scholarly journals Cloud‐Radiative Impact on the Regional Responses of the Midlatitude Jet Streams and Storm Tracks to Global Warming

2019 ◽  
Vol 11 (7) ◽  
pp. 1940-1958 ◽  
Author(s):  
Nicole Albern ◽  
Aiko Voigt ◽  
Joaquim G. Pinto
Keyword(s):  
Global Warming ◽  
Storm Tracks ◽  
Jet Streams ◽  
Radiative Impact ◽  
Regional Responses

Observed Associations Among Storm Tracks, Jet Streams and Midlatitude Oceanic Fronts

2013 ◽  
pp. 329-345 ◽  
Author(s):  
Hisashi Nakamura ◽  
Takeaki Sampe ◽  
Youichi Tanimoto ◽  
Akihiko Shimpo
Keyword(s):  
Storm Tracks ◽  
Jet Streams ◽  
Oceanic Fronts

scholarly journals Exploring the sensitivity of Northern Hemisphere atmospheric circulation to different surface temperature forcing using a statistical–dynamical atmospheric model

2019 ◽  
Vol 26 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Sonja Totz ◽  
Stefan Petri ◽  
Jascha Lehmann ◽  
Erik Peukert ◽  
Dim Coumou
Keyword(s):  
Temperature Gradient ◽  
Large Scale ◽  
Planetary Waves ◽  
Hadley Cell ◽  
Storm Tracks ◽  
Meridional Temperature Gradient ◽  
Jet Streams ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Global Mean

Abstract. Climate and weather conditions in the mid-latitudes are strongly driven by the large-scale atmosphere circulation. Observational data indicate that important components of the large-scale circulation have changed in recent decades, including the strength and the width of the Hadley cell, jets, storm tracks and planetary waves. Here, we use a new statistical–dynamical atmosphere model (SDAM) to test the individual sensitivities of the large-scale atmospheric circulation to changes in the zonal temperature gradient, meridional temperature gradient and global-mean temperature. We analyze the Northern Hemisphere Hadley circulation, jet streams, storm tracks and planetary waves by systematically altering the zonal temperature asymmetry, the meridional temperature gradient and the global-mean temperature. Our results show that the strength of the Hadley cell, storm tracks and jet streams depend, in terms of relative changes, almost linearly on both the global-mean temperature and the meridional temperature gradient, whereas the zonal temperature asymmetry has little or no influence. The magnitude of planetary waves is affected by all three temperature components, as expected from theoretical dynamical considerations. The width of the Hadley cell behaves nonlinearly with respect to all three temperature components in the SDAM. Moreover, some of these observed large-scale atmospheric changes are expected from dynamical equations and are therefore an important part of model validation.

The Effect of a Strong Zonal Jet Stream on the Temporal Evolution of Baroclinic Eddies

2020 ◽  
Author(s):  
Or Hadas ◽  
Yohai Kaspi
Keyword(s):  
General Circulation ◽  
Baroclinic Instability ◽  
Storm Track ◽  
Storm Tracks ◽  
Jet Stream ◽  
Similar Response ◽  
Jet Streams ◽  
Eddy Activity ◽  
Zonal Jets ◽  
The Pacific

<p>The midlatitude storm tracks are one of the most prominent features of the extratropical climate. Much of our understanding of what controls the storm tracks comes from linear theory of baroclinic instability, which explains generally most of the observed response of storms to the general circulation. One example to where this approach is lacking is the Pacific midwinter minimum, a decrease in the eddy activity over the Pacific storm track during midwinter when baroclinicity is at its peak due to extremely strong zonal jets. A similar response was found recently for the Atlantic storm track<strong>,</strong> in correlation to periods of strong zonal jets. Following on these findings we study the effect of strong zonal jet streams on eddy activity in the midlatitudes. In order to isolate the effect of the jet strength we used several idealized GCM experiments with different jet strengths, and analyze the formed storm track from a Lagrangian perspective by using a storm tracking algorithm. In both the Eulerian analysis and analysis of the tracks a strong reduction of high level eddy activity is prominent, as well as a modest weakening of the low-level activity. The observed response is then further analyzed by studying the connection between the upper and lower wave and how it changes with jet-stream intensity. </p><p> </p>

scholarly journals Extratropical Cyclones: A Century of Research on Meteorology’s Centerpiece

