scholarly journals Shorter cyclone clusters modulate changes in European wintertime precipitation extremes

2021 ◽  
Author(s):  
Emanuele Bevacqua ◽  
Giuseppe Zappa ◽  
Theodore G Shepherd
Keyword(s):  
Atmospheric Circulation ◽  
Extreme Precipitation ◽  
Climate Models ◽  
Precipitation Extremes ◽  
Southern Europe ◽  
Circulation Change ◽  
The Future ◽  
The Mean ◽  
Future Direction ◽  
Atmospheric Circulation Change

<p>Wintertime extreme precipitation from cyclone clusters, i.e. consecutive cyclones moving across the same region, can lead to flooding and devastating socio-economic impacts in Europe. Previous studies have suggested that the future direction of the changes in these events are uncertain across climate models. By employing an impact-based metric of accumulated precipitation extremes, we show that projections of cyclone clusters are instead broadly robust, i.e. consistent in sign, across models. A novel physical diagnostic shows that accumulated precipitation extremes are projected to grow by only +1.0 %/K on average across Europe, although the mean precipitation per cyclone increases by +4.7 %/K. This results from a decreased number of clustered cyclones, associated with decreased wintertime storminess, the extent of which varies from northern to southern Europe and depends on the future storyline of atmospheric circulation change. Neglecting the changes in the number of clustered cyclones, i.e. assuming that accumulated precipitation extremes would change as the mean precipitation per cyclone, would lead to overestimating the population affected by increased accumulated wintertime precipitation extremes by 130–490 million across Europe.</p>

scholarly journals Brief communication: Impact of the recent atmospheric circulation change in summer on the future surface mass balance of the Greenland Ice Sheet

2018 ◽  
Vol 12 (11) ◽  
pp. 3409-3418 ◽  
Author(s):  
Alison Delhasse ◽  
Xavier Fettweis ◽  
Christoph Kittel ◽  
Charles Amory ◽  
Cécile Agosta
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
Greenland Ice Sheet ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The North ◽  
Circulation Change ◽  
The Future ◽  
The North Atlantic ◽  
Atmospheric Circulation Change

Abstract. Since the 2000s, a change in the atmospheric circulation over the North Atlantic resulting in more frequent blocking events has favoured warmer and sunnier weather conditions over the Greenland Ice Sheet (GrIS) in summer, enhancing the melt increase. This circulation change is not represented by general circulation models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5), which do not predict any circulation change for the next century over the North Atlantic. The goal of this study is to evaluate the impact of an atmospheric circulation change (as currently observed) on projections of the future GrIS surface mass balance (SMB). We compare GrIS SMB estimates simulated by the regional climate model MAR forced by perturbed reanalysis (ERA-Interim with a temperature correction of +1, +1.5, and +2 ∘C at the MAR lateral boundaries) over 1980–2016 to projections of the future GrIS SMB from MAR simulations forced by three GCMs over selected periods for which a similar temperature increase of +1, +1.5, and +2 ∘C is projected by the GCMs in comparison to 1980–1999. Mean SMB anomalies produced with perturbed reanalysis over the climatologically stable period 1980–1999 are similar to those produced with MAR forced by GCMs over future periods characterised by a similar warming over Greenland. However, over the 2 last decades (2000–2016) when an increase in the frequency of blocking events has been observed in summer, MAR forced by perturbed reanalysis suggests that the SMB decrease could be amplified by a factor of 2 if such atmospheric conditions persist compared to projections forced by GCMs for the same temperature increase but without any circulation change.

Investigating the seasonal response of precipitation extremes to global warming using observations and large-ensembles of coupled climate models

2020 ◽  
Author(s):  
Andrew Williams ◽  
Paul O'Gorman
Keyword(s):  
Global Warming ◽  
Extreme Precipitation ◽  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Precipitation Extremes ◽  
Cmip5 Models ◽  
Historical Period ◽  
Societal Relevance ◽  
Coupled Climate Models

