A5017993305- Complex Systems and Time Series Analysis
- Statistical Mechanics and Entropy
- Advanced Thermodynamics and Statistical Mechanics
- Climate variability and models
- Fractal and DNA sequence analysis
- Theoretical and Computational Physics
- Nonlinear Dynamics and Pattern Formation
- stochastic dynamics and bifurcation
- Meteorological Phenomena and Simulations
- Time Series Analysis and Forecasting
- Marine Bivalve and Aquaculture Studies
- Marine and fisheries research
- Oceanographic and Atmospheric Processes
- Solid State Laser Technologies
- COVID-19 epidemiological studies
- Spectroscopy and Quantum Chemical Studies
- Luminescence Properties of Advanced Materials
- Quantum Mechanics and Applications
- Coral and Marine Ecosystems Studies
- Wind and Air Flow Studies
- Plant Water Relations and Carbon Dynamics
- Hydrology and Drought Analysis
- Marine and coastal ecosystems
- Complex Network Analysis Techniques
- Chaos control and synchronization
Institute of Atmospheric Sciences and Climate
2008-2018
Istituto Nazionale di Fisica Nucleare, Sezione di Lecce
2014-2016
University of Bologna
2013
University of Salento
2011-2012
National Interuniversity Consortium for the Physical Sciences of Matter
2011-2012
University of North Texas
2012
Sapienza University of Rome
2004-2007
University of Pisa
1999-2005
Institute for Complex Systems
2005
Istituto Nazionale per la Fisica della Materia
2000-2004
We study the statistical properties of time distribution seismicity in California by means a new method analysis, diffusion entropy. find that intervals between large earthquake (the main shock given seismic sequence) and next one does not obey Poisson statistics, as assumed current models. prove this is an inverse power law with exponent mu=2.06+/-0.01. propose long-range model, reproducing entropy describing triggering mechanisms induced earthquakes.
Abstract The multi-scale and nonlinear nature of the ocean dynamics dramatically affects spreading matter, like pollutants, marine litter, etc., physical chemical seawater properties, biological connectivity inside among different basins. Based on Finite-Scale Lyapunov Exponent analysis largest available near-surface Lagrangian data set from Global Drifter Program, our results show that, despite large variety flow features, relative dispersion can ultimately be described by a few parameters...
We study time series concerning rare events. The occurrence of a event is depicted as jump constant intensity always occurring in the same direction, thereby generating an asymmetric diffusion process. consider case where waiting distribution inverse power law with index μ. focus our attention on μ<3, and we evaluate scaling exponent δ resulting prove that gets its maximum value, δ=1, corresponding to ballistic motion, at μ=2. process by means joint use continuous random walk generalized...
Based on a limited number of noisy observations, estimation algorithms provide complete description the state system at current time. Estimation that go under name assimilation in unstable subspace (AUS) exploit nonlinear stability properties forecasting model their formulation. Errors grow due to sensitivity initial conditions are efficiently removed by confining analysis solution and neutral system, spanned Lyapunov vectors with positive zero exponents, while observational noise does not...
Abstract Distribution shifts are a common adaptive response of marine ectotherms to climate change but the pace redistribution depends on species-specific traits that may promote or hamper expansion northern habitats. Here we show recently, loggerhead turtle ( Caretta caretta ) has begun nest steadily beyond edge species’ range in Mediterranean basin. This is associated with significant warming spring and summer sea surface temperature (SST) offers wider thermal window suitable for nesting....
Abstract. When the Extended Kalman Filter is applied to a chaotic system, rank of error covariance matrices, after sufficiently large number iterations, reduces N+ + N0 where and are positive null Lyapunov exponents. This due collapse into unstable neutral tangent subspace solution full Filter. Therefore same as obtained by confining assimilation space spanned vectors with non-negative Theoretical arguments numerical verification provided show that asymptotic state estimates EKF its reduced...
Knowledge of the link between ocean hydrodynamics and distribution small pelagic fish species is fundamental for sustainable management fishery resources. Both commercial scientific communities are indeed seeking to provide services that could "connect dots" among in situ remote observations, numerical modelling, fisheries. In Mediterranean Sea and, particular, Sicily Channel reproductive strategy European Anchovy (Engraulis encrasicolus) strongly influenced by oceanographic patterns, which...
