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1. Robust but weak winter atmospheric circulation response to future Arctic sea ice loss

Author

Smith, DM, Eade, R, Andrews, MB, Ayres, H, Clark, A, Chripko, S, Deser, C, Dunstone, NJ, García-Serrano, J, Gastineau, G, Graff, LS, Hardiman, SC, He, B, Hermanson, L, Jung, T, Knight, J, Levine, X, Magnusdottir, G, Manzini, E, Matei, D, Mori, M, Msadek, R, Ortega, P, Peings, Y, Scaife, AA, Screen, JA, Seabrook, M, Semmler, T, Sigmond, M, Streffing, J, Sun, L, and Walsh, A

Subjects
Climate Action
Abstract

The possibility that Arctic sea ice loss weakens mid-latitude westerlies, promoting more severe cold winters, has sparked more than a decade of scientific debate, with apparent support from observations but inconclusive modelling evidence. Here we show that sixteen models contributing to the Polar Amplification Model Intercomparison Project simulate a weakening of mid-latitude westerlies in response to projected Arctic sea ice loss. We develop an emergent constraint based on eddy feedback, which is 1.2 to 3 times too weak in the models, suggesting that the real-world weakening lies towards the higher end of the model simulations. Still, the modelled response to Arctic sea ice loss is weak: the North Atlantic Oscillation response is similar in magnitude and offsets the projected response to increased greenhouse gases, but would only account for around 10% of variations in individual years. We further find that relationships between Arctic sea ice and atmospheric circulation have weakened recently in observations and are no longer inconsistent with those in models.

Published
2022

2. Opposite Responses of the Dry and Moist Eddy Heat Transport Into the Arctic in the PAMIP Experiments

Author

Audette, A, Fajber, RA, Kushner, PJ, Wu, Y, Peings, Y, Magnusdottir, G, Eade, R, Sigmond, M, and Sun, L

Subjects
Arctic amplification, isentropic overturning circulation, ocean surface warming, poleward heat transport, Meteorology & Atmospheric Sciences
Abstract

Given uncertainty in the processes involved in polar amplification, elucidating the role of poleward heat and moisture transport is crucial. The Polar Amplification Model Intercomparison Project (PAMIP) permits robust separation of the effects of sea ice loss from sea surface warming under climate change. We utilize a moist isentropic circulation framework that accounts for moisture transport, condensation, and eddy transport, in order to analyze the circulation connecting the mid-latitudes and the Arctic. In PAMIP's atmospheric general circulation model experiments, prescribed sea ice loss reduces poleward heat transport (PHT) by warming the returning moist isentropic circulation at high latitudes, while prescribed warming of the ocean surface increases PHT by strengthening the moist isentropic circulation. Inter-model spread of PHT into the Arctic reflects the tug-of-war between sea-ice and surface-warming effects.

Published
2021

3. Uncertainty in the response of sudden stratospheric warmings and stratosphere‐troposphere coupling to quadrupled CO_2 concentrations in CMIP6 models

Author

Ayarzagüena Porras, Blanca, Charlton‐Perez, A. J., Butler, A. H., Hitchcock, P., Simpson, I. R., Polvani, L. M., Butchart, L. M., Gerber, E. P., Gray, L., Hassler, B., Lin, P., Lott, F., Manzini, E., Mizuta, R., Orbe, C., Osprey, S., Saint‐Martin, D., Sigmond, M., Taguchi, M., Volodin, E. M., Watanabe, S., Ayarzagüena Porras, Blanca, Charlton‐Perez, A. J., Butler, A. H., Hitchcock, P., Simpson, I. R., Polvani, L. M., Butchart, L. M., Gerber, E. P., Gray, L., Hassler, B., Lin, P., Lott, F., Manzini, E., Mizuta, R., Orbe, C., Osprey, S., Saint‐Martin, D., Sigmond, M., Taguchi, M., Volodin, E. M., and Watanabe, S.

Abstract

Major sudden stratospheric warmings (SSWs), vortex formation, and final breakdown dates are key highlight points of the stratospheric polar vortex. These phenomena are relevant for stratosphere‐troposphere coupling, which explains the interest in understanding their future changes. However, up to now, there is not a clear consensus on which projected changes to the polar vortex are robust, particularly in the Northern Hemisphere, possibly due to short data record or relatively moderate CO2 forcing. The new simulations performed under the Coupled Model Intercomparison Project, Phase 6, together with the long daily data requirements of the DynVarMIP project in preindustrial and quadrupled CO2 (4xCO2) forcing simulations provide a new opportunity to revisit this topic by overcoming the limitations mentioned above. In this study, we analyze this new model output to document the change, if any, in the frequency of SSWs under 4xCO2 forcing. Our analysis reveals a large disagreement across the models as to the sign of this change, even though most models show a statistically significant change. As for the near‐surface response to SSWs, the models, however, are in good agreement as to this signal over the North Atlantic: There is no indication of a change under 4xCO2 forcing. Over the Pacific, however, the change is more uncertain, with some indication that there will be a larger mean response. Finally, the models show robust changes to the seasonal cycle in the stratosphere. Specifically, we find a longer duration of the stratospheric polar vortex and thus a longer season of stratosphere‐troposphere coupling., Ministerio de Ciencia, Innovación y Universidades, European Council, National Science Foundation (United States), NASA High-End Computing (HEC) Program, NASA Modeling, Analysis and Prediction program, Met Office Hadley Centre Climate Programme, MEXT| Integrated Research Program for Advancing Climate Models, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Published
2024

