In this article, we present a mathematical theory of the Walker circulation of the large-scale atmosphere over the tropics. This study leads to a new metastable state oscillation theory for the El Niño Southern Oscillation (ENSO), a typical inter-annual climate low frequency oscillation. The mathematical analysis is based on 1) the dynamic transition theory, 2) the geometric theory of incompres...

Low-frequency oscillations of the Atlantic Ocean meridional overturning circulation in a coupled climate model M. Schulz, M. Prange, and A. Klocker Department of Geosciences, University of Bremen, Germany DFG Research Center “Ocean Margins”, University of Bremen, Germany now at: CSIRO Marine and Atmospheric Research, Hobart, Australia Received: 15 August 2006 – Accepted: 13 September 2006 – Pub...

Long-term temperature and precipitation records in the Midwest are examined in order to determine if interdecadal variability associated with the Pacific Decadal Oscillation (PDO) acts to modulate the El Niño Southern Oscillation (ENSO) related interannual variability of Midwestern climates. Power spectrum analysis demonstrates that significant ENSO related variability between 3 and 7 years as ...

We examine the climate response to solar irradiance changes between the late 17th-century Maunder Minimum and the late 18th century. Global average temperature changes are small (about 0.3 degrees to 0.4 degrees C) in both a climate model and empirical reconstructions. However, regional temperature changes are quite large. In the model, these occur primarily through a forced shift toward the lo...

T El Nino/Southern Oscillation phenomenon (ENSO, for short) is the strongest source of natural variability in Earth's climate system. ' Although ENSO originates in the tropical latitudes of the Pacific Ocean, its climatic impact is felt globally. Variations in major rainfall systems that are attributed to ENSO range from droughts in Indonesia and Australia to storms and flooding in Ecuador and ...

Over recent decades, analyses of the structure and impact of atmospheric teleconnections have substantially increased our understanding of the climate system and the role of climate variability. Moving beyond simple correlations between teleconnection indices and temperature and precipitation anomalies, synoptic climatology has been able to provide insight on the spatiotemporal manifestation of...

[1] It has been proposed that solar cycle irradiance variations may affect the whole planet’s climate via the stratosphere, the Quasi-Biennial Oscillation (QBO) and Arctic Oscillation (AO). We test this hypothesis by examining causal links between time series of sunspot number and indices of QBO, AO and ENSO activity. We use various methods: wavelet coherence, average mutual information, and me...

To assess the significance of modern climate change, it is essential to place recent observed changes in a longer-term context. This review assesses the evidence from both “proxy” climate data and theoretical climate model simulations with regard to the nature and causes of climate variability over a time interval spanning roughly the past two millennia. Evidence is reviewed for changes in temp...

The climate system is, apart from anthropogenic forcing and other external perturbations, in a thermodynamically nonequilibrium steady-state. A major difference between fluctuations in nonequilibrium and equilibrium steady-states is that noneqilibrium steady-states violate time reversal symmetry. One manifestation is the presence of persistent probability currents, which form closed loops. In t...