scholarly journals Effect of Upper-Ocean Evolution on Projected Trends in Tropical Cyclone Activity

2015 ◽  
Vol 28 (20) ◽  
pp. 8165-8170 ◽  
Author(s):  
Kerry Emanuel
Keyword(s):  
Tropical Cyclone ◽  
Climate Models ◽  
Climate Model ◽  
Thermal Structure ◽  
Tropical Cyclone Activity ◽  
Cmip5 Models ◽  
Upper Ocean ◽  
Cyclone Activity ◽  
Climate Model Simulations ◽  
Projected Changes

Abstract Recent work has highlighted the possible importance of changing upper-ocean thermal and density stratification on observed and projected changes in tropical cyclone activity. Here seven CMIP phase 5 (CMIP5)-generation climate model simulations are downscaled under IPCC representative concentration pathway 8.5 using a coupled atmosphere–ocean tropical cyclone model, generating 100 events per year in the western North Pacific from 2006 to 2100. A control downscaling in which the upper-ocean thermal structure is fixed at its monthly values in the year 2006 is compared to one in which the upper ocean is allowed to evolve, as derived from the CMIP5 models. As found in earlier work, the thermal stratification generally increases as the climate warms, leading to increased ocean mixing–induced negative feedback on tropical cyclone intensity. While trends in the frequency of storms are unaffected, the increasing stratification of the upper ocean leads to a 13% reduction in the increase of tropical cyclone power dissipation over the twenty-first century, averaged across the seven climate models. Much of this reduction is associated with a moderation of the increase in the frequency of category-5 storms.

scholarly journals Response of Global Tropical Cyclone Activity to Increasing CO2: Results from Downscaling CMIP6 Models

2021 ◽  
Vol 34 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Kerry Emanuel
Keyword(s):  
Tropical Cyclone ◽  
Greenhouse Gases ◽  
Tropical Cyclones ◽  
Climate Models ◽  
Climate Model ◽  
Tropical Cyclone Activity ◽  
Cmip5 Models ◽  
Cyclone Activity ◽  
The North ◽  
Sixth Generation

AbstractGlobal models comprising the sixth-generation Coupled Climate Model Intercomparison Project (CMIP6) are downscaled using a very high-resolution but simplified coupled atmosphere–ocean tropical cyclone model, as a means of estimating the response of global tropical cyclone activity to increasing greenhouse gases. As with a previous downscaling of CMIP5 models, the results show an increase in both the frequency and severity of tropical cyclones, robust across the models downscaled, in response to increasing greenhouse gases. The increase is strongly weighted to the Northern Hemisphere, and especially noteworthy is a large increase in the higher latitudes of the North Atlantic. Changes are insignificant in the South Pacific across metrics. Although the largest increases in track density are far from land, substantial increases in global landfalling power dissipation are indicated. The incidence of rapid intensification increases rapidly with warming, as predicted by existing theory. Measures of robustness across downscaled climate models are presented, and comparisons to tropical cyclones explicitly simulated in climate models are discussed.

Projected changes in tropical cyclone activity under future warming scenarios using a high-resolution climate model

2016 ◽  
Vol 146 (3-4) ◽  
pp. 547-560 ◽  
Author(s):  
Julio T. Bacmeister ◽  
Kevin A. Reed ◽  
Cecile Hannay ◽  
Peter Lawrence ◽  
Susan Bates ◽  
...  
Keyword(s):  
High Resolution ◽  
Tropical Cyclone ◽  
Climate Model ◽  
Tropical Cyclone Activity ◽  
Cyclone Activity ◽  
Future Warming ◽  
Projected Changes

scholarly journals North American Climate in CMIP5 Experiments: Part III: Assessment of Twenty-First-Century Projections*

