Model projected changes of extreme wind events in response to global warming

&#160;Extreme weather events represent one of the most visible and immediate hazards to society. Many of these types of phenomena are projected to increase in intensity, duration or frequency as the climate warms. Of these extreme winds are among the most damaging historically over Europe yet assessments of their future changes remain fraught with uncertainty. This uncertainty arises due to both the rare nature of extreme wind events and the fact that most model are unable to faithfully represent them. Here we take advantage of a 15-member ensemble of high-resolution Euro-CORDEX simulations (~12km) and investigate projected changes in extreme winds using a peaks-over-threshold approach. Additionally, we show that - despite lingering model deficiencies and inadequate observational coverage - there is clear added value of the higher resolution simulations over coarser resolution counterparts. Further, the spatial heterogeneity and highly localized nature is well captured. Effects such as orographic interactions, drag due to urban areas, and even individual storm tracks over the oceans are clearly visible. As such future changes also exhibit strong spatial heterogeneity. These results emphasize the need for careful case-by-case treatment of extreme wind analysis, especially when done in a climate adaptation or decision-making context. However, for more general assessments the picture is clearer with increases in the return period (i.e., more frequent) extreme episodes projected for Northern, Central and Southern Europe throughout the 21st century. While models continue to improve in their representation of extreme winds, improved observational coverage is desperately needed to better constrain and obtain more robust assessments of future extreme winds over Europe and elsewhere.&#160;

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2 °C vs. High Warming: Transitions to Flood-Generating Mechanisms across Canada

Water ◽

10.3390/w13111494 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1494

Author(s):

Bernardo Teufel ◽

Laxmi Sushama

Keyword(s):

Climate Change ◽

Global Warming ◽

Climate Model ◽

Regional Climate ◽

Adaptation Measures ◽

Relative Contribution ◽

Late 21St Century ◽

Transient Climate Change ◽

Projected Changes ◽

Change Mitigation

Fluvial flooding in Canada is often snowmelt-driven, thus occurs mostly in spring, and has caused billions of dollars in damage in the past decade alone. In a warmer climate, increasing rainfall and changing snowmelt rates could lead to significant shifts in flood-generating mechanisms. Here, projected changes to flood-generating mechanisms in terms of the relative contribution of snowmelt and rainfall are assessed across Canada, based on an ensemble of transient climate change simulations performed using a state-of-the-art regional climate model. Changes to flood-generating mechanisms are assessed for both a late 21st century, high warming (i.e., Representative Concentration Pathway 8.5) scenario, and in a 2 °C global warming context. Under 2 °C of global warming, the relative contribution of snowmelt and rainfall to streamflow peaks is projected to remain close to that of the current climate, despite slightly increased rainfall contribution. In contrast, a high warming scenario leads to widespread increases in rainfall contribution and the emergence of hotspots of change in currently snowmelt-dominated regions across Canada. In addition, several regions in southern Canada would be projected to become rainfall dominated. These contrasting projections highlight the importance of climate change mitigation, as remaining below the 2 °C global warming threshold can avoid large changes over most regions, implying a low likelihood that expensive flood adaptation measures would be necessary.

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The Extreme Wind Events in the Ross Island Region of Antarctica

Weather and Forecasting ◽

10.1175/waf-d-15-0125.1 ◽

2016 ◽

Vol 31 (3) ◽

pp. 985-1000 ◽

Cited By ~ 1

Author(s):

Nicholas J. Weber ◽

Matthew A. Lazzara ◽

Linda M. Keller ◽

John J. Cassano

Keyword(s):

