the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 22 Aug 2023
UV solar radiation climatology and its behaviour during events of influence of the Antarctic ozone hole over south of Brazil
Abstract. Ultraviolet solar radiation that reaches the surface of the Earth has a very important role in the energy budget of our planet, although at certain amounts of exposure it can be harmful not only for human health, but animals and plants. Brazil is a tropical country receiving high intensity of UV radiation mostly of the year. UV radiation, specially UV-B is mainly absorbed in the ozone layer, changes in ozone content or ozone distribution directly affects UV radiation attenuation, so that surface UV. Ozone hole is characterized by an intense ozone depletion in the stratosphere in Antarctic region, happening during spring in the south hemisphere. There is evidence of poor-ozone air masses detachment from polar vortex and reaching mid-latitude regions, such as South of Brazil. Those air masses cause impact on the regions which they act due to low ozone content, allowing more radiation to reach the surface. UV index data from a Brewer Spectrophotometer (MKIII #167), located in south of Brazil, in the Southern Space Observatory (29.42° S, 53.87° W) was analysed with data collected between 2005 and 2017. Ground data was compared to satellite-derived from OMI/Aura, resulting in a correlation coefficient of 0.95 %. The climatology of Brewer data was done, analysing seasonal and interannual variability. Wavelet analysis showed the influence of ENSO, QBO and solar cycle on the variability of UV index. The results show a typical seasonal behaviour of UV Index, reaching extreme during summer season. Events of secondary effects of Antarctic ozone hole, identified between 2005 and 2016 (Bittencourt, 2018), were selected and the behavior of UV index and UV-B non-weighted during those events were studied. All ten events studied showed a significant increase in UV radiation at the days of events, the majority resulted in an increase of 4 % of UV index for each 1 % ozone total column decrease. One specific event was described in detail due to the major ozone depletion. Occurred in October 2016, ozone depletion was of almost 20 % while UV index increased 88 % in relation to the climatological mean, raising the concern with public health regarding excess exposure to UV radiation.
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RC1: 'Comment on egusphere-2023-1474', Jochen Wagner, 09 Oct 2023
Title:
UV solar radiation climatology and its behaviour during events of influence of the Antarctic ozone hole over south of Brazil
General Comments:
The manuscript aims to address the significant topic of UV solar radiation and its behavior, especially in the context of the Antarctic ozone hole's influence over the south of Brazil. The following findings are of general scientific interest:
- There's evidence of poor-ozone air masses detaching from the polar vortex and reaching mid-latitude regions, such as the South of Brazil.
- The study observed an atypical behavior of the ozone hole in the years 2020, 2021, and 2022, where it persisted longer than usual.
- The paper also discussed the influence of the Quasi-biennial circulation (QBO), El Niño Southern Oscillation (ENSO), and the solar cycle on UV radiation.
While these topics are of importance and relevance, generally known textbook knowledge is also discussed in the paper and complicates the readability. The paper should be shortened and the following topics should be omitted:
Excessive UV radiation exposure has negative effects on plants, aquatic life, and humans, leading to DNA damage and potential development of skin cancers.
UV radiation, especially UV-B, is mainly absorbed in the ozone layer. Changes in ozone content directly affect UV radiation attenuation.
At the same time, the methodological part could be expanded (see Specific Comments below).
Furthermore there are several concerns regarding the quality of the language and the methodology employed in the study.
Specific Comments:
- Language:
- The manuscript suffers from numerous language and grammatical errors, which hinder the clarity and comprehension of the content. Proper proofreading and editing are essential to ensure that the manuscript meets the standards of international publications.
- Some sentences are convoluted and could benefit from restructuring for better clarity.
- Data Collection and Validation:
- Criticism: The manuscript mentions the use of UV index data from a Brewer Spectrophotometer and its comparison with satellite-derived data. However, there's no clear description of how this data was collected, validated, and calibrated.
- Suggestion: The authors should provide a detailed section on data collection methods, including the time intervals, calibration procedures for the Brewer Spectrophotometer, and any validation checks performed against known standards or benchmarks.
- Statistical Analysis:
- Criticism: The correlation coefficient of 0.95% between ground data and satellite-derived data is mentioned, but there's no elaboration on the statistical tests used, the significance level, or the confidence intervals.
- Suggestion: The authors should employ rigorous statistical tests, such as Pearson's or Spearman's rank correlation, and report p-values. Additionally, scatter plots with regression lines could visually represent the correlation.
