The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift ...

This paper reviews the observational and theoretical basis for the prediction of seasonal-to-interannual (S/I) climate variability in the Atlantic sector. The emphasis is on the large-scale picture rather than on regional details. The paper is divided into two main parts: a discussion of the predictability of the North Atlantic Oscillation (NAO)—the dominant pattern of variability in the North ...

Much of the atmospheric variability in the North Atlantic sector is associated with variations in the eddy-driven component of the zonal flow. Here we present a simple method to specifically diagnose this component of the flow using the low-level wind field (925-700 hPa). We focus on the North Atlantic winter season in the ERA-40 reanalysis. Diagnostics of the latitude and speed of the eddy-dri...

Quasi-decadal variability in solar irradiance has been suggested to exert a substantial effect on Earth's regional climate. In the North Atlantic sector, the 11-year solar signal has been proposed to project onto a pattern resembling the North Atlantic Oscillation (NAO), with a lag of a few years due to ocean-atmosphere interactions. The solar/NAO relationship is, however, highly misrepresented...

[1] The North Atlantic Oscillation (NAO) has a profound effect on winter climate variability around the Atlantic basin. Strengthening of the NAO in recent decades has altered surface climate in these regions at a rate far in excess of global mean warming. However, only weak NAO trends are reproduced in climate simulations of the 20th Century, even with prescribed climate forcings and historical...

In this article, we apply the independent component analysis technique for mining spatio-temporal data. The technique has been applied to mine for patterns in weather data using the North Atlantic Oscillation (NAO) as a specific example. We find that the strongest independent components match the observed synoptic weather patterns corresponding to the NAO. We also validate our results by matchi...

The Granger causality test is used to examine the effects of the El Niño–Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the North Atlantic Oscillation (NAO) on global dry/wet conditions. The results show robust relationships between dry/wet conditions and the ocean states, as assessed through a multi-index (standardized precipitation evapotranspiration index and standar...

the main objective of this study was to reveal the impact of nine climate indices on temperature changes and climate oscillations in golestan province along the southern coast of the caspian sea. climate indices data from across the atlantic-eurasian sector were collected from the ncep/ncar, the climate prediction centre (cpc) and the climatic research unit (cru) over a period of 40 years (1971...

A large single-year reversal in the phase of the North Atlantic Oscillation (NAO) during 1996 led to a dramatic shift in the slope-water circulation patterns of the northwest (NW) Atlantic. Analyses of time-series data collected from the region over the past half century show that both physical and biological responses are commonly elicited by such phase reversals in the NAO. Here, we use a mod...

Two common indicators of Atlantic climate variability, viz., the North Atlantic oscillation (NAO) and the crossintertropical convergence zone (ITCZ) sea surface temperature (SST) gradient, are examined for their frequency characteristics and midlatitude-tropical links. SST anomalies north and south of the ITCZ are found to be uncorrelated on all time scales, while the sea level pressure (SLP) f...