WCRP Perspective Joint ICSC1/JSC6 17 July 2013, Geneva Michel Rixen, WCRP JPS

Mission & Objectives World Climate Research Programme supports climate-related decision making and adaptation planning by coordinating research required to improve (1)climate predictions and (2)understanding of human influence on climate for use in an increasing range of practical applications of direct relevance, benefit and value to society (WCRP Strategic Framework ).

Global Framework for Climate Services (GFCS)

CMIP5 Coupled Model Intercomparison Project 2+ Petabyte on Earth System Grid Federation 59 models, 24 groups Many studies contributing to the IPCC AR5 report Already 250+ papers Other modeling efforts within WCRP (Seasonal-to-internannual, Decadal, Regional-CORDEX) could likely follow similar schemes in the future Green coupled carbon- cycle climate models Red matches CMIP3 experimental suite A rich set of modeling experiments, drawn from several predecessor MIPs, focuses on model evaluation, projections, and understanding

Most leading seasonal forecasts models now included in CHFP 13 systems CMIP for seasonal WGSIP

© Crown copyright Met Office WGSIP Sub-projects: three experiments Land Surface: the GLACE and GLACE2 experiments: Soil moisture experiments in seasonal mode Led by R Koster Stratosphere: Stratospheric Historical Forecast Project High Top – Low Top hindcasts Led by A Butler Sea Ice: Ice Historical Forecast Project Case studies with/without initial sea-ice data Led by D Peterson

What are climate models missing? In pursuing the objective to generalize theoretical models we must ask ourselves whether greater detail in formulating the contributing processes is warranted by truncation errors, by sensitivity of the results to detail, by the resulting increase in computational complexity and time, and by ignorance of the way these processes really work. Very often this cannot be determined in advance, but must wait for computational experiments to be performed. (Smagorinsky,1963) Much of what we know, and even more of what we dont know, about Earths climate and its propensity to change is rooted in the interplay between water, air circulation, and temperature. (Stevens & Bony, 2013)

Relevant WMAC2 actions Model development: –summer schools: ECS, model physics, param –WCRP/WMO prize with academies (and WWRP?) Earth System Grid Framework: main mechanism for exchanging data (mod+obs+reanalyses) in the WCRP in the next decade

Relevant WMAC2 outcomes Workshop on Dynamics-Physics coupling: GASS to lead with GC4 and SPARC Transpose CMIP: systematic errors WDAC to coordinate effort on surface fluxes (budget closure)

Seamless predictions: opportunities for joint WWRP-WCRP collaborations WGNE (MJO TF, YOTC, Transpose-AMIP, Grey zone, etc) Polar Prediction Project & Polar Climate Prediction Initiative Subseasonal to Seasonal Project: connection to WGSIP/CHFP (ice, land, stratosphere projects) Metrics, verification: WGCM/WGNE metrics panel, JWGFVR …

Thank you for your attention!