Rosie Eade

• Mathematics BSc, Atmospheric Science MSc Mathematics PhD
• Researcher at Met Office

The North Atlantic Oscillation (NAO) dominates winters in Western Europe and eastern North America. Future climate model projections of the NAO are highly uncertain due to both modelled irreducible internal variability and different model responses. Here we show that some of the model spread in multi-decadal NAO simulations is caused by climatologi...

Multi-decadal trends in the wintertime North Atlantic Oscillation (NAO) are under-represented by coupled general circulation models (CGCMs), consistent with a lack of autocorrelation in their NAO index series. This study proposes and tests two simple “reddening” approaches for correcting this problem in simulated indices based on simple one paramet...

It is well established that the positive phase of El Niño Southern Oscillation (ENSO) tends to weaken the Northern Hemisphere stratospheric polar vortex (SPV), promoting a negative North Atlantic Oscillation (NAO). Pacific Decadal Variability (PDV) is characterized by a pattern of sea surface temperatures similar to ENSO, but its impacts are more u...

Climate trends over multiple decades are important drivers of regional climate change that need to be considered for climate resilience. Of particular importance are extreme trends that society may not be expecting and is not well adapted to. This study investigates approaches to assess the likelihood of maximum moving window trends in historical r...

The possibility that Arctic sea ice loss weakens mid-latitude westerlies, promoting more severe cold winters, has sparked more than a decade of scientific debate, with apparent support from observations but inconclusive modelling evidence. Here we show that sixteen models contributing to the Polar Amplification Model Intercomparison Project simulat...

Atlantic multidecadal variability (AMV) has been linked to the observed slowdown of global warming over 1998–2012 through its impact on the tropical Pacific. Given the global importance of tropical Pacific variability, better understanding this Atlantic–Pacific teleconnection is key for improving climate predictions, but the robustness and strength...

Plain Language Summary A major conundrum in current climate science is to understand what Arctic changes imply for the climate and environment in mid‐latitude regions. The Polar Amplification Model Intercomparison Project (PAMIP) designed a set of climate model experiments to specifically answer this question in a carefully designed, idealized fram...

Atlantic Multidecadal Variability (AMV) has been linked to the observed slowdown of global warming over 1998-2012 through its impact on the tropical Pacific. Given the global importance of tropical Pacific variability, better understanding this Atlantic-Pacific teleconnection is key for improving climate predictions, but the robustness and strength...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Recent studies suggest that the wintertime North Pacific eddy-driven jet stream will strengthen and extend eastward in response to Arctic sea ice loss. Using output from the Polar Amplification Model Intercomparison Project we examine the mean change of the North Pacific wintertime zonal winds, and use cluster analysis to explore the change in sub-...

Summer 2018 in the United Kingdom (UK) was its joint hottest on record and the associated impacts raise questions over societal resilience to extremes of this magnitude or greater occurring in upcoming years. Better information on the current likelihood of extreme and unprecedented events feeds into improved understanding of risk, relevant for poli...

Quantifying signals and uncertainties in climate models is essential for the detection, attribution, prediction and projection of climate change1–3. Although inter-model agreement is high for large-scale temperature signals, dynamical changes in atmospheric circulation are very uncertain4. This leads to low confidence in regional projections, espec...

The Northern European summer of 2018 was the driest for 35 years with resulting impacts on health, agriculture, energy, and water resources. Here we show that this rainfall anomaly was well predicted by a real‐time seasonal forecast. An anticyclonic circulation anomaly was correctly forecast over the North Sea and Scandinavia in 2018 and also in th...

There is increasing demand for near-time climate predictions to provide guidance for adaptation planning at policy-relevant timescales. Although previous work has shown some skill in forecasting decadal surface temperature, it has proven more difficult to make predictions for precipitation and atmospheric circulation. By using a large, multi-model...

Many of the current seasonal prediction systems show useful skill in Madden–Julian Oscillation (MJO) prediction but limited skill in forecasting tropical cyclones (TC). Quantifying the influences of MJO on TC in an operational prediction system is therefore useful for prediction purposes. The results in this study show that forecast skill of boreal...

