scholarly journals Natural and Forced North Atlantic Hurricane Potential Intensity Change in CMIP5 Models*

2015 ◽  
Vol 28 (10) ◽  
pp. 3926-3942 ◽  
Author(s):  
Mingfang Ting ◽  
Suzana J. Camargo ◽  
Cuihua Li ◽  
Yochanan Kushnir
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
First Century ◽  
Intensity Change ◽  
Cmip5 Models ◽  
Historical Period ◽  
Hurricane Intensity ◽  
Multidecadal Variability ◽  
Atlantic Hurricane ◽  
Twenty First Century

Abstract Possible future changes of North Atlantic hurricane intensity and the attribution of past hurricane intensity changes in the historical period are investigated using phase 5 of the Climate Model Intercomparison Project (CMIP5), multimodel, multiensemble simulations. For this purpose, the potential intensity (PI), the theoretical upper limit of the tropical cyclone intensity given the large-scale environment, is used. The CMIP5 models indicate that the PI change as a function of sea surface temperature (SST) variations associated with the Atlantic multidecadal variability (AMV) is more effective than that associated with climate change. Thus, relatively small changes in SST due to natural multidecadal variability can lead to large changes in PI, and the model-simulated multidecadal PI change during the historical period has been largely dominated by AMV. That said, the multimodel mean PI for the Atlantic main development region shows a significant increase toward the end of the twenty-first century under both the RCP4.5 and RCP8.5 emission scenarios. This is because of enhanced surface warming, which would place the North Atlantic PI largely above the historical mean by the mid-twenty-first century, based on CMIP5 model projection. The authors further attribute the historical PI changes to aerosols and greenhouse gas (GHG) forcing using CMIP5 historical single-forcing simulations. The model simulations indicate that aerosol forcing has been more effective in causing PI changes than the corresponding GHG forcing; the decrease in PI due to aerosols and increase due to GHG largely cancel each other. Thus, PI increases in the recent 30 years appears to be dominated by multidecadal natural variability associated with the positive phase of the AMV.

A spatial climatology of North Atlantic hurricane intensity change

2013 ◽  
Vol 34 (9) ◽  
pp. 2918-2924 ◽  
Author(s):  
Erik Fraza ◽  
James B. Elsner
Keyword(s):  
North Atlantic ◽  
Intensity Change ◽  
Hurricane Intensity ◽  
Atlantic Hurricane

scholarly journals Dynamical Properties of the North Atlantic Atmospheric Circulation in the Past 150 Years in CMIP5 Models and the 20CRv2c Reanalysis

2018 ◽  
Vol 31 (15) ◽  
pp. 6097-6111 ◽  
Author(s):  
David Rodrigues ◽  
M. Carmen Alvarez-Castro ◽  
Gabriele Messori ◽  
Pascal Yiou ◽  
Yoann Robin ◽  
...  
Keyword(s):  
Dynamical Systems ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
Large Scale ◽  
Cmip5 Models ◽  
Historical Period ◽  
Local Dimension ◽  
The North ◽  
The North Atlantic ◽  
Over Time

It is of fundamental importance to evaluate the ability of climate models to capture the large-scale atmospheric circulation patterns and, in the context of a rapidly increasing greenhouse forcing, the robustness of the changes simulated in these patterns over time. Here we approach this problem from an innovative point of view based on dynamical systems theory. We characterize the atmospheric circulation over the North Atlantic in the CMIP5 historical simulations (1851–2000) in terms of two instantaneous metrics: local dimension of the attractor and stability of phase-space trajectories. We then use these metrics to compare the models to the Twentieth Century Reanalysis version 2c (20CRv2c) over the same historical period. The comparison suggests that (i) most models capture to some degree the median attractor properties, and models with finer grids generally perform better; (ii) in most models the extremes in the dynamical systems metrics match large-scale patterns similar to those found in the reanalysis; (iii) changes in the attractor properties observed for the ensemble-mean 20CRv2c are artifacts resulting from inhomogeneities in the standard deviation of the ensemble over time; and (iv) the long-term trends in local dimension observed among the 56 members of the 20CR ensemble have the same sign as those observed in the CMIP5 multimodel mean, although the multimodel trend is much weaker.

scholarly journals Trends in CMIP5 Rainfall Patterns over Southwestern Australia

2017 ◽  
Vol 30 (5) ◽  
pp. 1779-1788 ◽  
Author(s):  
Bhupendra A. Raut ◽  
Michael J. Reeder ◽  
Christian Jakob
Keyword(s):  
Summer Rainfall ◽  
First Century ◽  
Cmip5 Models ◽  
Historical Period ◽  
Gradual Reduction ◽  
Winter Rainfall ◽  
Light Rain ◽  
Southwestern Australia ◽  
Rainfall Patterns ◽  
Twenty First Century