Structural Damage ◽

Ross Sea ◽

Enso Event ◽

Central Pacific ◽

Island Region ◽

Back Trajectories ◽

Extreme Wind ◽

Mcmurdo Station ◽

Wind Events ◽

Upper Level

Abstract Numerous incidents of structural damage at the U.S. Antarctic Program’s (USAP) McMurdo Station due to extreme wind events (EWEs) have been reported over the past decade. Utilizing nearly 20 yr (~1992–2013) of University of Wisconsin automatic weather station (AWS) data from three different stations in the Ross Island region (Pegasus North, Pegasus South, and Willie Field), statistical analysis shows no significant trends in EWE frequency, intensity, or duration. EWEs more frequently occur during the transition seasons. To assess the dynamical environment of these EWEs, Antarctic Mesoscale Prediction System (AMPS) forecast back trajectories are computed and analyzed in conjunction with several other AMPS fields for the strongest events at McMurdo Station. The synoptic analysis reveals that McMurdo Station EWEs are nearly always associated with strong southerly flow due to an approaching Ross Sea cyclone and an upper-level trough around Cape Adare. A Ross Ice Shelf air stream (RAS) environment is created with enhanced barrier winds along the Transantarctic Mountains, downslope winds in the lee of the glaciers and local topography, and a tip jet effect around Ross Island. The position and intensity of these Ross Sea cyclones are most influenced by the occurrence of a central Pacific ENSO event, which causes the upper-level trough to move westward. An approaching surface cyclone would then be in position to trigger an event, depending on how the wind direction and speed impinges on the complex topography around McMurdo Station.

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Response of Tropical Cyclone Potential Intensity to a Global Warming Scenario in the IPCC AR4 CGCMs

Journal of Climate ◽

10.1175/2009jcli2843.1 ◽

2010 ◽

Vol 23 (6) ◽

pp. 1354-1373 ◽

Cited By ~ 18

Author(s):

Jinhua Yu ◽

Yuqing Wang ◽

Kevin Hamilton

Keyword(s):

Global Warming ◽

Tropical Cyclone ◽

Large Scale ◽

Linear Trend ◽

Relative Effect ◽

Vertical Shear ◽

Model Parameters ◽

Climate Projections ◽

South Indian ◽

Projected Changes

Abstract This paper reports on an analysis of the tropical cyclone (TC) potential intensity (PI) and its control parameters in transient global warming simulations. Specifically, the TC PI is calculated for phase 3 of the Coupled Model Intercomparison Project (CMIP3) integrations during the first 70 yr of a transient run forced by a 1% yr−1 CO2 increase. The linear trend over the period is used to project a 70-yr change in relevant model parameters. The results for a 15-model ensemble-mean climate projection show that the thermodynamic potential intensity (THPI) increases on average by 1.0% to ∼3.1% over various TC basins, which is mainly attributed to changes in the disequilibrium in enthalpy between the ocean and atmosphere in the transient response to increasing CO2 concentrations. This modest projected increase in THPI is consistent with that found in other recent studies. In this paper the effects of evolving large-scale dynamical factors on the projected TC PI are also quantified, using an empirical formation that takes into account the effects of vertical shear and translational speed based on a statistical analysis of present-day observations. Including the dynamical efficiency in the formulation of PI leads to larger projected changes in PI relative to that obtained using just THPI in some basins and smaller projected changes in others. The inclusion of the dynamical efficiency has the largest relative effect in the main development region (MDR) of the North Atlantic, where it leads to a 50% reduction in the projected PI change. Results are also presented for the basin-averaged changes in PI for the climate projections from each of the 15 individual models. There is considerable variation among the results for individual model projections, and for some models the projected increase in PI in the eastern Pacific and south Indian Ocean regions exceeds 10%.

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Projected changes to extreme wind and snow environmental loads for buildings and infrastructure across Canada

Sustainable Cities and Society ◽

10.1016/j.scs.2017.10.004 ◽

2018 ◽

Vol 36 ◽

pp. 225-236 ◽

Cited By ~ 9

Author(s):

Dae Il Jeong ◽

Laxmi Sushama

Keyword(s):

Environmental Loads ◽

Extreme Wind ◽

Projected Changes

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Extreme winds in a WRF downscaling for the SAM-22 CORDEX domain for the 1979-2018 Historical Period

10.5194/egusphere-egu21-10363 ◽

2021 ◽

Author(s):

Natalia Pillar da Silva ◽

Rosmeri Porfírio da Rocha ◽

Natália Machado Crespo ◽

Ricardo de Camargo ◽

Jose Antonio Moreira Lima ◽

...