Preindustrial control simulations with the third Hadley Centre Global Environmental Model, run in the Global Coupled configuration 3.1 of the Met Office Unified Model (HadGEM3‐GC3.1) are presented at two resolutions. These are N216ORCA025, which has a horizontal resolution of 60 km in the atmosphere and 0.25° in the ocean, and N96ORCA1, which has a...

Preindustrial control simulations with the third Hadley Centre Global Environmental Model, run in the Global Coupled configuration 3.1 of the Met Office Unified Model (HadGEM3‐GC3.1) are presented at two resolutions. These are N216ORCA025, which has a horizontal resolution of 60 km in the atmosphere and 0.25° in the ocean, and N96ORCA1, which has a...

The Paris Agreement calls for efforts to limit anthropogenic global warming to less than 1.5oC above pre-industrial levels. However, natural internal variability may exacerbate anthropogenic warming to produce temporary excursions above 1.5oC. Such excursions would not necessarily exceed the Paris Agreement, but would provide a warning that the thr...

The sea surface temperature anomalies (SSTAs) in the tropical Indian Ocean (TIO) show two dominant modes at interannual time scales, referred to as the Indian Ocean basin mode (IOBM) and dipole mode (IOD). Recent studies have shown that the IOBM and IOD not only affect the local climate, but also induce remarkable influences in East Asia via teleco...

The magnitude of observed multidecadal variations in the North Atlantic Oscillation (NAO) in winter is at the upper end of the range simulated by climate models and a clear explanation for this remains elusive. Recent research shows that observed multidecadal winter NAO variability is more strongly associated with North Atlantic (NA) jet strength t...

During 2016 boreal summer and fall, a strong negative Indian Ocean Dipole (IOD) event occurred, which led to large climate impacts such as the drought over East Africa. In this study, efforts are made to understand the dynamics of this IOD event and to evaluate real-time IOD predictions from current operational seasonal forecast systems. We show th...

Year-to-year variability in Northern European summer rainfall has profound societal and economic impacts; however current seasonal forecast systems show no significant forecast skill. Here we show skilful predictions are possible (r~0.5, p<0.001) using the latest high-resolution Met Office near-term prediction system over 1960-2017. The model predi...

Supplementary Figures, Supplementary Notes and Supplementary References

Summer rainfall in the Sahel region of Africa exhibits one of the largest signals of climatic variability and with a population reliant on agricultural productivity, the Sahel is particularly vulnerable to major droughts such as occurred in the 1970s and 1980s. Rainfall levels have subsequently recovered, but future projections remain uncertain. He...

The Decadal Climate Prediction Project (DCPP) is a coordinated multi-model investigation into decadal climate prediction, predictability, and variability. The DCPP makes use of past experience in simulating and predicting decadal variability and forced climate change gained from the fifth Coupled Model Intercomparison Project (CMIP5) and elsewhere....

The winter North Atlantic Oscillation is the primary mode of atmospheric variability in the North Atlantic region and has a profound influence on European and North American winter climate. Until recently, seasonal variability of the North Atlantic Oscillation was thought to be largely driven by chaotic and inherently unpredictable processes. Howev...

The rate of global mean surface temperature (GMST) warming has slowed this century despite the increasing concentrations of greenhouse gases. Climate model experiments show that this slowdown was largely driven by a negative phase of the Pacific Decadal Oscillation (PDO), with a smaller external contribution from solar variability, and volcanic and...

The Earth’s global average surface climate is primarily determined by the exchange of energy between the atmosphere, the oceans and space. However, changes in regional climate are often governed by changes in the circulation of the atmosphere and ocean. These form coherent patterns like the El Niño Southern Oscillation (ENSO) fluctuations in tropic...

We investigate seasonal forecasts of the winter North Atlantic Oscillation (NAO) and their relationship with the stratosphere. Climatological frequencies of sudden stratospheric warming (SSW) and strong polar vortex (SPV) events are well represented and the predicted risk of events varies between 25 and 90% from winter to winter, indicating predict...

