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Forecasting extreme stratospheric polar vortex events

Extreme polar vortex events known as sudden stratospheric warmings can influence surface winter weather conditions, but their timing is difficult to predict. Here, we examine factors that influence their occurrence, with a focus on their timing and …

Comparing Methods to Constrain Future European Climate Projections Using a Consistent Framework

Political decisions, adaptation planning, and impact assessments need reliable estimates of future climate change and related uncertainties. To provide these estimates, different approaches to constrain, filter, or weight climate model projections …

Constraining Projections Using Decadal Predictions

There is increasing demand for robust, reliable, and actionable climate information for the next 1 to 50 years. This is challenging for the scientific community as the longest initialized predictions are limited to 10 years (decadal predictions). …

Assessing the robustness of multidecadal variability in Northern Hemisphere wintertime seasonal forecast skill

Recent studies have found evidence of multidecadal variability in Northern Hemisphere wintertime seasonal forecast skill. Here we assess the robustness of this finding by extending the analysis to a diverse set of ensemble atmospheric model …

Seasonal Forecasts of the Twentieth Century

Forecasts of seasonal climate anomalies using physically based global circulation models are routinely made at operational meteorological centers around the world. A crucial component of any seasonal forecast system is the set of retrospective …

Tropical atmospheric drivers of wintertime European precipitation events

From observations, we identify a wave-like pattern associated with northwestern European seasonal precipitation events. These events are associated with tropical precipitation anomalies, prompting us to investigate if there are any …

An Interdecadal Shift of the Extratropical Teleconnection From the Tropical Pacific During Boreal Summer

The extratropical teleconnection from the tropical Pacific in boreal summer exhibits a significant shift over the past 70 years. Cyclonic circulation anomalies over the North Atlantic and Eurasia associated with El Niño in the later period …

Seasonal Predictability of the Winter North Atlantic Oscillation From a Jet Stream Perspective

Abstract The winter North Atlantic Oscillation (NAO) has varied on interannual and decadal timescales over the last century, associated with variations in the speed and latitude of the eddy-driven jet stream. This paper uses hindcasts from two …

Forced summer stationary waves: the opposing effects of direct radiative forcing and sea surface warming

We investigate the opposing effects of direct radiative forcing and sea surface warming on the atmospheric circulation using a hierarchy of models. In large ensembles of three general circulation models, direct $$$backslash$hbox CO_2$$CO2forcing …

How confident are predictability estimates of the winter North Atlantic Oscillation?

Atmospheric seasonal predictability in winter over the Euro-Atlantic region is studied with an emphasis on the signal-to-noise paradox of the North Atlantic Oscillation. Seasonal hindcasts of the ECMWF model for the recent period 1981–2009 show, in …