An open workflow to gain insights about low‐likelihood high‐impact weather events from initialized predictions

Meteorological Applications, Год журнала: 2022, Номер 29(3)

Опубликована: Май 1, 2022

Abstract Low‐likelihood weather events can cause dramatic impacts, especially when they are unprecedented. In 2020, amongst other high‐impact events, UK floods caused more than £300 million damage, prolonged heat over Siberia led to infrastructure failure and permafrost thawing, while wildfires ravaged California. Such rare phenomena cannot be studied well from historical records or reanalysis data. One way improve our awareness is exploit ensemble prediction systems, which represent large samples of simulated events. This ‘UNSEEN’ method has been successfully applied in several scientific studies, but uptake hindered by data processing requirements, uncertainty regarding the credibility simulations. Here, we provide a protocol apply ensure UNSEEN for studying low‐likelihood globally, including an open workflow based on Copernicus Climate Change Services (C3S) seasonal predictions. Demonstrating using European Centre Medium‐Range Weather Forecasts (ECMWF) SEAS5, find that 2020 March–May Siberian heatwave was predicted one members; record‐shattering August California‐Mexico temperatures were part strong increasing trend. However, each case studies exposes challenges with respect sensitivity outcomes user decisions. We conclude new insights about decisions transparent, sensitivities acknowledged. Anticipating plausible extreme uncovering unforeseen hazards under changing climate warrants further research at science‐policy interface manage high impacts.

Язык: Английский

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Typicality of the 2021 Western North America summer heatwave

Environmental Research Letters, Год журнала: 2022, Номер 18(1), С. 015004 - 015004

Опубликована: Дек. 14, 2022

Abstract Elucidating the statistical properties of extreme meteo-climatic events and capturing physical processes responsible for their occurrence are key steps improving our understanding climate variability change better evaluating associated hazards. It has recently become apparent that large deviation theory (LDT) is very useful investigating persistent events, specifically, flexibly estimating long return periods introducing a notion dynamical typicality. Using methodological framework based on LDT taking advantage simulations by state-of-the-art Earth system model, we investigate 2021 Western North America summer heatwave. Indeed, analysis shows event can be seen as an unlikely but possible manifestation variability, whilst its probability greatly amplified ongoing change. We also clarify spatial coherence heatwave elucidate role played Rocky Mountains in modulating hot, dry, Pacific region America.

Язык: Английский

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Increasing Risks of Future Compound Climate Extremes With Warming Over Global Land Masses

Earth s Future, Год журнала: 2023, Номер 11(9)

Опубликована: Сен. 1, 2023

Abstract Compound climate extremes (here referred to compound dry–hot events and pluvial–hot events) result in devastating disasters which threaten water‐food‐energy security. However, a warming scenario, the risk of occurrence, quantification uncertainty, associated drivers extremes—particularly events—have not been fully explored. By leveraging model large ensembles, it is revealed that projected increase 2–3 times over most global land masses future Representative Concentration Pathway (RCP) 8.5 forcing compared with historical forcing. Increased risks are mainly attributed changes temperature dependence between precipitation temperature, while change contributing these two exhibits approximately spatial complementary. In world, hot spots lie Europe, South Africa, Amazon, those mostly eastern USA, southern Asia, Australia, central Africa. These findings help stakeholders decision makers develop package adaptation strategies manage mitigate extremes.

Язык: Английский

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Machine learning–based extreme event attribution

Science Advances, Год журнала: 2024, Номер 10(34)

Опубликована: Авг. 21, 2024

The observed increase in extreme weather has prompted recent methodological advances event attribution. We propose a machine learning–based approach that uses convolutional neural networks to create dynamically consistent counterfactual versions of historical events under different levels global mean temperature (GMT). apply this technique one heat (southcentral North America 2023) and several have been previously analyzed using established attribution methods. estimate temperatures during the southcentral were 1.18° 1.42°C warmer because warming similar will occur 0.14 0.60 times per year at 2.0°C above preindustrial GMT. Additionally, we find learned relationships between daily GMT are influenced by seasonality forced response meteorological conditions. Our results broadly agree with other techniques, suggesting learning can be used perform rapid, low-cost events.

Язык: Английский

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Could an extremely cold central European winter such as 1963 happen again despite climate change?

Weather and Climate Dynamics, Год журнала: 2024, Номер 5(3), С. 943 - 957

Опубликована: Июль 24, 2024

Abstract. Central European winters have warmed markedly since the mid-20th century. Yet cold are still associated with severe societal impacts on energy systems, infrastructure, and public health. It is therefore crucial to anticipate storylines of worst-case winter conditions understand whether an extremely winter, such as coldest historical record Germany in 1963 (−6.3 °C or −3.4σ seasonal December–January–February (DJF) temperature anomaly relative 1981–2010), possible a warming climate. Here, we first show based multiple attribution methods that similar circulation would lead extreme about −4.9 −4.7 (best estimates across methods) under present-day This rank second-coldest last 75 years. Second, conceive two independent rare event sampling (climate model boosting empirical importance sampling): physically central Europe today, albeit very unlikely. While hazards become less frequent intense climate overall, it remains possibility avoid potential maladaptation increased vulnerability.