Abstract Previous work has shown that the sharp fall in winter rainfall over coastal southwestern Australia in the 1970s was mainly due to a fall in the frequency of fronts; the gradual reduction in rainfall since the late 1990s was due to a reduction in the number of light-rain days; and the increased inland summer rainfall in the 1970s was due to an increased number of easterly troughs. The current paper extends this earlier work by identifying the rainfall patterns in the region in 14 CMIP5 models for the period 1980–2005 and by calculating how these patterns are projected to change in the twenty-first century. The patterns are identified using k-means clustering of the rainfall, which are validated against observed rainfall clusters. Although the agreement between the models and the observation is generally good, the models underestimate the frequency of raining fronts. In both representative concentration pathway 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios the number of dry days increases significantly at the expense of light-rain days and frontal rainfall. However, these trends are twice as large in the RCP8.5 scenario as in the RCP4.5 scenario. The reduction in the rainfall from the historical period to the second half of the twenty-first century is produced mainly by a reduction in both the frequency and intensity of light rain and a reduction in the frequency of fronts in the westerlies.

Twenty-first-century projections of North Atlantic tropical storms from CMIP5 models

2012 ◽  
Vol 2 (8) ◽  
pp. 604-607 ◽  
Author(s):  
Gabriele Villarini ◽  
Gabriel A. Vecchi
Keyword(s):  
North Atlantic ◽  
First Century ◽  
Cmip5 Models ◽  
Tropical Storms ◽  
Twenty First Century

scholarly journals North Atlantic Multidecadal Variability Enhancing Decadal Extratropical Extremes in Boreal Late Summer in the Early Twenty-First Century

2020 ◽  
Vol 33 (14) ◽  
pp. 6047-6064 ◽  
Author(s):  
Jie Zhang ◽  
Zhiheng Chen ◽  
Haishan Chen ◽  
Qianrong Ma ◽  
Asaminew Teshome
Keyword(s):  
Energy Transfer ◽  
North Atlantic ◽  
Low Frequency ◽  
Late Summer ◽  
First Century ◽  
Stationary Waves ◽  
Frequency Wave ◽  
Multidecadal Variability ◽  
Longitudinal Temperature Gradient ◽  
Twenty First Century

AbstractIn the beginning of the twenty-first century, weather and climate extremes occurred more and more in extratropical summer, linked to the magnified amplitudes of quasi-stationary waves and external forcing. The study analyzes the relations between multidecadal extratropical extremes in boreal late summer and the North Atlantic (NA; 35°–65°N, 40°W–0°) multidecadal variability (NAMV) in the mid- to high latitudes. The results show that multidecadal extratropical extremes link with the intensified NAMV and the related positive–negative–positive (+ − +) zonal mode of sea surface temperature (SST). 1) The SST mode favors the eastward shift of the negative-phase NA oscillation (NNAO), with a latitudinal pattern of cyclone anomalies over the western European coast and anticyclones over Greenland; NNAO is helpful to baroclinic energy transfer and a longitudinal wavelike pattern. 2) The SST mode and the eddy-driven jet of NNAO are conducive to a southeast extension of the NA jet in close conjunction with the Afro-Asian jet, thereby enhancing the jet waveguide and barotropic energy transfer for the maintenance of a low-frequency wave. 3) The effect of the intensified NAMV on warming Europe contributes to the longitudinal temperature gradient–like “cooling ocean and warming land” pattern, which enhances the meridional wind and wave amplitude of the low-frequency wave. Based on these causes, the intensified NAMV and the + − + SST mode favor the enhancement of the low-frequency wave and quasi-resonant probability, which magnifies the amplitude of the quasi-stationary wave and enhances extratropical extremes on the decadal time scale.

scholarly journals Projected Increases in North Atlantic Tropical Cyclone Intensity from CMIP5 Models

2013 ◽  
Vol 26 (10) ◽  
pp. 3231-3240 ◽  
Author(s):  
Gabriele Villarini ◽  
Gabriel A. Vecchi
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
North Atlantic ◽  
Radiative Forcing ◽  
First Century ◽  
Cmip5 Models ◽  
Tropical Cyclone Intensity ◽  
Cyclone Intensity ◽  
Twenty First Century ◽  
Atlantic Tropical Cyclone

Abstract Tropical cyclones—particularly intense ones—are a hazard to life and property, so an assessment of the changes in North Atlantic tropical cyclone intensity has important socioeconomic implications. In this study, the authors focus on the seasonally integrated power dissipation index (PDI) as a metric to project changes in tropical cyclone intensity. Based on a recently developed statistical model, this study examines projections in North Atlantic PDI using output from 17 state-of-the-art global climate models and three radiative forcing scenarios. Overall, the authors find that North Atlantic PDI is projected to increase with respect to the 1986–2005 period across all scenarios. The difference between the PDI projections and those of the number of North Atlantic tropical cyclones, which are not projected to increase significantly, indicates an intensification of North Atlantic tropical cyclones in response to both greenhouse gas (GHG) increases and aerosol changes over the current century. At the end of the twenty-first century, the magnitude of these increases shows a positive dependence on projected GHG forcing. The projected intensification is significantly enhanced by non-GHG (primarily aerosol) forcing in the first half of the twenty-first century.

