the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Compound events in Germany in 2018: drivers and case studies
Abstract. The European continent is regularly affected by a wide range of extreme events and natural hazards including heatwaves, extreme precipitation, droughts, cold spells, windstorms, and storm surges. Many of these events do not occur as single extreme events, but rather show a multivariate character, the so-called compound events. Within the scope of the interdisciplinary project climXtreme (https://climxtreme.net/), we investigate the interplay of extreme weather events, their characteristics and changes, intensity, frequency and uncertainties in the past, present and future and associated impacts on various socio-economic sectors in Germany and Central Europe. This contribution presents several case studies with special emphasis on the calendar year of 2018, which is of particular interest given the exceptional sequence of different compound events across large parts of Europe, with devastating impacts on human lives, ecosystems and infrastructure. We provide new evidence on drivers of spatially and temporally compound events (heat and drought; heavy precipitation in combination with extreme winds) with adverse impacts on ecosystems and society using large-scale atmospheric patterns. We shed light on the interannual influence of droughts on surface water and the impact of water scarcity and heatwaves on agriculture and forests. We assessed projected changes in compound events at different current and future global surface temperature levels, demonstrating the importance of better quantifying the likelihood of future extreme events for adaptation planning. Finally, we addressed research needs and future pathways, emphasising the need to define composite events primarily in terms of their impacts prior to their statistical characterisation.
- Preprint
(5757 KB) - Metadata XML
-
Supplement
(486 KB) - BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2023-1460', Anonymous Referee #1, 11 Oct 2023
The manuscript describes a set of specific analyses done to understand and characterize complex extremes, such as the ones occurred in 2018. The text is well written and results clearly discussed. Despite the great readability, methods should be better explained and more details provided. This would give all readers the possibility to better appreciate the main findings and the figures. This is especially true for sections 2.2, 2.3, 2.8. For instance: the EPI and the TPDM are barely described; the choice of the ensemble size of the hydrological simulations is not discussed, neither is the experimental setting.
Citation: https://doi.org/10.5194/egusphere-2023-1460-RC1 -
RC2: 'Comment on egusphere-2023-1460', Anonymous Referee #2, 02 Jul 2024
Review of “Compound events in Germany in 2018: drivers and case studies” by Elena Xoplaki and colleagues.
This manuscript sets out to discuss compound events on the example of Germany in 2018. It is reasonably well-written and structured. A number of very long sentences make it hard to follow at times and the structure of the methods could be improved.
I acknowledge the effort that went into this work and I’m reasonably sure that it will be a good resource to look up European extremes in 2018 and case studies. But I also feel that the authors could have done a better job at building a more concise (i.e., shorter) story and make the paper feel less like a loosely connected collection of results in particular given the topic of compound events.
I do not expect the authors to overhaul the entire paper but I would encourage them to include some more connecting and structuring elements like tables or flow charts summarizing the methods and comparing the different results and their relation.My only major issue is the almost complete lack of conclusions in the conclusion section. One thing that might be good to address would be: What did we learn from this study that we did not already know (apart from collecting it in one place).
Specific comments
49: switch to past tense?
71: “Zscheischler et al. (2018) further defined CEs as combinations of events that are individually not necessarily extreme, or multiple drivers and/or hazards, but in combination often lead to disproportionate impacts on people and ecosystems”
How is this different from line 68?
“3) a combination of events that are not themselves extremes but lead to an extreme event or impact
when combined.”74 “To quantify the probability of CEs in today’s and future climate is of great importance specifically adaptation planning for” → “for adaptation planning for”?
105: This is just an opinion and I appreciate that the authors also want to advertise their project with this paper but maybe they could tune down the references to climxtreme a bit? At least I can not see why it is relevant to the reader how climXtreme organized the investigation underlying this manuscript and the manuscript is already very long.
Also 134, 613, ...Section 2: I am sorry but find this section quite hard to follow and at the same time it probably does not provide enough information to actually understand what was done in detail. I appreciate that it is not easy to write a concise method section for such an extensive paper but I think this could be done better. Currently the reader is thrown into more than 10 sub-sections mixing individual extreme definitions, compound events, and impacts. In addition, the level of detail somewhat differs between sections and there are many design choices that are not really reflected or compared.