9. Robust but weak winter atmospheric circulation response to future Arctic sea ice loss

Author

Smith, D. M., Eade, R., Andrews, M. B., Ayres, H., Clark, A., Chripko, S., Deser, Clara, Dunstone, N. J., García-Serrano, Javier, Gastineau, G., Graff, L. S., Hardiman, S. C., He, B., Hermanson, L., Jung, Thomas, Knight, J., Levine, X., Magnusdottir, G., Manzini, E., Matei, Daniela, Mori, M., Msadek, Rym, Ortega, P., Peings, Y., Scaife, A. A., Screen, J. A., Seabrook, M., Semmler, Tido, Sigmond, M., Streffing, Jan, Sun, L., Walsh, A., Smith, D. M., Eade, R., Andrews, M. B., Ayres, H., Clark, A., Chripko, S., Deser, Clara, Dunstone, N. J., García-Serrano, Javier, Gastineau, G., Graff, L. S., Hardiman, S. C., He, B., Hermanson, L., Jung, Thomas, Knight, J., Levine, X., Magnusdottir, G., Manzini, E., Matei, Daniela, Mori, M., Msadek, Rym, Ortega, P., Peings, Y., Scaife, A. A., Screen, J. A., Seabrook, M., Semmler, Tido, Sigmond, M., Streffing, Jan, Sun, L., and Walsh, A.

Abstract

The possibility that Arctic sea ice loss weakens mid-latitude westerlies, promoting more severe cold winters, has sparked more than a decade of scientific debate, with apparent support from observations but inconclusive modelling evidence. Here we show that sixteen models contributing to the Polar Amplification Model Intercomparison Project simulate a weakening of mid-latitude westerlies in response to projected Arctic sea ice loss. We develop an emergent constraint based on eddy feedback, which is 1.2 to 3 times too weak in the models, suggesting that the real-world weakening lies towards the higher end of the model simulations. Still, the modelled response to Arctic sea ice loss is weak: the North Atlantic Oscillation response is similar in magnitude and offsets the projected response to increased greenhouse gases, but would only account for around 10% of variations in individual years. We further find that relationships between Arctic sea ice and atmospheric circulation have weakened recently in observations and are no longer inconsistent with those in models.

Published
2022

10. Clean air policies are key for successfully mitigating Arctic warming

Author

von Salzen, K., Whaley, C.H., Anenberg, S.C., Van Dingenen, R., Klimont, Z., Flanner, M.G., Mahmood, R., Arnold, S.R., Beagley, S., Chien, R.-Y., Christensen, J.H., Eckhardt, S., Ekman, A.M.L., Evangeliou, N., Faluvegi, G., Fu, J.S., Gauss, M., Gong, W., Hjorth, J.L., Im, U., Krishnan, S., Kupiainen, K., Kühn, T., Langner, J., Law, K.S., Marelle, L., Olivié, D., Onishi, T., Oshima, N., Paunu, V.-V., Peng, Y., Plummer, D., Pozzoli, L., Rao, S., Raut, J.-C., Sand, M., Schmale, J., Sigmond, M., Thomas, M.A., Tsigaridis, K., Tsyro, S., Turnock, S.T., Wang, M., Winter, B., von Salzen, K., Whaley, C.H., Anenberg, S.C., Van Dingenen, R., Klimont, Z., Flanner, M.G., Mahmood, R., Arnold, S.R., Beagley, S., Chien, R.-Y., Christensen, J.H., Eckhardt, S., Ekman, A.M.L., Evangeliou, N., Faluvegi, G., Fu, J.S., Gauss, M., Gong, W., Hjorth, J.L., Im, U., Krishnan, S., Kupiainen, K., Kühn, T., Langner, J., Law, K.S., Marelle, L., Olivié, D., Onishi, T., Oshima, N., Paunu, V.-V., Peng, Y., Plummer, D., Pozzoli, L., Rao, S., Raut, J.-C., Sand, M., Schmale, J., Sigmond, M., Thomas, M.A., Tsigaridis, K., Tsyro, S., Turnock, S.T., Wang, M., and Winter, B.

