The climate community is still faced with large uncertainties in estimating possible climate changes in the next decades and quantifying the relative role of anthropogenic contribution to climate change. Although most modern climate models are able to reproduce reasonably well global climatologies and patterns of interannual variations, they still struggle with pervasive biases and the representation of some of the climate phenomena involving the interaction and coupling between the atmosphere, the ocean and the cryosphere. The problem is compounded by the limited understanding of some of the physical mechanisms giving rise to both our present mean climate and its natural variability at different time scales.

One possible way forward is the use of a hierarchy of models to tackle the most pressing questions in climate dynamics and modeling. Key among them, is whether the climate is stable, or whether internal feedbacks could lead to tipping points, abrupt changes, and transitions to fundamentally different equilibria. Changes in the oceanic overturning, ice-albedo effects, land-surface and vegetation coupling to the atmosphere, and radiative-convective properties of the atmosphere have all been suggested as possible causes of instability in the climate system. Advances in our understanding, quantification, and modelling of these processes are necessary both for the interpretation of the paleoclimate record and for the projection of possible future climate states. A variety of studies have found that multiple equilibria exist both in highly idealized and more comprehensive models of the climate system. Whether multiple equilibria do exist in state-of-the-art climate models is still a subject of controversy.

A fundamental understanding of key processes within a hierarchical modeling framework will eventually translate into a better representation and simulation within state-of-the-art climate models, as it brings new insights for process-based evaluation of climate model reliability and fit for purpose. The use of hierarchies additionally promotes the use of standardized performance metrics and highlights instances when post-processing approaches (e.g. bias correction) or diverse model tuning practices should be explored.

The school will be based on lectures on theoretical aspects of atmosphere, ocean and climate dynamics, with a focus on the present state of established knowledge and relevant mechanisms. The topic of the school, Multiple Equilibra in the Climate System, will be the subject of afternoon lectures, giving an overview of the most recent progress and hypotheses suggesting the existence of multiple equilibrium states, and consequences for past and future climates. Afternoons will also be devoted to practical sessions, involving the use of simplified climate models and analysis of relevant data sets.

The school will be followed by the workshop WCRP Grand Challenge on Clouds, Circulation and Climate Sensitivity: 2nd Meeting on Monsoons and Tropical Rain Belts , SMR3252, 2 - 5 July 2018, go to link
http://indico.ictp.it/event/8457/
 
 

Confirmed speakers:

• Simona Bordoni, CalTech, USA
• David Ferreira, Reading U., UK
• In-Sik Kang, SNU, Republic of Korea
• John Marshall, MIT, USA
• Franco Molteni, ECMWF, UK
• Brian Rose, U. Albany, USA
• Stephen Thomson, U. exeter, UK
• Adrian M. Tompkins, ICTP, Italy
• Geoff K. Vallis, U. Exeter, UK
• Shang-Ping Xie, SCRIPPS, USA

APPLICATION HERE IS FOR BOTH SCHOOL AND WORKSHOP,
DEADLINE 1 MARCH 2018

SHOULD YOU WISH TO APPLY TO THE WORKSHOP ONLY, PLEASE VISIT THE RELEVANT PAGE http://indico.ictp.it/event/8457/
AND APPLY THERE