Just two examples:
- the authors repeatedly state that the summer months JJA are used (lines 157, 199, 272) but in other sections they only refer to summer (145, 161) or other periods such as the hydrological year (161) or the warm season (282). Given that this study is about compounding it seems important to be clear on the properties of the different events considered and their relation.
- There are a range of relative thresholds used to define extremes. I fond some based on the 90, 95, and 98 percentiles. I’m not saying that this is inherently problematic but it should be made clear.My suggestion would be to start with an overview section explaining the structure of this section. This could include a table summarizing the main features of each analysis to ensure a similar level of detail and ease comparing differences.
150: Note that using a 15 day running window do define extreme thresholds (as done Fischer and Schär)of has been shown to be methodologically wrong and prone to biases recently: https://www.nature.com/articles/s41467-024-46349-x
229: “The co-occurrence should be on the same day or the following day for precipitation, in the same grid cell and within a radius of 50 km, respectively.” I’m not sure I understand what it means for an event to be within the same grid cell and at the same time within 50km. If we assume the 0.25deg resolution corresponds to 25km, this would mean it can be a maximum of two grid cells away in the horizontal as an example? Is that correct? Can the authors clarify this?
274: “The compound precipitation-wind events are defined on the winter (December to February) daily mean precipitation and daily maximum surface wind. The selection of events is based on the
exceedance of the 98th percentile for the period 1975-2025…”
and then later
278: “Extreme compound wind and precipitation years exceed the 20-year return levels for precipitation and wind individually, defined as the 95th percentiles for the period 1975-2025.”
Sorry but this confuses me. Can the authors clarify the difference between “compound precipitation-wind events” and “ Extreme compound wind and precipitation years”?303: “a large blocking system at 500 hPa, and a double jet stream
configuration is visible in the 250mb zonal wind field”
Maybe settle for one unit?
Also I read the sentence as saying that a 500hPa blocking is visible in the 250mb zonal wind field. I think I understand what the authors try to say here but you can not see 500hPa at 250hPa by definition…Figure 12: what do the dashed lines represent?
Figure 13: Fontsize way too small
(b) the title says CMIP5 1975-2021, the caption says historical CMIP5 ensemble. Maybe I’m not aware that the CMIP5 historical runs where extended otherwise this is wrong.
“Significant model ensemble grid points are shaded dark.” Unclear what that dark means here.
614: “The showcases presented in this paper include multivariate, pre-conditioning, temporally and spatial Ces”
Again, a summarizing table would be nice to give an overview.
611-648: Delete or shorten by a lot? This is not a conclusion but basically a reiteration of the results.655: “Further studies aim at expanding the current knowledge on the complex
relationships between CEs and large-scale fields at different time horizons in order to improve the detection and thus the understanding of the climate system.”
Not sure what this sentence is trying to say? What further studies?Citation: https://doi.org/10.5194/egusphere-2023-1460-RC2
Data sets
Cropdata – spatial yield productivity data base for the ten most cultivated crops in Germany from 1989 to 2020 - version 1.0 F. Ellsäßer and E. Xoplaki http://dx.doi.org/10.22029/jlupub-7177
Cropdata – yield anomaly catalogue for the ten most cultivated crops in Germany from 1989 to 2020 - version 1.0 F. Ellsäßer and E. Xoplaki http://dx.doi.org/10.22029/jlupub-7176
Cropdata – supplementary data (for spatial yield productivity data base for the ten most cultivated crops in Germany from 1989 to 2020) - version 1.0 F. Ellsäßer and E. Xoplaki http://dx.doi.org/10.22029/jlupub-7203
Viewed
HTML | XML | Total | Supplement | BibTeX | EndNote | |
---|---|---|---|---|---|---|
656 | 261 | 37 | 954 | 44 | 37 | 29 |
- HTML: 656
- PDF: 261
- XML: 37
- Total: 954
- Supplement: 44
- BibTeX: 37
- EndNote: 29
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1