Articles | Volume 5, issue 4
https://doi.org/10.5194/wcd-5-1489-2024
© Author(s) 2024. 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-5-1489-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
06 Dec 2024
Research article |
| 06 Dec 2024
| 06 Dec 2024
Role of the quasi-biennial oscillation in alleviating biases in the semi-annual oscillation
Aleena M. Jaison
CORRESPONDING AUTHOR
Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, United Kingdom
now at: Department of Physics, Imperial College London, London, United Kingdom
Lesley J. Gray
Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, United Kingdom
National Centre for Atmospheric Science, Oxford, United Kingdom
Scott M. Osprey
Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, United Kingdom
National Centre for Atmospheric Science, Oxford, United Kingdom
Jeff R. Knight
Met Office Hadley Centre, Exeter, United Kingdom
Martin B. Andrews
Met Office Hadley Centre, Exeter, United Kingdom
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Blanca Ayarzagüena, Amy H. Butler, Peter Hitchcock, Chaim I. Garfinkel, Zac D. Lawrence, Wuhan Ning, Philip Rupp, Zheng Wu, Hilla Afargan-Gerstman, Natalia Calvo, Álvaro de la Cámara, Martin Jucker, Gerbrand Koren, Daniel De Maeseneire, Gloria L. Manney, Marisol Osman, Masakazu Taguchi, Cory Barton, Dong-Chang Hong, Yu-Kyung Hyun, Hera Kim, Jeff Knight, Piero Malguzzi, Daniele Mastrangelo, Jiyoung Oh, Inna Polichtchouk, Jadwiga H. Richter, Isla R. Simpson, Seok-Woo Son, Damien Specq, and Tim Stockdale
EGUsphere, https://doi.org/10.5194/egusphere-2025-3611, https://doi.org/10.5194/egusphere-2025-3611, 2025
This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
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Sudden Stratospheric Warmings (SSWs) are known to follow a sustained wave dissipation in the stratosphere, which depends on both the tropospheric and stratospheric states. However, the relative role of each state is still unclear. Using a new set of subseasonal to seasonal forecasts, we show that the stratospheric state does not drastically affect the precursors of three recent SSWs, but modulates the stratospheric wave activity, with impacts depending on SSW features.
Mark D. Rhodes-Smith, Victoria A. Bell, Nicky Stringer, Helen Baron, Helen Davies, and Jeff Knight
EGUsphere, https://doi.org/10.5194/egusphere-2025-2506, https://doi.org/10.5194/egusphere-2025-2506, 2025
This preprint is open for discussion and under review for Hydrology and Earth System Sciences (HESS).
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River flow forecasts up to three months ahead can allow early preparations for future floods and droughts. We test a new forecasting system using weather forecasts made by selecting historical weather patterns that match current conditions and running them through a simulation of Great Britain's rivers. Our tests show that this system performs particularly well in the winter and spring, in northern Scotland and in southern England. We now use this system to produce forecasts regularly.
Wilson Chan, Katie Facer-Childs, Maliko Tanguy, Eugene Magee, Burak Bulut, Nicky Stringer, Jeff Knight, and Jamie Hannaford
EGUsphere, https://doi.org/10.5194/egusphere-2025-2369, https://doi.org/10.5194/egusphere-2025-2369, 2025
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The UK Hydrological Outlook river flow forecasting system recently implemented the Historic Weather Analogues method. The method improves winter river flow forecast skill across the UK, especially in upland, fast-responding catchments with low catchment storage. Forecast skill is highest in winter due to accurate prediction of atmospheric circulation patterns like the North Atlantic Oscillation. The Ensemble Streamflow prediction method remains a robust benchmark, especially for other seasons.
Hiroaki Naoe, Jorge L. Garcia-Franco, Chang-Hyun Park, Mario Rodrigo, Froila M. Palmeiro, Federico Serva, Masakazu Taguchi, Kohei Yoshida, James A. Anstey, Javier Garcia-Serrano, Seok-Woo Son, Yoshio Kawatani, Neal Butchart, Kevin Hamilton, Chih-Chieh Chen, Anne Glanville, Tobias Kerzenmacher, Francois Lott, Clara Orbe, Scott Osprey, Mijeong Park, Jadwiga H. Richter, Stefan Versick, and Shingo Watanabe
EGUsphere, https://doi.org/10.5194/egusphere-2025-1148, https://doi.org/10.5194/egusphere-2025-1148, 2025
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This study examines links between the stratospheric Quasi-Biennial Oscillation (QBO) and large-scale atmospheric circulations in the tropics, subtropics, and polar regions. The QBO teleconnections and their modulation by the El Niño-Southern Oscillation (ENSO) are investigated through a series of climate model experiments. While QBO teleconnections are qualitatively reproduced by the multi-model ensemble, they are not consistent due to modelled QBO bias and other systematic model biases.
Dillon Elsbury, Federico Serva, Julie M. Caron, Seung-Yoon Back, Clara Orbe, Jadwiga H. Richter, James A. Anstey, Neal Butchart, Chih-Chieh Chen, Javier García-Serrano, Anne Glanville, Yoshio Kawatani, Tobias Kerzenmacher, Francois Lott, Hiroaki Naoe, Scott Osprey, Froila M. Palmeiro, Seok-Woo Son, Masakazu Taguchi, Stefan Versick, Shingo Watanabe, and Kohei Yoshida
EGUsphere, https://doi.org/10.5194/egusphere-2024-3950, https://doi.org/10.5194/egusphere-2024-3950, 2025
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This study examines how the Madden-Julian Oscillation (MJO), a major tropical weather pattern, is influenced by persistent El Niño or La Niña sea surface temperature conditions during winter. Using a coordinated set of climate model experiments, we find that El Niño strengthens Kelvin waves, speeding up MJO propagation, while La Niña strengthens Rossby waves, slowing it down. Better understanding these interactions between the MJO and ocean helps us better understand natural climate variability.
Yoshio Kawatani, Kevin Hamilton, Shingo Watanabe, James A. Anstey, Jadwiga H. Richter, Neal Butchart, Clara Orbe, Scott M. Osprey, Hiroaki Naoe, Dillon Elsbury, Chih-Chieh Chen, Javier García-Serrano, Anne Glanville, Tobias Kerzenmacher, François Lott, Froila M. Palmerio, Mijeong Park, Federico Serva, Masakazu Taguchi, Stefan Versick, and Kohei Yoshioda
EGUsphere, https://doi.org/10.5194/egusphere-2024-3270, https://doi.org/10.5194/egusphere-2024-3270, 2024
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The Quasi-Biennial Oscillation (QBO) of the tropical stratospheric mean winds has been relatively steady over the 7 decades it has been observed, but there are always cycle-to-cycle variations. This study used several global atmospheric models to investigate systematic modulation of the QBO by the El Niño/La Niña cycle. All models simulated shorter periods during El Niño, in agreement with observations. By contrast, the models disagreed even on the sign of the El Niño effect on QBO amplitude.
Paula L. M. Gonzalez, Lesley J. Gray, Stergios Misios, Scott Osprey, and Hedi Ma
EGUsphere, https://doi.org/10.5194/egusphere-2024-2487, https://doi.org/10.5194/egusphere-2024-2487, 2024
Preprint archived
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This study has examined a set of reanalyses, both modern and 20th Century, to evaluate the robustness of the signatures of the 11-yr solar cycle in the North Atlantic climate. We find a robust response to the 11-yr solar cycle over the North Atlantic sector with a positive SLP anomaly north of the Azores region at lags of +2–3 years following solar maximum. An ocean reanalysis dataset shows that thermal inertia of the ocean could explain the lag in the SC response.
Timothy P. Banyard, Corwin J. Wright, Scott M. Osprey, Neil P. Hindley, Gemma Halloran, Lawrence Coy, Paul A. Newman, Neal Butchart, Martina Bramberger, and M. Joan Alexander
Atmos. Chem. Phys., 24, 2465–2490, https://doi.org/10.5194/acp-24-2465-2024, https://doi.org/10.5194/acp-24-2465-2024, 2024
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In 2019/2020, the tropical stratospheric wind phenomenon known as the quasi-biennial oscillation (QBO) was disrupted for only the second time in the historical record. This was poorly forecasted, and we want to understand why. We used measurements from the first Doppler wind lidar in space, Aeolus, to observe the disruption in an unprecedented way. Our results reveal important differences between Aeolus and the ERA5 reanalysis that affect the timing of the disruption's onset and its evolution.
Jorge L. García-Franco, Lesley J. Gray, Scott Osprey, Robin Chadwick, and Zane Martin
Weather Clim. Dynam., 3, 825–844, https://doi.org/10.5194/wcd-3-825-2022, https://doi.org/10.5194/wcd-3-825-2022, 2022
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This paper establishes robust links between the stratospheric quasi-biennial oscillation (QBO) and several features of tropical climate. Robust precipitation responses, as well as changes to the Walker circulation, were found to be robustly linked to the variability in the lower stratosphere associated with the QBO using a 500-year simulation of a state-of-the-art climate model.
Peter Hitchcock, Amy Butler, Andrew Charlton-Perez, Chaim I. Garfinkel, Tim Stockdale, James Anstey, Dann Mitchell, Daniela I. V. Domeisen, Tongwen Wu, Yixiong Lu, Daniele Mastrangelo, Piero Malguzzi, Hai Lin, Ryan Muncaster, Bill Merryfield, Michael Sigmond, Baoqiang Xiang, Liwei Jia, Yu-Kyung Hyun, Jiyoung Oh, Damien Specq, Isla R. Simpson, Jadwiga H. Richter, Cory Barton, Jeff Knight, Eun-Pa Lim, and Harry Hendon
Geosci. Model Dev., 15, 5073–5092, https://doi.org/10.5194/gmd-15-5073-2022, https://doi.org/10.5194/gmd-15-5073-2022, 2022
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This paper describes an experimental protocol focused on sudden stratospheric warmings to be carried out by subseasonal forecast modeling centers. These will allow for inter-model comparisons of these major disruptions to the stratospheric polar vortex and their impacts on the near-surface flow. The protocol will lead to new insights into the contribution of the stratosphere to subseasonal forecast skill and new approaches to the dynamical attribution of extreme events.
