[1] A kinematic mechanism for the positive feedback between the North Atlantic Oscillation (NAO) and synoptic eddies are depicted based on observational data analyses. Using three-point rescaled covariance statistics of bandpass-filtered (2–8 days) synoptic eddy fields, we examined observed eddy structure changes associated with wintermean NAO anomalous flow. It is demonstrated that the NAO flo...

[1] A global ice-ocean model shows increasing Atlantic water (AW) inflow at the Iceland-Scotland Ridge (ISR) during 1953–2002. As a result, the Greenland-IcelandNorwegian (GIN) Sea is gaining more heat and salt from the North Atlantic Ocean, while the latter is being freshened mainly by exporting more salt to the GIN Sea. The exchanges of volume, heat, and freshwater at the Greenland-Scotland R...

A regular and distinct feature of seasonal plankton succession in temperate lakes is the early summer period of algal suppression by herbivores, i.e. the clear water phase. Within the last 30 years the timing of this food-web interaction between algae and herbivores has advanced on average by approximately two weeks in central European lakes due to faster population growth of herbivores in warm...

The Pacific–North American (PNA) teleconnection is a major mode of Northern Hemisphere wintertime climate variability, with well-known impacts on North American temperature and precipitation. To assess whether the PNA teleconnection has extended predictability, comprehensive data analysis is conducted to elucidate PNA evolution, with an emphasis on patterns of PNA development and decay. These p...

Understanding and predicting the state of North Atlantic Oscillation (NAO) is key to forecasting weather in United Kingdom (UK). It has been shown that particular phases Madden–Julian (MJO) act as precursors either NAO+ or NAO? events. We assess ability UK Met Office coupled climate model (HadGEM3-GC3.1-MM) simulate these NAO responses at lead times 1–2 weeks show improvements are needed modell...

A nonlinear projection of the tropical Pacific sea surface temperature anomalies (SSTA) onto the Northern Hemisphere winter sea level pressure (SLP) anomalies by neural networks (NN) was performed to investigate the nonlinear association between ENSO and the Euro-Atlantic winter climate. While the linear impact of ENSO on the Euro-Atlantic winter SLP is weak, the NN projection reveals statistic...

[1] Observed multidecadal variability (30 yr runningmeans, trends, and moving standard deviations) of the North Atlantic Oscillation (NAO) during the instrumental record is compared to that simulated by two different coupled general circulation models in extended-range control experiments. Simulated NAO exhibits strong low frequency fluctuations, even on multi-centennial time scale. Observed mu...

Climate variability is simply represented by teleconnection patterns such as the Arctic Oscillation (AO), Antarctic Oscillation (AAO), North Atlantic Oscillation (NAO), Pacific–North American pattern (PNA), and Southern Oscillation (SO) with associated indices. Two approaches can be used to predict the indices: forward and backward methods. The forward method is commonly used to predict the ind...

This paper proposes the hypothesis that the low-frequency variability of the North Atlantic Oscillation (NAO) arises as a result of variations in the occurrence of upper-level Rossby wave–breaking events over the North Atlantic. These events lead to synoptic situations similar to midlatitude blocking that are referred to as high-latitude blocking episodes. A positive NAO is envisaged as being a...