Publications


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


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)

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

Three 10 year ensemble decadal forecast experiments have been performed with the European Centre for Medium-Range Weather Forecasts coupled forecast system using an initialization strategy common in seasonal forecasting with realistic initial conditions. One experiment initializes the ocean in a standard way using an ocean-only simulation forced with an atmospheric reanalysis and with strong relaxation to observed sea surface temperatures. The other two experiments initialize the ocean from a similar ocean-only run that, in addition, assimilates subsurface observations. This is the first time that these experiments were performed. The system drifts from the realistic initial conditions toward the model climate, the drift being of the same order as, if not larger than, the interannual signal. There are small drift differences in the three experiments that reflect mainly the influence of dynamical ocean processes in controlling the adjustment between the initialized state and the model climate in the extratropics. In spite of the drift, the predictions show that the system is able to skillfully predict some of the interannual variability of the global and regional air and ocean temperature. No significant forecast quality benefit of the assimilation of ocean observations is found over the extratropics, although a negative impact of the assimilation of incorrect expendable bathythermograph profiles has been found for the global mean upper ocean heat content and the Atlantic multidecadal oscillation. The results illustrate the importance of reducing the important model drift and the ocean analysis uncertainty. Copyright 2011 by the American Geophysical Union.


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.


Verification of medium-range MJO forecasts with TIGGE

GEOPHYSICAL RESEARCH LETTERS 38 (2011) ARTN L11801

M Matsueda, H Endo


Predictability of Euro-Russian blocking in summer of 2010

GEOPHYSICAL RESEARCH LETTERS 38 (2011) ARTN L06801

M Matsueda


Uncertainty in weather and climate prediction

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369 (2011) 4751-4767

J Slingo, T Palmer


Evaluation of probabilistic quality and value of the ENSEMBLES multimodel seasonal forecasts: Comparison with DEMETER

Monthly Weather Review 139 (2011) 581-607

A Alessandri, A Borrelli, A Navarra, A Arribas, M Déqué, P Rogel, A Weisheimer

The performance of the new multimodel seasonal prediction system developed in the framework of the European Commission FP7 project called ENSEMBLE-based predictions of climate changes and their impacts (ENSEMBLES) is compared with the results from the previous project [i.e., Development of a European Multimodel Ensemble System for Seasonal-to-Interannual Prediction (DEMETER)]. The comparison is carried out over the five seasonal prediction systems (SPSs) that participated in both projects. Since DEMETER, the contributing SPSs have improved in all aspects with the main advancements including the increase in resolution, the better representation of subgrid physical processes, land, sea ice, and greenhouse gas boundary forcing, and the more widespread use of assimilation for ocean initialization. The ENSEMBLES results show an overall enhancement for the prediction of anomalous surface temperature conditions. However, the improvement is quite small and with considerable space-time variations. In the tropics, ENSEMBLES systematically improves the sharpness and the discrimination attributes of the forecasts. Enhancements of the ENSEMBLES resolution attribute are also reported in the tropics for the forecasts started 1 February, 1 May, and 1 November. Our results indicate that, in ENSEMBLES, an increased portion of prediction signal from the single-models effectively contributes to amplify the multimodel forecasts skill. On the other hand, a worsening is shown for the multimodel calibration over the tropics compared to DEMETER. Significant changes are also shown in northern midlatitudes, where the ENSEMBLES multimodel discrimination, resolution, and reliability improve for February, May, and November starting dates. However, the ENSEMBLES multimodel decreases the capability to amplify the performance with respect to the contributing single models for the forecasts started in February, May, and August. This is at least partly due to the reduced overconfidence of the ENSEMBLES single models with respect to the DEMETER counterparts. Provided that they are suitably calibrated beforehand, it is shown that the ENSEMBLES multimodel forecasts represent a step forward for the potential economical value they can supply. A warning for all potential users concerns the need for calibration due to the degraded tropical reliability compared to DEMETER. In addition, the superiority of recalibrating the ENSEMBLES predictions through the discrimination information is shown. Concerning the forecasts started inAugust, ENSEMBLES exhibitsmixed results over both tropics and northernmidlatitudes. In this case, the increased potential predictability compared to DEMETER appears to be balanced by the reduction in the independence of the SPSs contributing to ENSEMBLES. Consequently, for the August start dates no clear advantage of using one multimodel system instead of the other can be evidenced. © 2011 American Meteorological Society.


Handling uncertainty in science.

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

TN Palmer, PJ Hardaker


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


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.

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