Comparison of a Barotropic Blocking Theory with Observation

Charney, J. G.; Shukla, J.; Mo, Kingtse C.

doi:10.1175/1520-0469(1981)038<0762:coabbt>2.0.co;2

Cited by 103 publications

(79 citation statements)

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“…Figure 6a displays the annually averaged frequency of blocked longitude distribution for the whole period. As has been noted extensively in the literature, two main sectors with a higher tendency for blocking can be distinguished, encompassing Euro-Atlantic and Pacific regions respectively (Rex, 1950a,b;LO83;Charney et al 1981;Colucci and Alberta 1996). The Pacific blocking activity extended between 100°and 240°E with a maximum located near the central Pacific (180°) while the Euro-Atlantic counterpart is more prominent, expanding from 270°to 90°E with greater frequencies near 10°E.…”

Section: Nh Blocking Characterization a Temporal And Spatial Distribmentioning

confidence: 70%

“…According to this theory, the blocking phenomenon can be a metastable equilibrium state between two equilibrium solutions of highindex flow (weak like-wave component) and low-index flow (strong wave component). Additionally, in the view of Charney and DeVore (1979), stable states can be considered in a regional context, and they view studies that consider blocking regional consistent with their own studies. Additionally, both topographical and thermal forcing between land continents and oceans are responsible in determining one or another stable solution.…”

Section: B the Dynamic Role Of Tcps In Blocking Occurrencementioning

confidence: 88%

“…Additionally, conceptual models link low-frequency transient eddies and blocking events (Shutts 1983;Tsou and Smith 1990). Recently, Shabbar et al (2001) demonstrate the decisive contribution of the NAO to the wintertime blocking occurrence over the Atlantic sector, establishing a simple conceptual model based on the Charney and DeVore (1979) theory. According to this theory, the blocking phenomenon can be a metastable equilibrium state between two equilibrium solutions of highindex flow (weak like-wave component) and low-index flow (strong wave component).…”

Section: B the Dynamic Role Of Tcps In Blocking Occurrencementioning

confidence: 99%

“…Other methodologies detected blocking events as positive height anomalies at the midtroposheric flow persisting for several days (Charney et al 1981;Dole and Gordon 1983) or from normalized indices based on daily height projections over mean blocking patterns (Liu 1994;Renwick and Wallace 1996). The most recent methodologies combine traditional subjective and objective criteria, as those used by Lupo and Smith (1995, hereafter LS95) or Wiedenmann et al (2002, hereafter WI02), or use quantities derived from dynamical properties related to blocking patterns, such as the meridional potential temperature () gradient on a potential vorticity (PV) surface representative of the tropopause (Pelly and Hoskins 2003), or negative anomalies of vertically integrated potential vorticity within the 500-150-hPa layer (Schwierz et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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A Climatology of Northern Hemisphere Blocking

et al. 2006

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In this paper a 55-yr (1948-2002) Northern Hemisphere blocking climatology is presented. Traditional blocking indices and methodologies are revised and a new blocking detection method is designed. This algorithm detects blocked flows and provides for a better characterization of blocking events with additional information on blocking parameters such as the location of the blocking center, the intensity, and extension. Additionally, a new tracking procedure has been incorporated following simultaneously the individual evolution of blocked flows and identifying coherently persistent blocked patterns.Using this method, the longest known Northern Hemisphere blocking climatology is obtained and compared with previous studies. A new regional classification into four independent blocking sectors has been obtained based on the seasonally preferred regions of blocking formation: Atlantic (ATL), European (EUR), West Pacific (WPA), and East Pacific (EPA). Global and regional blocking characteristics have been described, examining their variability from the seasonal to interdecadal scales.The global long-term blocking series in the North Hemisphere showed a significant trend toward weaker and less persistent events, as well as regional increases (decreases) in blocking frequency over the WPA (ATL and EUR) sector. The influence of teleconnection patterns (TCPs) on blocking parameters is also explored, being confined essentially to wintertime, except in the WPA sector. Additionally, regional blocking parameters, especially frequency and duration, are sensitive to regional TCPs, supporting the regional classification obtained in this paper. The ENSO-related blocking variability is evident in blocking intensities and preferred locations but not in frequency. Finally, the dynamical connection between blocking occurrence and regional TCPs is examined through the conceptual model proposed by Charney and DeVore. Observational evidence of a dynamical link between the asymmetrical temperature distributions induced by TCPs and blocking variability is provided with a distinctive contrast "warm ocean/cold land" pattern favoring the blocking occurrence in winter. However, the conceptual model is not coherent in the WPA sector, suggesting different blocking mechanisms operating in this sector.