2014 ◽  
Vol 27 (6) ◽  
pp. 2230-2270 ◽  
Author(s):  
Eric D. Maloney ◽  
Suzana J. Camargo ◽  
Edmund Chang ◽  
Brian Colle ◽  
Rong Fu ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
North American ◽  
Tropical Cyclone Activity ◽  
First Century ◽  
Cmip5 Models ◽  
Cmip5 Model ◽  
Cyclone Activity ◽  
North American Climate ◽  
Twenty First Century ◽  
Projected Changes

Abstract In part III of a three-part study on North American climate in phase 5 of the Coupled Model Intercomparison Project (CMIP5) models, the authors examine projections of twenty-first-century climate in the representative concentration pathway 8.5 (RCP8.5) emission experiments. This paper summarizes and synthesizes results from several coordinated studies by the authors. Aspects of North American climate change that are examined include changes in continental-scale temperature and the hydrologic cycle, extremes events, and storm tracks, as well as regional manifestations of these climate variables. The authors also examine changes in the eastern North Pacific and North Atlantic tropical cyclone activity and North American intraseasonal to decadal variability, including changes in teleconnections to other regions of the globe. Projected changes are generally consistent with those previously published for CMIP3, although CMIP5 model projections differ importantly from those of CMIP3 in some aspects, including CMIP5 model agreement on increased central California precipitation. The paper also highlights uncertainties and limitations based on current results as priorities for further research. Although many projected changes in North American climate are consistent across CMIP5 models, substantial intermodel disagreement exists in other aspects. Areas of disagreement include projections of changes in snow water equivalent on a regional basis, summer Arctic sea ice extent, the magnitude and sign of regional precipitation changes, extreme heat events across the northern United States, and Atlantic and east Pacific tropical cyclone activity.

scholarly journals Tracking Scheme Dependence of Simulated Tropical Cyclone Response to Idealized Climate Simulations

2014 ◽  
Vol 27 (24) ◽  
pp. 9197-9213 ◽  
Author(s):  
Michael Horn ◽  
Kevin Walsh ◽  
Ming Zhao ◽  
Suzana J. Camargo ◽  
Enrico Scoccimarro ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
General Circulation ◽  
Climate Model ◽  
Circulation Model ◽  
General Circulation Models ◽  
Tropical Cyclone Activity ◽  
Model Data ◽  
Cyclone Activity ◽  
Sensitivity Testing

Abstract Future tropical cyclone activity is a topic of great scientific and societal interest. In the absence of a climate theory of tropical cyclogenesis, general circulation models are the primary tool available for investigating the issue. However, the identification of tropical cyclones in model data at moderate resolution is complex, and numerous schemes have been developed for their detection. The influence of different tracking schemes on detected tropical cyclone activity and responses in the Hurricane Working Group experiments is examined herein. These are idealized atmospheric general circulation model experiments aimed at determining and distinguishing the effects of increased sea surface temperature and other increased CO2 effects on tropical cyclone activity. Two tracking schemes are applied to these data and the tracks provided by each modeling group are analyzed. The results herein indicate moderate agreement between the different tracking methods, with some models and experiments showing better agreement across schemes than others. When comparing responses between experiments, it is found that much of the disagreement between schemes is due to differences in duration, wind speed, and formation-latitude thresholds. After homogenization in these thresholds, agreement between different tracking methods is improved. However, much disagreement remains, accountable for by more fundamental differences between the tracking schemes. The results indicate that sensitivity testing and selection of objective thresholds are the key factors in obtaining meaningful, reproducible results when tracking tropical cyclones in climate model data at these resolutions, but that more fundamental differences between tracking methods can also have a significant impact on the responses in activity detected.

scholarly journals Dynamical Simulations of North Atlantic Tropical Cyclone Activity Using Observed Low-Frequency SST Oscillation Imposed on CMIP5 Model RCP4.5 SST Projections

2014 ◽  
Vol 27 (21) ◽  
pp. 8055-8069 ◽  
Author(s):  
Timothy E. LaRow ◽  
Lydia Stefanova ◽  
Chana Seitz
Keyword(s):  
Tropical Cyclone ◽  
North Atlantic ◽  
Climate Models ◽  
The United States ◽  
Tropical Cyclone Activity ◽  
First Century ◽  
Cyclone Activity ◽  
The Mean ◽  
Twenty First Century ◽  
Atlantic Tropical Cyclone

