Publications


Recent Advances in Radiation Transfer Parametrizations. ECMWF Tech Memo.

(2007) 539

J-J Morcrette, P Bechtold, A Beljaars, A Weisheimer


Historical Overview of Climate Change Science

in Intergovernmental Panel on Climate Change (IPCC), 4th Assessment Report, Working Group 1: The Physical Basis of Climate Change, (2007) 1

H Le Treut, R Somerville, A Weisheimer


How good is an ensemble an capturing truth? Using bounding boxes for forecast evaluation

Quarterly Journal of the Royal Meteorological Society 133 (2007) 1309-1325

KT Judd, LA Smith, A Weisheimer

Ensemble prediction systems aim to account for uncertainties of initial conditions and model error. Ensemble forecasting is sometimes viewed as a method of obtaining (objective) probabilistic forecasts. How is one to judge the quality of an ensemble at forecasting a system? The probability that the bounding box of an ensemble captures some target (such as 'truth' in a perfect model scenario) provides new statistics for quantifying the quality of an ensemble prediction system: information that can provide insight all the way from ensemble system design to user decision support. These simple measures clarify basic questions, such as the minimum size of an ensemble. To illustrate their utility, bounding boxes are used in the imperfect model context to quantify the differences between ensemble forecasting with a stochastic model ensemble prediction system and a deterministic model prediction system. Examining forecasts via their bounding box statistics provides an illustration of how adding stochastic terms to an imperfect model may improve forecasts even when the underlying system is deterministic. Copyright © 2007 Royal Meteorological Society.


Malaria early warnings based on seasonal climate forecasts from multi-model ensembles

NATURE 439 (2006) 576-579

MC Thomson, FJ Doblas-Reyes, SJ Mason, R Hagedorn, SJ Connor, T Phindela, AP Morse, TN Palmer


Multi-Center Grand Ensemble using Three Operational Ensemble Forecasts

SOLA Meteorological Society of Japan 2 (2006) 33-36

M Matsueda, M Kyouda, HL Tanaka, T Tsuyuki

In this study, we investigate the impact of Multi-Center Grand Ensemble (MCGE) forecasts, consisting of three operational ensemble forecasts by the Japan Meteorological Agency (JMA), the National Centers for Environmental Prediction, and the Canadian Meteorological Center. We verified the skill of MCGE forecasts in comparison with that of JMA ensemble forecast using root mean square error, anomaly correlation, and Brier skill score for 500 hPa geopotential height and 850 hPa temperature in the Northern Hemisphere (20°N-90°N) in September 2005.Our results show that MCGE forecasts are more skillful than single-center ensemble forecast without considering weight among ensemble members and bias corrections. This implies that considering weight or bias corrections may result in further improvement of MCGE forecasts, specifically in probabilistic forecasts.


Erratum: "Changing frequency of occurrence of extreme seasonal temperatures under global warming" (Geophysical Research Letters (2005) vol. 32 10.1029/2005GL023365)

Geophysical Research Letters 33 (2006)

A Weisheimer, TN Palmer


Developments in dynamical seasonal forecasting relevant to agricultural management

CLIMATE RESEARCH 33 (2006) 19-26

FJ Doblas-Reyes, R Hagedorn, TN Palmer


Changing frequency of occurrence of extreme seasonal temperatures under global warming (vol 32, art no L20721, 2005)

GEOPHYSICAL RESEARCH LETTERS 33 (2006) ARTN L07712

A Weisheimer, TN Palmer


Impact of increasing greenhouse gas concentrations in seasonal ensemble forecasts

GEOPHYSICAL RESEARCH LETTERS 33 (2006) ARTN L07708

FJ Doblas-Reyes, R Hagedorn, TN Palmer, JJ Morcrette


Multi-center grand ensemble using three operational ensemble forecasts

SOLA 2 (2006) 33-36

M MATSUEDA


A new view of seasonal forecast skill: Bounding boxes from the DEMETER ensemble forecasts

Tellus, Series A: Dynamic Meteorology and Oceanography 57 (2005) 265-279

A Weisheimer, LA Smith, KT Judd

Insight into the likely weather several months in advance would be of great economic and societal value. The DEMETER project has made coordinated multi-model, multi-initial-condition simulations of the global weather as observed over the last 40 years; transforming these model simulations into forecasts is non-trivial. One approach is to extract merely a single forecast (e.g. best-first-guess) designed to minimize some measure of forecast error. A second approach would be to construct a full probability forecast. This paper explores a third option, namely to see how often this collection of simulations can be said to capture the target value, in the sense that the target lies within the bounding box of the forecasts. The DEMETER forecast system is shown to often capture the 2-m temperature target in this sense over continental areas at lead times up to six months. The target is captured over 95% of the time at over a third of the grid points and maintains a bounding box range less than that of the local climatology. Such information is of immediate value from a user's perspective. Implications for the minimum ensemble size as well as open foundational issues in translating a set of multi-model multi-initial-condition simulations into a forecast are discussed; in particular, those involving 'bias correction' are consider. Copyright © Blackwell Munksgaard, 2005.


Influence of a stochastic parameterization on the frequency of occurrence of North Pacific weather regimes in the ECMWF model

GEOPHYSICAL RESEARCH LETTERS 32 (2005) ARTN L23811

T Jung, TN Palmer, GJ Shutts


Recurrent climate winter regimes in reconstructed and modelled 500 hPa geopotential height fields over the North Atlantic/European sector 1659-1990

CLIMATE DYNAMICS 24 (2005) 809-822

C Casty, D Handorf, CC Raible, JF Gonzalez-Rouco, A Weisheimer, E Xoplaki, J Luterbacher, K Dethloff, H Wanner


Representing model uncertainty in weather and climate prediction

ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES 33 (2005) 163-193

TN Palmer, GJ Shutts, R Hagedorn, E Doblas-Reyes, T Jung, M Leutbecher


Quantum reality complex numbers, and the meteorological butterfly effect

BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 86 (2005) 519-+

TN Palmer


More power needed to probe cloud systems

NATURE 434 (2005) 271-271

TN Palmer


The rationale behind the success of multi-model ensembles in seasonal forecasting - II. Calibration and combination

TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY 57 (2005) 234-252

FJ Doblas-Reyes, R Hagedorn, TN Palmer


The rationale behind the success of multi-model ensembles in seasonal forecasting - I. Basic concept

TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY 57 (2005) 219-233

R Hagedorn, FJ Doblas-Reyes, TN Palmer


Probabilistic prediction of climate using multi-model ensembles: from basics to applications.

Philos Trans R Soc Lond B Biol Sci 360 (2005) 1991-1998

TN Palmer, FJ Doblas-Reyes, R Hagedorn, A Weisheimer

The development of multi-model ensembles for reliable predictions of inter-annual climate fluctuations and climate change, and their application to health, agronomy and water management, are discussed.


A forecast quality assessment of an end-to-end probabilistic multi-model seasonal forecast system using a malaria model

TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY 57 (2005) 464-475

AP Morse, FJ Doblas-Reyes, MB Hoshen, R Hagedorn, TN Palmer