Articles | Volume 1, issue 2 
            
                
                    
            
            
            https://doi.org/10.5194/wcd-1-745-2020
                    © Author(s) 2020. This work is distributed under 
the Creative Commons Attribution 4.0 License.
                the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-1-745-2020
                    © Author(s) 2020. This work is distributed under 
the Creative Commons Attribution 4.0 License.
                the Creative Commons Attribution 4.0 License.
Increasing frequency in off-season tropical cyclones and its relation to climate variability and change
José J. Hernández Ayala
CORRESPONDING AUTHOR
                                            
                                    
                                            Climate Research Center, Department of Geography, Environment, & Planning, Sonoma State University, California, USA
                                        
                                    Rafael Méndez-Tejeda
                                            Research Laboratory in Atmospheric Science, University of Puerto Rico at Carolina, Puerto Rico. P. O. Box 4800, 00984, Carolina, Puerto Rico
                                        
                                    Related subject area
            Other aspects of weather and climate dynamics
            
                    
                        
                            
                            
                                     
                                ClimaMeter: contextualizing extreme weather in a changing climate
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Large-ensemble assessment of the Arctic stratospheric polar vortex morphology and disruptions
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Elevation-dependent warming: observations, models, and energetic mechanisms
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Meeting summary: Exploring cloud dynamics with Cloud Model 1 and 3D visualization – insights from a university modeling workshop
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Waviness of the Southern Hemisphere wintertime polar and subtropical jets
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                The importance of regional sea-ice variability for the coastal climate and near-surface temperature gradients in Northeast Greenland
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Decadal variability and trends in extratropical Rossby wave packet amplitude, phase, and phase speed
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Stratospheric intrusion depth and its effect on surface cyclogenetic forcing: an idealized potential vorticity (PV) inversion experiment
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Supercell convective environments in Spain based on ERA5: hail and non-hail differences
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Trends in the tropospheric general circulation from 1979 to 2022
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A characterisation of Alpine mesocyclone occurrence
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Intraseasonal variability of ocean surface wind waves in the western South Atlantic: the role of cyclones and the Pacific South American pattern
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A dynamical adjustment perspective on extreme event attribution
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                The signature of the tropospheric gravity wave background in observed mesoscale motion
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
            
        
        Davide Faranda, Gabriele Messori, Erika Coppola, Tommaso Alberti, Mathieu Vrac, Flavio Pons, Pascal Yiou, Marion Saint Lu, Andreia N. S. Hisi, Patrick Brockmann, Stavros Dafis, Gianmarco Mengaldo, and Robert Vautard
                                    Weather Clim. Dynam., 5, 959–983, https://doi.org/10.5194/wcd-5-959-2024, https://doi.org/10.5194/wcd-5-959-2024, 2024
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                                                We introduce ClimaMeter, a tool offering real-time insights into extreme-weather events. Our tool unveils how climate change and natural variability affect these events, affecting communities worldwide. Our research equips policymakers and the public with essential knowledge, fostering informed decisions and enhancing climate resilience. We analysed two distinct events, showcasing ClimaMeter's global relevance.
                                            
                                            
                                        Ales Kuchar, Maurice Öhlert, Roland Eichinger, and Christoph Jacobi
                                    Weather Clim. Dynam., 5, 895–912, https://doi.org/10.5194/wcd-5-895-2024, https://doi.org/10.5194/wcd-5-895-2024, 2024
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                                                Exploring the polar vortex's impact on climate, the study evaluates model simulations against the ERA5 reanalysis data. Revelations about model discrepancies in simulating disruptive stratospheric warmings and vortex behavior highlight the need for refined model simulations of past climate. By enhancing our understanding of these dynamics, the research contributes to more reliable climate projections of the polar vortex with the impact on surface climate.
                                            
                                            
                                        Michael P. Byrne, William R. Boos, and Shineng Hu
                                    Weather Clim. Dynam., 5, 763–777, https://doi.org/10.5194/wcd-5-763-2024, https://doi.org/10.5194/wcd-5-763-2024, 2024
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                                                In this study we investigate why climate change is amplified in mountain regions, a phenomenon known as elevation-dependent warming (EDW). We examine EDW using observations and models and assess the roles of radiative forcing vs. internal variability in driving the historical signal. Using a forcing–feedback framework we also quantify for the first time the processes driving EDW on large scales. Our results have important implications for understanding future climate change in mountain regions.
                                            
