On the problem of subtropical anticyclone regeneration as a factor of its stabilization (Case study for the summer of 2010)

Semenov, E. K.; Sokolikhina, N. N.; Tudrii, K. O.

doi:10.3103/s1068373912100019

Cited by 6 publications

(3 citation statements)

References 3 publications

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“…The overall idea is that the blocked and zonal regimes correspond to fixed points, and the transitions between the two states result from the noise due to synoptic variability. Building on this, Dymnikov (1990) introduced dynamical indices, recently shown to predict well the blocking duration (Semenov et al 2012). The theory of weather regimes is able explain quite accurately some nontrivial statistical properties of the mid-latitude atmosphere (Ruti et al 2006) and can be used to look into the outputs of laboratory experiments.…”

Section: Understanding Blocking Eventsmentioning

confidence: 99%

A New Mathematical Framework for Atmospheric Blocking Events

Lucarini

2021

Preprint

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We use a simple yet Earth-like atmospheric model to propose a new framework for understanding the mathematics of blocking events, which are associated with low frequency, large scale waves in the atmosphere. Analysing error growth rates along a very long model trajectory, we show that blockings are associated with conditions of anomalously high instability of the atmosphere. Additionally, the lifetime of a blocking is positively correlated with the intensity of such an anomaly, against intuition. In the case of Atlantic blockings, predictability is especially reduced at the onset and decay of the blocking, while a relative increase of predictability is found in the mature phase, while the opposite holds for Pacific blockings, for which predictability is lowest in the mature phase. We associate blockings to a specific class of unstable periodic orbits (UPOs), natural modes of variability that cover the attractor of the system. The UPOs differ substantially in terms of instability, which explains the diversity of the atmosphere in terms predictability. The UPOs associated to blockings are indeed anomalously unstable, which leads to them being rarely visited. The onset of a blocking takes place when the trajectory of the system hops into the neighbourhood of one of these special UPOs. The decay takes place when the trajectory hops back to the neighbourhood of usual, less unstable UPOs associated with zonal flow. This justifies the classical Markov chains-based analysis of transitions between weather regimes. The existence of UPOs differing in the dimensionality of their unstable manifold indicates a very strong violation of hyperbolicity in the model, which leads to a lack of structural stability. We propose that this is could be a generic feature of atmospheric models and might be a fundamental cause behind difficulties in representing blockings for the current climate and uncertainties in predicting how their statistics will change as a result of climate change. References: V. Lucarini, A. Gritsun, A. A new mathematical framework for atmospheric blocking events. Climate Dynamics 54, 575&#8211;598 (2020).&#160;https://doi.org/10.1007/s00382-019-05018-2 M. Ghil, V. Lucarini, The Physics of Climate Variability and Climate, Rev. Modern Physics, 92, 035002 (2020). https://link.aps.org/doi/10.1103/RevModPhys.92.035002 &#160; S. Schubert, V. Lucarini, Dynamical analysis of blocking events: spatial and temporal fluctuations of covariant Lyapunov vectors. Q. J. R. Meteorol. Soc. 142, 2143-2158 (2016).&#160;https://doi.org/10.1002/qj.2808

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Section: Understanding Blocking Eventsmentioning

confidence: 99%

A New Mathematical Framework for Atmospheric Blocking Events

Lucarini

2021

Preprint

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“…As seen from Figure 4, this role is played by the process of absolute vorticity advection. As explained in [21] blocking events over North Pacific region are maintained by fluxes of anticyclonic vorticity into the blocking domain by synoptic-scale eddies, the same mechanism dominates over the East European Plain during the catastrophic "Summer 2010" [22], while North Atlantic blocking is shown to be planetary-scale dominant [23].…”

Section: Discussionmentioning

confidence: 82%

Blocking Anticyclone in the Atlantic Sector of the Arctic as an Example of an Individual Atmospheric Vortex

Kislov¹,

Sokolikhina²,

Semenov³

et al. 2017

ACS

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The task of vortex boundaries setting is one of the most complexes in examination of factors influencing on the vortex (circulation system) development and destruction. In this study a new approach of vortex analysis as a whole system is proposed. It is based on vorticity equation where vorticity (left part of the equation) is defined as time coefficients of EOF-decomposition, which is integrated indexes characterizing individual vortex dynamics. Right part of the vorticity equation depicts internal and external factors influencing on the vortex. It's approbation is done on the example of an arctic-subarctic circulation system including blocking anticyclone in winter 2012 which persisted for a long time over the Atlantic sector of the Arctic and led to the formation of the largest positive air temperature anomalies and the minimum ice cover area in the Barents and Kara seas in the entire history of regular observations. It is shown that the main factor in long-term maintenance of the blocking anticyclone over the Arctic was vorticity advection, which was stabilized by horizontal heat advection.

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“…This was directly caused by the evolution of a blocking anti cyclone over the central parts of the East European Plain in the third 10 day period of June and its persis tence through mid August [1][2][3]. The stability of this anticyclone was maintained by "feeding" high pres sure nuclei [4].…”

Section: Introductionmentioning

confidence: 99%

Role of spring soil moisture in the formation of large-scale droughts in the East European Plain in 2002 and 2010

Kislov

Varentsov

Tarasova

2015

Izv. Atmos. Ocean. Phys.

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Using COSMO CLM (a nonhydrostatic atmospheric model designed for climate experiments), we simulate the summer anomalies in the meteorological regime of 2010 and 2002 over the central part of the East European Plain. The module of soil moisture treatment is shown to demonstrate reliable results and the radiation module of the model needs to incorporate the optical properties of haze generated by the smoke of forest and peat fires. It is shown that the soil moisture content formed in the spring can (due to its inertial behavior and by changing the heat balance structure) participate in the formation of temperature and humid ity anomalies over 3-4 months. The extremeness of the thermal regime in the summer of 2010 in the central part of the East European Plain is due to (all other conditions being equal) the specific values of soil moisture content w 0 = 0.6-0.65. The revealed fine dependence of the phenomenon on the spring state of soil moisture makes it important to improve the monitoring of soil moisture as a key factor in the dynamics of extreme weather anomalies.

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On the problem of subtropical anticyclone regeneration as a factor of its stabilization (Case study for the summer of 2010)

Cited by 6 publications

References 3 publications

A New Mathematical Framework for Atmospheric Blocking Events

A New Mathematical Framework for Atmospheric Blocking Events

Blocking Anticyclone in the Atlantic Sector of the Arctic as an Example of an Individual Atmospheric Vortex

Role of spring soil moisture in the formation of large-scale droughts in the East European Plain in 2002 and 2010

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