26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI PPAI Concluding Report Proposed focus: DROUGHT ENSOExtreme Events Decadal Variability MJO Nowcasting Climate Change D R O U G H T D R O U G H T

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI PPAI Concluding Report Proposed focus: DROUGHT Diagnosis & prediction of drought across space & time scales Scientific challenge: DECADAL VARIABILITY Examples of societally relevant questions:  What are the leading causes of the current drought?  What is the likelihood for a break in the drought this year?  Can we expect more/worse drought over the next 10 years?  How much are temperature trends exacerbating the drought?  What happens to frequency/severity of drought in a changing climate?

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI PPAI WG Suggestion Decadal Climate Variability WG: * Focus on tropics – esp. Pacific - Role of ENSO in drought - Role of ENSO in US prediction skill - Role of ENSO in hurricane development * Tasks would include studies of predictability & experimental predictions for tropical Pacific variability characteristics * Leverage ongoing decadal predictability experiments at GFDL & NCAR; experimental decadal predictions from ENSEMBLES Societally relevant question (e.g.): “ Can we expect more/stronger El Nino events in the next 10 years?”

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI PPAI Goals 1)Further fundamental understanding of climate predictability at sub-seasonal to centennial time scales 2)Improve provision of climate forecast information, particularly with respect to drought and other extreme events 3)Foster research and development of prediction systems of climate impacts on ecosystems and hydrology 4)Enable use of CLIVAR science for improved decision support

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI Goal 1: Understanding Predictability Activities: Characterize current predictability and prioritize associated research challenges for seasonal-to- interannual prediction (Goddard) Paper(s) on drought prediction across timescales and/or intersection between decadal variability and climate change (Delworth, Hall ??) Propose WG on Decadal Variability of Tropics (Mehta + PPAI) Activities: 3-5 years & beyond Advise on Quasi-Regular process for the assessment of prediction skill (Mason)

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI Goal 2: Improved provision of climate forecast information Activities: 1-3 years Special session at Fall AGU 2006 on ‘Improving Credibility of Climate Predictions’ Propose CMEP activity focused on drought (Meehl) Activities: 3-5 years & beyond Coordinate with COPES Modeling Panel and the COPES- TFSP on the development of a unified days to decades prediction strategy to be implemented by 2015 (Kirtman)

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI Goal 3: Ecosystems and Hydrology Activities: 1-3 years Make connections with networks of ecosystems researchers, such as National Phenology Network and Vegetation Dynamics Groups (Redmond; Koster) Coordinate with GEWEX on hydrology/water resources issues, in particular scoping potential process study on land-atmosphere interaction relevant to drought maintenance (Koster) Add ecosystems or hydrology person to panel

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI Goal 4: CLIVAR science & decision support Activities: 1-3 years Implement US CLIVAR Applications Interface Postdoctoral Program (Goddard & Redmond) Become more proactive with “intermediaries”, e.g. contacts at meetings, teleconference invitations (PPAI) Activities: 3-5 years & beyond Promote and help implement USC-AI post-doc program (PPAI) Encourage multi-agency support for development of web-based information delivery and decision support tools Coordinate and prioritize efforts to downscale climate information and forecasts, emphasizing responsible provision and use of high-resolution information

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI Research Activity proposed by PPAI Drought: Understanding, predicting and projecting changes 1.Methodology—CMEP analyses of multi-model datasets (unforced control runs, 20 th century simulations, 21 st century scenario projections) 2.Drought session in decadal workshop, April, Drought Workshop – CMEP session: spring 2008 Considerations: Drought processes and timescales (seasonal/interannual for individual droughts, decadal/centennial for statistics/changes in drought; past/present/future) Drought impacts (water resources, ecosystems, land surface)

26-28 July 2006US CLIVAR Summit -- Breckenridge, CO PPAI Ties to other US CLIVAR Panels and Working Groups: 1. Drought Working Group 2. POS: decadal variability and predictability of droughts (role of ocean in drought, natural variability vs. anthropogenic climate change aspects of drought) 3. PSMIP: drought processes represented in models, effect of systematic errors, model improvements to better represent drought processes