limited conditions (instruments and funds), there are relatively few aircraft observation data on cloud microphysical characteristics. The aircraft observations of cloud microphysical characteristics in China are mostly concentrated in the Beijing-Tianjin-Hebei region, and related research on southern China is still very rare. Guangxi, as a typical province in southern China, has significant differences in climate characteristics and source emissions from the central and eastern of China. Therefore, the observation of cloud microphysical characteristics in Guangxi is of great significance for a comprehensive understanding of aerosol-cloud interactions in the East Asia. This study gives the data of 9 cloud-crossing aircraft observations, which can provide valuable data support for our in-depth understanding of aerosol-cloud interactions. More importantly, this paper gives the vertical distribution and interaction relationship of aerosols and clouds at different times of the day. Although there is a lack of aircraft observation data at nighttime, the vertical distribution of aerosols and clouds changes little at nighttime due to relatively stable atmospheric conditions, that is, the planetary boundary layer is relatively stable at nighttime and its impact is relatively small. The diurnal variations of the vertical distribution of aerosols and clouds, especially the discussion on the impact of diurnal variations in the planetary boundary layer on their vertical distribution and interaction, are the highlights of this paper. Additionally, this paper discussed the differences in the impact of aerosols from different sources on cloud microphysical properties. They demonstrated that this region's correlation between aerosols and clouds conforms to the Twomey effect. The ultimate goal is to provide observational constraints for the simulation of aerosol radiative forcing in global climate models. Therefore, I recommend that the article should be published after revision.
- There are some formatting errors in the manuscript that need to be carefully revised, such as the lack of space in line 19 and the lack of superscript in line 145. I will not list them one by one, and the author needs to carefully check and revise the entire manuscript.
- abstract, line 37-38, the specific response characteristics of the Twomey effect of aerosol-cloud should be discussed in detail. On the contrary, the observation overview of line 16-21 needs to be simplified and a brief description is sufficient. The direct verification of the Twomey effect through aircraft observation is a very important observational fact and needs to be described in detail.
- Line 113-116 does not need to be divided into a separate paragraph and can be directly merged with the previous paragraph.
- 2.1. Aircraft data and reanalyze data. In this section the aircraft data and the reanalysis data are best presented separately.
- line 164. Need to give a reason why Zn is defined?
- 3.2 Diurnal variation of the vertical distribution of cloud microphysical quantities. This section is the research highlight of this paper, but the title does not highlight of the research. I recommended to highlight the impact of planetary boundary layer evolution in the title and analysis content. Since this manuscript lacks nighttime observation data, it cannot be strictly called diurnal variation. I recommended that the authors weaken the description of diurnal variation.
- 3.3 Influence of aerosols on microphysical quantities of stratified clouds. The title of this section directly points to the impact of the Twomey effect.
Citation: https://doi.org/10.5194/egusphere-2024-2756-CC1 -
RC2: 'Comment on egusphere-2024-2756', Anonymous Referee #2, 18 Nov 2024
The manuscript presents a comprehensive investigation into the diurnal variation, vertical distribution, and aerosol-cloud relationships of stratocumulus clouds over Guangxi Province, China, utilizing aircraft observations. It offers insights into the impact of aerosol number concentration on cloud microphysical quantities, including cloud droplet concentration and effective diameter. The study reveals the interaction between the vertical structure of aerosols and the planetary boundary layer, highlighting the critical role of aerosols in influencing cloud microphysical characteristics. Given that China, particularly the region of Guangxi, is known for its high aerosol concentrations, this research contributes to the regional understanding of aerosol-cloud interactions, a topic that has been understudied in southern China.
The manuscript offers a detailed exploration of the diurnal variation, vertical distribution, and aerosol-cloud relationships of stratocumulus clouds over Guangxi Province, China, with a clear articulation of results and conclusions. To strengthen the manuscript, the authors should discuss the comparability of their findings with other regions globally, especially considering the unique meteorological conditions of Guangxi. At least add some discussion on this point. Enhancing the description of aircraft observation methods, including instrument calibration and data validation, is essential for credibility. Additionally, a thorough explanation of the statistical methods, including the choice of tests, significance levels, and assumptions, is necessary for the reader to replicate your results. Deepening the comparison with the existing literature\data report would provide better contextualization of the study's contributions. Further exploration of the physical mechanisms behind aerosol-cloud interactions would enrich the paper. Finally, outlining the possible implications for climate modeling, weather forecasting, and air quality management, along with suggestions for future research, would make the manuscript more impactful. Addressing these aspects will not only bolster the study's rigor but also its relevance to the broader scientific community.
Considering the above points, I recommend that the manuscript be accepted for publication in Atmospheric Chemistry and Physics (ACP) after the authors have addressed these revisions. The study's findings have the potential to significantly contribute to the field of atmospheric science, particularly in understanding the complex dynamics of aerosol-cloud interactions in regions with high aerosol loading. But overall, I cannot require a data measurement report with the same requirements as an article, therefore I recommend a minor revision.Specific comments:
1. interstitial aerosol or interstitial aerosol particles, you didn't provide any information on it, which makes it hard to understand for the reader who is not familiar with this concept, (interstitial aerosol particles: particles too small to activate to cloud droplets)
2. line 245, Nc was 13~2052, should be 13-2052 cm-3, please don't use '~'.
3. The manuscript comprehensively analyzes the vertical distribution of aerosols and cloud microphysical quantities in stratocumulus clouds over Guangxi Province, China. The findings contribute to the understanding of interactions between aerosols and clouds. However, the authors should consider providing a more detailed comparison of their results with previous studies, especially those conducted in other regions with different meteological conditions.
4. Authors should ensure a clearer accounting method or reference for definitions such as Zn, boundary layer height, FIE, etc.
5. Line 136: In Table 1, please provide the meaning of the data in brackets.
6. In Section 3.2, the authors have provided a detailed analysis of the diurnal variation of cloud microphysical quantities, especially the effects of vertical wind direction and aerosol number concentration. It would be interesting to see if they could correlate these variations with specific meteorological conditions, such as changes in temperature and humidity.
7. Section 3.2, Figure 6 shows the diurnal variation of cloud and aerosol number concentration spectra at different altitudes. However, the explanation of this content in the manuscript is relatively brief. It is recommended that the authors provide additional explanations better to understand the characteristics and causes of these changes.
8. In Section 3.3, the study first mentions the influence of air mass sources on cloud microphysical properties. Then, it selects two examples to analyze the interaction between aerosols and clouds in detail. How is the source of the air mass determined? Is there any relationship between the selection of individual cases and the air mass source? Why were October 29 and November 2 chosen?
9. Figure 10 illustrates the correlation between aerosol number concentration and effective droplet diameter; however, there is currently insufficient detail regarding the basis for the calculations. Additionally, the meaning of the function presented in the figure has not been explained. It is recommended that the authors provide supplementary data and detailed explanations to help readers better understand the information conveyed by this figure and the significance of the research.
10 The manuscript would benefit from a more explicit conclusion section that summarizes the key findings, their implications, and potential areas for future research.Citation: https://doi.org/10.5194/egusphere-2024-2756-RC2
Data sets
Data for Aircraft observations of aerosol and microphysical quantities of stratocumulus in autumn over Guangxi Province, China: Diurnal variation, vertical distribution and aerosol-cloud relationship Honglei Wang https://doi.org/10.5281/zenodo.13719678
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 229 | 36 | 95 | 360 | 5 | 7 |
- HTML: 229
- PDF: 36
- XML: 95
- Total: 360
- BibTeX: 5
- EndNote: 7
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1