- Analysis of Atypical Behavior of Ozone Hole:
- Criticism: The paper notes an atypical behavior of the ozone hole in the years 2020, 2021, and 2022 but doesn't provide a comparative analysis with previous years or a clear methodology on how this atypical behavior was determined.
- Suggestion: A time-series analysis comparing the ozone hole's behavior over the past decades would provide context. The authors should also consider using anomaly detection techniques to statistically determine the atypical behavior.
- Influence of QBO, ENSO, and Solar Cycle:
- Criticism: The manuscript touches upon the influence of QBO, ENSO, and the solar cycle on UV radiation but lacks depth in the methodology used to determine these influences.
- Suggestion: The authors should consider multivariate regression or time-series decomposition to isolate and quantify the effects of QBO, ENSO, and the solar cycle on UV radiation. This would provide a clearer picture of each factor's contribution.
- Secondary Effects of Antarctic Ozone Hole:
- Criticism: The paper mentions secondary effects of the Antarctic ozone hole but doesn't elaborate on how these effects were identified or measured.
- Suggestion: A clear methodology on how these secondary effects were determined is essential. Only using HSPLIT trajectory analysis or any other modeling technique is not enough.
- General Analysis Improvements:
- Criticism: The manuscript lacks high quality visual representations of the data. Some graphs give almost no new information to the reader, since the same time series is shown again. Plotting the typical diurnal cycle of UV-Index simply show the dependence on solar zenith angle.
- Suggestion: The climatology plot should show daily/monthly mean, median, min, max values and the variability. Visual representations can often convey findings more effectively than textual descriptions alone, but again, like in the text the interesting findings are hidden by not meaningful graphs.
In summary, while the manuscript touches upon significant points, it requires a more rigorous and detailed approach in its methodology and analysis to meet the standards of scientific research. The authors should consider revisiting each section, ensuring clarity, depth, and scientific rigor.
Citation: https://doi.org/10.5194/egusphere-2023-1474-RC1 -
RC2: 'Comment on egusphere-2023-1474', Sasha Madronich, 10 Oct 2023
I cannot support publication of this paper. The major conclusion, highlighted in the abstract, is that the UV Index increases by some 4% for each 1% decrease in ozone. This contradicts three decades of solid theoretical and observational studies showing that this sensitivity factor (often called the Radiation Amplification Factor or RAF) is close to 1.1. Sometimes it is 1.2 and other times 1.0, but never anywhere near 4. New measurements do sometimes supersede old ones, but here the many earlier studies are not even mentioned. See for example
doi:10.1007/s43630-022-00281-5
for many relevant references, and Fig. 11 of that paper which shows that the UV index increases by 1.1 % for each -1% O3 change, based on modeling as well as observations at different locations, different solar zenith angles, and a wide range of O3 changes. The much larger impact of ozone depletion presented here could cause serious but unnecessary alarm in the public, possibly even over-reaction.If the authors wish to publish their results, the first step should be to figure out why their sensitivities are so much higher than the many previously published values. The manuscript seems to suggest that clear sky values were used for this purpose, but perhaps they are being compared to climatological values that include clouds? If so, then much of the UV increase could be due to differences in clouds, not ozone. Some of the wavelet analysis could be interesting if it can identify different meteorological regimes.
Citation: https://doi.org/10.5194/egusphere-2023-1474-RC2 -
AC1: 'Reply on RC2', Bibiana Lopes, 07 Dec 2023
First of all, thank you very much for your comment. Some criteria were considered in this part of the analysis, the ozone depletion and the clear sky condition are the most important. The specific days studied were clear sky days, especially with a significant drop in ozone content. It is important to mention the mean increase in UV index was calculated based on the UV index climatological mean, secondary effects of AOH normally occur between September and October, and the climatological mean of UV index in these months varies between 6 and 7. The increase in UV index in some days of events was more than 50% which is very significant, in one specific case the increase reached more than 80%, so the mean increase of UV index for each 1% decrease in ozone, resulted in 4%.
Citation: https://doi.org/10.5194/egusphere-2023-1474-AC1
-
AC1: 'Reply on RC2', Bibiana Lopes, 07 Dec 2023
-
AC2: 'Comment on egusphere-2023-1474', Bibiana Lopes, 07 Dec 2023
Thank you very much for your comment. The manuscript was rewritten considering all the suggestions. The QBO, ENSO, and solar cycle analysis were removed from the manuscript because it is not the focus of the present study.