Abstract

A tighter integration of modeling frameworks for climate and air quality is urgently needed to assess the impacts of clean air policies on future Arctic and global climate. We combined a new model emulator and comprehensive emissions scenarios for air pollutants and greenhouse gases to assess climate and human health co-benefits of emissions reductions. Fossil fuel use is projected to rapidly decline in an increasingly sustainable world, resulting in far-reaching air quality benefits. Despite human health benefits, reductions in sulfur emissions in a more sustainable world could enhance Arctic warming by 0.8 °C in 2050 relative to the 1995–2014, thereby offsetting climate benefits of greenhouse gas reductions. Targeted and technically feasible emissions reduction opportunities exist for achieving simultaneous climate and human health co-benefits. It would be particularly beneficial to unlock a newly identified mitigation potential for carbon particulate matter, yielding Arctic climate benefits equivalent to those from carbon dioxide reductions by 2050.

Published
2022
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11. Long-range prediction and the stratosphere

Author

Scaife, A. A., Baldwin, M. P., Butler, A. H., Charlton-Perez, A. J., Domeisen, D. I. V., Garfinkel, C.I., Hardiman, S. C., Haynes, P., Karpechko, A. Y., Lim, E.-P., Noguchi, S., Perlwitz, J., Polvani, L., Richter, J. H., Scinocca, J., Sigmond, M., Shepherd, T. G., Son, S.-W., and Thompson, D. W. J.

Abstract

Over recent years there have been concomitant advances in the development of stratosphere-resolving numerical models, our understanding of stratosphere–troposphere interaction, and the extension of long-range forecasts to explicitly include the stratosphere. These advances are now allowing for new and improved capability in long-range prediction. We present an overview of this development and show how the inclusion of the stratosphere in forecast systems aids monthly, seasonal, and annual-to-decadal climate predictions and multidecadal projections. We end with an outlook towards the future and identify areas of improvement that could\ud further benefit these rapidly evolving predictions.

Published
2022

19. Uncertainty in the Response of Sudden Stratospheric Warmings and Stratosphere‐Troposphere Coupling to Quadrupled CO2 Concentrations in CMIP6 Models

Author

Ayarzagüena, B., primary, Charlton‐Perez, A. J., additional, Butler, A. H., additional, Hitchcock, P., additional, Simpson, I. R., additional, Polvani, L. M., additional, Butchart, N., additional, Gerber, E. P., additional, Gray, L., additional, Hassler, B., additional, Lin, P., additional, Lott, F., additional, Manzini, E., additional, Mizuta, R., additional, Orbe, C., additional, Osprey, S., additional, Saint‐Martin, D., additional, Sigmond, M., additional, Taguchi, M., additional, Volodin, E. M., additional, and Watanabe, S., additional

Published
2020
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20. Sub-Seasonal to Seasonal Prediction

Author

Butler, A, Charlton-Perez, A, Domeisen, DIV, Garfinkel, C, Gerber, EP, Hitchcock, P, Karpechko, AY, Maycock, AC, Sigmond, M, Simpson, I, Son, S-W, Robertson, A, and Vitart, F

Abstract

The stratosphere and the troposphere are coupled in many ways. Because their interactions span days to weeks (or even longer), understanding these linkages and simulating them correctly in forecast models may provide a source of sub-seasonal to seasonal (S2S) prediction skill. This chapter reviews the tropical and extratropical coupling between the stratosphere and the troposphere and summarizes the most recent research showing how adequate simulation of the stratosphere may contribute to better prediction skill in the troposphere.

Published
2018

21. Canadian snow and sea ice: assessment of snow, sea ice, and related climate processes in Canada’s Earth system model and climate-prediction system

Author

Kushner, P.J., Mudryk, L.R., Merryfield, W., Ambadan, J.T., Berg, A., Bichet, A., Brown, R., Derksen, C., Dery, S.J., Dirkson, A., Flato, G., Fletcher, C.G., Fyfe, J.C., Gillet, N., Haas, C., Howell, S., Laliberte, F., McCusker, K., Sigmond, M., Sospedra-Alfonso, R., Tandon, N.F., Thackeray, C., Tremblay, B., Zwiers, F.W., Kushner, P.J., Mudryk, L.R., Merryfield, W., Ambadan, J.T., Berg, A., Bichet, A., Brown, R., Derksen, C., Dery, S.J., Dirkson, A., Flato, G., Fletcher, C.G., Fyfe, J.C., Gillet, N., Haas, C., Howell, S., Laliberte, F., McCusker, K., Sigmond, M., Sospedra-Alfonso, R., Tandon, N.F., Thackeray, C., Tremblay, B., and Zwiers, F.W.

