CLIVAR Report to WOAP4 Detlef Stammer

CLIVAR (Climate Variability and Predictability) Mission To observe, simulate and predict changes in the earth’s climate system with a focus on ocean-atmosphere interactions, enabling better understanding of climate variability, predictability and change, to the benefit of society and the environment in which we live. See p. 2 of Draft IP 2

New: Clivar/CliC Arctic Panel

Planning is moving forward with no sun-set date in effect any more. Focus of next 2 years Planning is moving forward with no sun-set date in effect any more. www.clivar.org

Each panel/WG was asked to identify: Building consensus until 2013 and beyond Each panel/WG was asked to identify: Imperatives over the coming years to 2013 and, perhaps, continuing over the next decade? Activities that "must" be continued and/or implemented because they are of the highest scientific importance with a high likelihood of success. What are the frontiers for the next decade and beyond? What key developments to enabling infrastructure necessary to deliver to the above. Organized around WCRP crosscutting topics (ACC, AC&C, decadal and seasonal prediction, sea level rise, monsoon and extremes) under COPES Additional focus on ocean observations, synthesis and modeling as particular CLIVAR contributions to overarching COPES themes. Outcomes factored into WCRP Implementation Plan

CLIVAR Imperatives Anthropogenic Climate Change Long term change Natural versus forced variability Regional phenomena and impacts Extremes Decadal Variability, Predictability and Prediction Determination of predictability Mechanisms of variability Role of oceans Adequacy of observing system Initialization Monsoons Extremes - drought Intraseasonal and Seasonal Predictability and Prediction Role of land/ocean (GOALS) Initialization Monsoons, ISV/MJO

CLIVAR Imperatives Anthropogenic Climate Change Decadal Variability, Predictability and Prediction Intraseasonal and Seasonal Predictability and Prediction Improved Atmosphere and Ocean Components of ESMs Ocean model development Analysis and Evaluation Process studies/“Climate Process Teams” Data Synthesis and Analysis Ocean Coupled Data Assimilation Systems (with WOAP) Ocean Observing System Development and System Design (Build LINKS WITH IGBP for Carbon, Biogeochemistry, Ecosystems) Capacity Building

GSOP Efforts Chairs: B. Sloyan, K. Haines (WOAP member), D. Stammer Implementation of OO’09 Outcome (jointly with OOPC) Reanalaysis of global historic hydrography Reanalysis of XBT data Analyze global budgets and sea level EazyInit: Providing initial conditions for seasonal- to decadal predictions. Improving initial conditions and initializations. Preparing for Coupled Data assimilation GSOP Efforts

Decadal variability and predictability Some key questions To what extent is decadal variability in the oceans and atmosphere predictable? What are the mechanisms of variability? Does the oceanic variability have atmospheric relevance? Do we have the proper tools to realize the predictability? Need for (coupled) data assimilation systems to initialize models Are models “good enough” to make skillful predictions? Adequacy of climate observing system? Global number of temperature observations per month as a function of depth 1980-2006

Decadal variability & predictability First attempts already underway Decadal prediction part of CMIP5 protocol – Joint design by WCRP/WGCM/WGSIP/CLIVAR sub group Opportunities for diagnostic sub-projects CLIVAR Workshops AIP/GSOP Earth System Initialization for Decadal Predictions Workshop (4 – 6 Nov 2009) – KNMI, Utrecht, The Netherlands Upcoming: WGOMD/GSOP Workshop on Decadal Variability, Predictability and Predictions: Understanding the Role of the Ocean - 20-23 Sep 2010, NCAR, Colorado, USA Atlantic Panel coordination of activities to monitor the Atlantic MOC Ocean observations will be at the heart of decadal climate prediction systems. Major challenges will, therefore, be to continually assess whether existing and planned ocean observing systems are optimal for decadal predictions and to address any identified deficiencies. As one example, a tremendous advance has been the measurements of temperature and salinity over the upper 2000 m of the global ocean currently provided by ARGO profiling floats. There exists, however, a need to assess whether observations from below 2000 m would be of use in decadal climate predictions by more completely characterizing deep ocean conditions, such as the lower limb of the MOC, and in assessing other changes such as in abyssal ocean heat content. Also, with a lifetime of individual ARGO floats of only a few years, there is a need to evaluate and minimize the impact of instrumentation changes on the quality of the records both for climate analyses and for initializing prediction models.

MOC – issues and challenges Our present understanding and observations of the deep ocean and MOC are inadequate to carry out a rigorous process of setting priorities and evaluating trade-offs. No systematic observing system design studies have yet been carried out for the global MOC and deep inventory. Nonetheless, substantial progress has been made in recent years (there are currently 25 individual contributions measuring components of the Atlantic MOC). Two areas are still hanging fruits and need further progress: the Arctic (CliC is mainly cryosphere) and the Atlantic Warm pool (with ties to VAMOS). A challenge for the community is to make the transition from a collection of observing elements to an integrated, coherent observing system.