                                            
                                        Lisa Schielicke, Yidan Li, Jerome Schyns, Aaron Sperschneider, Jose Pablo Solano Marchini, and Christoph Peter Gatzen
                                    Weather Clim. Dynam., 5, 703–710, https://doi.org/10.5194/wcd-5-703-2024, https://doi.org/10.5194/wcd-5-703-2024, 2024
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                                                We present course contents and results of a 2-week educational block course with a focus on Cloud Model 1 (CM1) and 3D visualization. Through hands-on experience, students gained skills in setting up and customizing the model and visualizing its output in 3D. The research aimed to bridge the gap between classroom learning and practical applications, fostering a deeper understanding of convective processes and preparing students for future careers in the field.
                                            
                                            
                                        Jonathan E. Martin and Taylor Norton
                                    Weather Clim. Dynam., 4, 875–886, https://doi.org/10.5194/wcd-4-875-2023, https://doi.org/10.5194/wcd-4-875-2023, 2023
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                                                The polar and subtropical jets are important weather-producing features and influential governors of regional climate. This study considers trends in the waviness of the two jets in Southern Hemisphere winter using three data sets and reveals three important results: (1) the waviness of both jets has increased since about 1960, (2) only the maximum speed of the subtropical jet has increased, and (3) both the polar and subtropical jets have been shifting poleward over the last several decades.
                                            
                                            
                                        Sonika Shahi, Jakob Abermann, Tiago Silva, Kirsty Langley, Signe Hillerup Larsen, Mikhail Mastepanov, and Wolfgang Schöner
                                    Weather Clim. Dynam., 4, 747–771, https://doi.org/10.5194/wcd-4-747-2023, https://doi.org/10.5194/wcd-4-747-2023, 2023
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                                                This study highlights how the sea ice variability in the Greenland Sea affects the terrestrial climate and the surface mass changes of peripheral glaciers of the Zackenberg region (ZR), Northeast Greenland, combining model output and observations. Our results show that the temporal evolution of sea ice influences the climate anomaly magnitude in the ZR. We also found that the changing temperature and precipitation patterns due to sea ice variability can affect the surface mass of the ice cap.
                                            
                                            
                                        Georgios Fragkoulidis
                                    Weather Clim. Dynam., 3, 1381–1398, https://doi.org/10.5194/wcd-3-1381-2022, https://doi.org/10.5194/wcd-3-1381-2022, 2022
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                                                Assessing the seasonal distributions of local Rossby wave packet (RWP) amplitude, phase, and phase speed on reanalysis data of the 1979–2019 period reveals that patterns of robust trends emerge and vary substantially between seasons and regions. While an absence of covariance is evident between RWP amplitude and phase speed at decadal scales, the frequency of DJF large-amplitude quasi-stationary RWPs increases in several areas of the N Pacific and N America during 1999–2019.
                                            
                                            
                                        Michael A. Barnes, Thando Ndarana, Michael Sprenger, and Willem A. Landman
                                    Weather Clim. Dynam., 3, 1291–1309, https://doi.org/10.5194/wcd-3-1291-2022, https://doi.org/10.5194/wcd-3-1291-2022, 2022
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                                                Stratospheric air can intrude into the troposphere and is associated with cyclonic development throughout the atmosphere. Through a highly idealized systematic approach, the effect that different intrusion characteristics have on surface cyclogenetic forcing is investigated. The proximity of stratospheric intrusions to the surface is shown to be the main factor in surface cyclogenetic forcing, whilst its width is an additional contributing factor.
                                            
                                            
                                        Carlos Calvo-Sancho, Javier Díaz-Fernández, Yago Martín, Pedro Bolgiani, Mariano Sastre, Juan Jesús González-Alemán, Daniel Santos-Muñoz, José Ignacio Farrán, and María Luisa Martín
                                    Weather Clim. Dynam., 3, 1021–1036, https://doi.org/10.5194/wcd-3-1021-2022, https://doi.org/10.5194/wcd-3-1021-2022, 2022
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                                                Supercells are among the most complex and dangerous severe convective storms due to their associated phenomena (lightning, strong winds, large hail, flash floods, or tornadoes). In this survey we study the supercell synoptic configurations and convective environments in Spain using the atmospheric reanalysis ERA5. Supercells are grouped into hail (greater than 5 cm) and non-hail events in order to compare and analyze the two events. The results reveal statistically significant differences.
                                            