Oscar Dimdore-Miles, Lesley Gray, Scott Osprey, Jon Robson, Rowan Sutton, and Bablu Sinha
Atmos. Chem. Phys., 22, 4867–4893, https://doi.org/10.5194/acp-22-4867-2022, https://doi.org/10.5194/acp-22-4867-2022, 2022
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This study examines interactions between variations in the strength of polar stratospheric winds and circulation in the North Atlantic in a climate model simulation. It finds that the Atlantic Meridional Overturning Circulation (AMOC) responds with oscillations to sets of consecutive Northern Hemisphere winters, which show all strong or all weak polar vortex conditions. The study also shows that a set of strong vortex winters in the 1990s contributed to the recent slowdown in the observed AMOC.
Beatriz M. Monge-Sanz, Alessio Bozzo, Nicholas Byrne, Martyn P. Chipperfield, Michail Diamantakis, Johannes Flemming, Lesley J. Gray, Robin J. Hogan, Luke Jones, Linus Magnusson, Inna Polichtchouk, Theodore G. Shepherd, Nils Wedi, and Antje Weisheimer
Atmos. Chem. Phys., 22, 4277–4302, https://doi.org/10.5194/acp-22-4277-2022, https://doi.org/10.5194/acp-22-4277-2022, 2022
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The stratosphere is emerging as one of the keys to improve tropospheric weather and climate predictions. This study provides evidence of the role the stratospheric ozone layer plays in improving weather predictions at different timescales. Using a new ozone modelling approach suitable for high-resolution global models that provide operational forecasts from days to seasons, we find significant improvements in stratospheric meteorological fields and stratosphere–troposphere coupling.
Marta Abalos, Natalia Calvo, Samuel Benito-Barca, Hella Garny, Steven C. Hardiman, Pu Lin, Martin B. Andrews, Neal Butchart, Rolando Garcia, Clara Orbe, David Saint-Martin, Shingo Watanabe, and Kohei Yoshida
Atmos. Chem. Phys., 21, 13571–13591, https://doi.org/10.5194/acp-21-13571-2021, https://doi.org/10.5194/acp-21-13571-2021, 2021
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The stratospheric Brewer–Dobson circulation (BDC), responsible for transporting mass, tracers and heat globally in the stratosphere, is evaluated in a set of state-of-the-art climate models. The acceleration of the BDC in response to increasing greenhouse gases is most robust in the lower stratosphere. At higher levels, the well-known inconsistency between model and observational BDC trends can be partly reconciled by accounting for limited sampling and large uncertainties in the observations.
Seán Donegan, Conor Murphy, Shaun Harrigan, Ciaran Broderick, Dáire Foran Quinn, Saeed Golian, Jeff Knight, Tom Matthews, Christel Prudhomme, Adam A. Scaife, Nicky Stringer, and Robert L. Wilby
Hydrol. Earth Syst. Sci., 25, 4159–4183, https://doi.org/10.5194/hess-25-4159-2021, https://doi.org/10.5194/hess-25-4159-2021, 2021
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We benchmarked the skill of ensemble streamflow prediction (ESP) for a diverse sample of 46 Irish catchments. We found that ESP is skilful in the majority of catchments up to several months ahead. However, the level of skill was strongly dependent on lead time, initialisation month, and individual catchment location and storage properties. We also conditioned ESP with the winter North Atlantic Oscillation and show that improvements in forecast skill, reliability, and discrimination are possible.
Oscar Dimdore-Miles, Lesley Gray, and Scott Osprey
Weather Clim. Dynam., 2, 205–231, https://doi.org/10.5194/wcd-2-205-2021, https://doi.org/10.5194/wcd-2-205-2021, 2021
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Observations of the stratosphere span roughly half a century, preventing analysis of multi-decadal variability in circulation using these data. Instead, we rely on long simulations of climate models. Here, we use a model to examine variations in northern polar stratospheric winds and find they vary with a period of around 90 years. We show that this is possibly due to variations in the size of winds over the Equator. This result may improve understanding of Equator–polar stratospheric coupling.
Jane P. Mulcahy, Colin Johnson, Colin G. Jones, Adam C. Povey, Catherine E. Scott, Alistair Sellar, Steven T. Turnock, Matthew T. Woodhouse, Nathan Luke Abraham, Martin B. Andrews, Nicolas Bellouin, Jo Browse, Ken S. Carslaw, Mohit Dalvi, Gerd A. Folberth, Matthew Glover, Daniel P. Grosvenor, Catherine Hardacre, Richard Hill, Ben Johnson, Andy Jones, Zak Kipling, Graham Mann, James Mollard, Fiona M. O'Connor, Julien Palmiéri, Carly Reddington, Steven T. Rumbold, Mark Richardson, Nick A. J. Schutgens, Philip Stier, Marc Stringer, Yongming Tang, Jeremy Walton, Stephanie Woodward, and Andrew Yool
Geosci. Model Dev., 13, 6383–6423, https://doi.org/10.5194/gmd-13-6383-2020, https://doi.org/10.5194/gmd-13-6383-2020, 2020
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Aerosols are an important component of the Earth system. Here, we comprehensively document and evaluate the aerosol schemes as implemented in the physical and Earth system models, HadGEM3-GC3.1 and UKESM1. This study provides a useful characterisation of the aerosol climatology in both models, facilitating the understanding of the numerous aerosol–climate interaction studies that will be conducted for CMIP6 and beyond.
Steven T. Turnock, Robert J. Allen, Martin Andrews, Susanne E. Bauer, Makoto Deushi, Louisa Emmons, Peter Good, Larry Horowitz, Jasmin G. John, Martine Michou, Pierre Nabat, Vaishali Naik, David Neubauer, Fiona M. O'Connor, Dirk Olivié, Naga Oshima, Michael Schulz, Alistair Sellar, Sungbo Shim, Toshihiko Takemura, Simone Tilmes, Kostas Tsigaridis, Tongwen Wu, and Jie Zhang
Atmos. Chem. Phys., 20, 14547–14579, https://doi.org/10.5194/acp-20-14547-2020, https://doi.org/10.5194/acp-20-14547-2020, 2020
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A first assessment is made of the historical and future changes in air pollutants from models participating in the 6th Coupled Model Intercomparison Project (CMIP6). Substantial benefits to future air quality can be achieved in future scenarios that implement measures to mitigate climate and involve reductions in air pollutant emissions, particularly methane. However, important differences are shown between models in the future regional projection of air pollutants under the same scenario.
Jorge L. García-Franco, Lesley J. Gray, and Scott Osprey
Weather Clim. Dynam., 1, 349–371, https://doi.org/10.5194/wcd-1-349-2020, https://doi.org/10.5194/wcd-1-349-2020, 2020
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The American monsoon system is the main source of rainfall for the subtropical Americas and an important element of Latin American agriculture. Here we use state-of-the-art climate models from the UK Met Office in different configurations to analyse the performance of these models in the American monsoon. Resolution is found to be a key factor to improve monsoon representation, whereas integrated chemistry does not improve the simulated monsoon rainfall.
Lesley J. Gray, James A. Anstey, Yoshio Kawatani, Hua Lu, Scott Osprey, and Verena Schenzinger
Atmos. Chem. Phys., 18, 8227–8247, https://doi.org/10.5194/acp-18-8227-2018, https://doi.org/10.5194/acp-18-8227-2018, 2018
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A major phenomenon in the stratosphere is the Quasi Biennial Oscillation (QBO). Although a feature of the equatorial stratosphere, its influence extends to surface weather at both equatorial and mid latitudes. Improved knowledge of mechanisms of influence should help to improve weather forecasts. In this paper, QBO impacts at the surface are characterized and dominant mechanisms explored. Three pathways are identified, referred to as the tropical, subtropical and polar routes.
Neal Butchart, James A. Anstey, Kevin Hamilton, Scott Osprey, Charles McLandress, Andrew C. Bushell, Yoshio Kawatani, Young-Ha Kim, Francois Lott, John Scinocca, Timothy N. Stockdale, Martin Andrews, Omar Bellprat, Peter Braesicke, Chiara Cagnazzo, Chih-Chieh Chen, Hye-Yeong Chun, Mikhail Dobrynin, Rolando R. Garcia, Javier Garcia-Serrano, Lesley J. Gray, Laura Holt, Tobias Kerzenmacher, Hiroaki Naoe, Holger Pohlmann, Jadwiga H. Richter, Adam A. Scaife, Verena Schenzinger, Federico Serva, Stefan Versick, Shingo Watanabe, Kohei Yoshida, and Seiji Yukimoto
Geosci. Model Dev., 11, 1009–1032, https://doi.org/10.5194/gmd-11-1009-2018, https://doi.org/10.5194/gmd-11-1009-2018, 2018
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This paper documents the numerical experiments to be used in phase 1 of the Stratosphere–troposphere Processes And their Role in Climate (SPARC) Quasi-Biennial Oscillation initiative (QBOi), which was set up to improve the representation of the QBO and tropical stratospheric variability in global climate models.
Verena Schenzinger, Scott Osprey, Lesley Gray, and Neal Butchart
Geosci. Model Dev., 10, 2157–2168, https://doi.org/10.5194/gmd-10-2157-2017, https://doi.org/10.5194/gmd-10-2157-2017, 2017
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The Quasi-Biennial Oscillation (QBO) is a pattern of winds in the equatorial stratosphere that has been observed for the past 60 years. It is thought to have long-range influences, e.g. on the Northern Hemisphere winter polar vortex and therefore Europe's winter weather. Since its period is about 2 years, being able to predict the QBO might also improve weather forecasting. Using a set of characteristic metrics, this paper examines how reliable current climate models are in simulating the QBO.