2019 ◽  
Vol 59 ◽  
pp. 16.1-16.56 ◽  
Author(s):  
David M. Schultz ◽  
Lance F. Bosart ◽  
Brian A. Colle ◽  
Huw C. Davies ◽  
Christopher Dearden ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Baroclinic Instability ◽  
Extratropical Cyclone ◽  
Storm Tracks ◽  
Structure Evolution ◽  
Extratropical Cyclones ◽  
Theoretical Frameworks ◽  
Jet Streams ◽  
American Meteorological Society ◽  
History Of

Abstract The year 1919 was important in meteorology, not only because it was the year that the American Meteorological Society was founded, but also for two other reasons. One of the foundational papers in extratropical cyclone structure by Jakob Bjerknes was published in 1919, leading to what is now known as the Norwegian cyclone model. Also that year, a series of meetings was held that led to the formation of organizations that promoted the international collaboration and scientific exchange required for extratropical cyclone research, which by necessity involves spatial scales spanning national borders. This chapter describes the history of scientific inquiry into the structure, evolution, and dynamics of extratropical cyclones, their constituent fronts, and their attendant jet streams and storm tracks. We refer to these phenomena collectively as the centerpiece of meteorology because of their central role in fostering meteorological research during this century. This extremely productive period in extratropical cyclone research has been possible because of 1) the need to address practical challenges of poor forecasts that had large socioeconomic consequences, 2) the intermingling of theory, observations, and diagnosis (including dynamical modeling) to provide improved physical understanding and conceptual models, and 3) strong international cooperation. Conceptual frameworks for cyclones arise from a desire to classify and understand cyclones; they include the Norwegian cyclone model and its sister the Shapiro–Keyser cyclone model. The challenge of understanding the dynamics of cyclones led to such theoretical frameworks as quasigeostrophy, baroclinic instability, semigeostrophy, and frontogenesis. The challenge of predicting explosive extratropical cyclones in particular led to new theoretical developments such as potential-vorticity thinking and downstream development. Deeper appreciation of the limits of predictability has resulted from an evolution from determinism to chaos. Last, observational insights led to detailed cyclone and frontal structure, storm tracks, and rainbands.

scholarly journals Climate model biases in jet streams, blocking and storm tracks resulting from missing orographic drag

2016 ◽  
Vol 43 (13) ◽  
pp. 7231-7240 ◽  
Author(s):  
Felix Pithan ◽  
Theodore G. Shepherd ◽  
Giuseppe Zappa ◽  
Irina Sandu
Keyword(s):  
Climate Model ◽  
Storm Tracks ◽  
Jet Streams ◽  
Model Biases ◽  
Orographic Drag

Will marine dimethylsulfide emissions amplify or alleviate global warming? A model study

2004 ◽  
Vol 61 (5) ◽  
pp. 826-835 ◽  
Author(s):  
Laurent Bopp ◽  
Olivier Boucher ◽  
Olivier Aumont ◽  
Sauveur Belviso ◽  
Jean-Louis Dufresne ◽  
...  
Keyword(s):  
Global Warming ◽  
Radiative Forcing ◽  
Sulfur Compound ◽  
Cloud Condensation Nuclei ◽  
Regional Climate ◽  
Climate Feedback ◽  
Model Study ◽  
Radiative Impact ◽  
Radiative Perturbation ◽  
First Time

Dimethylsulfide (DMS) is the most abundant volatile sulfur compound at the sea surface and has a strong marine phytoplanktonic origin. Once outgased into the atmosphere, it contributes to the formation of sulfate aerosol particles that affect the radiative budget as precursors of cloud condensation nuclei (CCN). It has been postulated that climate may be partly modulated by variations in DMS production. We test this hypothesis in the context of anthro pogenic climate change and present here, modelled for the first time, an estimate of the radiative impact resulting from changes in DMS air–sea fluxes caused by global warming. At 2× CO2, our model estimates a small increase (3%) in the global DMS flux to the atmosphere but with large spatial heterogeneities (from –15% to 30%). The radiative perturbation resulting from the DMS-induced change in cloud albedo is estimated to be –0.05 W·m–2, which represents only a small negative climate feedback on global warming. However, there are large regional changes, such as a perturbation of up to –1.5 W·m–2 in summer between 40°S and 50°S, that can impact the regional climate. In the Southern Ocean, the radiative impact resulting from changes in the DMS cycle may partly alleviate the radiative forcing resulting from anthropogenic CO2.