Predictability estimates of ensemble forecasting systems are prone to sampling uncertainty due to limited numbers of past forecasts and limited ensemble sizes. To account for such uncertainty, this study exploits a statistical signal-plus-noise framework to model observations and corresponding ensemble forecasts. The framework is formulated as a pr...

Figures S1–S3 and Tables S1–S3

Observational analyses of running 5 year ocean heat content trends (H t) and net downward top of atmosphere radiation (N) are significantly correlated (r ∼ 0.6) from 1960 to 1999, but a spike in H t in the early 2000s is likely spurious since it is inconsistent with estimates of N from both satellite observations and climate model simulations. Vari...

European and North American winter weather is dominated by year to year variations in the North Atlantic Oscillation (NAO) which controls the direction and speed of the prevailing winds. An ability to forecast the time-averaged NAO months to years ahead would be of great societal benefit, but current operational seasonal forecasts show little skill...

Decadal climate predictions are now established as a source of information on future climate alongside longer-term climate projections. This information has the potential to provide key evidence for decisions on climate change adaptation, especially at regional scales. Its importance implies that following the creation of an initial generation of d...

Seasonal to decadal predictions are inevitably uncertain, depending on the size of the predictable signal relative to unpredictable chaos. Uncertainties can be accounted for using ensemble techniques, permitting quantitative probabilistic forecasts. In a perfect system, each ensemble member would represent a potential realization of the true evolut...

Readme

Tables S1 and S2 and Figures S1–S8

Decadal variability in the North Atlantic and its subpolar gyre (SPG) has been shown to be predictable in climate models initialized with the concurrent ocean state. Numerous impacts over ocean and land have also been identified. Here we use three versions of the Met Office Decadal Prediction System (DePreSys) to provide a multi-model ensemble fore...

Until recently, long range forecast systems showed only modest levels of skill in predicting surface winter climate around the Atlantic basin and associated fluctuations in the North Atlantic Oscillation at seasonal lead times. Here we use a new forecast system to assess seasonal predictability of winter north Atlantic climate. We demonstrate that...

Useful probabilistic climate forecasts on decadal timescales should be reliable (i.e., forecast probabilities match the observed relative frequencies) but this is seldom examined. This paper assesses a necessary condition for reliability, which the ratio of ensemble spread to forecast error being close to one, for seasonal to decadal sea surface te...

The frequency of tropical storms in the North Atlantic region varies markedly on decadal timescales, with profound socio-economic impacts. Climate models largely reproduce the observed variability when forced by observed sea surface temperatures. However, the relative importance of natural variability and external influences such as greenhouse gase...

There are two main approaches for dealing with model biases in forecasts made with initialized climate models. In full-field initialization, model biases are removed during the assimilation process by constraining the model to be close to observations. Forecasts drift back towards the model’s preferred state, thereby re-establishing biases which ar...

Seasonal forecasts will be a vital part of adaptation strategies in a changing climate. With the exception of tropical storms, very few attempts have been made to make forecasts of extreme events on seasonal timescales. I will describe an investigation into the potential for skilfully predicting the number of daily temperature extremes over three-m...

The predictability of daily temperature and precipitation extremes is assessed out to a decade ahead using the Met Office Decadal Prediction System. Extremes are defined using a simple percentile based counting method applied to daily gridded observation data sets and corresponding model forecasts. We investigate moderate extremes, with a 10% proba...

Using idealised model experiments we show that the tropical Atlantic main hurricane development region (MDR) is potentially one of the most predictable regions for atmospheric variables such as precipitation and wind shear on multi-year timescales. Similarly we also find predictability for the number of tropical storms and the position of the inter...

North Atlantic hurricane activity has increased substantially since the 1970s (refs 1, 2), but whether this is attributable to natural internal variability or external forcing has not been resolved. Either way, hurricane frequency is potentially predictable, because climate models can directly simulate year-to-year variations in Atlantic tropical s...