Masatomo Fujiwara, Jonathon S. Wright, Gloria L. Manney, Lesley J. Gray, James Anstey, Thomas Birner, Sean Davis, Edwin P. Gerber, V. Lynn Harvey, Michaela I. Hegglin, Cameron R. Homeyer, John A. Knox, Kirstin Krüger, Alyn Lambert, Craig S. Long, Patrick Martineau, Andrea Molod, Beatriz M. Monge-Sanz, Michelle L. Santee, Susann Tegtmeier, Simon Chabrillat, David G. H. Tan, David R. Jackson, Saroja Polavarapu, Gilbert P. Compo, Rossana Dragani, Wesley Ebisuzaki, Yayoi Harada, Chiaki Kobayashi, Will McCarty, Kazutoshi Onogi, Steven Pawson, Adrian Simmons, Krzysztof Wargan, Jeffrey S. Whitaker, and Cheng-Zhi Zou
Atmos. Chem. Phys., 17, 1417–1452, https://doi.org/10.5194/acp-17-1417-2017, https://doi.org/10.5194/acp-17-1417-2017, 2017
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We introduce the SPARC Reanalysis Intercomparison Project (S-RIP), review key concepts and elements of atmospheric reanalysis systems, and summarize the technical details of and differences among 11 of these systems. This work supports scientific studies and intercomparisons of reanalysis products by collecting these background materials and technical details into a single reference. We also address several common misunderstandings and points of confusion regarding reanalyses.
C. J. Wright, S. M. Osprey, and J. C. Gille
Atmos. Chem. Phys., 15, 8459–8477, https://doi.org/10.5194/acp-15-8459-2015, https://doi.org/10.5194/acp-15-8459-2015, 2015
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Data from the HIRDLS instrument are used to study the numerical variability of gravity waves. Observed distributions are dominated by long-vertical-short-horizontal-wavelength waves, with a similar spectral form at all locations. We further divide our data into subspecies by wavelength, and investigate variation in these subspecies in time and space. We show that the variations associated with particular phenomena arise due to changes in specific parts of the spectrum.
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Pep Cos, Matias Olmo, Diego Campos, Raül Marcos-Matamoros, Lluís Palma, Ángel G. Muñoz, and Francisco J. Doblas-Reyes
Weather Clim. Dynam., 6, 609–626, https://doi.org/10.5194/wcd-6-609-2025, https://doi.org/10.5194/wcd-6-609-2025, 2025
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This work presents the identification of Saharan warm-air intrusions in the western Mediterranean, which are the displacement of air masses formed over the Sahara toward the west of the Mediterranean region. We focus on the recent past and obtain a catalogue of intrusion days. The results show the existence of different types of intrusions, important impacts on extremely high temperatures in the Mediterranean and Europe, and the dynamic mechanisms that can cause the onset of these events.
Corey Robinson, Sugata Narsey, Christian Jakob, and Hanh Nguyen
Weather Clim. Dynam., 6, 369–385, https://doi.org/10.5194/wcd-6-369-2025, https://doi.org/10.5194/wcd-6-369-2025, 2025
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Rainfall in the tropics is strongly related to the amount of moisture in the atmosphere. In this work, we examine a measure of moisture called the “moist margin”, which describes a transition between rainy and clear regions of the tropics. We show that movement of the moist margin is often related to a variety of weather systems. Cases where tropical moisture moves far poleward are often related to low-pressure systems or large-scale waves in the extratropics.
Hugo A. Braga and Victor Magaña
Weather Clim. Dynam., 6, 265–277, https://doi.org/10.5194/wcd-6-265-2025, https://doi.org/10.5194/wcd-6-265-2025, 2025
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This study presents a comprehensive dynamic and statistical analysis of mixed Rossby–gravity waves during the austral summer. It highlights the significant influence of upper-level lateral forcing on wave dynamics and the critical role of lower-tropospheric humidity in modulating asymmetric convection, providing new insights into the behavior of equatorial waves and their impact on regional weather patterns.
Quentin Nicolas and William R. Boos
Weather Clim. Dynam., 6, 231–244, https://doi.org/10.5194/wcd-6-231-2025, https://doi.org/10.5194/wcd-6-231-2025, 2025
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Rainfall in mountainous regions constitutes an important source of freshwater in the tropics. Yet how it will change with global warming remains an open question. Here, we reveal a strong sensitivity of this rainfall to the speed of prevailing winds. This relationship, validated by theory, simulations, and observational data, suggests that regional wind shifts will significantly influence future rainfall changes in the tropics.
Priya Bharati, Pranab Deb, and Kieran Mark Rainwater Hunt
Weather Clim. Dynam., 6, 197–210, https://doi.org/10.5194/wcd-6-197-2025, https://doi.org/10.5194/wcd-6-197-2025, 2025
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Our study highlights that the negative phase of the Pacific Decadal Oscillation (PDO) enhanced winter snowfall in the Karakoram and the Western Himalayas (KH) from 1940 to 2022. This is driven by deep convection, adiabatic cooling, and a wave-like atmospheric pattern linked to the subtropical jet (STJ). The PDO–STJ relationship offers insights into decadal snowfall predictability in KH, emphasizing the PDO's role in regional climate dynamics.
Matthias Fischer, Peter Knippertz, and Carsten Proppe
Weather Clim. Dynam., 6, 113–130, https://doi.org/10.5194/wcd-6-113-2025, https://doi.org/10.5194/wcd-6-113-2025, 2025
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The West African monsoon is vital for millions but difficult to represent with numerical models. Our research aims at improving monsoon simulations by optimizing three model parameters – entrainment rate, ice fall speed, and soil moisture evaporation – using an advanced surrogate-based multi-objective optimization framework. Results show that tuning these parameters can sometimes improve certain monsoon characteristics, however at the expense of others, highlighting the power of our approach.
Kieran M. R. Hunt, Jean-Philippe Baudouin, Andrew G. Turner, A. P. Dimri, Ghulam Jeelani, Pooja, Rajib Chattopadhyay, Forest Cannon, T. Arulalan, M. S. Shekhar, T. P. Sabin, and Eliza Palazzi
Weather Clim. Dynam., 6, 43–112, https://doi.org/10.5194/wcd-6-43-2025, https://doi.org/10.5194/wcd-6-43-2025, 2025
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Western disturbances (WDs) are storms that predominantly affect north India and Pakistan during the winter months, where they play an important role in regional water security, but can also bring a range of natural hazards. In this review, we summarise recent literature across a range of topics: their structure and lifecycle, precipitation and impacts, interactions with large-scale weather patterns, representation in models, how well they are forecast, and their response to changes in climate.
Kerry Emanuel, Tommaso Alberti, Stella Bourdin, Suzana J. Camargo, Davide Faranda, Manos Flaounas, Juan Jesus Gonzalez-Aleman, Chia-Ying Lee, Mario Marcello Miglietta, Claudia Pasquero, Alice Portal, Hamish Ramsay, and Romualdo Romero
EGUsphere, https://doi.org/10.5194/egusphere-2024-3387, https://doi.org/10.5194/egusphere-2024-3387, 2024
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Storms strongly resembling hurricanes are sometime observed to form well outside the tropics, even in polar latitudes. They behave capriciously, developing very rapidly and then dying just as quickly. We show that strong dynamical processes in the atmosphere can sometimes cause it to become locally much colder than the underlying ocean, creating the conditions for hurricanes to form, but only over small areas and for short times. We call the resulting storms "cyclops".
Aude Garin, Francesco S. R. Pausata, Mathieu Boudreault, and Roberto Ingrosso
EGUsphere, https://doi.org/10.5194/egusphere-2024-3435, https://doi.org/10.5194/egusphere-2024-3435, 2024
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As tropical cyclones move poleward, they can transform into extratropical cyclones, a process known as extratropical transition. These storms can pose serious risks to human lives and cause damage to infrastructure along the northeastern coasts of the U.S. & Canada. Our study investigates the impacts of climate change on the frequency, intensity, and location of extratropical transitions, revealing that transitioning storms may become more destructive in the future but may not be more frequent.
Yoshio Kawatani, Kevin Hamilton, Shingo Watanabe, James A. Anstey, Jadwiga H. Richter, Neal Butchart, Clara Orbe, Scott M. Osprey, Hiroaki Naoe, Dillon Elsbury, Chih-Chieh Chen, Javier García-Serrano, Anne Glanville, Tobias Kerzenmacher, François Lott, Froila M. Palmerio, Mijeong Park, Federico Serva, Masakazu Taguchi, Stefan Versick, and Kohei Yoshioda
EGUsphere, https://doi.org/10.5194/egusphere-2024-3270, https://doi.org/10.5194/egusphere-2024-3270, 2024
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The Quasi-Biennial Oscillation (QBO) of the tropical stratospheric mean winds has been relatively steady over the 7 decades it has been observed, but there are always cycle-to-cycle variations. This study used several global atmospheric models to investigate systematic modulation of the QBO by the El Niño/La Niña cycle. All models simulated shorter periods during El Niño, in agreement with observations. By contrast, the models disagreed even on the sign of the El Niño effect on QBO amplitude.
Matthew Davison and Peter Haynes
Weather Clim. Dynam., 5, 1153–1185, https://doi.org/10.5194/wcd-5-1153-2024, https://doi.org/10.5194/wcd-5-1153-2024, 2024
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A simple model is used to study the relation between small-scale convection and large-scale variability in the tropics arising from the coupling between moisture and dynamics. In the model, moisture preferentially lies at either moist or dry states, which merge to form large-scale aggregated regions. On an equatorial β plane, these aggregated regions are localised at the Equator and propagate zonally. This forms an intermediate model between past simpler models and general circulation models.
