Author
Alfonso Sutera
Other affiliations: Yale University, University of Camerino
Bio: Alfonso Sutera is an academic researcher from Sapienza University of Rome. The author has contributed to research in topics: Baroclinity & Tropopause. The author has an hindex of 26, co-authored 80 publications receiving 5850 citations. Previous affiliations of Alfonso Sutera include Yale University & University of Camerino.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, it was shown that a dynamical system subject to both periodic forcing and random perturbation may show a resonance (peak in the power spectrum) which is absent when either the forcing or the perturbations is absent.
Abstract: It is shown that a dynamical system subject to both periodic forcing and random perturbation may show a resonance (peak in the power spectrum) which is absent when either the forcing or the perturbation is absent.
2,774 citations
TL;DR: In this article, an amplification of random perturbations by the interaction of nonlinearities internal to the climatic system with external, orbital forcing is found, and this stochastic resonance is investigated in a highly simplified, zero-dimensional climate model.
Abstract: An amplification of random perturbations by the interaction of non-linearities internal to the climatic system with external, orbital forcing is found. This stochastic resonance is investigated in a highly simplified, zero-dimensional climate model. It is conceivable that this new type of resonance might play a role in explaining the 10 5 year peak in the power spectra of paleoclimatic records. DOI: 10.1111/j.2153-3490.1982.tb01787.x
837 citations
TL;DR: In this paper, an analysis of drought in Sicily from 1926 to 1996 is presented in identifying drought over the region, both the NCEP/NCAR reanalysis precipitation data and those observed in 43 gauges, located quite uniformly over the territory of the Island, are used Drought occurrence is estimated by means of the Standardized Precipitation Index (SPI) to study long-term drought variability, a Principal Component Analysis was applied to the SPI field Results suggest that the entire Island is characterised by a drought variability with a multi-year fluctuations and a tendency towards dri
Abstract: An analysis of drought in Sicily from 1926 to 1996 is presented In identifying drought over the region, both the NCEP/NCAR reanalysis precipitation data and those observed in 43 gauges, located quite uniformly over the territory of the Island, are used Drought occurrence is estimated by means of the Standardized Precipitation Index (SPI) To study long-term drought variability, a Principal Component Analysis was applied to the SPI field Results suggest that the entire Island is characterised by a drought variability with a multi-year fluctuations and a tendency towards drier periods from the seventies onward A preliminary comparison between results obtained using the meteorological large-scale analysis and that derived from actual observations on the ground shows a general good agreement, although further efforts are needed to get a better downscaling of the large-scale precipitation fields Furthermore, by applying orthogonal rotations to the principal com- ponent patterns, it has been found that three distinct areas having coherent climatic variability may be identified Finally, the sensitivity of the SPI values on the calibration period is also investigated
329 citations
TL;DR: In this article, the cooperative effect of the stochastic perturbation and periodic forcing leads to an amplification of the peak of the power spectrum, due to a mechanism that is called stochastically resonance, and a heuristic analysis of the resonance condition is presented.
Abstract: In this paper we study a one-dimensional, nonlinear stochastic differential equation when small amplitude, long-period forcing is applied. The equation arises in the theory of the climate of the earth. We find that the cooperative effect of the stochastic perturbation and periodic forcing lead to an amplification of the peak of the power spectrum, due to a mechanism that we call stochastic resonance. A heuristic analysis of the resonance condition is presented and our analytical findings are confirmed by numerical calculations.
263 citations
TL;DR: In this article, an amplification of random perturbations by the interaction of nonlinearities internal to the climatic system with external, orbital forcing is found, and this stochastic resonance is investigated in a highly simplified, zero-dimensional climate model.
Abstract: An amplification of random perturbations by the interaction of non-linearities internal to the climatic system with external, orbital forcing is found. This stochastic resonance is investigated in a highly simplified, zero-dimensional climate model. It is conceivable that this new type of resonance might play a role in explaining the 10 5 year peak in the power spectra of paleoclimatic records. DOI: 10.1111/j.2153-3490.1982.tb01787.x
179 citations
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6,278 citations
TL;DR: In this paper, the authors report, extend, and interpret much of our current understanding relating to theories of noise-activated escape, for which many of the notable contributions are originating from the communities both of physics and of physical chemistry.
Abstract: The calculation of rate coefficients is a discipline of nonlinear science of importance to much of physics, chemistry, engineering, and biology. Fifty years after Kramers' seminal paper on thermally activated barrier crossing, the authors report, extend, and interpret much of our current understanding relating to theories of noise-activated escape, for which many of the notable contributions are originating from the communities both of physics and of physical chemistry. Theoretical as well as numerical approaches are discussed for single- and many-dimensional metastable systems (including fields) in gases and condensed phases. The role of many-dimensional transition-state theory is contrasted with Kramers' reaction-rate theory for moderate-to-strong friction; the authors emphasize the physical situation and the close connection between unimolecular rate theory and Kramers' work for weakly damped systems. The rate theory accounting for memory friction is presented, together with a unifying theoretical approach which covers the whole regime of weak-to-moderate-to-strong friction on the same basis (turnover theory). The peculiarities of noise-activated escape in a variety of physically different metastable potential configurations is elucidated in terms of the mean-first-passage-time technique. Moreover, the role and the complexity of escape in driven systems exhibiting possibly multiple, metastable stationary nonequilibrium states is identified. At lower temperatures, quantum tunneling effects start to dominate the rate mechanism. The early quantum approaches as well as the latest quantum versions of Kramers' theory are discussed, thereby providing a description of dissipative escape events at all temperatures. In addition, an attempt is made to discuss prominent experimental work as it relates to Kramers' reaction-rate theory and to indicate the most important areas for future research in theory and experiment.
5,180 citations
Journal Article•
TL;DR: In this article, the authors present a document, redatto, voted and pubblicato by the Ipcc -Comitato intergovernativo sui cambiamenti climatici - illustra la sintesi delle ricerche svolte su questo tema rilevante.
Abstract: Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.
4,187 citations
Book•
01 Dec 1992TL;DR: In this paper, the existence and uniqueness of nonlinear equations with additive and multiplicative noise was investigated. But the authors focused on the uniqueness of solutions and not on the properties of solutions.
Abstract: Part I. Foundations: 1. Random variables 2. Probability measures 3. Stochastic processes 4. The stochastic integral Part II. Existence and Uniqueness: 5. Linear equations with additive noise 6. Linear equations with multiplicative noise 7. Existence and uniqueness for nonlinear equations 8. Martingale solutions Part III. Properties of Solutions: 9. Markov properties and Kolmogorov equations 10. Absolute continuity and Girsanov's theorem 11. Large time behaviour of solutions 12. Small noise asymptotic.
4,042 citations
TL;DR: In this paper, the authors provide a review of fundamental concepts of drought, classification of droughts, drought indices, historical Droughts using paleoclimatic studies, and the relation between DAs and large scale climate indices.
Abstract: Owing to the rise in water demand and looming climate change, recent years have witnessed much focus on global drought scenarios. As a natural hazard, drought is best characterized by multiple climatological and hydrological parameters. An understanding of the relationships between these two sets of parameters is necessary to develop measures for mitigating the impacts of droughts. Beginning with a discussion of drought definitions, this paper attempts to provide a review of fundamental concepts of drought, classification of droughts, drought indices, historical droughts using paleoclimatic studies, and the relation between droughts and large scale climate indices. Conclusions are drawn where gaps exist and more research needs to be focussed.
3,352 citations