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

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.

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Seasonal Variations in the Southern Hemisphere Storm Tracks and Jet Streams as Revealed in a Reanalysis Dataset

Journal of Climate ◽

10.1175/1520-0442(2004)017<1828:svitsh>2.0.co;2 ◽

2004 ◽

Vol 17 (9) ◽

pp. 1828-1844 ◽

Cited By ~ 134

Author(s):

Hisashi Nakamura ◽

Akihiko Shimpo

Keyword(s):

Southern Hemisphere ◽

Seasonal Variations ◽

Storm Tracks ◽

Jet Streams ◽

Reanalysis Dataset

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

10.5194/egusphere-egu2020-4648 ◽

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

The midlatitude storm tracks are one of the most prominent features of the extratropical climate.&#160;Much&#160;of our understanding of what controls the storm tracks comes from linear theory of baroclinic instability,&#160;which explains&#160;generally most of the observed&#160;response&#160;of storms to the general circulation. One example to where this approach&#160;is lacking&#160;is the Pacific midwinter minimum, a decrease in the eddy activity over the Pacific storm track during midwinter when baroclinicity is at its&#160;peak due&#160;to extremely strong zonal jets.&#160;A similar response was found recently for the Atlantic storm track,&#160;in correlation to&#160;periods&#160;of strong zonal jets. Following&#160;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&#160;weakening of the&#160;low-level&#160;activity. The observed&#160;response&#160;is then&#160;further analyzed by studying the connection between the upper and lower wave and how it changes&#160;with&#160;jet-stream&#160;intensity.&#160;&#160;

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

Meteorological Monographs ◽

10.1175/amsmonographs-d-18-0015.1 ◽

2019 ◽

Vol 59 ◽

pp. 16.1-16.56 ◽

Cited By ~ 14

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.

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

Geophysical Research Letters ◽

10.1002/2016gl069551 ◽

2016 ◽

Vol 43 (13) ◽

pp. 7231-7240 ◽

Cited By ~ 54

Author(s):

Felix Pithan ◽

Theodore G. Shepherd ◽

Giuseppe Zappa ◽

Irina Sandu

Keyword(s):

Climate Model ◽

Storm Tracks ◽

Jet Streams ◽

Model Biases ◽

Orographic Drag

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

10.5194/egusphere-egu2020-19711 ◽

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

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.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.

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The sensitivity of the large-scale atmosphere circulation to changes in surface temperature gradients in the Northern Hemisphere

10.5194/esd-2017-65 ◽

2017 ◽

Cited By ~ 1

Author(s):

Sonja Molnos ◽

Stefan Petri ◽

Jascha Lehmann ◽

Erik Peukert ◽

Dim Coumou

Keyword(s):

Temperature Gradient ◽

Surface Temperature ◽

Northern Hemisphere ◽

Large Scale ◽

Planetary Waves ◽

Hadley Cell ◽

Temperature Fields ◽

Storm Tracks ◽

Meridional Temperature Gradient ◽

Jet Streams

Abstract. Climate and weather conditions in the mid-latitudes are strongly driven by the large-scale atmosphere circulation. Observational data indicates that important components of the large-scale circulation have changed in recent decades including the strength of the Hadley cell, jet streams, storm tracks and planetary waves. Associated impacts cover a broad range, including changes in the frequency and nature of weather extremes and shifts of fertile habitats with implications for biodiversity and agriculture. Dynamical theories have been proposed that link the shift of the poleward edge of the Northern Hadley cell to changes in the meridional temperature gradient. Moreover, model simulations have been carried out to analyse the cause of observed and projected changes in the large-scale atmosphere circulation. However, the question of the underlying drivers and particularly the possible role of global warming is still debated. Here, we use a statistical-dynamical atmosphere model (SDAM) to analyse the sensitivity of the Northern Hemisphere Hadley cell, storm tracks, jet streams and planetary waves to changes in temperature fields by systematically altering the zonal and meridional temperature gradient as well as the global mean surface temperature.

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