Publications


ECMWF seasonal forecast system 3 and its prediction of sea surface temperature

CLIMATE DYNAMICS 37 (2011) 455-471

TN Stockdale, DLT Anderson, MA Balmaseda, F Doblas-Reyes, L Ferranti, K Mogensen, TN Palmer, F Molteni, F Vitart


Predictability of an atmospheric blocking event that occurred on 15 December 2005

Monthly Weather Review 139 (2011) 2455-2470

M Matsueda, M Kyouda, Z Toth, HL Tanaka, T Tsuyuki

Atmospheric blocking occurred over the Rocky Mountains at 1200 UTC 15 December 2005. The operational medium-range ensemble forecasts of the Canadian Meteorological Center (CMC), the Japan Meteorological Agency (JMA), and the National Centers for Environmental Prediction (NCEP), as initialized at 1200UTC10 December 2005, showed remarkable differences regarding this event. All of the NCEP members failed to predict the correct location of the blocking, whereas almost all of the JMA members and most of the CMC members were successful in predicting the correct location. The present study investigated the factors that caused NCEP to incorrectly predict the blocking location, based on an ensemble-based sensitivity analysis and the JMA global spectral model (GSM) multianalysis ensemble forecasts with NCEP, regionally amplified NCEP, and globally amplified NCEP analyses. A sensitive area for the blocking formation was detected over the central North Pacific. In this area, the NCEP control analysis experienced problems in the handling of a cutoff cyclone, and the NCEP initial perturbations were ineffective in reducing uncertainties in the NCEP control analysis. The JMA GSM multianalysis ensemble forecasts revealed that regional amplification of initial perturbations over the sensitive area could lead to further improvements in forecasts over the blocking region without degradation of forecasts over the Northern Hemisphere (NH), whereas the global amplification of initial perturbations could lead to improved forecasts over the blocking region and degraded forecasts over the NH. This finding may suggest that excessive amplification of initial perturbations over nonsensitive areas is undesirable, and that case-dependent rescaling of initial perturbations may be of value compared with climatology-based rescaling, which is widely used in current operational ensemble prediction systems. © 2011 American Meteorological Society.


A CERN for climate change

PHYSICS WORLD 24 (2011) 14-15

T Palmer


Toward a new generation of world climate research and computing facilities

Bulletin of the American Meteorological Society 91 (2010) 1407-1412

J Shukla, TN Palmer, R Hagedorn, B Hoskins, J Kinter, J Marotzke, M Miller, J Slingo

National climate research facilities must be enhanced and dedicated multi-national facilities should be established to accelerate progress in understanding and predicting regional climate change. In addition to the merits of running climate models at a resolution comparable with that of NWP models, the continual confrontation of an NWP model with observations can provide important constraints when the same model is used for much longer-time-scale climate predictions. Short-range forecast models give encouraging results using grid lengths of close to 1 km, without parameterizing deep convection. Prediction uncertainty, a key variable can be estimated by making an ensemble of forecasts with varying initial conditions, model equations, and other input fields such as greenhouse gas concentrations. The new generation of models will yield improved statistics of daily weather and, therefore, better predictions of regional climate variations on seasonal time scales.


Is science fiction a genre for communicating scientific research? A case study in climate prediction

Bulletin of the American Meteorological Society 91 (2010) 1413-1415

TN Palmer

The author, T. N. Palmer describes a book by Isaac Asimov titled Nightfall, which describes a civilization's first encounter with darkness for thousands of years. The civilization inhabits the planet Lagash, which orbits one of six gravitationally-bound suns. Nightfall occurs during a total eclipse, when only one of the suns is above the horizon. Although in this sense climate change is inherently predictable, the author is not confirm whether how reliable the predictions of climate change are in practice. The first message of the story is that reliable predictions of regional climate change are crucially important to guide decisions on infrastructure investment for societies to adapt to future climate change. The second message of the story is that if current climate models can systematically misrepresent the regional effects of the annual cycle, they can also misrepresent the regional effects of climate change. One way to reduce these systematic deficiencies would be to simulate more of the climate system with the proper equations of motion.


