Western Boundary Current Working Group CLIVAR Summit Irvine, CA

Panel Members WG Established Jan 2007 Kathie Kelly (co-chair), University of Washington Bo Qiu (co-Chair), University of Hawaii Michael Alexander (NOAA/ESRL) Nick Bond (U Washington) Meghan Cronin (NOAA/PMEL) Claude Frankignoul (LODYC, Paris) Terry Joyce (WHOI) Young-oh Kwon (WHOI) Hisashi Nakamura (U. of Tokyo, Frontier) Roger Samelson (Oregon State) Justin Small (Naval Research Lab Stennis Space Center) LuAnne Thompson (U Washington)

Scientific Issues How does air-sea interaction compare in the western North Atlantic and North Pacific? What are the implications of the differences?* What is the nature of atmosphere-ocean interaction in WBC regions? On what temporal and spatial scales does it occur? Is there predictability in the system? To what extent are coupled models getting the interaction right? Can we identify specific problems in ocean or atmosphere models? What numerical experiments need to be done to test hypotheses? To what extent does air-sea interaction extend beyond the boundary layer and influence broader climate variability in both the atmosphere and ocean?

Activities Write two review articles on Air-Sea Interaction in Kuroshio Extension/Gulf Stream Regions –1) Frontal-scale (Kelly, Qiu, Joyce, Frnakignoul, Small) –2) Basin-Scale (Kwon, Alexander, Frankignoul, Nakamura, Bond, Thompson) Topics Incorporate new findings from KESS/Climode (F/B) Findings from high resolution atmosphere and ocean models (F) Examine local and remote effects (F) Cross Scale Interactions (F/B) Assessment of current IPCC-Class models (B) Discuss outstanding issues (F/B) Conduct new analyses in support of papers Papers to be submitted to J. Climate Jan 09 Create on-line atlas of WBC relevant fields

Frontal Scale Air-Sea Interaction ● Mean and variability of the Gulf Stream and Kuroshio Extension ● Time-varying dynamic signals ● Time-varying thermodynamic signals ● Understanding the GS and KE indices Atmosphere-ocean interaction RMS of net surface heat flux (top) and SSH variability (bottom) for KE (left) and GS (right),contour mean SSH Courtesy of K. Kelly Poster by T. Joyce on fronts and surface expression of storm track variability

Observed Impact of the Gulf Stream on the Atmosphere Minobe et al., Nature, 2008

Winter SST Variability in Obs and Ocean Model for the Earth Simulator (OFES) 0.1° lat x 0.1° lon, 56 levels Nonaka et al., J Climate, 2006 JFM SST

Dynamics of KE region PDO SSH from data SSH from wave model PDO Wind Curl forcing

SST Impact of SST in the Kuroshio Extension on the Atmosphere Provided by C. Frankignoul Regression of a)SST (AMJ) b)z250 (AS0) c)on SSTA in KE Region in AMJ

Qiu et al., J Climate, 2007 Decadal variability in the North Pacific Atmosphere ocean system 3-equation observational based heuristic model

Workshop Logistics Phoenix, AZ January 2009 Thursday Jan 15th - Saturday 18th (3 full days) One day overlap with Annual AMS meeting coordinating with AMS Air-Sea Interaction Optional joint sessions on Wednesday 14th Hotel & other logistics worked out shortly Science I Four half day sessions with presentations on topics 1. Insights from KESS/CLIMODE field programs 2. Frontal-scale air-sea interaction over WBCs 3. Large-scale air-sea interaction in connection with WBCs 4. Impact of upper ocean variability in WBC regions on midlatitude climate variability and predictability

Workshop II II Discussion and future directions (3rd day) What are the cutting-edge science issues for the WBC air-sea interaction? What are beyond the KESS/CLIMODE programs? Identify requirements for ocean and atmospheric observing systems in WBC regions What WBC metrics are most relevant for the modeling community? What modeling experiments should be considered; e.g. impact of SST, ocean heat content anomalies on atmosphere? Potential outcomes Ideas for new field programs and/or observation systems Coordinated model experiments Identification of metrics for coupled models

Additional Activities Supporting Activities –Monthly teleconferences –Met in Portland in conjunction with AMS Air-Sea Interaction Conference Aug 07 –Climate Variations Article (Dec 2007) –Web page Telcon notes, science, references, links