Citation: https://doi.org/10.5194/egusphere-2023-1474-AC2 -
EC1: 'Comment on egusphere-2023-1474', Simone Tilmes, 16 Dec 2023
Dear authors,
Before a final version of the manuscript can be prepared, please address all the comments by the reviewers in a point-by-point manner. Currently, the response to the reviewers is not sufficient to motivate the submission of a revised manuscript.
Reviewer 1 points out:
“In summary, while the manuscript touches upon significant points, it requires a more rigorous and detailed approach in its methodology and analysis to meet the standards of scientific research. The authors should consider revisiting each section, ensuring clarity, depth, and scientific rigor.”
Please address and justify if or if not you plan to follow each of the suggested revisions by Reviewer 1.
Further, Reviewer 2 raised significant criticism of the results of this study. Here, I recommend a much more detailed response, including addressing findings from earlier studies as pointed out, including the paper mentioned, and discussing what is different in this analysis and its significance. Please also address if the differences could be because of the different considerations in clouds, not ozone. Please consider doing wavelet analysis as suggested, and if not, please justify your reasons.
Citation: https://doi.org/10.5194/egusphere-2023-1474-EC1
Status: closed
-
RC1: 'Comment on egusphere-2023-1474', Jochen Wagner, 09 Oct 2023
Title:
UV solar radiation climatology and its behaviour during events of influence of the Antarctic ozone hole over south of Brazil
General Comments:
The manuscript aims to address the significant topic of UV solar radiation and its behavior, especially in the context of the Antarctic ozone hole's influence over the south of Brazil. The following findings are of general scientific interest:
- There's evidence of poor-ozone air masses detaching from the polar vortex and reaching mid-latitude regions, such as the South of Brazil.
- The study observed an atypical behavior of the ozone hole in the years 2020, 2021, and 2022, where it persisted longer than usual.
- The paper also discussed the influence of the Quasi-biennial circulation (QBO), El Niño Southern Oscillation (ENSO), and the solar cycle on UV radiation.
While these topics are of importance and relevance, generally known textbook knowledge is also discussed in the paper and complicates the readability. The paper should be shortened and the following topics should be omitted:
Excessive UV radiation exposure has negative effects on plants, aquatic life, and humans, leading to DNA damage and potential development of skin cancers.
UV radiation, especially UV-B, is mainly absorbed in the ozone layer. Changes in ozone content directly affect UV radiation attenuation.
At the same time, the methodological part could be expanded (see Specific Comments below).
Furthermore there are several concerns regarding the quality of the language and the methodology employed in the study.
Specific Comments:
- Language:
- The manuscript suffers from numerous language and grammatical errors, which hinder the clarity and comprehension of the content. Proper proofreading and editing are essential to ensure that the manuscript meets the standards of international publications.
- Some sentences are convoluted and could benefit from restructuring for better clarity.
- Data Collection and Validation:
- Criticism: The manuscript mentions the use of UV index data from a Brewer Spectrophotometer and its comparison with satellite-derived data. However, there's no clear description of how this data was collected, validated, and calibrated.
- Suggestion: The authors should provide a detailed section on data collection methods, including the time intervals, calibration procedures for the Brewer Spectrophotometer, and any validation checks performed against known standards or benchmarks.
- Statistical Analysis:
- Criticism: The correlation coefficient of 0.95% between ground data and satellite-derived data is mentioned, but there's no elaboration on the statistical tests used, the significance level, or the confidence intervals.
- Suggestion: The authors should employ rigorous statistical tests, such as Pearson's or Spearman's rank correlation, and report p-values. Additionally, scatter plots with regression lines could visually represent the correlation.
- Analysis of Atypical Behavior of Ozone Hole:
- Criticism: The paper notes an atypical behavior of the ozone hole in the years 2020, 2021, and 2022 but doesn't provide a comparative analysis with previous years or a clear methodology on how this atypical behavior was determined.
- Suggestion: A time-series analysis comparing the ozone hole's behavior over the past decades would provide context. The authors should also consider using anomaly detection techniques to statistically determine the atypical behavior.
- Influence of QBO, ENSO, and Solar Cycle:
- Criticism: The manuscript touches upon the influence of QBO, ENSO, and the solar cycle on UV radiation but lacks depth in the methodology used to determine these influences.
- Suggestion: The authors should consider multivariate regression or time-series decomposition to isolate and quantify the effects of QBO, ENSO, and the solar cycle on UV radiation. This would provide a clearer picture of each factor's contribution.
- Secondary Effects of Antarctic Ozone Hole:
- Criticism: The paper mentions secondary effects of the Antarctic ozone hole but doesn't elaborate on how these effects were identified or measured.