Nicolás García-Lee, Claudio Bravo, Álvaro Gónzalez-Reyes, and Piero Mardones
Weather Clim. Dynam., 5, 1137–1151, https://doi.org/10.5194/wcd-5-1137-2024, https://doi.org/10.5194/wcd-5-1137-2024, 2024
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This study analyses the 0 °C isotherm in Patagonia from 1959 to 2021, using observational and fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis data. The model aligns well with observations, highlighting significant altitude variations between the western and eastern sides of the austral Andes, a correlation between isotherm fluctuations and the Southern Annular Mode index, and an upward trend in the study area (especially in northwestern Patagonia).
Ting-Yu Cha and Michael M. Bell
Weather Clim. Dynam., 5, 1013–1029, https://doi.org/10.5194/wcd-5-1013-2024, https://doi.org/10.5194/wcd-5-1013-2024, 2024
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Our study investigates the dynamics of polygonal eyewall structures observed in intensifying hurricanes like Michael (2018) by using a simplified modeling approach. We develop a two-layer model to simulate the interactions between the free atmosphere and boundary layer to demonstrate the importance of different physical mechanisms in the intensification process. This simplified model offers insights into the interactions between dynamics and convection during hurricane intensification.
Abu Bakar Siddiqui Thakur and Jai Sukhatme
Weather Clim. Dynam., 5, 839–862, https://doi.org/10.5194/wcd-5-839-2024, https://doi.org/10.5194/wcd-5-839-2024, 2024
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We analyze the present and future states of the tropical upper troposphere. Observations and climate model simulations suggest that interactions between disparate families of waves and the mean flow maintain present-day upper-level winds, and each component undergoes complex changes due to global warming. While the net east–west flow of the atmosphere may remain unaltered, this study indicates robust changes to local circulations that may influence tropical precipitation and regional climate.
Gill M. Martin and José M. Rodríguez
Weather Clim. Dynam., 5, 711–731, https://doi.org/10.5194/wcd-5-711-2024, https://doi.org/10.5194/wcd-5-711-2024, 2024
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Using sensitivity experiments, we show that model errors developing in the Maritime Continent region contribute substantially to the Asian summer monsoon (ASM) circulation and rainfall errors through their effects on the western North Pacific subtropical high-pressure region and the winds and sea surface temperatures in the equatorial Indian Ocean, exacerbated by local coupled feedback. Such information will inform future model developments aimed at improving model predictions for the ASM.
Clemens Spensberger
Weather Clim. Dynam., 5, 659–669, https://doi.org/10.5194/wcd-5-659-2024, https://doi.org/10.5194/wcd-5-659-2024, 2024
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It is well-established that variations in convection in the tropical Indo-Pacific can influence weather in far-away regions. In this idea, I argue that the main theory used to explain this influence over large distances is incomplete. I propose hypotheses that could lead the way towards a more fundamental explanation and outline a novel approach that could be used to test the hypotheses I raise. The suggested approach might be useful to address also other long-standing questions.
Richard J. Keane, Ankur Srivastava, and Gill M. Martin
Weather Clim. Dynam., 5, 671–702, https://doi.org/10.5194/wcd-5-671-2024, https://doi.org/10.5194/wcd-5-671-2024, 2024
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We evaluate the performance of two widely used models in forecasting the Indian summer monsoon, which is one of the most challenging meteorological phenomena to simulate. The work links previous studies evaluating the use of the models in weather forecasting and climate simulation, as the focus here is on seasonal forecasting, which involves intermediate timescales. As well as being important in itself, this evaluation provides insights into how errors develop in the two modelling systems.
Matthias Fischer, Peter Knippertz, Roderick van der Linden, Alexander Lemburg, Gregor Pante, Carsten Proppe, and John H. Marsham
Weather Clim. Dynam., 5, 511–536, https://doi.org/10.5194/wcd-5-511-2024, https://doi.org/10.5194/wcd-5-511-2024, 2024
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Our research enhances the understanding of the complex dynamics within the West African monsoon system by analyzing the impact of specific model parameters on its characteristics. Employing surrogate models, we identified critical factors such as the entrainment rate and the fall velocity of ice. Precise definition of these parameters in weather models could improve forecast accuracy, thus enabling better strategies to manage and reduce the impact of weather events.
Kieran M. R. Hunt
Weather Clim. Dynam., 5, 345–356, https://doi.org/10.5194/wcd-5-345-2024, https://doi.org/10.5194/wcd-5-345-2024, 2024
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This study investigates changes in weather systems that bring winter precipitation to south Asia. We find that these systems, known as western disturbances, are occurring more frequently and lasting longer into the summer months. This shift is leading to devastating floods, as happened recently in north India. By analysing 70 years of weather data, we trace this change to shifts in major air currents known as the subtropical jet. Due to climate change, such events are becoming more frequent.
William J. Dow, Christine M. McKenna, Manoj M. Joshi, Adam T. Blaker, Richard Rigby, and Amanda C. Maycock
Weather Clim. Dynam., 5, 357–367, https://doi.org/10.5194/wcd-5-357-2024, https://doi.org/10.5194/wcd-5-357-2024, 2024
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Changes to sea surface temperatures in the extratropical North Pacific are driven partly by patterns of local atmospheric circulation, such as the Aleutian Low. We show that an intensification of the Aleutian Low could contribute to small changes in temperatures across the equatorial Pacific via the initiation of two mechanisms. The effect, although significant, is unlikely to explain fully the recently observed multi-year shift of a pattern of climate variability across the wider Pacific.
Franco Molteni, Fred Kucharski, and Riccardo Farneti
Weather Clim. Dynam., 5, 293–322, https://doi.org/10.5194/wcd-5-293-2024, https://doi.org/10.5194/wcd-5-293-2024, 2024
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We describe some new features of an intermediate-complexity coupled model, including a three-layer thermodynamic ocean model suitable to explore the extratropical response to tropical ocean variability. We present results on the model climatology and show that important features of interdecadal and interannual variability are realistically simulated in a
pacemakercoupled ensemble of 70-year runs, where portions of the tropical Indo-Pacific are constrained to follow the observed variability.
Molly E. Menzel, Darryn W. Waugh, Zheng Wu, and Thomas Reichler
Weather Clim. Dynam., 5, 251–261, https://doi.org/10.5194/wcd-5-251-2024, https://doi.org/10.5194/wcd-5-251-2024, 2024
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Recent work exploring the tropical atmospheric circulation response to climate change has revealed a disconnect in the latitudinal location of two features, the subtropical jet and the Hadley cell edge. Here, we investigate if the surprising result from coupled climate model and meteorological reanalysis output is consistent across model complexity.
Julian F. Quinting, Christian M. Grams, Edmund Kar-Man Chang, Stephan Pfahl, and Heini Wernli
Weather Clim. Dynam., 5, 65–85, https://doi.org/10.5194/wcd-5-65-2024, https://doi.org/10.5194/wcd-5-65-2024, 2024
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Research in the last few decades has revealed that rapidly ascending airstreams in extratropical cyclones have an important effect on the evolution of downstream weather and predictability. In this study, we show that the occurrence of these airstreams over the North Pacific is modulated by tropical convection. Depending on the modulation, known atmospheric circulation patterns evolve quite differently, which may affect extended-range predictions in the Atlantic–European region.
Hyunju Jung, Peter Knippertz, Yvonne Ruckstuhl, Robert Redl, Tijana Janjic, and Corinna Hoose
Weather Clim. Dynam., 4, 1111–1134, https://doi.org/10.5194/wcd-4-1111-2023, https://doi.org/10.5194/wcd-4-1111-2023, 2023
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A narrow rainfall belt in the tropics is an important feature for large-scale circulations and the global water cycle. The accurate simulation of this rainfall feature has been a long-standing problem, with the reasons behind that unclear. We present a novel diagnostic tool that allows us to disentangle processes important for rainfall, which changes due to modifications in model. Using our diagnostic tool, one can potentially identify sources of uncertainty in weather and climate models.
Lina Boljka, Nour-Eddine Omrani, and Noel S. Keenlyside
Weather Clim. Dynam., 4, 1087–1109, https://doi.org/10.5194/wcd-4-1087-2023, https://doi.org/10.5194/wcd-4-1087-2023, 2023
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This study examines quasi-periodic variability in the tropical Pacific on interannual timescales and related physics using a recently developed time series analysis tool. We find that wind stress in the west Pacific and recharge–discharge of ocean heat content are likely related to each other on ~1.5–4.5-year timescales (but not on others) and dominate variability in sea surface temperatures on those timescales. This may have further implications for climate models and long-term prediction.
Sam Hardy, John Methven, Juliane Schwendike, Ben Harvey, and Mike Cullen
Weather Clim. Dynam., 4, 1019–1043, https://doi.org/10.5194/wcd-4-1019-2023, https://doi.org/10.5194/wcd-4-1019-2023, 2023
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We examine a Borneo vortex case using computer simulations and satellite observations. The vortex is identified with high humidity through the atmosphere and has heaviest rainfall on its northern flank. Simulations represent circulation and rainfall accumulation well. The low-level Borneo vortex is coupled with a higher-level wave, which moves westwards along a layer with a sharp vertical gradient in moisture. Vortex growth occurs through mechanisms usually considered outside the tropics.