Abstract

The Canadian Sea Ice and Snow Evolution (CanSISE) Network is a climate research network focused on developing and applying state-of-the-art observational data to advance dynamical prediction, projections, and understanding of seasonal snow cover and sea ice in Canada and the circumpolar Arctic. This study presents an assessment from the CanSISE Network of the ability of the second-generation Canadian Earth System Model (CanESM2) and the Canadian Seasonal to Interannual Prediction System (CanSIPS) to simulate and predict snow and sea ice from seasonal to multi-decadal timescales, with a focus on the Canadian sector. To account for observational uncertainty, model structural uncertainty, and internal climate variability, the analysis uses multi-source observations, multiple Earth system models (ESMs) in Phase 5 of the Coupled Model Intercomparison Project (CMIP5), and large initial-condition ensembles of CanESM2 and other models. It is found that the ability of the CanESM2 simulation to capture snow-related climate parameters, such as cold-region surface temperature and precipitation, lies within the range of currently available international models. Accounting for the considerable disagreement among satellite-era observational datasets on the distribution of snow water equivalent, CanESM2 has too much springtime snow mass over Canada, reflecting a broader northern hemispheric positive bias. Biases in seasonal snow cover extent are generally less pronounced. CanESM2 also exhibits retreat of springtime snow generally greater than observational estimates, after accounting for observational uncertainty and internal variability. Sea ice is biased low in the Canadian Arctic, which makes it difficult to assess the realism of long-term sea ice trends there. The strengths and weaknesses of the modelling system need to be understood as a practical tradeoff: the Canadian models are relatively inexpensive computationally because of their moderate resolution, thus enabling their

Published
2018

22. The Climate-system Historical Forecast Project: providing open access to seasonal forecast ensembles from centers around the globe

Author

Tompkins, A., Zárate, O., Inés, M., Saurral, R., Vera, C., Saulo, C., Merryfield, W., Sigmond, M., Lee, W., Baehr, J., Braun, A., Butler, A., Déqué, M., Doblas-Reyes, F., Gordon, M., Scaife, A., Imada, Y., Ishii, M., Ose, T., Kirtman, B., Kumar, A., Müller, W., Pirani, A., Stockdale, T., Rixen, M., and Yasuda, T.

Subjects
Atmospheric Science, SEASONAL FORECAST, 010504 meteorology & atmospheric sciences, Meteorology, Climate system, Globe, CHFP, 010502 geochemistry & geophysics, 01 natural sciences, Ciencias de la Tierra y relacionadas con el Medio Ambiente, purl.org/becyt/ford/1 [https], purl.org/becyt/ford/1.5 [https], medicine.anatomical_structure, Geography, medicine, Meteorología y Ciencias Atmosféricas, CIENCIAS NATURALES Y EXACTAS, 0105 earth and related environmental sciences
Abstract

Fil: Tompkins, Adrian M.. The Abdus Salam; Italia Fil: Ortiz de Zarate, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Centre National de la Recherche Scientifique; Francia Fil: Saurral, Ramiro Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Centre National de la Recherche Scientifique; Francia Fil: Vera, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Centre National de la Recherche Scientifique; Francia Fil: Saulo, Andrea Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Secretaria de Planeamiento. Servicio Meteorológico Nacional; Argentina Fil: Merryfield, William J.. Canadian Centre for Climate Modelling and Analysis; Canadá Fil: Sigmond, Michael. Canadian Centre for Climate Modelling and Analysis; Canadá Fil: Lee, Woo Sung. Canadian Centre for Climate Modelling and Analysis; Canadá Fil: Baehr, Johanna. Universitat Hamburg; Alemania Fil: Braun, Alain. Météo-France; Francia Fil: Amy Butler. National Ocean And Atmospheric Administration; Estados Unidos Fil: Déqué, Michel. Météo-France; Francia Fil: Doblas Reyes, Francisco J.. Institució Catalana de Recerca i Estudis Avancats; España. Barcelona Supercomputing Center - Centro Nacional de Supercomputacion; España Fil: Gordon, Margaret. Met Office; Reino Unido Fil: Scaife, Adam A.. University of Exeter; Reino Unido Fil: Yukiko Imada. Japan Meteorological Agency. Meteorological Research Institute. Climate Research Department; Japón Fil: Masayoshi Ishii. Japan Meteorological Agency. Meteorological Research Institute. Climate Research Department; Japón Fil: Tomoaki Ose. Japan Meteorological Agency. Meteorological Research Institute. Climate Research Department; Japón Fil: Kirtman, Ben. University of Miami; Estados Unidos Fil: Kumar, Arun. National Ocean And Atmospheric Administration; Estados Unidos Fil: Müller, Wolfgang A.. Max-Planck-Institut für Meteorologie; Alemania Fil: Pirani, Anna. Université Paris-Saclay; Francia Fil: Stockdale, Tim. European Centre for Medium-Range Weather; Reino Unido Fil: Rixen, Michel. World Meteorological Organization. World Climate Research Programme; Suiza Fil: Yasuda, Tamaki. Japan Meteorological Agency. Climate Prediction Division; Japón

Published
2017

23. Uncertainty in the Response of Sudden Stratospheric Warmings and Stratosphere‐Troposphere Coupling to Quadrupled CO2 Concentrations in CMIP6 Models.

