scholarly journals Investigating Global Tropical Cyclone Activity with a Hierarchy of AGCMs: The Role of Model Resolution

2013 ◽  
Vol 26 (1) ◽  
pp. 133-152 ◽  
Author(s):  
Jane Strachan ◽  
Pier Luigi Vidale ◽  
Kevin Hodges ◽  
Malcolm Roberts ◽  
Marie-Estelle Demory
Keyword(s):  
Tropical Cyclone ◽  
Interannual Variability ◽  
Tropical Cyclones ◽  
Tropical Cyclone Activity ◽  
Model Resolution ◽  
Cyclone Activity ◽  
Absolute Vorticity ◽  
Low Level ◽  
The North ◽  
The Impact

Abstract The ability to run general circulation models (GCMs) at ever-higher horizontal resolutions has meant that tropical cyclone simulations are increasingly credible. A hierarchy of atmosphere-only GCMs, based on the Hadley Centre Global Environmental Model version 1 (HadGEM1) with horizontal resolution increasing from approximately 270 to 60 km at 50°N, is used to systematically investigate the impact of spatial resolution on the simulation of global tropical cyclone activity, independent of model formulation. Tropical cyclones are extracted from ensemble simulations and reanalyses of comparable resolutions using a feature-tracking algorithm. Resolution is critical for simulating storm intensity and convergence to observed storm intensities is not achieved with the model hierarchy. Resolution is less critical for simulating the annual number of tropical cyclones and their geographical distribution, which are well captured at resolutions of 135 km or higher, particularly for Northern Hemisphere basins. Simulating the interannual variability of storm occurrence requires resolutions of 100 km or higher; however, the level of skill is basin dependent. Higher resolution GCMs are increasingly able to capture the interannual variability of the large-scale environmental conditions that contribute to tropical cyclogenesis. Different environmental factors contribute to the interannual variability of tropical cyclones in the different basins: in the North Atlantic basin the vertical wind shear, potential intensity, and low-level absolute vorticity are dominant, whereas in the North Pacific basins midlevel relative humidity and low-level absolute vorticity are dominant. Model resolution is crucial for a realistic simulation of tropical cyclone behavior, and high-resolution GCMs are found to be valuable tools for investigating the global location and frequency of tropical cyclones.

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.

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.

Hurricane “Amanda”: Rediscovery of a Forgotten U.S. Civil War Florida Hurricane

2013 ◽  
Vol 94 (11) ◽  
pp. 1735-1742 ◽  
Author(s):  
M. Chenoweth ◽  
C. J. Mock
Keyword(s):  
United States ◽  
Civil War ◽  
Tropical Cyclone ◽  
Natural Disaster ◽  
Tropical Cyclones ◽  
Tropical Cyclone Activity ◽  
Cyclone Activity ◽  
Major Hurricane ◽  
The U.S ◽  
States History

Among the most unusual and unexpected hurricanes in United States history is the only hurricane to make landfall in the month of May. This recently rediscovered storm that struck northwest Florida on 28 May 1863 created a natural disaster in the area that became lost to history because it was embedded in a much larger and important manmade event—in this case, the U.S. Civil War. The authors document the arrival of this storm both historically and meteorologically and anachronistically name it “Hurricane Amanda” in honor of the Union ship driven ashore by the hurricane. The hurricane revealed deficiencies and strengths in combat readiness by both sides. Meteorologically, the storm nearly achieved major hurricane status at landfall and its absence from modern databases of tropical cyclone activity is a useful reminder to users of important gaps in our knowledge of tropical cyclones even in the best-sampled storm basins.

scholarly journals Tropical Cyclones in the UPSCALE Ensemble of High-Resolution Global Climate Models*

2015 ◽  
Vol 28 (2) ◽  
pp. 574-596 ◽  
Author(s):  
Malcolm J. Roberts ◽  
Pier Luigi Vidale ◽  
Matthew S. Mizielinski ◽  
Marie-Estelle Demory ◽  
Reinhard Schiemann ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
North Atlantic ◽  
Global Climate ◽  
Future Climate ◽  
Model Resolution ◽  
Central Pacific ◽  
The North ◽  
The Future ◽  
The North Atlantic ◽  
The Impact

Abstract The U.K. on Partnership for Advanced Computing in Europe (PRACE) Weather-Resolving Simulations of Climate for Global Environmental Risk (UPSCALE) project, using PRACE resources, constructed and ran an ensemble of atmosphere-only global climate model simulations, using the Met Office Unified Model Global Atmosphere 3 (GA3) configuration. Each simulation is 27 years in length for both the present climate and an end-of-century future climate, at resolutions of N96 (130 km), N216 (60 km), and N512 (25 km), in order to study the impact of model resolution on high-impact climate features such as tropical cyclones. Increased model resolution is found to improve the simulated frequency of explicitly tracked tropical cyclones, and correlations of interannual variability in the North Atlantic and northwestern Pacific lie between 0.6 and 0.75. Improvements in the deficit of genesis in the eastern North Atlantic as resolution increases appear to be related to the representation of African easterly waves and the African easterly jet. However, the intensity of the modeled tropical cyclones as measured by 10-m wind speed remains weak, and there is no indication of convergence over this range of resolutions. In the future climate ensemble, there is a reduction of 50% in the frequency of Southern Hemisphere tropical cyclones, whereas in the Northern Hemisphere there is a reduction in the North Atlantic and a shift in the Pacific with peak intensities becoming more common in the central Pacific. There is also a change in tropical cyclone intensities, with the future climate having fewer weak storms and proportionally more strong storms.

scholarly journals Revisiting the Influence of the Quasi-Biennial Oscillation on Tropical Cyclone Activity

2010 ◽  
Vol 23 (21) ◽  
pp. 5810-5825 ◽  
Author(s):  
Suzana J. Camargo ◽  
Adam H. Sobel
Keyword(s):  
Tropical Cyclone ◽  
North Atlantic ◽  
Decadal Variability ◽  
Tropical Cyclone Activity ◽  
Solar Forcing ◽  
Cyclone Activity ◽  
Quasi Biennial Oscillation ◽  
The North ◽  
The Relationship ◽  
Biennial Oscillation

Abstract The statistical relationship between the quasi-biennial oscillation (QBO) and tropical cyclone (TC) activity is explored, with a focus on the North Atlantic. Although there is a statistically significant relationship between the QBO and TCs in the Atlantic from the 1950s to the 1980s, as found by previous studies, that relationship is no longer present in later years. Several possibilities for this change are explored, including the interaction with ENSO, volcanoes, QBO decadal variability, and interactions with solar forcing. None provides a completely satisfying explanation. In the other basins, the relationship is weaker than in the Atlantic, even in the early record.

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