Chiem van Straaten, Dim Coumou, Kirien Whan, Bart van den Hurk, and Maurice Schmeits
Weather Clim. Dynam., 4, 887–903, https://doi.org/10.5194/wcd-4-887-2023, https://doi.org/10.5194/wcd-4-887-2023, 2023
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Variability in the tropics can influence weather over Europe. This study evaluates a summertime connection between the two. It shows that strongly opposing west Pacific sea surface temperature anomalies have occurred more frequently since 1980, likely due to a combination of long-term warming in the west Pacific and the El Niño Southern Oscillation. Three to six weeks later, the distribution of hot and cold airmasses over Europe is affected.
Francis Nkrumah, Cornelia Klein, Kwesi Akumenyi Quagraine, Rebecca Berkoh-Oforiwaa, Nana Ama Browne Klutse, Patrick Essien, Gandomè Mayeul Leger Davy Quenum, and Hubert Azoda Koffi
Weather Clim. Dynam., 4, 773–788, https://doi.org/10.5194/wcd-4-773-2023, https://doi.org/10.5194/wcd-4-773-2023, 2023
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It is not yet clear which variations in broader atmospheric conditions of the West African monsoon may lead to mesoscale convective system (MCS) occurrences in southern West Africa (SWA). In this study, we identified nine different weather patterns and categorized them as dry-, transition-, or monsoon-season types using a method called self-organizing maps (SOMs). It was revealed that a warmer Sahel region can create favourable conditions for MCS formation in SWA.
Giorgia Di Capua, Dim Coumou, Bart van den Hurk, Antje Weisheimer, Andrew G. Turner, and Reik V. Donner
Weather Clim. Dynam., 4, 701–723, https://doi.org/10.5194/wcd-4-701-2023, https://doi.org/10.5194/wcd-4-701-2023, 2023
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Heavy rainfall in tropical regions interacts with mid-latitude circulation patterns, and this interaction can explain weather patterns in the Northern Hemisphere during summer. In this analysis we detect these tropical–extratropical interaction pattern both in observational datasets and data obtained by atmospheric models and assess how well atmospheric models can reproduce the observed patterns. We find a good agreement although these relationships are weaker in model data.
Daniel Baldassare, Thomas Reichler, Piret Plink-Björklund, and Jacob Slawson
Weather Clim. Dynam., 4, 531–541, https://doi.org/10.5194/wcd-4-531-2023, https://doi.org/10.5194/wcd-4-531-2023, 2023
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Using ensemble members from the ERA5 reanalysis, the most widely used method for estimating tropical-width trends, the meridional stream function, was found to have large error, particularly in the Northern Hemisphere and in the summer, because of weak gradients at the tropical edge and poor data quality. Another method, using the latitude where the surface wind switches from westerly to easterly, was found to have lower error due to better-observed data.
Nele Tim, Eduardo Zorita, Birgit Hünicke, and Ioana Ivanciu
Weather Clim. Dynam., 4, 381–397, https://doi.org/10.5194/wcd-4-381-2023, https://doi.org/10.5194/wcd-4-381-2023, 2023
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As stated by the IPCC, southern Africa is one of the two land regions that are projected to suffer from the strongest precipitation reductions in the future. Simulated drying in this region is linked to the adjacent oceans, and prevailing winds as warm and moist air masses are transported towards the continent. Precipitation trends in past and future climate can be partly attributed to the strength of the Agulhas Current system, the current along the east and south coasts of southern Africa.
William Torgerson, Juliane Schwendike, Andrew Ross, and Chris J. Short
Weather Clim. Dynam., 4, 331–359, https://doi.org/10.5194/wcd-4-331-2023, https://doi.org/10.5194/wcd-4-331-2023, 2023
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We investigated intensity fluctuations that occurred during the rapid intensification of Hurricane Irma (2017) to understand their effects on the storm structure. Using high-resolution model simulations, we found that the fluctuations were caused by local regions of strong ascent just outside the eyewall that disrupted the storm, leading to a larger and more symmetrical storm eye. This alters the location and intensity of the strongest winds in the storm and hence the storm's impact.
Anne Martin, Martin Weissmann, and Alexander Cress
Weather Clim. Dynam., 4, 249–264, https://doi.org/10.5194/wcd-4-249-2023, https://doi.org/10.5194/wcd-4-249-2023, 2023
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Global wind profiles from the Aeolus satellite mission are an important recent substitute for the Global Observing System, showing an overall positive impact on numerical weather prediction forecasts. This study highlights atmospheric dynamic phenomena constituting pathways for significant improvement of Aeolus for future studies, including large-scale tropical circulation systems and the interaction of tropical cyclones undergoing an extratropical transition with the midlatitude waveguide.
Elliott Michael Sainsbury, Reinhard K. H. Schiemann, Kevin I. Hodges, Alexander J. Baker, Len C. Shaffrey, Kieran T. Bhatia, and Stella Bourdin
Weather Clim. Dynam., 3, 1359–1379, https://doi.org/10.5194/wcd-3-1359-2022, https://doi.org/10.5194/wcd-3-1359-2022, 2022
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Post-tropical cyclones (PTCs) can bring severe weather to Europe. By tracking and identifying PTCs in five global climate models, we investigate how the frequency and intensity of PTCs may change across Europe by 2100. We find no robust change in the frequency or intensity of Europe-impacting PTCs in the future. This study indicates that large uncertainties surround future Europe-impacting PTCs and provides a framework for evaluating PTCs in future generations of climate models.
Kieran M. R. Hunt and Andrew G. Turner
Weather Clim. Dynam., 3, 1341–1358, https://doi.org/10.5194/wcd-3-1341-2022, https://doi.org/10.5194/wcd-3-1341-2022, 2022
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More than half of India's summer monsoon rainfall arises from low-pressure systems: storms originating over the Bay of Bengal. In observation-based data, we examine how the generation and pathway of these storms are changed by the
boreal summer intraseasonal oscillation– the chief means of large-scale control on the monsoon at timescales of a few weeks. Our study offers new insights for useful prediction of these storms, important for both water resources planning and disaster early warning.
Cornelius Immanuel Weiß, Alexander Gohm, Mathias Walter Rotach, and Thomas Torora Minda
Weather Clim. Dynam., 3, 1003–1019, https://doi.org/10.5194/wcd-3-1003-2022, https://doi.org/10.5194/wcd-3-1003-2022, 2022
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Two gap flow events in the Great Rift Valley in Ethiopia were investigated based on observations, ERA5 reanalysis data, and simulations with the numerical weather prediction model WRF. The main focus was on strong winds in the area around Lake Abaya since the winds may generate waves on the lake which help to sustain the lake's ecology. That is important in terms of food supply for the local population. The gap winds exhibit a diurnal cycle and a seasonal dependence.
Matic Pikovnik, Žiga Zaplotnik, Lina Boljka, and Nedjeljka Žagar
Weather Clim. Dynam., 3, 625–644, https://doi.org/10.5194/wcd-3-625-2022, https://doi.org/10.5194/wcd-3-625-2022, 2022
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Potential future changes in the Hadley cells (HCs), either to their strength or their meridional extent, will profoundly impact the global distribution of precipitation. Therefore, to objectively evaluate and inter-compare past and future changes in the overall HC strength between different studies, a unified metric is required. The study proposes two new metrics, which alleviate the spatial inhomogeneities of the HC strength trend.
Ambrogio Volonté, Andrew G. Turner, Reinhard Schiemann, Pier Luigi Vidale, and Nicholas P. Klingaman
Weather Clim. Dynam., 3, 575–599, https://doi.org/10.5194/wcd-3-575-2022, https://doi.org/10.5194/wcd-3-575-2022, 2022
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In this study we analyse the complex seasonal evolution of the East Asian summer monsoon. Using reanalysis data, we show the importance of the interaction between tropical and extratropical air masses converging at the monsoon front, particularly during its northward progression. The upper-level flow pattern (e.g. the westerly jet) controls the balance between the airstreams and thus the associated rainfall. This framework provides a basis for studies of extreme events and climate variability.
Peter Pfleiderer, Shruti Nath, and Carl-Friedrich Schleussner
Weather Clim. Dynam., 3, 471–482, https://doi.org/10.5194/wcd-3-471-2022, https://doi.org/10.5194/wcd-3-471-2022, 2022
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Tropical cyclones are amongst the most dangerous weather events. Here we develop an empirical model that allows us to estimate the number and strengths of tropical cyclones for given atmospheric conditions and sea surface temperatures. An application of the model shows that atmospheric circulation is the dominant factor for seasonal tropical cyclone activity. However, warming sea surface temperatures have doubled the likelihood of extremely active hurricane seasons in the past decades.
Jean-Philippe Baudouin, Michael Herzog, and Cameron A. Petrie
Weather Clim. Dynam., 2, 1187–1207, https://doi.org/10.5194/wcd-2-1187-2021, https://doi.org/10.5194/wcd-2-1187-2021, 2021
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Western disturbances are mid-latitude, high-altitude, low-pressure areas that bring orographic precipitation into the Upper Indus Basin. Using statistical tools, we show that the interaction between western disturbances and relief explains the near-surface, cross-barrier wind activity. We also reveal the existence of a moisture pathway from the nearby seas. Overall, we offer a conceptual framework for western-disturbance activity, particularly in terms of precipitation.
Anantha Aiyyer and Terrell Wade
Weather Clim. Dynam., 2, 1051–1072, https://doi.org/10.5194/wcd-2-1051-2021, https://doi.org/10.5194/wcd-2-1051-2021, 2021
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We diagnose the mean circulations in the extratropics that are associated with rapid changes in the tropical storm storm speeds in the Atlantic. We show that rapid acceleration and deceleration are associated with distinct phasing between the tropical cyclone and weather waves of the extratropics. Over the past 5 decades, rapid acceleration and deceleration of tropical cyclones have reduced in magnitude. This might be related to the poleward shift and weakening of these extratropical waves.