Author

Ayarzagüena, B., Charlton‐Perez, A. J., Butler, A. H., Hitchcock, P., Simpson, I. R., Polvani, L. M., Butchart, N., Gerber, E. P., Gray, L., Hassler, B., Lin, P., Lott, F., Manzini, E., Mizuta, R., Orbe, C., Osprey, S., Saint‐Martin, D., Sigmond, M., Taguchi, M., and Volodin, E. M.

Subjects
STRATOSPHERE, TROPOSPHERE, POLAR vortex, CARBON dioxide, CHEMOSPHERE
Abstract

Major sudden stratospheric warmings (SSWs), vortex formation, and final breakdown dates are key highlight points of the stratospheric polar vortex. These phenomena are relevant for stratosphere‐troposphere coupling, which explains the interest in understanding their future changes. However, up to now, there is not a clear consensus on which projected changes to the polar vortex are robust, particularly in the Northern Hemisphere, possibly due to short data record or relatively moderate CO2 forcing. The new simulations performed under the Coupled Model Intercomparison Project, Phase 6, together with the long daily data requirements of the DynVarMIP project in preindustrial and quadrupled CO2 (4xCO2) forcing simulations provide a new opportunity to revisit this topic by overcoming the limitations mentioned above. In this study, we analyze this new model output to document the change, if any, in the frequency of SSWs under 4xCO2 forcing. Our analysis reveals a large disagreement across the models as to the sign of this change, even though most models show a statistically significant change. As for the near‐surface response to SSWs, the models, however, are in good agreement as to this signal over the North Atlantic: There is no indication of a change under 4xCO2 forcing. Over the Pacific, however, the change is more uncertain, with some indication that there will be a larger mean response. Finally, the models show robust changes to the seasonal cycle in the stratosphere. Specifically, we find a longer duration of the stratospheric polar vortex and thus a longer season of stratosphere‐troposphere coupling. Key Points: The tropospheric signal of sudden stratospheric warming (SSWs) in the North Atlantic does not change under 4xCO2 forcingThere is high uncertainty in changes of SSW frequency under 4xCO2 forcing; single models show the rate to be significantly halved or doubledThe boreal polar vortex will form earlier and disappear later under increased CO2, extending the season of stratosphere‐troposphere coupling [ABSTRACT FROM AUTHOR]

Published
2020
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26. The Arctic Predictability and Prediction on Seasonal-to-Interannual TimEscales (APPOSITE) data set

Author

Day, J. J., primary, Tietsche, S., additional, Collins, M., additional, Goessling, H. F., additional, Guemas, V., additional, Guillory, A., additional, Hurlin, W. J., additional, Ishii, M., additional, Keeley, S. P. E., additional, Matei, D., additional, Msadek, R., additional, Sigmond, M., additional, Tatebe, H., additional, and Hawkins, E., additional

Published
2015
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27. Enhanced seasonal forecast skill following stratospheric sudden warmings

Author

Sigmond, M., Scinocca, J. F., Kharin, V. V., and Shepherd, T. G.

Abstract

Advances in seasonal forecasting have brought widespread\ud socio-economic benefits. However, seasonal forecast skill\ud in the extratropics is relatively modest, prompting the\ud seasonal forecasting community to search for additional\ud sources of predictability. For over a decade it has been\ud suggested that knowledge of the state of the stratosphere\ud can act as a source of enhanced seasonal predictability; long-lived circulation anomalies in the lower stratosphere that follow stratospheric sudden warmings are associated with circulation anomalies in the troposphere that can last up to two months. Here, we show by performing retrospective\ud ensemble model forecasts that such enhanced predictability\ud can be realized in a dynamical seasonal forecast system with\ud a good representation of the stratosphere. When initialized at the onset date of stratospheric sudden warmings, the model forecasts faithfully reproduce the observed mean tropospheric conditions in the months following the stratospheric sudden warmings. Compared with an equivalent set of forecasts that are not initialized during stratospheric sudden warmings, we document enhanced forecast skill for atmospheric circulation patterns, surface temperatures over northern Russia and eastern Canada and North Atlantic precipitation. We suggest\ud that seasonal forecast systems initialized during stratospheric sudden warmings are likely to yield significantly greater forecast skill in some regions.

Published
2013

29. Modeling Evidence that Ozone Depletion Has Impacted Extreme Precipitation in the Austral Summer

Author

Kang, S. M., Polvani, Lorenzo M., Fyfe, J. C., Son, S.-W., Sigmond, M., and Correa, Gustavo P.

