Studying extreme events and how they evolve in a changing climate is one of the most important current scientific challenges. Starting from complex models, key difficulty to be able run long enough simulations order observe those extremely rare events. In physics, chemistry, biology, event algorithms have recently been developed compute probabilities that cannot observed direct numerical simulations. Here we propose such an algorithm, specifically designed for heat or cold waves, based on...

We discuss the Giardinà-Kurchan-Peliti population dynamics method for evaluating large deviations of time-averaged quantities in Markov processes [Phys. Rev. Lett. 96, 120603 (2006)PRLTAO0031-900710.1103/PhysRevLett.96.120603]. This exhibits systematic errors which can be some circumstances, particularly systems with weak noise, many degrees freedom, or close to dynamical phase transitions. show how these mitigated by introducing control forces within algorithm. These are determined an...

Because of the impact extreme heat waves and domes on society biodiversity, their study is a key challenge. We specifically long-lasting waves, which are among most important for climate impacts. Physics driven weather forecast systems or models can be used to occurrence predict probability. The present work explores use deep learning architectures, trained using outputs model, as an alternative strategy heatwave. This new approach will useful several scientific goals include model...

Forecasting extreme climate events, for instance heat waves, is key society and a scientific challenge. In this paper we propose novel machine learning approach that successfully forecasts waves up to 45 days before the end of event. The allows dynamical process studies. A message optimal require large amount data. image shows temperature (colors) geopotential height (lines) anomalies typical atmospheric situation.

We study the two-dimensional (2D) stochastic Navier-Stokes (SNS) equations in inertial limit of weak forcing and dissipation. The stationary measure is concentrated close to steady solutions 2D Euler equations. For such flows, we prove that bifurcations flow topology occur either by changing domain shape, nonlinearity vorticity--stream-function relation, or energy. Associated with this, observe bistable behavior SNS random changes from dipoles unidirectional flows. theoretical explanation...

Owing to the large dipole associated with its nitrile bond, 8OCB (cyano-octyloxybiphenyl) tends associate as antiparallel pairs. The number of pairs, $N$, increases increasing mole fraction, ${x}_{6\mathrm{OCB}}$, a shorter homolog, 6OCB (cyanohexyloxybiphenyl). stability nematic and smectic-$A$ phase depends upon $N$: $N$ favors decreasing phase. When saturates, no longer exists reenters. Experimental results which support above are presented. (1) Density measurements 8OCB-6OCB system yield...

Many turbulent flows undergo drastic and abrupt configuration changes with huge impacts. As a paradigmatic example we study the multistability of jet dynamics in barotropic beta plane model atmosphere dynamics. It is considered as Ising for Jupiter troposphere Using adaptive multilevel splitting, rare event algorithm, are able to get very large statistics transition paths, extremely transitions from one state system another. This new approach opens way addressing set questions that out reach...

We explain the ubiquity and extremely slow evolution of non-Gaussian out-of-equilibrium distributions for Hamiltonian mean-field model, by means traditional kinetic theory. Deriving Fokker-Planck equation a test particle, one also unambiguously explains predicts striking algebraic relaxation momenta autocorrelation, previously found in numerical simulations. Finally, angular anomalous diffusion are predicted large class initial distributions. Nonextensive statistical mechanics is shown to be...

A theoretical description for the equilibrium states of a large class models two-dimensional and geophysical flows is presented. statistical ensemble equivalence found to exist generically in these models, related occurrence peculiar phase transitions flow topology. The first example bicritical point (a bifurcation from toward two second order transitions) context systems with long-range interactions reported. Academic ocean Fofonoff flows, are studied perspective results.

Abstract In this work, we study and compare the influence of Atlantic Multidecadal Variability (AMV) spring soil moisture in Southern Europe on duration intensity European summer heat waves. We waves with return times a few years also propose new methodological approach, time maps, that allows us to rare 10 or 50 years. use outputs from three climate models, namely IPSL-CM6A-LR, EC-Earth3, CNRM-CM6-1, which North sea surface temperatures are restored towards observed AMV anomalies. The...

Heatwaves are among the most impactful extreme weather events, posing significant risks to human health, ecosystems, and energy systems. Understanding return times of these events assessing how climate change alters their frequency intensity critical for effective adaptation strategies. However, rarity record-breaking heatwaves in observational datasets makes this task highly challenging. Climate models, while capable simulating such rare require prohibitively long simulations generate...

The risk of extreme weather under climate change is paramount importance, but remains one the most difficult problems to study using conventional physics-based global models (GCMs). This due high uncertainty in estimates return times owing computational cost evolving these for long enough observe very rare events. AI trained on historical reanalysis emulate dynamics atmosphere have demonstrated both forecast accuracy and greatly reduced cost. Some emulators can generate stable, decades-long...

We explain the emergence and robustness of intense jets in highly turbulent planetary atmospheres, like that on Jupiter, by a general statistical mechanics approach to potential vorticity patches. The idea is mixing leads formation steady organized coarse-grained flow, corresponding equilibrium state. Our starting point quasi-geostrophic 1-1/2 layer model, we consider relevant limit small Rossby radius deformation. Then narrow are obtained, sense they scale These can be either zonal, or...