Julianna Carvalho-Oliveira, Leonard Friedrich Borchert, Aurélie Duchez, Mikhail Dobrynin, and Johanna Baehr
Weather Clim. Dynam., 2, 739–757, https://doi.org/10.5194/wcd-2-739-2021, https://doi.org/10.5194/wcd-2-739-2021, 2021
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This work questions the influence of the Atlantic Meridional Overturning Circulation, an important component of the climate system, on the variability in North Atlantic sea surface temperature (SST) a season ahead, particularly how this influence affects SST prediction credibility 2–4 months into the future. While we find this relationship is relevant for assessing SST predictions, it strongly depends on the time period and season we analyse and is more subtle than what is found in observations.
Andrea M. Jenney, David A. Randall, and Elizabeth A. Barnes
Weather Clim. Dynam., 2, 653–673, https://doi.org/10.5194/wcd-2-653-2021, https://doi.org/10.5194/wcd-2-653-2021, 2021
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Storm activity in the tropics is one of the key phenomena that provide weather predictability on an extended timescale of about 10–40 d. The influence of tropical storminess on places like North America is sensitive to the overall average state of the climate system. In this study, we try to unpack the reasons why climate models do not agree on how the influence of these storms on weather over the North Pacific and North America will change in the future.
Philip Rupp and Peter Haynes
Weather Clim. Dynam., 2, 413–431, https://doi.org/10.5194/wcd-2-413-2021, https://doi.org/10.5194/wcd-2-413-2021, 2021
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We study a range of dynamical aspects of the Asian monsoon anticyclone as the response of a simple numerical model to a steady imposed heating distribution with different background flow configurations. Particular focus is given on interactions between the monsoon anticyclone and active mid-latitude dynamics, which we find to have a zonally localising effect on the time-mean circulation and to be able to qualitatively alter the temporal variability of the bulk anticyclone.
Joshua White and Anantha Aiyyer
Weather Clim. Dynam., 2, 311–329, https://doi.org/10.5194/wcd-2-311-2021, https://doi.org/10.5194/wcd-2-311-2021, 2021
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Using a simple general circulation model, we examine the structure of waves in the mid-tropospheric jet over North Africa. We show that waves occur in near-stationary groups or wave packets. As they are not swept out of the jet, this may provide the opportunity for the packets to amplify via feedback from other energy sources like rain-producing cloud complexes and mineral dust that are known to operate here. Our results address the criticism that the easterly jet is too short to sustain waves.
Franziska Aemisegger, Raphaela Vogel, Pascal Graf, Fabienne Dahinden, Leonie Villiger, Friedhelm Jansen, Sandrine Bony, Bjorn Stevens, and Heini Wernli
Weather Clim. Dynam., 2, 281–309, https://doi.org/10.5194/wcd-2-281-2021, https://doi.org/10.5194/wcd-2-281-2021, 2021
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The interaction of clouds in the trade wind region with the atmospheric flow is complex and at the heart of uncertainties associated with climate projections. In this study, a natural tracer of atmospheric circulation is used to establish a link between air originating from dry regions of the midlatitudes and the occurrence of specific cloud patterns. Two pathways involving transport within midlatitude weather systems are identified, by which air is brought into the trades within 5–10 d.
Jack Giddings, Adrian J. Matthews, Nicholas P. Klingaman, Karen J. Heywood, Manoj Joshi, and Benjamin G. M. Webber
Weather Clim. Dynam., 1, 635–655, https://doi.org/10.5194/wcd-1-635-2020, https://doi.org/10.5194/wcd-1-635-2020, 2020
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The impact of chlorophyll on the southwest monsoon is unknown. Here, seasonally varying chlorophyll in the Bay of Bengal was imposed in a general circulation model coupled to an ocean mixed layer model. The SST increases by 0.5 °C in response to chlorophyll forcing and shallow mixed layer depths in coastal regions during the inter-monsoon. Precipitation increases significantly to 3 mm d-1 across Myanmar during June and over northeast India and Bangladesh during October, decreasing model bias.
Giorgia Di Capua, Jakob Runge, Reik V. Donner, Bart van den Hurk, Andrew G. Turner, Ramesh Vellore, Raghavan Krishnan, and Dim Coumou
Weather Clim. Dynam., 1, 519–539, https://doi.org/10.5194/wcd-1-519-2020, https://doi.org/10.5194/wcd-1-519-2020, 2020
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We study the interactions between the tropical convective activity and the mid-latitude circulation in the Northern Hemisphere during boreal summer. We identify two circumglobal wave patterns with phase shifts corresponding to the South Asian and the western North Pacific monsoon systems at an intra-seasonal timescale. These patterns show two-way interactions in a causal framework at a weekly timescale and assess how El Niño affects these interactions.
Benjamin A. Stephens and Charles S. Jackson
Weather Clim. Dynam., 1, 389–404, https://doi.org/10.5194/wcd-1-389-2020, https://doi.org/10.5194/wcd-1-389-2020, 2020
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We analyze abrupt transitions between tropical rainfall regimes in a single-column model (SCM) of the tropical atmosphere. Multiple equilibria have been observed before in SCMs, but here we analyze actual bifurcations. We attribute the transitions to a sudden loss of evaporative cooling in the lower column due to nonlinearities in microphysics. This study may have implications for atmospheric dynamics more broadly but also for understanding abrupt transitions in paleoclimate.
Jorge L. García-Franco, Lesley J. Gray, and Scott Osprey
Weather Clim. Dynam., 1, 349–371, https://doi.org/10.5194/wcd-1-349-2020, https://doi.org/10.5194/wcd-1-349-2020, 2020
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The American monsoon system is the main source of rainfall for the subtropical Americas and an important element of Latin American agriculture. Here we use state-of-the-art climate models from the UK Met Office in different configurations to analyse the performance of these models in the American monsoon. Resolution is found to be a key factor to improve monsoon representation, whereas integrated chemistry does not improve the simulated monsoon rainfall.
Cited articles
Andrews, D. G., Holton, J. R., and Leovy, C. B.: Chapter 3 – Basic Dynamics, in: Middle Atmosphere Dynamics, vol. 40, edited by: Andrews, D. G., Holton, J. R., and Leovy, C. B., Academic Press, 113–149, https://doi.org/10.1016/B978-0-12-058575-5.50008-6, 1987.
Anstey, J. A. and Shepherd, T. G.: High-latitude influence of the quasi-biennial oscillation, Q. J. Roy. Meteor. Soc., 140, 1–21, https://doi.org/10.1002/qj.2132, 2014.
Anstey, J. A., Butchart, N., Hamilton, K., and Osprey, S. M.: The SPARC quasi-biennial oscillation initiative, Q. J. Roy. Meteor. Soc., 148, 1455–1458, https://doi.org/10.1002/qj.3820, 2020.
Anstey, J. A., Simpson, I. R., Richter, J. H., Naoe, H., Taguchi, M., Serva, F., Gray, L. J., Butchart, N., Hamilton, K., Osprey, S., Bellprat, O., Braesicke, P., Bushell, A. C., Cagnazzo, C., Chen, C.-C., Chun, H.-Y., Garcia, R. R., Holt, L., Kawatani, Y., Kerzenmacher, T., Kim, Y.-H., Lott, F., McLandress, C., Scinocca, J., Stockdale, T. N., Versick, S., Watanabe, S., Yoshida, K., and Yukimoto, S.: Teleconnections of the Quasi-Biennial Oscillation in a multi-model ensemble of QBO-resolving models, Q. J. Roy. Meteor. Soc., 148, 1568–1592, https://doi.org/10.1002/qj.4048, 2022.
Baldwin, M. P., Gray, L. J., Dunkerton, T. J., Hamilton, K., Haynes, P. H., Randel, W. J., Holton, J. R., Alexander, M. J., Hirota, I., Horinouchi, T., Jones, D. B. A., Kinnersley, J. S., Marquardt, C., Sato, K., and Takahashi, M.: The quasi-biennial oscillation, Rev. Geophys., 39, 179–229, https://doi.org/10.1029/1999RG000073, 2001.
Baldwin, M. P., Birner, T., Brasseur, G., Burrows, J., Butchart, N., Garcia, R., Geller, M., Gray, L., Hamilton, K., Harnik, N., Hegglin, M. I., Langematz, U., Robock, A., Sato, K., and Scaife, A. A.: 100 Years of Progress in Understanding the Stratosphere and Mesosphere, Meteor. Mon., 59, 27.1–27.62, https://doi.org/10.1175/AMSMONOGRAPHS-D-19-0003.1, 2019.
Brewer, A. W.: Evidence for a world circulation provided by the measurements of helium and water vapour distribution in the stratosphere, Q. J. Roy. Meteor. Soc., 75, 351–363, https://doi.org/10.1002/qj.49707532603, 1949.
Burrage, M. D., Vincent, R. A., Mayr, H. G., Skinner, W. R., Arnold, N. F., and Hays, P. B.: Long-term variability in the equatorial middle atmosphere zonal wind, J. Geophys. Res.-Atmos., 101, 12847–12854, https://doi.org/10.1029/96JD00575, 1996.
Bushell, A. C., Butchart, N., Derbyshire, S. H., Jackson, D. R., Shutts, G. J., Vosper, S. B., and Webster, S.: Parameterized Gravity Wave Momentum Fluxes from Sources Related to Convection and Large-Scale Precipitation Processes in a Global Atmosphere Model, J. Atmos. Sci., 72, 4349–4371, https://doi.org/10.1175/JAS-D-15-0022.1, 2015.
Butchart, N.: The Brewer-Dobson circulation, Rev. Geophys., 52, 157–184, https://doi.org/10.1002/2013RG000448, 2014.