Subjects
Meteorology, Atmosphere, Climatic changes
Abstract

The impacts of stratospheric ozone depletion on the extremes of daily precipitation in the austral summer are explored using two global climate models. Both models indicate that stratospheric ozone losses since the late 1970s may have increased the frequency and intensity of very heavy precipitation in austral summer over southern high and subtropical latitudes, and may have decreased the frequency and intensity over southern midlatitudes. This hemispheric wide pattern of extreme precipitation response projects strongly onto a previously identified pattern of seasonal mean precipitation response, both of which are shown to be likely of dynamic rather than thermodynamic origin.

Published
2013
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30. Recent developments in gravity wave effects in climate models, and the global distribution of gravity wave momentum flux from observations and models

Author

Alexander, M. J., Geller, M., McLandress, C., Polavarapu, S., Preusse, P., Sassi, F., Sato, K., Eckermann, S., Ern, M., Hertzog, A., Kawatani, Y., Pulido, Manuel Arturo, Shaw, T., Sigmond, M., Vincent, R., and Watanabe, S.

Subjects
WIND TENDENCY, MISSING FORCE, GRAVITY WAVE, CLIMATE MODELS, GLOBAL MODEL, ATMOSPHERE, Meteorología y Ciencias Atmosféricas, MOMENTUM FLUX, CIENCIAS NATURALES Y EXACTAS, DRAG, Ciencias de la Tierra y relacionadas con el Medio Ambiente
Abstract

Recent observational and theoretical studies of the global properties of small-scale atmospheric gravity waves have highlighted the global effects of these waves on the circulation from the surface to the middle atmosphere. The effects of gravity waves on the large-scale circulation have long been treated via parametrizations in both climate and weather forecasting applications. In these parametrizations, key parameters describe the global distributions of gravity wave momentum flux, wavelengths, and frequencies of the waves. Until recently, global observations could not define the needed parameters because the waves are small in scale and intermittent in occurrence. Recent satellite and other global data sets with improved resolution along with innovative analysis methods are now providing constraints for the parametrizations that can improve the treatment of these waves in climate prediction models. Research using very high resolution global models has also recently demonstrated the capability of resolving gravity waves and their circulation effects, and when tested against observations, these models are showing some very realistic properties. Here we review recent studies on gravity wave effects in stratosphere-resolving climate models, recent observations and analysis methods that reveal global patterns in gravity wave momentum fluxes, and results of the very high resolution model studies, and we outline some future research needs to improve the treatment of these waves in climate simulations. Fil: Alexander, M. J.. NWRA/Colorado Research Association; Estados Unidos Fil: Geller, M.. SUNY-Stonybrook; Estados Unidos Fil: McLandress, C.. University of Toronto; Canadá Fil: Polavarapu, S.. Environment; Canadá Fil: Preusse, P.. Forschungzentrum Jülich; Alemania Fil: Sassi, F.. Naval Research Laboratory; Estados Unidos Fil: Sato, K.. University of Tokyo; Japón Fil: Eckermann, S.. Naval Research Laboratory; Estados Unidos Fil: Ern, M.. Forschungzentrum Jülich; Alemania Fil: Hertzog, A.. UPMC Université Paris 06. Laboratoire de Météorologie Dynamique; Francia Fil: Kawatani, Y.. Japan Agency for Marine-Earth Science and Technology; Japón Fil: Pulido, Manuel Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnologica; Argentina Fil: Shaw, T.. New York University; Estados Unidos Fil: Sigmond, M.. University of Toronto; Canadá Fil: Vincent, R.. University of Adelaide; Australia Fil: Watanabe, S.. Japan Agency for Marine-Earth Science and Technology; Japón

Published
2010

32. Recent developments in gravity-wave effects in climate models and the global distribution of gravity-wave momentum flux from observations and models

Author

Alexander, M.J., Geller, M., Mclandress, C., Polavarapu, S., Preusse, P., Sassi, F., Sato, K., Eckermann, S., Ern, M., Hertzog, A., Kawatani, Y., Pulido, M., Shaw, T. A., Sigmond, M., Vincent, R., Watanabe, S., NorthWest Research Associates [Boulder] (NWRA), Stony Brook University [SUNY] (SBU), State University of New York (SUNY), Department of Physics [Toronto], University of Toronto, Environment and Climate Change Canada, The University of Tokyo (UTokyo), Naval Research Laboratory (NRL), Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Center for Atmosphere Ocean Science [NYU] (CAOS), Courant Institute of Mathematical Sciences [New York] (CIMS), New York University [New York] (NYU), NYU System (NYU)-NYU System (NYU)-New York University [New York] (NYU), NYU System (NYU)-NYU System (NYU), Physics Department [Adelaide], University of Adelaide, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Physics::Atmospheric and Oceanic Physics
Abstract