An Earth-system prediction initiative for the twenty-first century

Bulletin of the American Meteorological Society 91 (2010) 1377-1388

M Shapiro, J Shukla, G Brunet, C Nobre, M Béland, R Dole, K Trenberth, R Anthes, G Asrar, L Barrie, P Bougeault, G Brasseur, D Burridge, A Busalacchi, J Caughey, D Chen, J Church, T Enomoto, B Hoskins, Ø Hov, A Laing, H Le Treut, J Marotzke, G McBean, G Meehl, M Miller, B Mills, J Mitchell, M Moncrieff, T Nakazawa, H Olafsson, T Palmer, D Parsons, D Rogers, A Simmons, A Troccoli, Z Toth, L Uccellini, C Velden, JM Wallace

Some scientists have proposed the Earth-System Prediction Initiative (EPI) at the 2007 GEO Summit in Cape Town, South Africa. EPI will draw upon coordination between international programs for Earth system observations, prediction, and warning, such as the WCRP, WWRP, GCOS, and hence contribute to GEO and the GEOSS. It will link with international organizations, such as the International Council for Science (ICSU), Intergovernmental Oceanographic Commission (IOC), UNEP, WMO, and World Health Organization (WHO). The proposed initiative will provide high-resolution climate models that capture the properties of regional high-impact weather events, such as tropical cyclones, heat wave, and sand and dust storms associated within multi-decadal climate projections of climate variability and change. Unprecedented international collaboration and goodwill are necessary for the success of EPI.


Future change in Southern Hemisphere summertime and wintertime atmospheric blockings simulated using a 20-km-mesh AGCM

GEOPHYSICAL RESEARCH LETTERS 37 (2010) ARTN L02803

M Matsueda, H Endo, R Mizuta


EXTENDED-RANGE PROBABILISTIC FORECASTS OF GANGES AND BRAHMAPUTRA FLOODS IN BANGLADESH

BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 91 (2010) 1493-U121

PJ Webster, J Jian, TM Hopson, CD Hoyos, PA Agudelo, H-R Chang, JA Curry, RL Grossman, TN Palmer, AR Subbiah


Impact of 2007 and 2008 Arctic ice anomalies on the atmospheric circulation: Implications for long-range predictions

QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 136 (2010) 1655-1664

MA Balmaseda, L Ferranti, F Molteni, TN Palmer


Understanding the Anomalously Cold European Winter of 2005/06 Using Relaxation Experiments

MONTHLY WEATHER REVIEW 138 (2010) 3157-3174

T Jung, TN Palmer, MJ Rodwell, S Serrar


Diagnosing the Origin of Extended-Range Forecast Errors

MONTHLY WEATHER REVIEW 138 (2010) 2434-2446

T Jung, MJ Miller, TN Palmer


EC-Earth: A seamless Earth-system prediction approach in action

Bulletin of the American Meteorological Society 91 (2010) 1357-1363

W Hazeleger, C Severijns, T Semmler, S Ştefǎnescu, S Yang, X Wang, K Wyser, E Dutra, JM Baldasano, R Bintanja, P Bougeault, R Caballero, AML Ekman, JH Christensen, B Van Den Hurk, P Jimenez, C Jones, P Kållberg, T Koenigk, R McGrath, P Miranda, T Van Noije, T Palmer, JA Parodi, T Schmith, F Selten, T Storelvmo, A Sterl, H Tapamo, M Vancoppenolle, P Viterbo, U Willén

The EC-Earth consortium is a grouping of meteorologists and Earth-system scientists from 10 European countries, put together to face the challenges of climate and weather forecasting. The NWP system of the European Centre for Medium-Range Weather Forecasts (ECWMF) forms the basis of the EC-Earth Earth-system model. NWP models are designed to accurately capture short-term atmospheric fluctuations. They are used for forecasts at daily-to-seasonal time scales and include data assimilation capabilities. Climate models are designed to represent the global coupled ocean-atmosphere system. The atmospheric model of EC-Earth version 2, is based on ECMWF's Integrated Forecasting System (IFS), cycle 31R1, corresponding to the current seasonal forecast system of ECMWF. The EC-Earth consortium and ECMWF are collaborating on development of initialization procedures to improve long-term predictions. The EC-Earth model displays good performance from daily up to inter-annual time scales and for long-term mean climate.


Model uncertainty in seasonal to decadal forecasting - insight from the ENSEMBLES project.

ECMWF Newsletter ECMWF 122 (2010) 21-26

A Weisheimer, FJ Doblas-Reyes, TN Palmer


Forecast quality assessment of the ENSEMBLES seasonal-to-decadal Stream 2 hindcasts. ECMWF Tech Memo.

ECMWF (2010) 621

FJ Doblas-Reyes, A Weisheimer, TN Palmer, JM Murphy, D Smith


Decadal climate prediction with the ECMWF coupled forecast system: Impact of ocean observations. ECMWF Tech Memo.

(2010) 633

FJ Doblas-Reyes, MA Balmaseda, A Weisheimer, TN Palmer


The Tat Protein Export Pathway.