Butchart, N., Anstey, J. A., Hamilton, K., Osprey, S., McLandress, C., Bushell, A. C., Kawatani, Y., Kim, Y.-H., Lott, F., Scinocca, J., Stockdale, T. N., Andrews, M., Bellprat, O., Braesicke, P., Cagnazzo, C., Chen, C.-C., Chun, H.-Y., Dobrynin, M., Garcia, R. R., Garcia-Serrano, J., Gray, L. J., Holt, L., Kerzenmacher, T., Naoe, H., Pohlmann, H., Richter, J. H., Scaife, A. A., Schenzinger, V., Serva, F., Versick, S., Watanabe, S., Yoshida, K., and Yukimoto, S.: Overview of experiment design and comparison of models participating in phase 1 of the SPARC Quasi-Biennial Oscillation initiative (QBOi), Geosci. Model Dev., 11, 1009–1032, https://doi.org/10.5194/gmd-11-1009-2018, 2018.
Butchart, N., Anstey, J. A., Kawatani, Y., Osprey, S. M., Richter, J. H., and Wu, T.: QBO Changes in CMIP6 Climate Projections, Geophys. Res. Lett., 47, e2019GL086903, https://doi.org/10.1029/2019GL086903, 2020.
Calvo, N., Giorgetta, M. A., and Peña-Ortiz, C.: Sensitivity of the boreal winter circulation in the middle atmosphere to the quasi-biennial oscillation in MAECHAM5 simulations, J. Geophys. Res.-Atmos., 112, D10124, https://doi.org/10.1029/2006JD007844, 2007.
Delisi, D. P. and Dunkerton, T. J.: Seasonal Variation of the Semiannual Oscillation, J. Atmos. Sci., 45, 2772–2787, https://doi.org/10.1175/1520-0469(1988)045<2772:SVOTSO>2.0.CO;2, 1988.
Dobson, G. M. B., Harrison, D. N., and Lawrence, J.: Measurements of the amount of ozone in the Earth's atmosphere and its relation to other geophysical conditions. – Part III, P. R. Soc. Lond. A Mat., 122, 456–486, https://doi.org/10.1098/rspa.1929.0034, 1929.
Dunkerton, T. J. and Delisi, D. P.: Interaction of the quasi-biennial oscillation and stratopause semiannual oscillation, J. Geophys. Res.-Atmos., 102, 26107–26116, https://doi.org/10.1029/96JD03678, 1997.
Elsbury, D., Peings, Y., and Magnusdottir, G.: CMIP6 Models Underestimate the Holton-Tan Effect, Geophys. Res. Lett., 48, e2021GL094083, https://doi.org/10.1029/2021GL094083, 2021.
Ern, M. and Preusse, P.: Wave fluxes of equatorial Kelvin waves and QBO zonal wind forcing derived from SABER and ECMWF temperature space-time spectra, Atmos. Chem. Phys., 9, 3957–3986, https://doi.org/10.5194/acp-9-3957-2009, 2009.
Ern, M., Ploeger, F., Preusse, P., Gille, J. C., Gray, L. J., Kalisch, S., Mlynczak, M. G., Russell III, J. M., and Riese, M.: Interaction of gravity waves with the QBO: A satellite perspective, J. Geophys. Res.-Atmos., 119, 2329–2355, https://doi.org/10.1002/2013JD020731, 2014.
Ern, M., Preusse, P., and Riese, M.: Driving of the SAO by gravity waves as observed from satellite, Ann. Geophys., 33, 483–504, https://doi.org/10.5194/angeo-33-483-2015, 2015.
Ern, M., Diallo, M., Preusse, P., Mlynczak, M. G., Schwartz, M. J., Wu, Q., and Riese, M.: The semiannual oscillation (SAO) in the tropical middle atmosphere and its gravity wave driving in reanalyses and satellite observations, Atmos. Chem. Phys., 21, 13763–13795, https://doi.org/10.5194/acp-21-13763-2021, 2021.
Ern, M., Diallo, M. A., Khordakova, D., Krisch, I., Preusse, P., Reitebuch, O., Ungermann, J., and Riese, M.: The quasi-biennial oscillation (QBO) and global-scale tropical waves in Aeolus wind observations, radiosonde data, and reanalyses, Atmos. Chem. Phys., 23, 9549–9583, https://doi.org/10.5194/acp-23-9549-2023, 2023.
Eyring, V., Bony, S., Meehl, G. A., Senior, C. A., Stevens, B., Stouffer, R. J., and Taylor, K. E.: Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization, Geosci. Model Dev., 9, 1937–1958, https://doi.org/10.5194/gmd-9-1937-2016, 2016.
Fritts, D. C. and Alexander, M. J.: Gravity wave dynamics and effects in the middle atmosphere, Rev. Geophys., 41, 1003, https://doi.org/10.1029/2001RG000106, 2003.
Garcia, R. R. and Sassi, F.: Modulation of the mesospheric semiannual oscillation by the quasibiennial oscillation, Earth, Planets and Space, 51, 563–569, https://doi.org/10.1186/BF03353215, 1999.
Garcia, R. R., Dunkerton, T. J., Lieberman, R. S., and Vincent, R. A.: Climatology of the semiannual oscillation of the tropical middle atmosphere, J. Geophys. Res.-Atmos., 102, 26019–26032, https://doi.org/10.1029/97JD00207, 1997.
Garfinkel, C. I., Gerber, E. P., Shamir, O., Rao, J., Jucker, M., White, I., and Paldor, N.: A QBO Cookbook: Sensitivity of the Quasi-Biennial Oscillation to Resolution, Resolved Waves, and Parameterized Gravity Waves, J. Adv. Model Earth Sy., 14, e2021MS002568, https://doi.org/10.1029/2021MS002568, 2022.
Gelaro, R., McCarty, W., Suárez, M. J., Todling, R., Molod, A., Takacs, L., Randles, C. A., Darmenov, A., Bosilovich, M. G., Reichle, R., Wargan, K., Coy, L., Cullather, R., Draper, C., Akella, S., Buchard, V., Conaty, A., da Silva, A. M., Gu, W., Kim, G.-K., Koster, R., Lucchesi, R., Merkova, D., Nielsen, J. E., Partyka, G., Pawson, S., Putman, W., Rienecker, M., Schubert, S. D., Sienkiewicz, M., and Zhao, B.: The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2), J. Climate, 30, 5419–5454, https://doi.org/10.1175/JCLI-D-16-0758.1, 2017.
Gerber, E. P. and Manzini, E.: The Dynamics and Variability Model Intercomparison Project (DynVarMIP) for CMIP6: assessing the stratosphere–troposphere system, Geosci. Model Dev., 9, 3413–3425, https://doi.org/10.5194/gmd-9-3413-2016, 2016.
Global Modeling and Assimilation Office (GMAO): MERRA-2 tavg3_3d_asm_Nv: 3d,3-Hourly,Time-Averaged,Model-Level,Assimilation,Assimilated Meteorological Fields V5.12.4, Greenbelt, MD, USA, Goddard Earth Sciences Data and Information Services Center (GES DISC) [data set], https://doi.org/10.5067/SUOQESM06LPK, 2015
Gray, L. J., Crooks, S., Pascoe, C., Sparrow, S., and Palmer, M.: Solar and QBO Influences on the Timing of Stratospheric Sudden Warmings, J. Atmos. Sci., 61, 2777–2796, https://doi.org/10.1175/JAS-3297.1, 2004.
Gray, L. J., Brown, M. J., Knight, J., Andrews, M., Lu, H., O'Reilly, C., and Anstey, J.: Forecasting extreme stratospheric polar vortex events, Nat. Commun., 11, 4630, https://doi.org/10.1038/s41467-020-18299-7, 2020.
Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz-Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., De Chiara, G., Dahlgren, P., Dee, D., Diamantakis, M., Dragani, R., Flemming, J., Forbes, R., Fuentes, M., Geer, A., Haimberger, L., Healy, S., Hogan, R. J., Hólm, E., Janisková, M., Keeley, S., Laloyaux, P., Lopez, P., Lupu, C., Radnoti, G., de Rosnay, P., Rozum, I., Vamborg, F., Villaume, S., and Thépaut, J.-N.: The ERA5 global reanalysis, Q. J. Roy. Meteor. Soc., 146, 1999–2049, https://doi.org/10.1002/qj.3803, 2020.
Hirota, I.: Observational evidence of the semiannual oscillation in the tropical middle atmosphere – A review, Pure Appl. Geophys., 118, 217–238, https://doi.org/10.1007/BF01586452, 1980.
Hitchcock, P. and Haynes, P. H.: Zonally Symmetric Adjustment in the Presence of Artificial Relaxation, J. Atmos. Sci., 71, 4349–4368, https://doi.org/10.1175/JAS-D-14-0013.1, 2014.
Hitchcock, P. and Simpson, I. R.: The Downward Influence of Stratospheric Sudden Warmings, J. Atmos. Sci., 71, 3856–3876, https://doi.org/10.1175/JAS-D-14-0012.1, 2014.
Hitchcock, P., Butler, A., Charlton-Perez, A., Garfinkel, C. I., Stockdale, T., Anstey, J., Mitchell, D., Domeisen, D. I. V., Wu, T., Lu, Y., Mastrangelo, D., Malguzzi, P., Lin, H., Muncaster, R., Merryfield, B., Sigmond, M., Xiang, B., Jia, L., Hyun, Y.-K., Oh, J., Specq, D., Simpson, I. R., Richter, J. H., Barton, C., Knight, J., Lim, E.-P., and Hendon, H.: Stratospheric Nudging And Predictable Surface Impacts (SNAPSI): a protocol for investigating the role of stratospheric polar vortex disturbances in subseasonal to seasonal forecasts, Geosci. Model Dev., 15, 5073–5092, https://doi.org/10.5194/gmd-15-5073-2022, 2022.
Holton, J. R. and Lindzen, R. S.: An Updated Theory for the Quasi-Biennial Cycle of the Tropical Stratosphere, J. Atmos. Sci., 29, 1076–1080, https://doi.org/10.1175/1520-0469(1972)029<1076:AUTFTQ>2.0.CO;2, 1972.