International audience; Recent observational and theoretical studies of the global properties of small-scale atmospheric gravity waves have highlighted the global effects of these waves on the circulation from the surface to the middle atmosphere. The effects of gravity waves on the large-scale circulation have long been treated via parametrizations in both climate and weather-forecasting applications. In these parametrizations, key parameters describe the global distributions of gravity-wave momentum flux, wavelengths and frequencies. Until recently, global observations could not define the required parameters because the waves are small in scale and intermittent in occurrence. Recent satellite and other global datasets with improved resolution, along with innovative analysis methods, are now providing constraints for the parametrizations that can improve the treatment of these waves in climate-prediction models. Research using very-high-resolution global models has also recently demonstrated the capability to resolve gravity waves and their circulation effects, and when tested against observations these models show some very realistic properties. Here we review recent studies on gravity-wave effects in stratosphere-resolving climate models, recent observations and analysis methods that reveal global patterns in gravity-wave momentum fluxes and results of very-high-resolution model studies, and we outline some future research requirements to improve the treatment of these waves in climate simulations. Copyright © 2010 Royal Meteorological Society and Crown in the right of Canada

Published
2010

33. Impact of sudden Arctic sea-ice loss on stratospheric polar ozone recovery

Author

Scinocca, J.F., Reader, M.C., Plummer, D.A., Sigmond, M., Kushner, P.J., Shepherd, T.G., and Ravishankara, A.R.

Abstract

We investigate the sensitivity of Northern Hemisphere polar ozone recovery to a scenario in which there is rapid loss of Arctic summer sea ice in the first half of the 21st century. The issue is addressed by coupling a chemistry climate model to an ocean general circulation model and performing simulations of ozone recovery with, and without, an external perturbation designed to cause a rapid and complete loss of summertime Arctic sea ice. Under this extreme perturbation, the stratospheric response takes the form of a springtime polar cooling which is dynamical rather than radiative in origin, and is caused by reduced wave forcing from the troposphere. The response lags the onset of the sea-ice perturbation by about one decade and lasts for more than two decades, and is associated with an enhanced weakening of the North Atlantic meridional overturning circulation. The stratospheric dynamical response leads to a 10 DU reduction in polar column ozone, which is statistically robust. While this represents a modest loss, it has the potential to induce a delay of roughly one decade in Arctic ozone recovery estimates made in the 2006 Scientific Assessment of Ozone Depletion.

Published
2009

34. How does the northern-winter wave driving of the Brewer-Dobson circulation increase in an enhanced-CO₂ climate simulation?

Author

Haklander, A.J., Siegmund, P.C., Sigmond, M., Kelder, H.M., and Fluids and Flows

Subjects
SDG 13 - Climate Action
Abstract

Recent climate studies show that the northern-winter wave driving of the Brewer-Dobson circulation is enhanced if greenhouse gas concentrations increase. An explanation for this enhancement does not yet exist. In this study, the enhanced wave driving, as simulated in a doubled-CO2 experiment with the MA-ECHAM4 climate model, is analyzed in detail. The extratropical poleward eddy heat flux increases (decreases) in the stratosphere (troposphere) mainly due to the stationary (transient) heat-flux component. The heat flux at 100 hPa is a measure of the stratospheric wave driving, and is found to increase by 12% in the doubled-CO2 climate. This increase is dominated by the stationary-wave 1 heat flux, which is also enhanced in the midlatitude troposphere. The heat flux increase at 100 hPa is almost entirely due to an increase in the longitudinal temperature variability. The latter increase is mainly due to the well-understood sharpening of the lower-stratospheric meridional temperature gradient.

Published
2008

36. Recent Developments in Gravity Wave Effects in Climate Models, and the Global Distribution of Gravity Wave Momentum Flux from Observations and Models

Author

NAVAL RESEARCH LAB WASHINGTON DC, Alexander, M. J., Geller, M., McLandress, C., Polavarapu, S., Preusse, P., Sassi, F., Sato, K., Eckermann, S., Ern, M., Hertzog, A., Kawatani, Y., Pulido, M., Shaw, T., Sigmond, M., Vincent, R., Watanabe, S., NAVAL RESEARCH LAB WASHINGTON DC, Alexander, M. J., Geller, M., McLandress, C., Polavarapu, S., Preusse, P., Sassi, F., Sato, K., Eckermann, S., Ern, M., Hertzog, A., Kawatani, Y., Pulido, M., Shaw, T., Sigmond, M., Vincent, R., and Watanabe, S.

