scholarly journals Projected changes in persistent extreme summer weather events: The role of quasi-resonant amplification

2018 ◽  
Vol 4 (10) ◽  
pp. eaat3272 ◽  
Author(s):  
Michael E. Mann ◽  
Stefan Rahmstorf ◽  
Kai Kornhuber ◽  
Byron A. Steinman ◽  
Sonya K. Miller ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Coupled Model ◽  
High Amplitude ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Anthropogenic Aerosols ◽  
Pronounced Increase ◽  
Weather Events

Persistent episodes of extreme weather in the Northern Hemisphere summer have been associated with high-amplitude quasi-stationary atmospheric Rossby waves, with zonal wave numbers 6 to 8 resulting from the phenomenon of quasi-resonant amplification (QRA). A fingerprint for the occurrence of QRA can be defined in terms of the zonally averaged surface temperature field. Examining state-of-the-art [Coupled Model Intercomparison Project Phase 5 (CMIP5)] climate model projections, we find that QRA events are likely to increase by ~50% this century under business-as-usual carbon emissions, but there is considerable variation among climate models. Some predict a near tripling of QRA events by the end of the century, while others predict a potential decrease. Models with amplified Arctic warming yield the most pronounced increase in QRA events. The projections are strongly dependent on assumptions regarding the nature of changes in radiative forcing associated with anthropogenic aerosols over the next century. One implication of our findings is that a reduction in midlatitude aerosol loading could actually lead to Arctic de-amplification this century, ameliorating potential increases in persistent extreme weather events.

scholarly journals Multi-thousand member ensemble atmospheric simulations with global 60km resolution using climateprediction.net

2020 ◽  
Author(s):  
Peter Watson ◽  
Sarah Sparrow ◽  
William Ingram ◽  
Simon Wilson ◽  
Drouard Marie ◽  
...  
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Atmospheric Model ◽  
Computing System ◽  
Extreme Weather ◽  
Global Climate Models ◽  
Extreme Weather Events ◽  
Weather Events ◽  
The Impact

<p>Multi-thousand member climate model simulations are highly valuable for showing how extreme weather events will change as the climate changes, using a physically-based approach. However, until now, studies using such an approach have been limited to using models with a resolution much coarser than the most modern systems. We have developed a global atmospheric model with 5/6°x5/9° resolution (~60km in middle latitudes) that can be run in the climateprediction.net distributed computing system to produce such large datasets. This resolution is finer than that of many current global climate models and sufficient for good simulation of extratropical synoptic features such as storms. It will also allow many extratropical extreme weather events to be simulated without requiring regional downscaling. We will show that this model's simulation of extratropical weather is competitive with that in other current models. We will also present results from the first multi-thousand member ensembles produced at this resolution, showing the impact of 1.5°C and 2°C global warming on extreme winter rainfall and extratropical cyclones in Europe.</p>

scholarly journals Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Michael E. Mann ◽  
Stefan Rahmstorf ◽  
Kai Kornhuber ◽  
Byron A. Steinman ◽  
Sonya K. Miller ◽  
...  
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Climate Model ◽  
High Amplitude ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Weather Events ◽  
Zonal Wavenumber ◽  
Climate Model Simulations ◽  
Favorable Conditions

Abstract Persistent episodes of extreme weather in the Northern Hemisphere summer have been shown to be associated with the presence of high-amplitude quasi-stationary atmospheric Rossby waves within a particular wavelength range (zonal wavenumber 6–8). The underlying mechanistic relationship involves the phenomenon of quasi-resonant amplification (QRA) of synoptic-scale waves with that wavenumber range becoming trapped within an effective mid-latitude atmospheric waveguide. Recent work suggests an increase in recent decades in the occurrence of QRA-favorable conditions and associated extreme weather, possibly linked to amplified Arctic warming and thus a climate change influence. Here, we isolate a specific fingerprint in the zonal mean surface temperature profile that is associated with QRA-favorable conditions. State-of-the-art (“CMIP5”) historical climate model simulations subject to anthropogenic forcing display an increase in the projection of this fingerprint that is mirrored in multiple observational surface temperature datasets. Both the models and observations suggest this signal has only recently emerged from the background noise of natural variability.

scholarly journals Why Are Siberian Temperatures Plummeting While the Arctic Warms?

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Kimberly Cartier
Keyword(s):  
Climate Models ◽  
Extreme Weather ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Weather Events ◽  
Stratospheric Circulation

The answer involves the intricacies of stratospheric circulation, which, if better represented in climate models, could help predict extreme weather events in Siberia and elsewhere.

scholarly journals On the attribution of the impacts of extreme weather events to anthropogenic climate change

2021 ◽  
Author(s):  
Sarah E Perkins-Kirkpatrick ◽  
Daithi Stone ◽  
Dann M. Mitchell ◽  
Suzanne M. Rosier ◽  
Andrew David King ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Model ◽  
Anthropogenic Impacts ◽  
Extreme Weather ◽  
Anthropogenic Climate Change ◽  
Extreme Weather Events ◽  
Climate Change Signal ◽  
Care Needs ◽  
Weather Events ◽  
The Impact