Holton, J. R. and Tan, H.-C.: The Influence of the Equatorial Quasi-Biennial Oscillation on the Global Circulation at 50 mb, J. Atmos. Sci., 37, 2200–2208, https://doi.org/10.1175/1520-0469(1980)037<2200:TIOTEQ>2.0.CO;2, 1980.
Holton, J. R. and Wehrbein, W. M.: A numerical model of the zonal mean circulation of the middle atmosphere, Pure Appl. Geophys., 118, 284–306, https://doi.org/10.1007/BF01586455, 1980.
Jaison, A. M., Gray, L. J., Osprey, S., Smith, A. K., and Garcia, R. R.: A momentum budget study of the semi-annual oscillation in the Whole Atmosphere Community Climate Model, Q. J. Roy. Meteor. Soc., 1–22, https://doi.org/10.1002/qj.4782, 2024.
Knight, J., Scaife, A., Bett, P. E., Collier, T., Dunstone, N., Gordon, M., Hardiman, S., Hermanson, L., Ineson, S., Kay, G., McLean, P., Pilling, C., Smith, D., Stringer, N., Thornton, H., and Walker, B.: Predictability of European Winters 2017/2018 and 2018/2019: Contrasting influences from the Tropics and stratosphere, Atmos. Sci. Lett., 22, e1009, https://doi.org/10.1002/asl.1009, 2021.
Lindzen, R. S. and Holton, J. R.: A Theory of the Quasi-Biennial Oscillation, J. Atmos. Sci., 25, 1095–1107, https://doi.org/10.1175/1520-0469(1968)025<1095:ATOTQB>2.0.CO;2, 1968.
Lu, H., Hitchman, M. H., Gray, L. J., Anstey, J. A., and Osprey, S. M.: On the role of Rossby wave breaking in the quasi-biennial modulation of the stratospheric polar vortex during boreal winter, Q. J. Roy. Meteor. Soc., 146, 1939–1959, https://doi.org/10.1002/qj.3775, 2020.
Martin, Z., Orbe, C., Wang, S., and Sobel, A.: The MJO–QBO Relationship in a GCM with Stratospheric Nudging, J. Climate, 34, 4603–4624, https://doi.org/10.1175/JCLI-D-20-0636.1, 2021.
Meyer, W. D.: A Diagnostic Numerical Study of the Semiannual Variation of the Zonal Wind in the Tropical Stratosphere and Mesosphere, J. Atmos. Sci., 27, 820–830, https://doi.org/10.1175/1520-0469(1970)027<0820:ADNSOT>2.0.CO;2, 1970.
Molod, A., Takacs, L., Suarez, M., and Bacmeister, J.: Development of the GEOS-5 atmospheric general circulation model: evolution from MERRA to MERRA2, Geosci. Model Dev., 8, 1339–1356, https://doi.org/10.5194/gmd-8-1339-2015, 2015.
Pahlavan, H. A., Fu, Q., Wallace, J. M., and Kiladis, G. N.: Revisiting the Quasi-Biennial Oscillation as Seen in ERA5. Part I: Description and Momentum Budget, J. Atmos. Sci., 78, 673–691, https://doi.org/10.1175/JAS-D-20-0248.1, 2021.
Pascoe, C. L., Gray, L. J., Crooks, S. A., Juckes, M. N., and Baldwin, M. P.: The quasi-biennial oscillation: Analysis using ERA-40 data, J. Geophys. Res.-Atmos., 110, D08105, https://doi.org/10.1029/2004JD004941, 2005.
Pascoe, C. L., Gray, L. J., and Scaife, A. A.: A GCM study of the influence of equatorial winds on the timing of sudden stratospheric warmings, Geophys. Res. Lett., 33, L06825, https://doi.org/10.1029/2005GL024715, 2006.
Peña-Ortiz, C., Ribera, P., García-Herrera, R., Giorgetta, M. A., and García, R. R.: Forcing mechanism of the seasonally asymmetric quasi-biennial oscillation secondary circulation in ERA-40 and MAECHAM5, J. Geophys. Res.-Atmos., 113, D16103, https://doi.org/10.1029/2007JD009288, 2008.
Peña-Ortiz, C., Schmidt, H., Giorgetta, M. A., and Keller, M.: QBO modulation of the semiannual oscillation in MAECHAM5 and HAMMONIA, J. Geophys. Res.-Atmos., 115, D21106, https://doi.org/10.1029/2010JD013898, 2010.
Plumb, R. A. and McEwan, A. D.: The Instability of a Forced Standing Wave in a Viscous Stratified Fluid: A Laboratory Analogue of the Quasi-Biennial Oscillation, J. Atmos. Sci., 35, 1827–1839, https://doi.org/10.1175/1520-0469(1978)035<1827:TIOAFS>2.0.CO;2, 1978.
Quiroz, R. S. and Miller, A.: NOTE ON THE SEMI-ANNUAL WIND VARIATION IN THE EQUATORIAL STRATOSPHERE, Mon. Weather Rev., 95, 635–641, https://doi.org/10.1175/1520-0493(1967)095<0635:NOTSAW>2.3.CO;2, 1967.
Rao, J., Garfinkel, C. I., and White, I. P.: Impact of the Quasi-Biennial Oscillation on the Northern Winter Stratospheric Polar Vortex in CMIP5/6 Models, J. Climate, 33, 4787–4813, https://doi.org/10.1175/JCLI-D-19-0663.1, 2020.
Ray, E. A., Alexander, M. J., and Holton, J. R.: An analysis of the structure and forcing of the equatorial semiannual oscillation in zonal wind, J. Geophys. Res.-Atmos., 103, 1759–1774, https://doi.org/10.1029/97JD02679, 1998.
Reed, R. J.: Zonal wind behavior in the equatorial stratosphere and lower mesosphere, J. Geophys. Res., 71, 4223–4233, https://doi.org/10.1029/JZ071i018p04223, 1966.
Richter, J. H. and Garcia, R. R.: On the forcing of the Mesospheric Semi-Annual Oscillation in the Whole Atmosphere Community Climate Model, Geophys. Res. Lett., 33, L01806, https://doi.org/10.1029/2005GL024378, 2006.
Scaife, A. A., Butchart, N., Warner, C. D., Stainforth, D., Norton, W., and Austin, J.: Realistic quasi-biennial oscillations in a simulation of the global climate, Geophys. Res. Lett., 27, 3481–3484, https://doi.org/10.1029/2000GL011625, 2000.
Scaife, A. A., Butchart, N., Warner, C. D., and Swinbank, R.: Impact of a Spectral Gravity Wave Parameterization on the Stratosphere in the Met Office Unified Model, J. Atmos. Sci., 59, 1473–1489, https://doi.org/10.1175/1520-0469(2002)059<1473:IOASGW>2.0.CO;2, 2002.
Shepherd, T. G., Polichtchouk, I., Hogan, R., and Simmons, A. J.: Report on Stratosphere Task Force, ECMWF, https://doi.org/10.21957/0vkp0t1xx, 2018.
Smith, A. K., Garcia, R. R., Moss, A. C., and Mitchell, N. J.: The Semiannual Oscillation of the Tropical Zonal Wind in the Middle Atmosphere Derived from Satellite Geopotential Height Retrievals, J. Atmos. Sci., 74, 2413–2425, https://doi.org/10.1175/JAS-D-17-0067.1, 2017.
Smith, A. K., Holt, L. A., Garcia, R. R., Anstey, J. A., Serva, F., Butchart, N., Osprey, S., Bushell, A. C., Kawatani, Y., Kim, Y.-H., Lott, F., Braesicke, P., Cagnazzo, C., Chen, C.-C., Chun, H.-Y., Gray, L., Kerzenmacher, T., Naoe, H., Richter, J., Versick, S., Schenzinger, V., Watanabe, S., and Yoshida, K.: The equatorial stratospheric semiannual oscillation and time-mean winds in QBOi models, Q. J. Roy. Meteor. Soc., 148, 1593–1609, https://doi.org/10.1002/qj.3690, 2022.
Smith, A. K., Gray, L. J., and Garcia, R. R.: Evidence for the Influence of the Quasi-Biennial Oscillation on the Semiannual Oscillation in the Tropical Middle Atmosphere, J. Atmos. Sci., 80, 1755–1769, https://doi.org/10.1175/JAS-D-22-0255.1, 2023.
Warner, C. D. and McIntyre, M. E.: On the Propagation and Dissipation of Gravity Wave Spectra through a Realistic Middle Atmosphere, J. Atmos. Sci., 53, 3213–3235, https://doi.org/10.1175/1520-0469(1996)053<3213:OTPADO>2.0.CO;2, 1996.
Warner, C. D. and McIntyre, M. E.: Toward an ultra-simple spectral gravity wave parameterization for general circulation models, Earth, Planets and Space, 51, 475–484, https://doi.org/10.1186/BF03353209, 1999.
Warner, C. D. and McIntyre, M. E.: An Ultrasimple Spectral Parameterization for Nonorographic Gravity Waves, J. Atmos. Sci., 58, 1837–1857, https://doi.org/10.1175/1520-0469(2001)058<1837:AUSPFN>2.0.CO;2, 2001.
Short summary
Models have biases in semi-annual oscillation (SAO) representation, mainly due to insufficient eastward wave forcing. We examined if the bias is from increased wave absorption due to circulation biases in the low–middle stratosphere. Alleviating biases at lower altitudes improves the SAO, but substantial bias remains. Alternative methods like gravity wave parameterization changes should be explored to enhance the modelled SAO, potentially improving sudden stratospheric warming predictability.
Models have biases in semi-annual oscillation (SAO) representation, mainly due to insufficient...