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Section: Nh Blocking Characterization a Temporal And Spatial Distribmentioning

confidence: 70%

Section: B the Dynamic Role Of Tcps In Blocking Occurrencementioning

confidence: 88%

Section: B the Dynamic Role Of Tcps In Blocking Occurrencementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Climatology of Northern Hemisphere Blocking

et al. 2006

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“…The main contribution of Charney and associates (17,47) to explaining the existence and persistence of blocked flows was to move away from dynamic meteorology's prevailing paradigm throughout the 1950s and 1960s. In this paradigm, all atmospheric motions were explained as linear perturbations of purely zonal flow, seen as the unique equilibrium of the governing equations.…”

Section: Interpretation Of the Regimes Rossby Wave Propagation And Imentioning

confidence: 99%

“Waves” vs. “particles” in the atmosphere's phase space: A pathway to long-range forecasting?

Ghil

Robertson

2002

Proc. Natl. Acad. Sci. U.S.A.

168

169

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Thirty years ago, E. N. Lorenz provided some approximate limits to atmospheric predictability. The details-in space and time-of atmospheric flow fields are lost after about 10 days. Certain gross flow features recur, however, after times of the order of 10 -50 days, giving hope for their prediction. Over the last two decades, numerous attempts have been made to predict these recurrent features. The attempts have involved, on the one hand, systematic improvements in numerical weather prediction by increasing the spatial resolution and physical faithfulness in the detailed models used for this prediction. On the other hand, theoretical attempts motivated by the same goal have involved the study of the large-scale atmospheric motions' phase space and the inhomogeneities therein. These ''coarse-graining'' studies have addressed observed as well as simulated atmospheric data sets. Two distinct approaches have been used in these studies: the episodic or intermittent and the oscillatory or periodic. The intermittency approach describes multiple-flow (or weather) regimes, their persistence and recurrence, and the Markov chain of transitions among them. The periodicity approach studies intraseasonal oscillations, with periods of 15-70 days, and their predictability. We review these two approaches, ''particles'' vs. ''waves,'' in the quantum physics analogy alluded to in the title of this article, discuss their complementarity, and outline unsolved problems.

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Low‐frequency nonlinearity and regime behavior in the Northern Hemisphere extratropical atmosphere

Hannachi

Straus

Franzke³

et al. 2017

Reviews of Geophysics

134

140

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The extratropical atmosphere is characterized by robust circulations which have time scales longer than that associated with developing baroclinic systems but shorter than a season. Such low-frequency variability is governed to a large extent by nonlinear dynamics and, hence, is chaotic. A useful aspect of this low-frequency circulation is that it can often be described by just a few quasi-stationary regime states, broadly defined as recurrent or persistent large-scale structures, that exert a significant impact on the probability of experiencing extreme surface weather conditions. We review a variety of techniques for identifying circulation regimes from reanalysis and numerical model output. While various techniques often yield similar regime circulation patterns, they offer different perspectives on the regimes. The regimes themselves are manifest in planetary scale patterns. They affect the structure of synoptic scale patterns. Extratropical flow regimes have been identified in simplified atmospheric models and comprehensive coupled climate models and in reanalysis data sets. It is an ongoing challenge to accurately model these regime states, and high horizontal resolutions are often needed to accurately reproduce them. The regime paradigm helps to understand the response to external forcing on a variety of time scales, has been helpful in categorizing a large number of weather types and their effect on local conditions, and is useful in downscaling. Despite their usefulness, there is a debate on the "nonequivocal" and systematic existence of these nonlinear circulation regimes. We review our current understanding of the nonlinear and regime paradigms and suggest future research

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Comparison of a Barotropic Blocking Theory with Observation

Cited by 103 publications

References 0 publications

A Climatology of Northern Hemisphere Blocking

A Climatology of Northern Hemisphere Blocking

“Waves” vs. “particles” in the atmosphere's phase space: A pathway to long-range forecasting?

Low‐frequency nonlinearity and regime behavior in the Northern Hemisphere extratropical atmosphere

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