<p>Changes in extreme precipitation are amongst the most impactful consequences of global warming, with potential effects ranging from increased flood risk and landslides to crop failures and impacts on ecosystems. Thus, understanding historical and future changes in extreme precipitation is not only important from a scientific perspective, but also has direct societal relevance.</p><p>However, while most current research has focused on annual precipitation extremes and their response to warming, it has recently been noted that climate model projections show a distinct seasonality to future changes in extreme precipitation. In particular, CMIP5 models suggest that over Northern Hemisphere (NH) land the summer response is weaker than the winter response in terms of percentage changes.</p><p>Here we investigate changes in seasonal precipitation extremes using observations and simulations with coupled climate models. First, we analyse observed trends from the Hadley Centre’s global climate extremes dataset (HadEX2) to investigate to what extent there is already a difference between summer and winter trends over NH land. Second, we use 40 ensemble members from the CESM Large Ensemble to characterize the role played by internal variability in trends over the historical period. Lastly, we use CMIP5 simulations to explore the possibility of a link between the seasonality of changes in precipitation extremes and decreases in surface relative humidity over land.</p>

scholarly journals Anomalous mid-twentieth century atmospheric circulation change over the South Atlantic compared to the last 6000 years

2016 ◽  
Vol 11 (6) ◽  
pp. 064009 ◽  
Author(s):  
Chris S M Turney ◽  
Richard T Jones ◽  
David Lister ◽  
Phil Jones ◽  
Alan N Williams ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Atmospheric Circulation ◽  
South Atlantic ◽  
The South ◽  
Circulation Change ◽  
Atmospheric Circulation Change

scholarly journals RELATION BETWEEN EXTENSIVE EXTREME PRECIPITATION IN POLAND AND ATMOSPHERIC CIRCULATION

2014 ◽  
Vol 33 (1) ◽  
pp. 115-129 ◽  
Author(s):  
Jakub Nowosad ◽  
Alfred Stach
Keyword(s):  
Seasonal Variation ◽  
Atmospheric Circulation ◽  
Coefficient Of Variation ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Precipitation Data ◽  
Precipitation Volume ◽  
Spatial Features ◽  
The Mean

Abstract The basic aim of this study was to find relations between the dates of occurrence and characteristics of extensive extreme daily (24-h) precipitation totals (EEDPTs) and pressure systems. The analysis was conducted on the basis of precipitation data from the multi-year period 1956-1980 and the Grosswetterlagen classification of circulation situations. EEDPTs were taken to embrace those cases of maximum annual daily precipitation totals that were registered on the same day at a minimum of 75 precipitation stations. In the years 1956-1980 there were 209 such events. The hypothesis about the effect of a circulation situation on the probability of occurrence of an EEDPT was verified in quantitative terms, the reference being both the entire multi-year period and the seasonal variation in the occurrence of precipitation of this type. Next, circulation situations were compared in terms of amount-related parameters of EEDPTs (mean precipitation, coefficient of variation), their spatial features (perimeter, area), and precipitation volume. The analyses performed show a statistically significant dependence between the atmospheric circulation and extensive extreme precipitation. It was demonstrated that there were circulation situations during which EEDPTs occurred much more often or much more rarely than over the entire multi-year period under study. Also identified was the connection of an atmospheric circulation with the mean amount, coefficient of variation and volume of extensive extreme precipitation.

scholarly journals Brief communication: Impact of the recent atmospheric circulation change in summer on the future surface mass balance of the Greenland ice sheet

2018 ◽  
Author(s):  
Alison Delhasse ◽  
Xavier Fettweis ◽  
Christoph Kittel ◽  
Charles Amory ◽  
Cécile Agosta
Keyword(s):  
Mass Balance ◽  
Atmospheric Circulation ◽  
Temperature Increase ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Mass Balance ◽  
Future Projections ◽  
Surface Mass ◽  
Circulation Change ◽  
Atmospheric Circulation Change

Abstract. Since the 2000's, a change in the atmospheric circulation over North Atlantic has favored warmer and sunnier weather conditions over the Greenland Ice sheet (GrIS) in summer enhancing the melt increase. This circulation change is not represented by General Circulation Models (GCMs) of the 5th Coupled Model Intercomparison Project (CMIP5) which do not predict any circulation change for the next century over the Atlantic. The goal of this study is to evaluate the impact of an atmospheric circulation change (as currently observed) in a warmer climate on future projections of the GrIS surface mass balance (SMB). We compare GrIS SMB estimates from the regional climate model MAR forced by warmer reanalysis (ERA-Interim with a temperature correction of +1 °C, +1.5 °C and +2 °C at the MAR lateral boundaries) over 1980–2016 to future projections of GrIS SMB from MAR simulations forced with three GCMs over a future period for which a similar temperature increase of +1 °C, +1.5 °C and +2 °C is projected by the GCMs in comparison to 1980–1999. Mean SMB anomalies produced with warmer reanalysis over the climatologically stable period 1980–1999 is similar to those produced with MAR forced with GCMs over future periods characterized by a similar warming over Greenland. However, over the two last decades (2000–2016) when a circulation change has been observed in summer, MAR forced with warmer reanalysis suggests that the SMB decrease could be amplified by a factor of two if such atmospheric conditions will persist compared to future projections forced by GCMs for the same temperature increase but without any circulation change.

