The first multi-model ensemble of regional climate simulations at kilometer-scale resolution, part I: evaluation of precipitation

Climate Dynamics, Год журнала: 2021, Номер 57(1-2), С. 275 - 302

Опубликована: Апрель 9, 2021

Abstract Here we present the first multi-model ensemble of regional climate simulations at kilometer-scale horizontal grid spacing over a decade long period. A total 23 run with $$\sim $$ ∼ 3 km, driven by ERA-Interim reanalysis, and performed 22 European research groups are analysed. Six different models (RCMs) represented in ensemble. The compared against available high-resolution precipitation observations coarse resolution ( 12 km) RCMs parameterized convection. model respect to mean precipitation, intensity frequency, heavy on daily hourly timescales seasons. results show that produce more realistic representation than RCMs. most significant improvements found for frequency both time scales summer season. In general, tend intense reduced wet-hour models. On average, shows reduction bias from \,$$ −40% km −3% summer. Furthermore, uncertainty ranges i.e. variability between wet hour is half use Although differences still exist, it evident these superior coarse-resolution RCM representing present-day climate, thus offer promising way forward investigations change local scales.

Язык: Английский

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Convection‐permitting modeling with regional climate models: Latest developments and next steps

Wiley Interdisciplinary Reviews Climate Change, Год журнала: 2021, Номер 12(6)

Опубликована: Авг. 16, 2021

Abstract Approximately 10 years ago, convection‐permitting regional climate models (CPRCMs) emerged as a promising computationally affordable tool to produce fine resolution (1–4 km) decadal‐long simulations with explicitly resolved deep convection. This explicit representation is expected reduce projection uncertainty related convection parameterizations found in most models. A recent surge CPRCM decadal over larger domains, sometimes covering continents, has led important insights into advantages and limitations. Furthermore, new observational gridded datasets spatial temporal (~1 km; ~1 h) resolutions have leveraged additional knowledge through evaluations of the added value CPRCMs. With an improved coordination frame ongoing international initiatives, production ensembles provide more robust projections better identification their associated uncertainties. review paper presents overview methodology latest research on current future climates. Impact studies that are already taking advantage these highlighted. ends by proposing next steps could be accomplished continue exploiting full potential article categorized under: Climate Models Modeling > Earth System

Язык: Английский

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Climate Change and Rainfall Intensity–Duration–Frequency Curves: Overview of Science and Guidelines for Adaptation

Journal of Hydrologic Engineering, Год журнала: 2021, Номер 26(10)

Опубликована: Авг. 3, 2021

One of the most important impacts a future warmer climate is projected increase in frequency and intensity extreme rainfall events. This increasing trend seen both observational record model projections. However, thorough review recent scientific literature paints complex picture which intensification extremes depends on multitude factors. While some indices follow Clausius-Clapeyron relationship scaling an ∼7% per 1°C warming, there substantial evidence that this frequency, with longer return period events seeing larger increases, leading to super cases. The now well documented at daily scale but less clear subdaily scale. In years, simulations finer spatial temporal resolution, including convection-permitting models, have provided more reliable projections rainfall. Recent analyses indicate may also as function duration, such shorter-duration, will likely see largest increases climate. has broad implications design use intensity–duration–frequency (IDF) curves, for overall magnitude steepening can be predicted. paper presents overview measures been adopted by various governing bodies adapt IDF curves changing Current vary from multiplying historical simple constant percentage modulating correction factors based periods them temperature increases. All these current fail recognize possible and, perhaps importantly, toward shorter-duration significantly impact stormwater runoff cities small rural catchments. discusses remaining gaps offers technical recommendations practitioners how improve resilience.

