Fifty-six years of surface solar radiation and sunshine duration over São Paulo, Brazil: 1961–2016

Yamasoe, Marcia Akemi; Rosário, Nilton Manuel Évora; Almeida, Samantha Novaes Santos Martins; Wild, Martin

doi:https://doi.org/10.5194/acp-21-6593-2021

Articles | Volume 21, issue 9

https://doi.org/10.5194/acp-21-6593-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-21-6593-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 21, issue 9

Research article

|

03 May 2021

Research article |

| 03 May 2021

Fifty-six years of surface solar radiation and sunshine duration over São Paulo, Brazil: 1961–2016

Marcia Akemi Yamasoe, Nilton Manuel Évora Rosário, Samantha Novaes Santos Martins Almeida, and Martin Wild

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Final revised paper (published on 03 May 2021)
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Preprint (discussion started on 09 Oct 2020)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Review of Akemi Yamasoe et al', Anonymous Referee #2, 25 Oct 2020
RC2: 'Review of Akemi Yamasoe et al 2020', Anonymous Referee #1, 26 Oct 2020
AC1: 'Comment on acp-2020-848', Marcia Yamasoe, 15 Feb 2021

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Marcia Yamasoe on behalf of the Authors (16 Feb 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (28 Feb 2021) by Stelios Kazadzis

RR by Anonymous Referee #2 (08 Mar 2021)

Suggestions for revision or reasons for rejection

The present version of the manuscript is much better than the previous version. However, I still have some objections regarding the analysis of the data, and especially the discussion about the results shown in Figure 2.

As I understand from the manuscript, and from the reply of the authors to one of my previous comments, they used the methodology of Rodionov (2004) and detected a statistically significant change in the direction of the trend of DTR in 1983. Based on this result, as well as the results of other studies, they decided to perform the analysis for two sub-periods: 1961 – 1983 and 1983 – 2016.

First of all, is 1983 the first, and the only year that the change in the direction of the trend in DTR is significant? For example, I would expect that the change would be significant for a range of 3-4 years around 1983. Some relative discussion should be added in the document. There should also be some similar discussion regarding all parameters shown in Figure 2.

Secondly, I would recommend to the authors to use a piece-wise linear regression model when they detect a significant change, instead of studying the two trends independently. This way the authors will be able to discuss the trend in e.g. the first period with respect to the trend in the second period. Else, the discussion may be misleading. For example, the discussion about the results for SSR in Figure 2 is misleading. Based on what is discussed in the document (especially in the introduction), the reader would expect that the SSR was decreasing by 0.4% per decade in 1961 – 1983, and then by 0.39% per decade in 1983 – 2016. Thus, an overall decrease of ~2.2% for the whole period (1961 - 2016). This is not of course truth since the SSR is relatively stable during 1961 – 2016.

Third, I strongly recommend adding some discussion about the average change throughout the whole period, at least for the parameters for which the regime of the trend is not changing significantly (e.g. SSR).

In any case, and even if the authors decide not to follow my advice regarding the methodology of the analysis, they should discuss in a much clearer way what has happened in the period of study, and in which cases the discussed results are significant.

I also recommend that the following corrections should be applied.
L23: Replace “up to” with “and”
L25: Delete “of”. Furthermore, the significance level is 89.9%. The p-value is 0.101.
L26-29: “A similar … 0.013)”. Please re-write this sentence because it is not clear.
L39: “each possible cause” instead of “each possible causes”
L132: “were monitored since” instead of “started to be monitored in”

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ED: Publish subject to minor revisions (review by editor) (10 Mar 2021) by Stelios Kazadzis

AR by Marcia Yamasoe on behalf of the Authors (19 Mar 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (23 Mar 2021) by Stelios Kazadzis

AR by Marcia Yamasoe on behalf of the Authors (26 Mar 2021) Manuscript

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Short summary

Spatio-temporal disparity to assess global dimming and brightening phenomena has been a critical topic. For instance, few studies addressed surface solar irradiation (SSR) long-term trend in South America. In this study, SSR, sunshine duration (SD) and the diurnal temperature range (DTR) are analysed for São Paulo, Brazil. We found a dimming phase, identified by SSR, SD and DTR, extending till 1983. Then, while SSR is still declining, consistent with cloud increasing, SD and DTR are increasing.