Temperature projections over Iran during the twenty-first century using CMIP5 models

2021 ◽  
Author(s):  
David Francisco Bustos Usta ◽  
Maryam Teymouri ◽  
Uday Chatterjee ◽  
Bappaditya Koley
Keyword(s):  
First Century ◽  
Cmip5 Models ◽  
Twenty First Century

Gang Research in the Twenty-First Century

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Caylin Louis Moore ◽  
Forrest Stuart
Keyword(s):  
Large Scale ◽  
Criminological Theory ◽  
First Century ◽  
Annual Review ◽  
Publication Date ◽  
Theoretical Frameworks ◽  
Twenty First Century ◽  
State Interventions ◽  
And Behavior ◽  
Analytical Approaches

For nearly a century, gang scholarship has remained foundational to criminological theory and method. Twenty-first-century scholarship continues to refine and, in some cases, supplant long-held axioms about gang formation, organization, and behavior. Recent advances can be traced to shifts in the empirical social reality and conditions within which gangs exist and act. We draw out this relationship—between the ontological and epistemological—by identifying key macrostructural shifts that have transformed gang composition and behavior and, in turn, forced scholars to revise dominant theoretical frameworks and analytical approaches. These shifts include large-scale economic transformations, the expansion of punitive state interventions, the proliferation of the Internet and social media, intensified globalization, and the increasing presence of women and LGBTQ individuals in gangs and gang research. By introducing historically unprecedented conditions and actors, these developments provide novel opportunities to reconsider previous analyses of gang structure, violence, and other related objects of inquiry. Expected final online publication date for the Annual Review of Criminology, Volume 5 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Atlantic Meridional Overturning Circulation (AMOC) in CMIP5 Models: RCP and Historical Simulations

2013 ◽  
Vol 26 (18) ◽  
pp. 7187-7197 ◽  
Author(s):  
Wei Cheng ◽  
John C. H. Chiang ◽  
Dongxiao Zhang
Keyword(s):  
North Atlantic ◽  
Coupled Model ◽  
Meridional Overturning Circulation ◽  
First Century ◽  
Model Intercomparison ◽  
The North ◽  
Intercomparison Project ◽  
Meridional Overturning ◽  
The North Atlantic ◽  
Twenty First Century

Abstract The Atlantic meridional overturning circulation (AMOC) simulated by 10 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) for the historical (1850–2005) and future climate is examined. The historical simulations of the AMOC mean state are more closely matched to observations than those of phase 3 of the Coupled Model Intercomparison Project (CMIP3). Similarly to CMIP3, all models predict a weakening of the AMOC in the twenty-first century, though the degree of weakening varies considerably among the models. Under the representative concentration pathway 4.5 (RCP4.5) scenario, the weakening by year 2100 is 5%–40% of the individual model's historical mean state; under RCP8.5, the weakening increases to 15%–60% over the same period. RCP4.5 leads to the stabilization of the AMOC in the second half of the twenty-first century and a slower (then weakening rate) but steady recovery thereafter, while RCP8.5 gives rise to a continuous weakening of the AMOC throughout the twenty-first century. In the CMIP5 historical simulations, all but one model exhibit a weak downward trend [ranging from −0.1 to −1.8 Sverdrup (Sv) century−1; 1 Sv ≡ 106 m3 s−1] over the twentieth century. Additionally, the multimodel ensemble–mean AMOC exhibits multidecadal variability with a ~60-yr periodicity and a peak-to-peak amplitude of ~1 Sv; all individual models project consistently onto this multidecadal mode. This multidecadal variability is significantly correlated with similar variations in the net surface shortwave radiative flux in the North Atlantic and with surface freshwater flux variations in the subpolar latitudes. Potential drivers for the twentieth-century multimodel AMOC variability, including external climate forcing and the North Atlantic Oscillation (NAO), and the implication of these results on the North Atlantic SST variability are discussed.

Vertical Arrangements

2020 ◽  
pp. 124-151
Author(s):  
Rex Ahdar
Keyword(s):  
Large Scale ◽  
Green Light ◽  
Competition Law ◽  
First Century ◽  
Resale Price Maintenance ◽  
Exclusive Dealing ◽  
Dominant Firms ◽  
Resale Price ◽  
Twenty First Century ◽  
Price Maintenance

Then law governing vertical arrangements is a comparatively undeveloped area in NZ competition law. With only resale price maintenance (RPM) expressly prohibited by the Act, it has fallen to the general prohibitions on anticompetitive arrangements and monopolization to address traditional antitrust mischiefs such as exclusive dealing and tying. The leading case on exclusive dealing was heavily influenced by Chicagoan thinking to the degree that the courts gave the green light to durable distribution arrangements that countenanced foreclosure on a large scale and were plainly anti-competitive. However, the few cases on tying have been more fruitful insofar as remedies have been granted to rectify blatant leveraging by dominant firms into related markets. A period of active enforcement of RPM by the Commerce Commission marked the first decade, but the swathe of prosecutions dried up as the twenty-first century began.

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