Язык: Английский

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21st Century alpine climate change

Climate Dynamics, Год журнала: 2022, Номер 60(1-2), С. 65 - 86

Опубликована: Май 10, 2022

Abstract A comprehensive assessment of twenty-first century climate change in the European Alps is presented. The analysis based on EURO-CORDEX regional model ensemble available at two grid spacings (12.5 and 50 km) for three different greenhouse gas emission scenarios (RCPs 2.6, 4.5 8.5). core simulation has been subject to a dedicated evaluation exercise carried out frame CH2018 Climate Scenarios Switzerland. Results reveal that entire Alpine region will face warmer course all considered. Strongest warming projected summer season, regions south main ridge high-end RCP 8.5 scenario. Depending medium high elevations might experience an amplified warming. Model uncertainty can be considerable, but major patterns are consistent across ensemble. For precipitation, seasonal shift precipitation amounts from winter over most parts domain projected. However, individual simulations show signals opposite sign. Daily intensity increase seasons sub-domains, while wet-day frequency decrease season. temperature negatively correlated with change, i.e. and/or strong mean typically stronger decrease. By contrast, positive correlation between found winter. Among other indicators, snow cover strongly affected by climatic changes widespread except very elevation settings. In general magnitude increases assumed forcing, i.e., smallest 2.6 largest being located between. These results largely agree previous works older generations RCM ensembles but, due comparatively large size spatial resolution, allow more decent inherent projection uncertainties details future change.

Язык: Английский

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Variability conceals emerging trend in 100yr projections of UK local hourly rainfall extremes

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Март 7, 2023

Extreme precipitation is projected to intensify with warming, but how this will manifest locally through time uncertain. Here, we exploit an ensemble of convection-permitting transient simulations examine the emerging signal in local hourly rainfall extremes over 100-years. We show events UK exceeding 20 mm/h that can cause flash floods are 4-times as frequent by 2070s under high emissions; contrast, a coarser resolution regional model shows only 2.6x increase. With every degree intensity extreme downpours increases 5-15%. Regional records occur 40% more often than absence warming. However, these changes not realised smooth trend. Instead, result internal variability, years record-breaking may be followed multiple decades no new records. The tendency for cluster poses key challenges communities trying adapt.

Язык: Английский

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The pseudo-global-warming (PGW) approach: methodology, software package PGW4ERA5 v1.1, validation, and sensitivity analyses

Geoscientific model development, Год журнала: 2023, Номер 16(3), С. 907 - 926

Опубликована: Фев. 6, 2023

Abstract. The term “pseudo-global warming” (PGW) refers to a simulation strategy in regional climate modeling. consists of directly imposing large-scale changes the system on control (usually representing current conditions) by modifying boundary conditions. This differs from traditional dynamic downscaling technique where output global model (GCM) is used drive models (RCMs). PGW are usually derived transient simulation. approach offers several benefits, such as lowering computational requirements, flexibility design, and avoiding biases models. However, implementing non-trivial, care must be taken not deteriorate physics when To simplify preparation simulations, we present detailed description methodology provide companion software PGW4ERA5 facilitating simulations. In describing methodology, particular attention devoted adjustment pressure geopotential fields. Such an required ensuring consistency between thermodynamical (temperature humidity) one hand dynamical other hand. It demonstrated that this important extratropics highly essential tropical subtropical regions. We show projections simulations prepared using presented closely comparable for most climatological variables.

Язык: Английский

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Convection-permitting climate models offer more certain extreme rainfall projections

npj Climate and Atmospheric Science, Год журнала: 2024, Номер 7(1)

Опубликована: Фев. 28, 2024

Abstract Extreme precipitation events lead to dramatic impacts on society and the situation will worsen under climate change. Decision-makers need reliable estimates of future changes as a basis for effective adaptation strategies, but projections at local scale from regional models (RCMs) are highly uncertain. Here we exploit km-scale convection-permitting multi-model (CPM) ensemble, generated within FPS Convection project, provide new understanding in extremes related uncertainties over greater Alpine region. The CPM ensemble shows stronger increase fractional contribution extreme than driving RCM during summer, when convection dominates. We find that substantially reduces model their total by more 50%. conclude realistic representation dynamical processes CPMs provides change, which essential policymakers plan measures.