We discuss the properties making a deterministic algorithm suitable to generate pseudo random sequence of numbers: high value Kolmogorov-Sinai entropy, dimensionality parent dynamical system, and very large period generated sequence. propose multidimensional Anosov symplectic (cat) map as number generator. show what chaotic features this are useful for generating numbers investigate numerically which them survive in discrete state version map. Testing comparisons with other generators performed.
Abstract The interannual variability in the transport of anchovy eggs and larvae Sicily Channel, relatively to period 1999–2012, is studied by means numerical simulations Mediterranean Forecasting System (MFS) circulation model provided INGV. Subgrid‐scale dynamics not resolved MFS parameterized terms kinematic fields. latter affect small‐scale tracer relative dispersion, while leaving mean large‐scale advection substantially unchanged. A Lagrangian Transport Index (LTI) can be defined...
We study the long-range correlations of heartbeat fluctuations with method diffusion entropy. show that this analysis yields a scaling parameter $\delta$ apparently conflicts direct evaluation distribution times sojourn in states given frequency. The strength memory responsible for discrepancy is by $\epsilon^{2}$, which derived from real data. patients ($\delta$, $\epsilon^{2}$)-plane neat separation healthy congestive heart failure subjects.
We discuss the problem of equivalence between continuous-time random walk (CTRW) and generalized master equation (GME). The walker, making instantaneous jumps from one site lattice to another, resides in each for extended times. sojourn times have a distribution density psi(t) that is assumed be an inverse power law with index micro. assume Onsager principle fulfilled, we use this assumption establish complete GME Montroll-Weiss CTRW. prove confined case where exponential. argue so because...
Abstract. In this paper we produce projections of seasonal precipitation for four Mediterranean areas: Apulia region (Italy), Ebro river basin (Spain), Po valley (Italy) and Antalya province (Turkey). We performed the statistical downscaling using Canonical Correlation Analysis (CCA) in two versions: one case Principal Component (PCA) filter is applied only to predictor other both predictand. After performing a validation test, CCA after PCA on predictand has been chosen. Sea level pressure...
In the first part of this paper, we review some important results on atmospheric predictability, from pioneering work Lorenz to recent with operational forecasting models. Particular relevance is given connection between predictability and theory Lyapunov exponents vectors. second part, briefly foundations data assimilation methods then discuss regarding application tools typical chaotic systems described in well established algorithms, Extended Kalman Filter (EKF) Four Dimensional...
Ecological connectivity is one of the most important processes that shape marine populations and ecosystems, determining their distribution, persistence, productivity. Here we use synergy Lagrangian back-trajectories, otolith-derived ages larvae, satellite-based chlorophyll-a to identify spawning areas European anchovy from ichthyoplanktonic data, collected in Strait Sicily (Central Mediterranean Sea), i.e., crucial channel between African continents. We obtain new evidence ecosystem North...
We study a two-state statistical process with non-Poisson distribution of sojourn times. In accordance earlier work, we find that this is characterized by aging and three different ways to define the correlation function arbitrary age corresponding dichotomous fluctuation based respectively on Generalized Master Equation formalism, Liouville-like approach trajectory perspective.
The Mediterranean Forecasting System (MFS) Ocean Model, provided by INGV, has been chosen as case study to analyze Lagrangian trajectory predictability means of a dynamical systems approach. To this regard, numerical trajectories are tested against large amount drifter data, used sample the actual tracer dynamics across sea. separation rate pair is measured computing Finite-Scale Lyapunov Exponent (FSLE) first and second kind. An additional kinematic model (KLM), suitably treated avoid...
When applied to strongly nonlinear chaotic dynamics the extended Kalman filter (EKF) is prone divergence due difficulty of correctly forecasting forecast error probability density function. In operational applications ensemble filters circumvent this problem with empirical procedures such as covariance inflation. This paper presents an extension EKF that includes terms in evolution estimate. achieved starting from a particular square-root implementation assimilation confined unstable...
A simplified version of a classical problem in thermodynamics -- the adiabatic piston is discussed framework kinetic theory. We consider limit gases whose relaxation time extremely fast so that contained on left and right chambers are always equilibrium (that molecules uniformly distributed their velocities obey Maxwell-Boltzmann distribution) after any collision with piston. Then by using theory we derive statistics from which obtain set ordinary differential equations for evolution...