Abstract Investigations into the role of anthropogenic climate change in extreme weather events are now starting to extend into analysis of anthropogenic impacts on non-climate (e.g. socio-economic) systems. However, care needs to be taken when making this extension, because methodological choices regarding extreme weather attribution can become crucial when considering the events’ impacts. The fraction of attributable risk (FAR) method, useful in extreme weather attribution research, has a very specific interpretation concerning a class of events, and there is potential to misinterpret results from weather event analyses as being applicable to specific events and their impact outcomes. Using two case studies of meteorological extremes and their impacts, we argue that FAR is not generally appropriate when estimating the magnitude of the anthropogenic signal behind a specific impact. Attribution assessments on impacts should always be carried out in addition to assessment of the associated meteorological event, since it cannot be assumed that the anthropogenic signal behind the weather is equivalent to the signal behind the impact because of lags and nonlinearities in the processes through which the impact system reacts to weather. Whilst there are situations where employing FAR to understand the climate change signal behind a class of impacts is useful (e.g. “system breaking” events), more useful results will generally be produced if attribution questions on specific impacts are reframed to focus on changes in the impact return value and magnitude across large samples of factual and counterfactual climate model and impact simulations. We advocate for constant interdisciplinary collaboration as essential for effective and robust impact attribution assessments.

Volcanic forcing of climate since 1850 in an interactive aerosol-chemistry-climate model

2021 ◽  
Author(s):  
Thomas Aubry ◽  
Anja Schmidt ◽  
Alix Harrow ◽  
Jeremy Walton ◽  
Jane Mulcahy ◽  
...  
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Coupled Model ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Aerosol Model ◽  
Volcanic Forcing

<p>Reconstructions of volcanic aerosol forcing and its climatic impacts are undermined by uncertainties in both the models used to build these reconstructions as well as the proxy and observational records used to constrain those models. Reducing these uncertainties has been a priority and in particular, several modelling groups have developed interactive stratospheric aerosol models. Provided with an initial volcanic injection of sulfur dioxide, these models can interactively simulate the life cycle and optical properties of sulfate aerosols, and their effects on climate. In contrast, most climate models that took part in the Coupled Model Intercomparison Project Phase 5 and 6 (CMIP6) directly prescribe perturbations in atmospheric optical properties associated with an eruption. However, before the satellite era, the volcanic forcing dataset used for CMIP6 mostly relies on a relatively simple aerosol model and a volcanic sulfur inventory derived from ice-cores, both of which have substantial associated uncertainties.</p><p>In this study, we produced a new set of historical simulations using the UK Earth System Model UKESM1, with interactive stratospheric aerosol capability (referred to as interactive runs hereafter) instead of directly prescribing the CMIP6 volcanic forcing dataset as was done for CMIP6 (standard runs, hereafter). We used one of the most recent volcanic sulfur inventories as input for the interactive runs, in which aerosol properties are consistent with the model chemistry, microphysics and atmospheric components. We analyzed how the stratospheric aerosol optical depth, the radiative forcing and the climate response to volcanic eruptions differed between interactive and standard runs, and how these compare to observations and proxy records. In particular, we investigate in detail the differences in the response to the large-magnitude Krakatoa 1883 eruption between the two sets of runs. We also discuss differences for the 1979-2015 period where the forcing data in standard runs is directly constrained from satellite observations. Our results shed new light on uncertainties affecting the reconstruction of past volcanic forcing and highlight some of the benefits and disadvantages of using interactive stratospheric aerosol capabilities instead of a unique prescribed volcanic forcing dataset in CMIP’s historical runs.</p>

Simulation of the observed climate extremes trends during 1901–2010 with INMCM5

2020 ◽  
Author(s):  
Maria Tarasevich ◽  
Evgeny Volodin
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Great Influence ◽  
Coupled Model ◽  
Climate Extremes ◽  
Reanalysis Data ◽  
Natural Systems ◽  
Weather Events ◽  
Intercomparison Project

<p>Extreme climate and weather events have a great influence on society and natural systems. That’s why it is important to be able to precisely simulate these events with the climate models. To asses the quality of such simulations 27 climate extremes indices were defined by ETCCDI. In the present work these indices are calculated for the 1901–2010 in order to estimate their trends.<br>Climate extremes trends are studied on the basis of ten historical runs with the up-to-date INM RAS climate model (INMCM5) under the scenario proposed for the Coupled Model Intercomparison Project Phase 6 (CMIP6). Developed by ECMWF ERA-20C and CERA-20C reanalyses are taken as observational data.<br>Trends obtained from the reanalysis data are compared with the simulation results of the INMCM5. The comparison shows that the simulated land-averaged climate extremes trends are in good agreement with the reanalysis data, but their spatial distributions differ significantly even between the reanalyses themselves.</p>

scholarly journals An Independent Assessment of Anthropogenic Attribution Statements for Recent Extreme Temperature and Rainfall Events