Язык: Английский

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Projections of Heavy Precipitation Characteristics Over the Greater Alpine Region Using a Kilometer–Scale Climate Model Ensemble

Journal of Geophysical Research Atmospheres, Год журнала: 2025, Номер 130(2)

Опубликована: Янв. 11, 2025

Abstract This study presents a detailed analysis of the CORDEX‐FPS multi‐model ensemble convection‐permitting climate simulations over greater Alpine region. These cover 10‐year time slices and were obtained by downscaling global model (GCM) projections, using regional models (RCMs) kilometer‐scale (CPMs). Our area agrees with previous studies in terms projected summer precipitation changes for end century, particular regarding decrease mean increases hourly intensities. In addition, we assess different subregions, provide analyses at monthly seasonal basis temporal aggregations ranging from 1 hr to 5 days, address extreme indices, present validation against an Alpine‐scale daily data set product based on 3 Doppler radars. The evaluation reveals that CPMs show refinement spatial patterns, reduce overestimation frequency, better capture intense characteristics. improvements are especially apparent sub‐daily scale season. Convection‐Permitting Model projections increase intensity all seasons across regions, except Mediterranean summer. qualitatively agree, despite significant differences GCMs circulation changes, suggesting heavy events is primarily due thermodynamic effects. We also hypothesis explaining why relative percentiles similar between RCMs, large biases RCMs.

Язык: Английский

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Modelling Mediterranean heavy precipitation events at climate scale: an object-oriented evaluation of the CNRM-AROME convection-permitting regional climate model

Climate Dynamics, Год журнала: 2021, Номер 56(5-6), С. 1717 - 1752

Опубликована: Янв. 11, 2021

Abstract Modelling the rare but high-impact Mediterranean Heavy Precipitation Events (HPEs) at climate scale remains a largely open scientific challenge. The issue is adressed here by running 38-year-long continuous simulation of CNRM-AROME Convection-Permitting Regional Climate Model (CP-RCM) 2.5 km horizontal resolution and over large pan-Alpine domain. First, evaluated through basic Eulerian statistical approach via comparison with selected high spatial temporal observational datasets. Northwestern fall extreme precipitation correctly represented daily even better an hourly scale, in terms location, intensity, frequency interannual variability, despite underestimation highest intensities above 200 mm/day 40 mm/h, respectively. A CP-RCM its forcing convection-parameterised 12.5 (RCM) demonstrates clear added value for CP-RCM, confirming previous studies. Secondly, object-oriented Lagrangian proposed implementation precipitating system detection tracking algorithm, applied to model reference COMEPHORE dataset twenty seasons. Using French HPEs as objects, CNRM-AROME’s ability represent main characteristics convective systems tracks highlighted number, area, duration, velocity severity. Further, able simulate long-lasting severe events similar observations. However, it fails reproduce (maximum mm/h) well, model’s tendency overestimate cell size increases intensity.

Язык: Английский

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The CORDEX-CORE EXP-I Initiative: Description and Highlight Results from the Initial Analysis

Bulletin of the American Meteorological Society, Год журнала: 2021, Номер 103(2), С. E293 - E310

Опубликована: Окт. 4, 2021

Abstract We describe the first effort within Coordinated Regional Climate Downscaling Experiment–Coordinated Output for Evaluation, or CORDEX-CORE EXP-I. It consists of a set twenty-first-century projections with two regional climate models (RCMs) downscaling three global model (GCM) simulations from CMIP5 program, greenhouse gas concentration pathways (RCP8.5 and RCP2.6), over nine CORDEX domains at ∼25-km grid spacing. Illustrative examples initial analysis this ensemble are presented, covering wide range topics, such as added value RCM nesting, extreme indices, tropical extratropical storms, monsoons, ENSO, severe storm environments, emergence change signals, energy production. They show that EXP-I can provide downscaled information unprecedented comprehensiveness to increase understanding processes relevant impacts, assess RCMs. The dataset, which will be incrementally augmented new simulations, is intended public resource available scientific end-user communities application process studies, impacts on different socioeconomic sectors, service activities. future initiative also discussed.

Язык: Английский

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