Ocean Analysis/Reanalysis – Team of Experts Phil Arkin, ESSIC, University of Maryland Background Concept and Implementa

1. Ocean Analysis/Reanalysis – Team of Experts • Phil Arkin, ESSIC, University of Maryland • Background • Concept and Implementation • Issues

2. We need more comprehensive climate observations and we must make more efficient use of those that are and will be available. THE NEED FOR A SYSTEMS APPROACH TO CLIMATE OBSERVATIONS BY KEVIN E. TRENBERTH, THOMAS R. KARL, AND THOMAS W. SPENCE Because climate is changing, we need to determine how and why. How do we best track and provide useful information of sufficient quality on climate? Bulletin of the American Meteorological Society: November 2002, 83, 1593-1602

3. Observing systemmeans a comprehensive approach, including • Climate observations from both space-based and in situ platforms taken in ways that address climate needs and adhere to the ten principles outlined by the NRC (1999). • A global telecommunications network and satellite data telemetry capacity to enable data and products to be disseminated. • A climate observations analysis capability that produces global and regional analyses of products for the atmosphere, oceans, land surface and hydrology, and the cryosphere, based on four dimensional data assimilation capabilities that process the multivariate data in a physically consistent framework to enable production of the analyses: for the atmosphere and oceans, land surface and so on. • Global climate models that encompass all parts of the climate system and which are utilized in data assimilation and in making ensemble predictions.

4. THE GEOSS/IEOS TEMPLATE Interagency Working Group on Earth Observations Sea Level Observation System. An integrated sea level observation system will provide accurate and timely observations of sea-level variability critical for forecasting and mitigating natural hazards as well as monitoring and understanding sea level and climate variability at global and regional scales. Further, the observing system coupled with a robust modeling strategy will provide information on all known contributors to sea level change, i.e. ocean thermal expansion and contraction, glacier and ice sheet growth and shrinkage, terrestrial impoundment of water, and movement (uplift and subsidence) of land in coastal regions. That information is all part of a larger ocean observation strategy. In collaboration with National Science and Technology Council Committees and Subcommittees, the Climate Change Science Program and the Interagency Committee on Ocean Science and Resource Management Integration, USGEO will provide an ocean observation plan in 2007.

5. Integrated Earth System Analysis • A Climate Change Science Program “Priority” • Provide an accurate description of the current and past state of the complete coupled climate system – ocean, land, atmosphere, … • Ocean Climate Observing System(s) must be accompanied by appropriate Climate Analysis System(s) • Utilize the analysis system to inform decisions on observing system design • OCO set up a “Team of Experts” – scientists doing research with ocean observations – to get started on this by using the observations to perform new and interesting research

6. Team of Experts: Goals/Objectives • Use products from the observing system and other sources, including operational and experimental analyses, to document the ocean’s role in climate variability and change • Regularly deliver a suite of ocean products that will describe sea level, ocean carbon content and its air-sea exchange, SST, surface currents, sea surface pressure and air-sea exchanges of heat, momentum, and fresh water, ocean heat and fresh water content and transports and sea ice thickness and concentrations • Assist the OCO in the development and implementation of appropriate quantitative performance metrics to evaluate the adequacy of the global ocean observing system in meeting the following climate goals: • Document long term trends in sea level change • Document ocean carbon sources and sinks • Document the ocean’s storage and global transport of heat and fresh water • Document the ocean-atmosphere exchange of heat and fresh water

7. Team of Experts: Deliverables • Products: analyze the present state of the global ocean; evaluate how the present state compares with the past, including confidence/uncertainty updated at least annually. Publicly available and understandable by decision-makers and non-scientists wherever possible. • Evaluation: help test the composite observing system against ocean climate variables and make recommendations at least annually for the evolution of the observing system. • Summary annual report: describe the state of the ocean with regard to the parameter(s) being analyzed and how the present state compares with the past. Contributions to State of the Ocean and other reports. • Performance metrics: once developed, calculate and report to OCO quarterly and meet NOAA requirements. • Reports: Each performance metric project must file with OCO, quarterly if appropriate but at least annually, reports recommending evolution of the observing system and/or better use of satellite and in situ data to improve observing system performance.

8. Progress Report • Team has been in place for two years now • Contributed ocean summaries for State of the Climate 2005 and 2006 coordinated by NCDC for publication in BAMS • Contributed similarly to State of the Ocean report • As last year, individual reports will comprise the rest of this session • Issues/questions: • Is Team structure still beneficial to OCO and program? • Course corrections needed?