scholarly journals Ensemble Projection of Extreme Precipitation Over China Based on Three Dynamical Downscaling Simulations

2021 ◽  
Vol 9 ◽  
Author(s):  
Guangtao Dong ◽  
Ye Xie ◽  
Ya Wang ◽  
Dongli Fan ◽  
Zhan Tian
Keyword(s):  
21St Century ◽  
Extreme Precipitation ◽  
North China ◽  
Climate Models ◽  
Climate Model ◽  
Dynamical Downscaling ◽  
Global Climate Models ◽  
Vapor Flux ◽  
The Future ◽  
Late 21St Century

Based on the outputs of the global climate models (GCMs) HadGEM2-ES, NorESM1-M and MPI-ESM-LR from Coupled Model Intercomparison Project Phase 5 (CMIP5) and the downscaling results with the regional climate model (RCM) REMO, the ability of the climate models to reproduce the extreme precipitation in China during the current period (1986–2005) is evaluated. Then, the future extreme precipitation in the mid (2036–2065) and the late 21st century (2066–2095) is projected under the RCP8.5 scenario. The results show that the RCM simulations have great improvements compared with the GCMs, and the ensemble mean of the RCM results (ensR) outperforms each single RCM simulation. The annual precipitation of the RCM simulations is more consistent with the observation than that of the GCMs, with the overestimation of the peak precipitation reduced, and the ensR further reduces the bias. For the extreme precipitation, the RCM simulations significantly decrease the underestimation of intensity in the GCMs. The RCM simulations and the ensR can greatly improve the simulations of Rx5day and CWD compared with the GCMs, decreasing the wet bias in North China and Northwest China. In the future, the consecutive dry days (CDD) will decrease in the northern arid regions, especially in North China and Northeast China. However, the southern regions will experience longer dry period. Both the amount and the intensity of precipitation will increase in various regions of China. The number of wet days will decrease in the south and increase in the north area. The significantly greater Rx5day and R95t indicate more intensive extreme precipitation in the future, and the intensity in the late 21st century will be stronger than that in the middle. Attribution analysis indicates that the extreme precipitation indices especially the R95t have significant positive temporal and spatial correlations with the water vapor flux.

scholarly journals Land–Sea Thermal Contrast and Intensity of the North American Monsoon under Climate Change Conditions

2014 ◽  
Vol 27 (12) ◽  
pp. 4566-4580 ◽  
Author(s):  
Abraham Torres-Alavez ◽  
Tereza Cavazos ◽  
Cuauhtemoc Turrent
Keyword(s):  
North American ◽  
Climate Models ◽  
Global Climate ◽  
Coastal Region ◽  
Global Climate Models ◽  
North American Monsoon ◽  
Thermal Contrast ◽  
The North ◽  
The Future ◽  
The Mean

Abstract The hypothesis that global warming during the twenty-first century will increase the land–sea thermal contrast (LSTC) and therefore the intensity of early season precipitation of the North American monsoon (NAM) is examined. To test this hypothesis, future changes (2075–99 minus 1979–2004 means) in LSTC, moisture flux convergence (MFC), vertical velocity, and precipitation in the region are analyzed using six global climate models (GCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) under the representative concentration pathway 8.5 (RCP8.5) emission scenario. A surface LSTC index shows that the continent becomes warmer than the ocean in May in the North American Regional Reanalysis (NARR) and ECMWF Interim Re-Analysis (ERA-Interim) and in June in the mean ensemble of the GCMs (ens_GCMs), and the magnitude of the positive LSTC is greater in the reanalyses than in the ens_GCMs during the historic period. However, the reanalyses underestimate July–August precipitation in the NAM region, while the ens_GCMs reproduces the peak season surprisingly well but overestimates it the rest of the year. The future ens_GCMs projects a doubling of the magnitude of the positive surface LSTC and an earlier start of the continental summer warming in mid-May. Contrary to the stated hypothesis, however, the mean projection suggests a slight decrease of monsoon coastal precipitation during June–August (JJA), which is attributed to increased midtropospheric subsidence, a reduced midtropospheric LSTC, and reduced MFC in the NAM coastal region. In contrast, the future ens_GCMs produces increased MFC and precipitation over the adjacent mountains during JJA and significantly more rainfall over the entire NAM region during September–October, weakening the monsoon retreat.

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