Investigating the contribution of grown new particles to cloud condensation nuclei with largely varying pre-existing particles – Part 1: Observational data analysis
Abstract. This study employed multiple techniques to investigate the contribution of grown new particles to the number concentration of cloud condensation nuclei (CCN) at various supersaturation (SS) levels at a rural mountain site in North China Plain from 29 June to 14 July 2019. On eight new particle formation (NPF) days, the total particle number concentrations (Ncn) were 8.4±6.1 ×103 cm-3, which were substantially higher compared to 4.7±2.6 ×103 cm-3 on non-NPF days. However, the Nccn at 0.2 %SS and 0.4 %SS on the NPF days were significantly lower than those observed on non-NPF days (P<0.05). This was due to the lower cloud activation efficiency of pre-existing particles resulting from organic vapor condensation and smaller number concentrations of pre-existing particles on NPF days. A case-by-case examination showed that the grown new particles only yielded a detectable contribution to Nccn at 0.4 % SS and 1.0 % SS during the NPF event on 1 July 2019, accounting for 12±11 % and 23±12 % of Nccn, respectively. The increased Nccn during two other NPF events and at 0.2 % SS on 1 July 2019 were detectable, but determined mainly by varying pre-existing particles rather than grown new particles. In addition, the hygroscopicity parameter values, concentrations of inorganic and organic particulate components, and surface chemical composition of different sized particles were analyzed in terms of chemical drivers to grow new particles. The results showed that the grown new particles via organic vapor condensation generally had no detectable contribution to Nccn, but incidentally did. However, this conclusion was drawn from a small size of observational data, leaving more observations, particularly for long-term observations and the growth of pre-existing particles to the CCN required size, needed for further investigation.
Xing Wei et al.
Status: final response (author comments only)
- RC1: 'Comment on egusphere-2023-539', Anonymous Referee #1, 13 Apr 2023
- RC2: 'Comment on egusphere-2023-539', Anonymous Referee #2, 20 Apr 2023
Xing Wei et al.
Xing Wei et al.
Viewed (geographical distribution)
The manuscript discusses the impact of new particle formation on CCN based on a measurement campaign conducted on a mountain site situated in the North China Plain. The subject matter is significant, and the dataset is valuable, making me eager to see a comprehensive study that is worthy of publication. However, I have concerns about the manuscript's quality and the inadequate discussion of the findings. At its present state, I cannot recommend it for publication in ACP. Major revisions are necessary before it can be considered for publication. Please refer to my comments and suggestions below.
L20 in P4: It should be "splitter" rather than "spitter".
L36 in P4: What are the start and end times of the TSP sampling?
L16-19 in P8: This sentence is unclear. Please revise for clarity.
L39-40 in P8: This sentence is unclear. Please revise for clarity.
L25 in P10: It's odd to say "organic vapor was growing on the pre-existing particles". Use "condensing" instead.
L3 in P15: There is no definition of PC1 or PC2. Please provide a definition.
Fig. 2: The range of the Y-axis in panel (c) is too large, and it appears that there is no variation of CDNC with time. Please adjust the range of the Y-axis.
Fig. 3-5: Please include a time series of the critical diameter (Dc) in the panel of PNSD.
Fig. 7: The markers in panel (a) are too small to identify. Please increase their size.
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