Search Results

You are looking at 1 - 3 of 3 items for :

  • Author or Editor: Jochem Marotzke x
  • Bulletin of the American Meteorological Society x
  • Refine by Access: All Content x
Clear All Modify Search
Florian Rauser
,
Peter Gleckler
, and
Jochem Marotzke

Abstract

We discuss the current code of practice in the climate sciences to routinely create climate model ensembles as ensembles of opportunity from the newest phase of the Coupled Model Intercomparison Project (CMIP). We give a two-step argument to rethink this process. First, the differences between generations of ensembles corresponding to different CMIP phases in key climate quantities are not large enough to warrant an automatic separation into generational ensembles for CMIP3 and CMIP5. Second, we suggest that climate model ensembles cannot continue to be mere ensembles of opportunity but should always be based on a transparent scientific decision process. If ensembles can be constrained by observation, then they should be constructed as target ensembles that are specifically tailored to a physical question. If model ensembles cannot be constrained by observation, then they should be constructed as cross-generational ensembles, including all available model data to enhance structural model diversity and to better sample the underlying uncertainties. To facilitate this, CMIP should guide the necessarily ongoing process of updating experimental protocols for the evaluation and documentation of coupled models. With an emphasis on easy access to model data and facilitating the filtering of climate model data across all CMIP generations and experiments, our community could return to the underlying idea of using model data ensembles to improve uncertainty quantification, evaluation, and cross-institutional exchange.

Full access
Jochem Marotzke
,
Wolfgang A. Müller
,
Freja S. E. Vamborg
,
Paul Becker
,
Ulrich Cubasch
,
Hendrik Feldmann
,
Frank Kaspar
,
Christoph Kottmeier
,
Camille Marini
,
Iuliia Polkova
,
Kerstin Prömmel
,
Henning W. Rust
,
Detlef Stammer
,
Uwe Ulbrich
,
Christopher Kadow
,
Armin Köhl
,
Jürgen Kröger
,
Tim Kruschke
,
Joaquim G. Pinto
,
Holger Pohlmann
,
Mark Reyers
,
Marc Schröder
,
Frank Sienz
,
Claudia Timmreck
, and
Markus Ziese

Abstract

Mittelfristige Klimaprognose (MiKlip), an 8-yr German national research project on decadal climate prediction, is organized around a global prediction system comprising the Max Planck Institute Earth System Model (MPI-ESM) together with an initialization procedure and a model evaluation system. This paper summarizes the lessons learned from MiKlip so far; some are purely scientific, others concern strategies and structures of research that target future operational use.

Three prediction system generations have been constructed, characterized by alternative initialization strategies; the later generations show a marked improvement in hindcast skill for surface temperature. Hindcast skill is also identified for multiyear-mean European summer surface temperatures, extratropical cyclone tracks, the quasi-biennial oscillation, and ocean carbon uptake, among others. Regionalization maintains or slightly enhances the skill in European surface temperature inherited from the global model and also displays hindcast skill for wind energy output. A new volcano code package permits rapid modification of the predictions in response to a future eruption.

MiKlip has demonstrated the efficacy of subjecting a single global prediction system to a major research effort. The benefits of this strategy include the rapid cycling through the prediction system generations, the development of a sophisticated evaluation package usable by all MiKlip researchers, and regional applications of the global predictions. Open research questions include the optimal balance between model resolution and ensemble size, the appropriate method for constructing a prediction ensemble, and the decision between full-field and anomaly initialization.

Operational use of the MiKlip system is targeted for the end of the current decade, with a recommended generational cycle of 2–3 years.

Full access
Melvyn Shapiro
,
Jagadish Shukla
,
Gilbert Brunet
,
Carlos Nobre
,
Michel Béland
,
Randall Dole
,
Kevin Trenberth
,
Richard Anthes
,
Ghassem Asrar
,
Leonard Barrie
,
Philippe Bougeault
,
Guy Brasseur
,
David Burridge
,
Antonio Busalacchi
,
Jim Caughey
,
Deliang Chen
,
John Church
,
Takeshi Enomoto
,
Brian Hoskins
,
Øystein Hov
,
Arlene Laing
,
Hervé Le Treut
,
Jochem Marotzke
,
Gordon McBean
,
Gerald Meehl
,
Martin Miller
,
Brian Mills
,
John Mitchell
,
Mitchell Moncrieff
,
Tetsuo Nakazawa
,
Haraldur Olafsson
,
Tim Palmer
,
David Parsons
,
David Rogers
,
Adrian Simmons
,
Alberto Troccoli
,
Zoltan Toth
,
Louis Uccellini
,
Christopher Velden
, and
John M. Wallace

The necessity and benefits for establishing the international Earth-system Prediction Initiative (EPI) are discussed by scientists associated with the World Meteorological Organization (WMO) World Weather Research Programme (WWRP), World Climate Research Programme (WCRP), International Geosphere–Biosphere Programme (IGBP), Global Climate Observing System (GCOS), and natural-hazards and socioeconomic communities. The proposed initiative will provide research and services to accelerate advances in weather, climate, and Earth system prediction and the use of this information by global societies. It will build upon the WMO, the Group on Earth Observations (GEO), the Global Earth Observation System of Systems (GEOSS) and the International Council for Science (ICSU) to coordinate the effort across the weather, climate, Earth system, natural-hazards, and socioeconomic disciplines. It will require (i) advanced high-performance computing facilities, supporting a worldwide network of research and operational modeling centers, and early warning systems; (ii) science, technology, and education projects to enhance knowledge, awareness, and utilization of weather, climate, environmental, and socioeconomic information; (iii) investments in maintaining existing and developing new observational capabilities; and (iv) infrastructure to transition achievements into operational products and services.

Full access