EcoSal Plus 4 (2010)

T Palmer, F Sargent, BC Berks

Proteins that reside partially or completely outside the bacterial cytoplasm require specialized pathways to facilitate their localization. Globular proteins that function in the periplasm must be translocated across the hydrophobic barrier of the inner membrane. While the Sec pathway transports proteins in a predominantly unfolded conformation, the Tat pathway exports folded protein substrates. Protein transport by the Tat machinery is powered solely by the transmembrane proton gradient, and there is no requirement for nucleotide triphosphate hydrolysis. Proteins are targeted to the Tat machinery by N-terminal signal peptides that contain a consensus twin arginine motif. In Escherichia coli and Salmonella there are approximately thirty proteins with twin arginine signal peptides that are transported by the Tat pathway. The majority of these bind complex redox cofactors such as iron sulfur clusters or the molybdopterin cofactor. Here we describe what is known about Tat substrates in E. coli and Salmonella, the function and mechanism of Tat protein export, and how the cofactor insertion step is coordinated to ensure that only correctly assembled substrates are targeted to the Tat machinery.


ENSEMBLES: A new multi-model ensemble for seasonal-to-annual predictions - Skill and progress beyond DEMETER in forecasting tropical Pacific SSTs

Geophysical Research Letters 36 (2009)

A Weisheimer, FJ Doblas-Reyes, TN Palmer, A Alessandri, A Arribas, M Déqué, N Keenlyside, M MacVean, A Navarra, P Rogel

A new 46-year hindcast dataset for seasonal-to-annual ensemble predictions has been created using a multi-model ensemble of 5 state-of-the-art coupled atmosphere-ocean circulation models. The multi-model outperforms any of the single-models in forecasting tropical Pacific SSTs because of reduced RMS errors and enhanced ensemble dispersion at all lead-times. Systematic errors are considerably reduced over the previous generation (DEMETER). Probabilistic skill scores show higher skill for the new multi-model ensemble than for DEMETER in the 4-6 month forecast range. However, substantially improved models would be required to achieve strongly statistical significant skill increases. The combination of ENSEMBLES and DEMETER into a grand multi-model ensemble does not improve the forecast skill further. Annual-range hindcasts show anomaly correlation skill of ∼0.5 up to 14 months ahead. A wide range of output from the multi-model simulations is becoming publicly available and the international community is invited to explore the full scientific potential of these data. Copyright 2009 by the American Geophysical Union.


The Invariant Set Postulate: a new geometric framework for the foundations of quantum theory and the role played by gravity

PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 465 (2009) 3165-3185

TN Palmer


The characteristics of Hessian singular vectors using an advanced data assimilation scheme

QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY 135 (2009) 1117-1132

AR Lawrence, A Leutbecher, TN Palmer


Addressing model uncertainty in seasonal and annual dynamical ensemble forecasts

Quarterly Journal of the Royal Meteorological Society 135 (2009) 1538-1559

FJ Doblas-Reyes, A Weisheimer, A Déqué, N Keenlyside, M McVean, JM Murphy, P Rogel, D Smith, TN Palmer

The relative merits of three forecast systems addressing the impact of model uncertainty on seasonal/annual forecasts are described. One system consists of a multi-model, whereas two other systems sample uncertainties by perturbing the parametrization of reference models through perturbed parameter and stochastic physics techniques. Ensemble reforecasts over 1991 to 2001 were performed with coupled climate models started from realistic initial conditions. Forecast quality varies due to the different strategies for sampling uncertainties, but also to differences in initialisation methods and in the reference forecast system. Both the stochastic-physics and perturbed-parameter ensembles improve the reliability with respect to their reference forecast systems, but not the discrimination ability. Although the multi-model experiment has an ensemble size larger than the other two experiments, most of the assessment was done using equally-sized ensembles. The three ensembles show similar levels of skill: significant differences in performance typically range between 5 and 20%. However, a nine-member multi-model shows better results for seasonal predictions with lead times shorter than five months, followed by the stochastic-physics and perturbed-parameter ensembles. Conversely, for seasonal predictions with lead times longer than four months, the perturbed-parameter ensemble gives more often better results. All systems suggest that spread cannot be considered a useful predictor of skill. Annual-mean predictions showed lower forecast quality than seasonal predictions. Only small differences between the systems were found. The full multi-model ensemble has improved quality with respect to all other systems, mainly from the larger ensemble size for lead times longer than four months and annual predictions. © 2009 Royal Meteorological Society and Crown Copyright.

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