1. Western Boundary Current Working Group CLIVAR Summit Annapolis, MD July 2009

2. Panel Members WG Established Jan 2007 => Jan 2009 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)

3. Scientific Issues and the WG action WG grew attempt to draw broader lessons about air-sea interaction from the CLIMODE (Atlantic) and KESS (Pacific) Programs Document air-sea interaction compare in the western North Atlantic and North Pacific. Web Page What have we learned about the nature of atmosphere-ocean interaction in WBC regions? On what temporal and spatial scales does it occur? Review articles on frontal and large scale air-sea interaction What are the outstanding issues and what research is being done to address these questions. e.g. To what extent does air- sea interaction extend beyond the boundary layer and influence broader climate variability in both the atmosphere and ocean? WBC Air-Sea Interaction Workshop J. Climate Special Volume

4. WBC Web page (http://www.cdc.noaa.gov/WBC)

7. Review Articles 1) “ Western Boundary Currents and Air-Sea Interaction Gulf Stream and Kuroshio Extension” –Kelly, Small, Samelson, Joyce, Kwon, Qiu, Joyce, Cronin 2) “Role of Gulf Stream, Kuroshio-Oyashio and Their Extensions in Large-Scale Atmosphere-Ocean Interaction : A Review” –Kwon, Alexander, