It is shown that a dynamical system subject to both periodic forcing and random perturbation may show resonance (peak in the power spectrum) which absent when either or absent.

An amplification of random perturbations by the interaction non-linearities internal to climatic system with external, orbital forcing is found.This stochastic resonance investigated in a highly simplified, zero-dimensional climate model.It conceivable that this new type might play role explaining lo5 year peak power spectra paleoclimatic records.

An amplification of random perturbations by the interaction non-linearities internal to climatic system with external, orbital forcing is found. This stochastic resonance investigated in a highly simplified, zero-dimensional climate model. It conceivable that this new type might play role explaining 105 year peak power spectra paleoclimatic records.

In this paper we study a one-dimensional, nonlinear stochastic differential equation when small amplitude, long-period forcing is applied. The arises in the theory of climate earth. We find that cooperative effect perturbation and periodic lead to an amplification peak power spectrum, due mechanism call resonance. A heuristic analysis resonance condition presented our analytical findings are confirmed by numerical calculations.

Abstract. Linear and nonlinear trends of drought wetness are analysed in terms the gridded Standardized Precipitation Index (SPI) determined from monthly precipitation Europe (NCEP/NCAR). In characterizing meteorological hydrological aspects, index is computed on a seasonal bi-annual time scale. Two datasets compared: one 1949 to 1997 other includes update last decade (to February 2009). The following results noted: (i) series area coverage (number grid points above/below severity threshold)...

Problems related to the identification and monitoring of drought are investigated. In particular, conditions in Italy examined using Standardized Precipitation Index (SPI) on different time scales for August 2000. Historical reconstruction events is also shown particular locations last fifty years. These preliminary applications show interesting results demonstrate that index considered a tool should be used operationally as part national watch system monitor objectively. An example monthly...

An amplification of random perturbations by the interaction non-linearities internal to climatic system with external, orbital forcing is found. This stochastic resonance investigated in a highly simplified, zero-dimensional climate model. It conceivable that this new type might play role explaining 10 5 year peak power spectra paleoclimatic records. DOI: 10.1111/j.2153-3490.1982.tb01787.x

The statistical properties of a measure planetary-scale wave activity are investigated in 16 winter NMC dataset. probability density distribution the wavenumber 2 to 4 amplitude is found be bimodal, confirming earlier results from smaller significance this result established empirically with simulations. It also shown that bimodality not connected any periodicity time series. Partitioning data based on estimation reveals two flow regimes physical space. One corresponds an amplified pattern...

Abstract In this paper we address the problem of constructing a minimal model atmospheric circulation able to describe bulk statistical properties general in middle latitudes. After brief reexamination Charney‐DeVore theory multiple equilibria, compare that can be deduced from it with those resulting analysis observations northern hemisphere middle‐latitude at 500 mb. While prediction concerning amplitude waves seems confirmed by presence clear bimodality distribution, find no trace zonal...

Based on a more detailed model developed previously, governing possible feedbacks between sea ice extent (η), deep-ocean temperature (θ), and atmospheric carbon dioxide, we have constructed simple, deterministic, dynamical system for η θ that yields stable limit cycle as solution. To make the realistic add random (white noise) forcing explore new response function of amplitude this stochastic forcing. Included in analysis are examples sample time series, phase trajectories, variance spectra,...

Abstract A very simple energy‐balance equation for the mean surface temperature of planet (Budyko‐type model) is perturbed by a stochastic term, simulating numerous ‘weather’ processes not considered in deterministic feed‐back term. In first instance, symmetrical process with three equilibrium states considered. Using standard methods determination probability density distribution, characteristic time which climate system spends neighbourhood one stable before shifting to other expressed...

The mechanism of stochastic resonance is studied in the case Landau-Ginzburg equation stochastically and periodically perturbed, by taking advantage recent developments on partial differential equations. Analytical expressions are given for computing exit times system to estimate range noise which possible.

A simplified version of a previously described dynamical model governing global ice mass, atmospheric carbon dioxide, and mean ocean temperature is shown to possess solutions, in realistic parameter range, that can replicate the main features climatic variations implied by full, two million years, Quaternary delta-O-18 record. These include major 'transition' between low-ice delta-O-18, low variance mode before roughly 900 kyr BP high-ice, high (near 100 period) after time present. The...

Because of the small net rates energy flow involved in very long-term changes ice mass (10−1 W m−2) it will be impossible to proceed a purely deductive manner develop theory for these changes. An inductive approach necessary-perhaps beg formulated terms multi-component stochastic-dynamical systems equations governing variables and feedbacks thought relevant from qualitative physical reasoning (e.g., "conceptual models"). The output such models should required conform as closely possible all...

Abstract. Space-time variability of hydrological drought and wetness over Iran is investigated using the National Centers for Environmental Prediction/National Center Atmospheric Research (NCEP/NCAR) reanalysis Global Precipitation Climatology Centre (GPCC) dataset common period 1948–2007. The aim to complement previous studies on detection long-term trends in drought/wetness time series applicability data monitoring Iran. Climate conditions area are assessed through Standardized Index (SPI)...

The time mean spectral energy and enstrophy budgets for blocking versus nonblocking periods from the winters of 1978–79 1976–77 are calculated. major differences in cases were nonlinear interaction terms. A pronounced upscale cascade kinetic intermediate to planetary-scale wavenumbers during was found. During December 1976, a case Atlantic very similar 1978–79, but quite different persistent, greatly amplified, planetary-wave pattern that followed January February 1977 (as identified by...