                                            
                                        Adrian J. Simmons
                                    Weather Clim. Dynam., 3, 777–809, https://doi.org/10.5194/wcd-3-777-2022, https://doi.org/10.5194/wcd-3-777-2022, 2022
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                                                This study of changes in temperature and wind since 1979 met its twin aims of (i) increasing confidence in some findings of the latest IPCC assessment and (ii) identifying changes that had received little or no previous attention. It reports a small overall intensification and shift in position of the North Atlantic jet stream and associated storms, and a strengthening of tropical upper-level easterlies. Increases in low-level winds over tropical and southern hemispheric oceans are confirmed.
                                            
                                            
                                        Monika Feldmann, Urs Germann, Marco Gabella, and Alexis Berne
                                    Weather Clim. Dynam., 2, 1225–1244, https://doi.org/10.5194/wcd-2-1225-2021, https://doi.org/10.5194/wcd-2-1225-2021, 2021
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                                                Mesocyclones are the rotating updraught of supercell thunderstorms that present a particularly hazardous subset of thunderstorms. A first-time characterisation of the spatiotemporal occurrence of mesocyclones in the Alpine region is presented, using 5 years of Swiss operational radar data. We investigate parallels to hailstorms, particularly the influence of large-scale flow, daily cycles and terrain. Improving understanding of mesocyclones is valuable for risk assessment and warning purposes.
                                            
                                            
                                        Dalton K. Sasaki, Carolina B. Gramcianinov, Belmiro Castro, and Marcelo Dottori
                                    Weather Clim. Dynam., 2, 1149–1166, https://doi.org/10.5194/wcd-2-1149-2021, https://doi.org/10.5194/wcd-2-1149-2021, 2021
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                                                Extratropical cyclones are relevant in the western South Atlantic and influence the climate of ocean surface wave. Propagating atmospheric features from the South Pacific to the South Atlantic are relevant to the cyclones and waves, and its intensified westerlies lead to more cyclones and, as a consequence, to higher wave heights. The opposite happens with its weakening. These features are similar to the so-called Pacific South American patterns and present periods between 30 and 180 d.
                                            
                                            
                                        Laurent Terray
                                    Weather Clim. Dynam., 2, 971–989, https://doi.org/10.5194/wcd-2-971-2021, https://doi.org/10.5194/wcd-2-971-2021, 2021
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                                                Attribution of the causes of extreme temperature events has become active research due to the wide-ranging impacts of recent heat waves and cold spells. Here we show that a purely observational approach based on atmospheric circulation analogues and resampling provides a robust quantification of the various dynamic and thermodynamic contributions to specific extreme temperature events. The approach can easily be integrated in the toolbox of any real-time extreme event attribution system.
                                            
                                            
                                        Claudia Christine Stephan and Alexis Mariaccia
                                    Weather Clim. Dynam., 2, 359–372, https://doi.org/10.5194/wcd-2-359-2021, https://doi.org/10.5194/wcd-2-359-2021, 2021
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                                                Vertical motion on horizontal scales of a few hundred kilometers can influence cloud properties. This motion is difficult to measure directly but can be inferred from the area-averaged mass divergence. The latter can be derived from horizontal wind measurements at the area’s perimeter. This study derives vertical properties of area-averaged divergence from an extensive network of atmospheric soundings and proposes an explanation for the variation of divergence magnitudes with area size.
                                            
                                            
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                Short summary
            This study focused on exploring if off-season tropical cyclones, those that develop outside of the peak months, have been increasing over time in the Atlantic Ocean and Pacific Ocean basins and if that higher frequency could be explained by climate variability or change. We found that off-season tropical cyclones are exhibiting an increase in total numbers by decade in the North Atlantic and East Pacific ocean basins and that climate change explained much of the increasing trends over time.
            This study focused on exploring if off-season tropical cyclones, those that develop outside of...