Abstract The effects on early and late twenty-first-century North Atlantic tropical cyclone statistics resulting from imposing the patterns of maximum/minimum phases of the observed Atlantic multidecadal oscillation (AMO) onto projected sea surface temperatures (SSTs) from two climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are examined using a 100-km resolution global atmospheric model. By imposing the observed maximum positive and negative phases of the AMO onto two CMIP5 SST projections from the representative concentration pathway (RCP) 4.5 scenario, this study places bounds on future North Atlantic tropical cyclone activity during the early (2020–39) and late (2080–99) twenty-first century. Averaging over both time periods and both AMO phases, the mean named tropical cyclones (NTCs) count increases by 35% when compared to simulations using observed SSTs from 1982 to 2009. The positive AMO simulations produce approximately a 68% increase in mean NTC count, while the negative AMO simulations are statistically indistinguishable from the mean NTC count determined from the 1995–2009 simulations—a period of observed positive AMO phase. Examination of the tropical cyclone track densities shows a statistically significant increase in the tracks along the East Coast of the United States in the future simulations compared to the models’ 1982–2009 climate simulations. The increase occurs regardless of AMO phase, although the negative phase produces higher track densities. The maximum wind speeds increase by 6%, in agreement with other climate change studies. Finally, the NTC-related precipitation is found to increase (approximately by 13%) compared to the 1982–2009 simulations.

Assessing the Risk of Persistent Drought Using Climate Model Simulations and Paleoclimate Data

2014 ◽  
Vol 27 (20) ◽  
pp. 7529-7549 ◽  
Author(s):  
Toby R. Ault ◽  
Julia E. Cole ◽  
Jonathan T. Overpeck ◽  
Gregory T. Pederson ◽  
David M. Meko
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
State Of The Art ◽  
Global Climate ◽  
Global Climate Models ◽  
Mitigation Strategies ◽  
Drought Risk ◽  
Climate Model Simulations ◽  
Projected Changes ◽  
Paleoclimate Data

Abstract Projected changes in global rainfall patterns will likely alter water supplies and ecosystems in semiarid regions during the coming century. Instrumental and paleoclimate data indicate that natural hydroclimate fluctuations tend to be more energetic at low (multidecadal to multicentury) than at high (interannual) frequencies. State-of-the-art global climate models do not capture this characteristic of hydroclimate variability, suggesting that the models underestimate the risk of future persistent droughts. Methods are developed here for assessing the risk of such events in the coming century using climate model projections as well as observational (paleoclimate) information. Where instrumental and paleoclimate data are reliable, these methods may provide a more complete view of prolonged drought risk. In the U.S. Southwest, for instance, state-of-the-art climate model projections suggest the risk of a decade-scale megadrought in the coming century is less than 50%; the analysis herein suggests that the risk is at least 80%, and may be higher than 90% in certain areas. The likelihood of longer-lived events (>35 yr) is between 20% and 50%, and the risk of an unprecedented 50-yr megadrought is nonnegligible under the most severe warming scenario (5%–10%). These findings are important to consider as adaptation and mitigation strategies are developed to cope with regional impacts of climate change, where population growth is high and multidecadal megadrought—worse than anything seen during the last 2000 years—would pose unprecedented challenges to water resources in the region.

scholarly journals High-resolution regional climate model projections of future tropical cyclone activity in the Philippines

2018 ◽  
Vol 39 (3) ◽  
pp. 1181-1194 ◽  
Author(s):  
Florian Gallo ◽  
Joseph Daron ◽  
Ian Macadam ◽  
Thelma Cinco ◽  
Marcelino Villafuerte ◽  
...  
Keyword(s):  
High Resolution ◽  
Tropical Cyclone ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
The Philippines ◽  
Tropical Cyclone Activity ◽  
Cyclone Activity
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