the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Analysis of diurnal, seasonal and annual variations of fair weather atmospheric potential gradient at reduced number concentration of condensation nuclei from long-term measurements at Świder, Poland
Abstract. The ground-level atmospheric potential gradient (PG) has been measured with a radioactive collector method in Stanisław Kalinowski Geophysical Observatory in Świder (52.12° N, 21.23° E), Poland, for several decades. Long-term measurements analysed previously revealed rather typical behaviour in the diurnal and seasonal variations of the PG of a land station controlled by pollution. Observation of the potential gradient at such a station usually show a maximum at local winter months which are mostly affected by anthropogenic pollution. The 1965–2005 series has been newly analysed to describe the Świder PG variations in greater detail, also in connection with an analysis of simultaneous measurements of condensation nuclei measured at 6, 12, 18 UT. An attempt is made to calculate the diurnal and seasonal variations at condensation nuclei number concentrations below 10000 cm-3. There is a decrease of the PG in the diurnal variation by up to 11 % in the winter, and no significant change in the summer. The reduction in the annual variation is 11–26 % with the biggest difference in February. In the summer months, this difference is negligible. Such differences can be predicted with a simplified model of electrical conductivity including the aerosol composition of water soluble and soot particles, the main components of continental aerosol. With this model we obtained changes in the conductivity and the PG in up to 30 % in the winter, and 6 % in the summer. Despite the efforts to minimise the aerosol effect on the PG, the character of the PG seasonal and annual variation preserves its character with a maximum in the Northern Hemisphere winter and the minimum in the summer.
- Preprint
(3494 KB) - Metadata XML
- BibTeX
- EndNote
Status: open (until 01 May 2024)
-
RC1: 'Comment on angeo-2024-1', Earle Williams, 03 Apr 2024
reply
Publisher’s note: a supplement was added to this comment on 8 Apr 2024.
The authors should be encouraged to interact with Marek Kubicki of the same institution in Poland, and work to incorporate the conductivity data in this study.
Please see also longer review attached below.
-
RC2: 'Comment on angeo-2024-1', Anonymous Referee #2, 21 Apr 2024
reply
The paper contains a reinterpretation of historic data to investigate the relationship between aerosol concentration and atmospheric potential gradient. Many investigations similar to this have used proxies or estimates for aerosol concentrations, so the inclusion of real aerosol data makes this a useful addition to the literature.
In my view, the manuscript could aid the reader more my adding more technical information on the measurements and some additional statistical analysis. The site description may be included in the references, but it would benefit the manuscript to put pertinent information on the measurement site and places of interest nearby. For example, how near is the measurement site to major population centers, roads, the coast or industry. This would aid in understanding potential sources of aerosol.
The measurement instrumentation is listed but more detail on the instruments used would also be helpful. Of particular importance is the measurement range, sensitivity and error of the aerosol measurement. I believe more detail of the aerosol instrumentation needs to be repeated within the manuscript, as the references are not easily available. Please could you include details of what kind of aerosol counter is used, the size range that are counted and details of inlet tubing. In section 2.3, who assessed the criteria for fair weather, was this done by observatory staff, or more recently?
Finally, I would suggest that the paper could be strengthened by adding some more statistical testing to the analysis. For example, it is claimed that limiting the condensation nuclei concentrations does not significantly change the distributions of corresponding potential gradient values – was a test used to prove the difference is not significant? When comparing the shape of distributions, could you consider using a non-parametric distribution test, eg, Kolmogorov-Smirnov test?
A few small corrections:
Section 2.1, there was a change if instrumentation, was any cross checking done to verify if there was a change in response?
In Figure 1, is there any exclusion criteria before a data point can be included, for example, is there a minimum number of fair weather data points required for the month to be included?
In Figure 2 (and some subsequent figures) the values separated by commas are not clear which plot they belong too and this should be made explicit.
In Figure 6 can you clarify how long the measurement is that the means at 6h, 12h and 18h are?
Line 47: in the statement ‘less than 10,000’ could you say what size these particle fall under?
Line 228: What is the justification for the values given for the variable in equation 1, are they based on measured quantities?
Line 230: What is the justification in assuming both mobilities are equal, as they are often not different to each other. Is it possible to run a sensitivity analysis to see what a difference would make?
Line 242: Please provide more information on where and when these size distributions were measured.
Line 254: Why was relative humidity excluded?
Some smaller changes:
Line 133, change “except of” to “except in”
Line 176, superscript should be -3
Line 273: Should this read 1.3 times by?
Citation: https://doi.org/10.5194/angeo-2024-1-RC2
Viewed
HTML | XML | Total | BibTeX | EndNote | |
---|---|---|---|---|---|
257 | 34 | 14 | 305 | 12 | 12 |
- HTML: 257
- PDF: 34
- XML: 14
- Total: 305
- BibTeX: 12
- EndNote: 12
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1