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 American Meteorological Society 139 (2011) 2455-2470

M MATSUEDA

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 1200 UTC 10 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.


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.


Rossby wave dynamics of the North Pacific extra-tropical response to El Niño: Importance of the basic state in coupled GCMs

Climate Dynamics 37 (2011) 391-405

A Dawson, AJ Matthews, DP Stevens


Verification of medium-range MJO forecasts with TIGGE

GEOPHYSICAL RESEARCH LETTERS 38 (2011) ARTN L11801

M Matsueda, H Endo


Future changes in the East Asian rain band projected by global atmospheric models with 20-km and 60-km grid size

CLIMATE DYNAMICS 37 (2011) 2481-2493

S Kusunoki, R Mizuta, M Matsueda


On the predictability of the extreme summer 2003 over Europe

Geophysical Research Letters 38 (2011)

A Weisheimer, FJ Doblas-Reyes, T Jung, TN Palmer

The European summer 2003 is a prominent example for an extreme hot and dry season. The main mechanisms that contributed to the growth of the heat wave are still disputed and state-of-the-art climate models have difficulty to realistically simulate the extreme conditions. Here we analyse simulations using recent versions of the European Centre for Medium-Range Weather Forecasts seasonal ensemble forecasting system and present, for the first time, retrospective forecasts which simulate accurately not only the abnormal warmth but also the observed precipitation and mid-tropospheric circulation patterns. It is found that while the land surface hydrology plays a crucial role, the successful simulations also required revised formulations of the radiative and convective parameterizations. We conclude that the predictability of the event was less due to remote teleconnections effects and more due to in situ processes which helped maintain the dry surface anomalies occurring at the beginning of the summer. Copyright 2011 by the American Geophysical Union.


Assessment of representations of model uncertainty in monthly and seasonal forecast ensembles

GEOPHYSICAL RESEARCH LETTERS 38 (2011) ARTN L16703

A Weisheimer, TN Palmer, FJ Doblas-Reyes


Predictability of Euro-Russian blocking in summer of 2010

GEOPHYSICAL RESEARCH LETTERS 38 (2011) ARTN L06801

M Matsueda


Handling uncertainty in science.

Philos Trans A Math Phys Eng Sci 369 (2011) 4681-4684

TN Palmer, PJ Hardaker


Decadal climate prediction with the European Centre for Medium-Range Weather Forecasts coupled forecast system: Impact of ocean observations

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 116 (2011) ARTN D19111

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


Climate Sensitivity via a Nonparametric Fluctuation–Dissipation Theorem

Journal of the Atmospheric Sciences 68 (2011) 937-953

FC Cooper, PH Haynes


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


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


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.


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


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.


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.


Diagnosing the Origin of Extended-Range Forecast Errors

MONTHLY WEATHER REVIEW 138 (2010) 2434-2446

T Jung, MJ Miller, TN Palmer


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