scholarly journals The response of the Northern Hemisphere storm tracks and jetstreams to climate change in the CMIP3, CMIP5, and CMIP6 climate models

2020 ◽  
Author(s):  
Ben Harvey ◽  
Peter Cook ◽  
Len Shaffrey ◽  
Reinhard Schiemann
Keyword(s):  
Climate Change ◽  
Spatial Pattern ◽  
North Atlantic ◽  
Climate Models ◽  
Climate Model ◽  
Storm Track ◽  
Coupled Model ◽  
Storm Tracks ◽  
Cmip5 Models ◽  
Jet Streams

<p>Understanding and predicting how extratropical cyclones might respond to climate change is essential for assessing future weather risks and informing climate change adaptation strategies. Climate model simulations provide a vital component of this assessment, with the caveat that their representation of the present-day climate is adequate. In this study the representation of the NH storm tracks and jet streams and their responses to climate change are evaluated across the three major phases of the Coupled Model Intercomparison Project: CMIP3 (2007), CMIP5 (2012), and CMIP6 (2019). The aim is to quantity how present-day biases in the NH storm tracks and jet streams have evolved with model developments, and to further our understanding of their responses to climate change.</p><p>The spatial pattern of the present-day biases in CMIP3, CMIP5, and CMIP6 are similar. However, the magnitude of the biases in the CMIP6 models is substantially lower in the DJF North Atlantic storm track and jet stream than in the CMIP3 and CMIP5 models. In summer, the biases in the JJA North Atlantic and North Pacific storm tracks are also much reduced in the CMIP6 models. Despite this, the spatial pattern of the climate change response in the NH storm tracks and jet streams are similar across the CMIP3, CMIP5, and CMIP6 ensembles. The SSP2-4.5 scenario responses in the CMIP6 models are substantially larger than in the corresponding RCP4.5 CMIP5 models, consistent with the larger climate sensitivities of the CMIP6 models compared to CMIP5.</p>

scholarly journals Euro-Atlantic winter storminess and precipitation extremes under 1.5 °C versus 2 °C warming scenarios

2017 ◽  
Author(s):  
Monika J. Barcikowska ◽  
Scott J. Weaver ◽  
Frauke Feser ◽  
Simone Russo ◽  
Frederik Schenk ◽  
...  
Keyword(s):  
Global Warming ◽  
Regional Scale ◽  
Storm Track ◽  
Precipitation Extremes ◽  
Storm Tracks ◽  
Atlantic Region ◽  
Storm Activity ◽  
Wind Speeds ◽  
North East ◽  
The North

Abstract. Severe winter storms in combination with precipitation extremes pose a serious threat to Europe. Located at the south-east exit of the North Atlantic's storm track, European coastlines are directly exposed to impacts by high wind speeds, storm floods and coastal erosion. In this study we analyze potential changes in simulated winter storminess and extreme precipitation which may occur under 1.5 °C or 2 °C warming scenarios. Here we focus on a first simulation suite of the atmospheric model CAM5 performed within the HAPPI project and evaluate how changes of the horizontal model resolution impact the results regarding atmospheric pressure, storm tracks, wind speed and precipitation extremes. The comparison of CAM5 simulations with different resolution indicates that an increased horizontal resolution to 0.25° is not only refining regional-scale information, but also improves large-scale atmospheric circulation features over the Euro-Atlantic region. The zonal bias in SLP and wind fields, which is typically found in low-resolution models, is considerably reduced. This allows us to analyze potential changes in regional- to local-scale extreme wind speeds and precipitation in a more realistic way. Our analysis of the future response for the 2 °C warming scenario generally confirms previous model simulations suggesting a poleward shift and intensification of the meridional circulation the Euro-Atlantic region. Additional analysis suggests that this shift occurs mainly after exceeding the 1.5 °C global warming level, when the midltatitude jetstream manifests a strengthening north-eastward. At the same time, this north-east shift of the storm tracks allows an intensification and north-east expansion of the Azores high leading to a tendency of less precipitation across the Bay of Biscay and North Sea. Regions impacted by the strengthening of the midlatitude jet, such as the northwest coasts of British Isles, Scandinavia and the Norwegian Sea, and over the North Atlantic east from Newfoundland experience an increase in the mean as well as daily and sub daily precipitation and wind extremes and storminess suggesting an important influence of increasing storm activity in these regions in response to global warming.

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