Abstract

Recent observational and theoretical studies of the global properties of small-scale atmospheric gravity waves have highlighted the global effects of these waves on the circulation from the surface to the middle atmosphere. The effects of gravity waves on the large-scale circulation have long been treated via parametrizations in both climate and weather forecasting applications. In these parametrizations, key parameters describe the global distributions of gravity wave momentum flux, wavelengths, and frequencies of the waves. Until recently, global observations could not define the needed parameters because the waves are small in scale and intermittent in occurrence. Recent satellite and other global data sets with improved resolution along with innovative analysis methods are now providing constraints for the parametrizations that can improve the treatment of these waves in climate prediction models. Research using very high resolution global models has also recently demonstrated the capability of resolving gravity waves and their circulation effects, and when tested against observations, these models are showing some very realistic properties. Here we review recent studies on gravity wave effects in stratosphere-resolving climate models, recent observations and analysis methods that reveal global patterns in gravity wave momentum fluxes, and results of the very high resolution model studies, and we outline some future research needs to improve the treatment of these waves in climate simulations., In Press, Quarterly Journal of the Royal Meterological Society. Prepared in collaboration with NWRA/Colorado Research Assoc., Boulder, CO; State University of New York at Sunnybrook, NY; University of Toronto, Toronto, Canada; Environment Canada; Forschungzentrum Juelich, Germany; University of Tokyo; UPMC Univ Paris 06, Laboratoire de Meteorologie Dynamique, France; Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan; New York University; and University of Adelaide, Australia. Sponsored in part by National Science Foundation's Physical and Dynamic Meteorology Program Grant no.0632378.

Published
2009

40. The Arctic Predictability and Prediction on Seasonal-to-Interannual TimEscales (APPOSITE) data set.

Author

Day, J. J., Tietsche, S., Collins, M., Goessling, H. F., Guemas, V., Guillory, A., Hurlin, W. J., Ishii, M., Keeley, S. P. E., Matei, D., Msadek, R., Sigmond, M., Tatebe, H., and Hawkins, E.

Subjects
ARCTIC climate, GENERAL circulation model, CLIMATE change
Abstract

Recent decades have seen significant developments in seasonal-to-interannual timescale climate prediction capabilities. However, until recently the potential of such systems to predict Arctic climate had not been assessed. This paper describes a multimodel predictability experiment which was run as part of the Arctic Predictability and Prediction On Seasonal to Inter-annual Timescales (APPOSITE) project. The main goal of APPOSITE was to quantify the timescales on which Arctic climate is predictable. In order to achieve this, a coordinated set of idealised initial-value predictability experiments, with seven general circulation models, was conducted. This was the first model intercomparison project designed to quantify the predictability of Arctic climate on seasonal to inter-annual timescales. Here we present a description of the archived data set (which is available at the British Atmospheric Data Centre) and an update of the project's results. Although designed to address Arctic predictability, this data set could also be used to assess the predictability of other regions and modes of climate variability on these timescales, such as the El Niño Southern Oscillation. [ABSTRACT FROM AUTHOR]

Published
2015
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43. Multimodel climate and variability of the stratosphere

Author

Butchart, N., primary, Charlton-Perez, A. J., additional, Cionni, I., additional, Hardiman, S. C., additional, Haynes, P. H., additional, Krüger, K., additional, Kushner, P. J., additional, Newman, P. A., additional, Osprey, S. M., additional, Perlwitz, J., additional, Sigmond, M., additional, Wang, L., additional, Akiyoshi, H., additional, Austin, J., additional, Bekki, S., additional, Baumgaertner, A., additional, Braesicke, P., additional, Brühl, C., additional, Chipperfield, M., additional, Dameris, M., additional, Dhomse, S., additional, Eyring, V., additional, Garcia, R., additional, Garny, H., additional, Jöckel, P., additional, Lamarque, J.-F., additional, Marchand, M., additional, Michou, M., additional, Morgenstern, O., additional, Nakamura, T., additional, Pawson, S., additional, Plummer, D., additional, Pyle, J., additional, Rozanov, E., additional, Scinocca, J., additional, Shepherd, T. G., additional, Shibata, K., additional, Smale, D., additional, Teyssèdre, H., additional, Tian, W., additional, Waugh, D., additional, and Yamashita, Y., additional

Published
2011
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46. Anthropogenic forcing of the Northern Annular Mode in CCMVal‐2 models

Author

Morgenstern, O., primary, Akiyoshi, H., additional, Bekki, S., additional, Braesicke, P., additional, Butchart, N., additional, Chipperfield, M. P., additional, Cugnet, D., additional, Deushi, M., additional, Dhomse, S. S., additional, Garcia, R. R., additional, Gettelman, A., additional, Gillett, N. P., additional, Hardiman, S. C., additional, Jumelet, J., additional, Kinnison, D. E., additional, Lamarque, J.‐F., additional, Lott, F., additional, Marchand, M., additional, Michou, M., additional, Nakamura, T., additional, Olivié, D., additional, Peter, T., additional, Plummer, D., additional, Pyle, J. A., additional, Rozanov, E., additional, Saint‐Martin, D., additional, Scinocca, J. F., additional, Shibata, K., additional, Sigmond, M., additional, Smale, D., additional, Teyssèdre, H., additional, Tian, W., additional, Voldoire, A., additional, and Yamashita, Y., additional

Published
2010
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