2017 ◽  
Vol 30 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Oliver Angélil ◽  
Dáithí Stone ◽  
Michael Wehner ◽  
Christopher J. Paciorek ◽  
Harinarayan Krishnan ◽  
...  
Keyword(s):  
Climate Model ◽  
Extreme Temperature ◽  
Extreme Weather ◽  
Data Sources ◽  
Extreme Weather Events ◽  
Systematic Bias ◽  
American Meteorological Society ◽  
Extreme Precipitation Events ◽  
Weather Events ◽  
Event Attribution

The annual “State of the Climate” report, published in the Bulletin of the American Meteorological Society (BAMS), has included a supplement since 2011 composed of brief analyses of the human influence on recent major extreme weather events. There are now several dozen extreme weather events examined in these supplements, but these studies have all differed in their data sources as well as their approaches to defining the events, analyzing the events, and the consideration of the role of anthropogenic emissions. This study reexamines most of these events using a single analytical approach and a single set of climate model and observational data sources. In response to recent studies recommending the importance of using multiple methods for extreme weather event attribution, results are compared from these analyses to those reported in the BAMS supplements collectively, with the aim of characterizing the degree to which the lack of a common methodological framework may or may not influence overall conclusions. Results are broadly similar to those reported earlier for extreme temperature events but disagree for a number of extreme precipitation events. Based on this, it is advised that the lack of comprehensive uncertainty analysis in recent extreme weather attribution studies is important and should be considered when interpreting results, but as yet it has not introduced a systematic bias across these studies.

scholarly journals Impacts of extreme weather events on transport infrastructure in Norway

2017 ◽  
Author(s):  
Regula Frauenfelder ◽  
Anders Solheim ◽  
Ketil Isaksen ◽  
Bård Romstad ◽  
Anita V. Dyrrdal ◽  
...  
Keyword(s):  
Debris Flows ◽  
Climate Models ◽  
Heavy Precipitation ◽  
Extreme Weather ◽  
Transport Infrastructure ◽  
Extreme Weather Events ◽  
Local Climate ◽  
Weather Events ◽  
Interdisciplinary Research Project ◽  
Heavy Rainfall Events

Abstract. This paper presents selected results of the interdisciplinary research project Impacts of extreme weather events on infrastructure in Norway (InfraRisk) carried out between 2010 to 2013, as part of the program NORKLIMA (2004 2013) of the Research Council of Norway (RCN). The project has systematized large amounts of existing data and generated new results that are important for our handling of risks associated with future extreme weather and natural hazards threatening the transport infrastructure in Norway. The results of the InfaRisk project range widely, from the establishment of trends in key weather elements to studies of human response to threats from extreme weather. The analyses of weather elements have provided a clearer understanding of the trends in the development of extreme weather. The studies are based on both historical data and available future scenarios (projections) from climate models. Compared to previous studies, we calculated changes in climate variables that are particularly important in relation to nature hazards. Overall, the analyses document an increase in frequency as well as intensity of both precipitation and wind. Results of projections show that the observed changes will continue throughout this century. We could also identify large regional differences, with some areas experiencing, e.g., a reduction in the intensity of heavy rainfall events. However, most of the country will experience the opposite, i.e., both increased intensity and increased frequency of heavy precipitation. Our analyses show that at least 27 per cent of Norwegian roads and 31 per cent of railroads are exposed to rock fall and snow avalanches hazards. The project has also assessed relationships between different parameters that can affect the likelihood of debris flows. Variables such as terrain slope and size of watercourses are important, while local climate, which varies widely in Norway, determines threshold values for rainfall that can trigger debris flows.

scholarly journals Connection of Quasi-Resonant Amplification to the Delay in Atmospheric Residence Times Over India

2021 ◽  
Vol 9 ◽  
Author(s):  
T. V. Lakshmi Kumar ◽  
G. Purna Durga ◽  
K. Koteswara Rao ◽  
Humberto Barbosa ◽  
Ashwini Kulkarni ◽  
...  
Keyword(s):  
Climate Models ◽  
Global Climate ◽  
Monsoon Season ◽  
Coupled Model ◽  
Southwest Monsoon ◽  
Global Climate Models ◽  
Extreme Weather Events ◽  
Residence Times ◽  
Tropical Country ◽  
Weather Events

Mean monthly Atmospheric Residence Times (ART), deduced from the global climate models of Coupled Model Intercomparison Project 5 (CMIP5) under RCP4.5 and RCP8.5 emission scenarios over Indian landmass, show a perceptible increase by the end of the 21st century. India, being a tropical country, faces prolonged ART, particularly during the June month of Southwest monsoon season (June to September) which will be an indicative measure of the increased frequency of extreme weather events. Here we show a possible connection of quasi-resonant amplification (QRA) to the recent (August 2018) Kerala heavy rains that resulted in severe floods and claimed more than 400 mortalities. Remarkable delay in residence times over India during June is shown to have an association with QRA evidenced by the higher magnitudes of amplitudes at the wavenumbers six and seven from the 19 global climate models of CMIP5 under the RCP4.5 and RCP8.5 scenarios.

scholarly journals Interpreting climate model projections of extreme weather events

2015 ◽  
Vol 10 ◽  
pp. 10-28 ◽  
Author(s):  
Stephen J. Vavrus ◽  
Michael Notaro ◽  
David J. Lorenz
Keyword(s):  
Climate Model ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Weather Events
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