Keyword(s):

Wind Speed ◽

Oil And Gas ◽

Offshore Structures ◽

Horizontal Resolution ◽

Historical Period ◽

Climate Projections ◽

Wind Speeds ◽

Extreme Wind ◽

Wind Events ◽

Extreme Winds

This study aims to evaluate how extreme winds (above the 95th percentile) are represented in a downscaling using the regional model WRF over the CORDEX South American domain in an approximate 25 km (0.22 degrees) horizontal resolution, along with CFSR as input. The main focus of the analysis resides over the coastal Brazilian region, given a large number of offshore structures from oil and gas industries subject to impact by severe events. Model results are compared with a reanalysis product (ERA5), &#160;estimates from satellites product (Cross-Calibrated Multi-Platform Wind Speed), and available buoy data (Brazilian National Buoy Project). Downscaling results from WRF show an underestimation of maximum and extreme wind speeds over the region when compared to all references, along with overestimation in the continental areas. This directly impacts results for extreme value estimation for a larger return period and severity evaluation of extreme wind events in future climate projections. To address this, a correction procedure based on the linear relationship between severe wind from satellite and model results is applied. After linearly corrected, the extreme and maximum wind speed values increase and errors in the representation of severe events are reduced in the downscaling results.

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Intraseasonal Precipitation Variability over West Africa under 1.5 °C and 2.0 °C Global Warming Scenarios: Results from CORDEX RCMs

Climate ◽

10.3390/cli8120143 ◽

2020 ◽

Vol 8 (12) ◽

pp. 143

Author(s):

Obed M. Ogega ◽

Benjamin A. Gyampoh ◽

Malcolm N. Mistry

Keyword(s):

Global Warming ◽

West Africa ◽

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Future Change ◽

North West ◽

Intensity Index ◽

South West Africa ◽

Projected Changes

This study assessed the performance of 24 simulations, from five regional climate models (RCMs) participating in the Coordinated Regional Climate Downscaling Experiment (CORDEX), in representing spatiotemporal characteristics of precipitation over West Africa, compared to observations. The top five performing RCM simulations were used to assess future precipitation changes over West Africa, under 1.5 °C and 2.0 °C global warming levels (GWLs), following the representative concentration pathway (RCP) 8.5. The performance evaluation and future change assessment were done using a set of seven ‘descriptors’ of West African precipitation namely the simple precipitation intensity index (SDII), the consecutive wet days (CWD), the number of wet days index (R1MM), the number of wet days with moderate and heavy intensity precipitation (R10MM and R30MM, respectively), and annual and June to September daily mean precipitation (ANN and JJAS, respectively). The performance assessment and future change outlook were done for the CORDEX–Africa subdomains of north West Africa (WA-N), south West Africa (WA-S), and a combination of the two subdomains. While the performance of RCM runs was descriptor- and subregion- specific, five model runs emerged as top performers in representing precipitation characteristics over both WA-N and WA-S. The five model runs are CCLM4 forced by ICHEC-EC-EARTH (r12i1p1), RCA4 forced by CCCma-CanESM2 (r1i1p1), RACMO22T forced by MOHC-HadGEM2-ES (r1i1p1), and the ensemble means of simulations made by CCLM4 and RACMO22T. All precipitation descriptors recorded a reduction under the two warming levels, except the SDII which recorded an increase. Unlike the WA-N that showed less frequency and more intense precipitation, the WA-S showed increased frequency and intensity. Given the potential impact that these projected changes may have on West Africa’s socioeconomic activities, adjustments in investment may be required to take advantage of (and enhance system resilience against damage that may result from) the potential changes in precipitation.

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