- Suggestion: A clear methodology on how these secondary effects were determined is essential. Only using HSPLIT trajectory analysis or any other modeling technique is not enough.
- General Analysis Improvements:
- Criticism: The manuscript lacks high quality visual representations of the data. Some graphs give almost no new information to the reader, since the same time series is shown again. Plotting the typical diurnal cycle of UV-Index simply show the dependence on solar zenith angle.
- Suggestion: The climatology plot should show daily/monthly mean, median, min, max values and the variability. Visual representations can often convey findings more effectively than textual descriptions alone, but again, like in the text the interesting findings are hidden by not meaningful graphs.
In summary, while the manuscript touches upon significant points, it requires a more rigorous and detailed approach in its methodology and analysis to meet the standards of scientific research. The authors should consider revisiting each section, ensuring clarity, depth, and scientific rigor.
Citation: https://doi.org/10.5194/egusphere-2023-1474-RC1 -
RC2: 'Comment on egusphere-2023-1474', Sasha Madronich, 10 Oct 2023
I cannot support publication of this paper. The major conclusion, highlighted in the abstract, is that the UV Index increases by some 4% for each 1% decrease in ozone. This contradicts three decades of solid theoretical and observational studies showing that this sensitivity factor (often called the Radiation Amplification Factor or RAF) is close to 1.1. Sometimes it is 1.2 and other times 1.0, but never anywhere near 4. New measurements do sometimes supersede old ones, but here the many earlier studies are not even mentioned. See for example
doi:10.1007/s43630-022-00281-5
for many relevant references, and Fig. 11 of that paper which shows that the UV index increases by 1.1 % for each -1% O3 change, based on modeling as well as observations at different locations, different solar zenith angles, and a wide range of O3 changes. The much larger impact of ozone depletion presented here could cause serious but unnecessary alarm in the public, possibly even over-reaction.If the authors wish to publish their results, the first step should be to figure out why their sensitivities are so much higher than the many previously published values. The manuscript seems to suggest that clear sky values were used for this purpose, but perhaps they are being compared to climatological values that include clouds? If so, then much of the UV increase could be due to differences in clouds, not ozone. Some of the wavelet analysis could be interesting if it can identify different meteorological regimes.
Citation: https://doi.org/10.5194/egusphere-2023-1474-RC2 -
AC1: 'Reply on RC2', Bibiana Lopes, 07 Dec 2023
First of all, thank you very much for your comment. Some criteria were considered in this part of the analysis, the ozone depletion and the clear sky condition are the most important. The specific days studied were clear sky days, especially with a significant drop in ozone content. It is important to mention the mean increase in UV index was calculated based on the UV index climatological mean, secondary effects of AOH normally occur between September and October, and the climatological mean of UV index in these months varies between 6 and 7. The increase in UV index in some days of events was more than 50% which is very significant, in one specific case the increase reached more than 80%, so the mean increase of UV index for each 1% decrease in ozone, resulted in 4%.
Citation: https://doi.org/10.5194/egusphere-2023-1474-AC1
-
AC1: 'Reply on RC2', Bibiana Lopes, 07 Dec 2023
-
AC2: 'Comment on egusphere-2023-1474', Bibiana Lopes, 07 Dec 2023
Thank you very much for your comment. The manuscript was rewritten considering all the suggestions. The QBO, ENSO, and solar cycle analysis were removed from the manuscript because it is not the focus of the present study.
Citation: https://doi.org/10.5194/egusphere-2023-1474-AC2 -
EC1: 'Comment on egusphere-2023-1474', Simone Tilmes, 16 Dec 2023
Dear authors,
Before a final version of the manuscript can be prepared, please address all the comments by the reviewers in a point-by-point manner. Currently, the response to the reviewers is not sufficient to motivate the submission of a revised manuscript.
Reviewer 1 points out:
“In summary, while the manuscript touches upon significant points, it requires a more rigorous and detailed approach in its methodology and analysis to meet the standards of scientific research. The authors should consider revisiting each section, ensuring clarity, depth, and scientific rigor.”
Please address and justify if or if not you plan to follow each of the suggested revisions by Reviewer 1.
Further, Reviewer 2 raised significant criticism of the results of this study. Here, I recommend a much more detailed response, including addressing findings from earlier studies as pointed out, including the paper mentioned, and discussing what is different in this analysis and its significance. Please also address if the differences could be because of the different considerations in clouds, not ozone. Please consider doing wavelet analysis as suggested, and if not, please justify your reasons.
Citation: https://doi.org/10.5194/egusphere-2023-1474-EC1
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