Язык: Английский

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Simulating record-shattering cold winters of the beginning of the 21st century in France

Weather and Climate Dynamics, Год журнала: 2025, Номер 6(1), С. 1 - 15

Опубликована: Янв. 7, 2025

Abstract. Extreme cold winter temperatures in Europe have huge societal impacts. Being able to simulate worst-case scenarios for such events present and future climates is hence crucial short- long-term adaptation. In this paper, we are interested persistent events, whose probability will decrease with climate change. Large ensembles of simulations allow us better analyse the mechanisms characteristics but can require significant computational resources. Rather than simulating very large normal trajectories, rare-event algorithms sampling tail distributions more efficiently. Such been applied extreme heat waves. They emphasized role atmospheric circulation extremes. The goal study evaluate dynamics spells simulated by a algorithm. We focus on that occurred France from 1950 2021. investigate mean (December, January February) identify record-shattering event 1963. find although frequency decreases time, their intensity stationary. apply stochastic weather generator (SWG) approach importance coldest winters could occur factual counterfactual climate. thus worst consistent reanalysis data. few reach colder historical This shows present-day conditions trigger as record spite global warming. prevails during those analysed compared observed record-breaking showing no main change leading type event.

Язык: Английский

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Maximal reachable temperatures for Western Europe in current climate

Environmental Research Letters, Год журнала: 2023, Номер 18(9), С. 094061 - 094061

Опубликована: Сен. 1, 2023

Abstract Human bodies, ecosystems and infrastructures display a non-linear sensibility to extreme temperatures occurring during heatwave events. Preparing for such events entails know how high surface air can go. Here we examine the maximal reachable in Western Europe. Taking July 2019 record-breaking as case study employing flow analogues methodology, find that exceeding 50 ∘ C cannot be ruled out most urban areas, even under current climate conditions. We analyze changes upper bound of between past (1940–1980) present (1981–2021) periods. Our results show significant increase daily maximum period is only partially explained by bound. suggest warming result from strengthened diabatic fluxes rather than free troposphere warming.

Язык: Английский

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The probability of unprecedented high rainfall in wine regions of northern Portugal

Climate Services, Год журнала: 2023, Номер 30, С. 100363 - 100363

Опубликована: Фев. 10, 2023

Climate is arguably one of the most important factors determining quality wine from any given grapevine variety. This study focuses on three wine-growing regions in northern Portugal: Vinho Verde, Trás-os-Montes and Douro, latter coinciding with Porto. High rainfall during late spring (April to June) can promote growth vines but increases risk fungal disease. harvest time (August October) also bears potential for severe operational disruption heavy economic losses. The probability unprecedented totals season over Portugal has been assessed. A large ensemble initialised climate model simulations analysed, each quantified. Seasonal considerably higher than observed are possible current climate. An event either could occur a between 0.01 0.05 present Extreme value analysis was applied observations ensemble, return periods known extreme events calculated. Similar probabilities were year similar 1993, when both seasons exceptionally wet, would be expected occur, average, just once next 70–80 years These results inform requirements improved vineyard management resilience, such as design drainage channels, access roads terraces.

Язык: Английский

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Statistical physics and dynamical systems perspectives on geophysical extreme events

Physical review. E, Год журнала: 2024, Номер 110(4)

Опубликована: Окт. 4, 2024

Statistical physics and dynamical systems theory are key tools to study high-impact geophysical events such as temperature extremes, cyclones, thunderstorms, geomagnetic storms, many others. Despite the intrinsic differences between these events, they all originate temporary deviations from typical trajectories of a system, resulting in well-organized, coherent structures at characteristic spatial temporal scales. While statistical extreme value analysis techniques capable providing return times probabilities occurrence certain not apt account for their underlying physics. Their focus is compute probability that large or small with respect some specific observable (e.g., temperature, precipitation, solar wind), rather than relate rare phenomena anomalous regimes. This paper outlines this knowledge gap, presenting related challenges, new formalisms briefly commenting on how stochastic approaches tailored can help advance understanding.

Язык: Английский

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Frontiers in attributing climate extremes and associated impacts

Frontiers in Climate, Год журнала: 2024, Номер 6

Опубликована: Окт. 14, 2024

The field of extreme event attribution (EEA) has rapidly developed over the last two decades. Various methods have been and implemented, physical modelling capabilities generally improved, impact emerged, assessments serve as a popular communication tool for conveying how climate change is influencing weather events in lived experience. However, number non-trivial challenges still remain that must be addressed by community to secure further advancement whilst ensuring scientific rigour appropriate use findings stakeholders associated applications. As part concept series commissioned World Climate Research Programme, this article discusses contemporary developments six key domains relevant EEA, provides recommendations where focus EEA should concentrated coming decade. These are: (1) observations context EEA; (2) definitions; (3) statistical methods; (4) (5) attribution; (6) communication. Broadly, call increased capacity building, particularly more vulnerable regions; guidelines assessing suitability models; establishing best-practice methodologies on compound record-shattering extremes; co-ordinated interdisciplinary engagement develop scaffolding their broader applications; ongoing investment To address these requires significant multiple fields either underpin (e.g., monitoring; modelling) or are closely related events; impacts) well working consistently with experts outside science generally. if approached investment, dedication, coordination, tackling next decade will ensure robust analysis, tangible benefits global community.

Язык: Английский

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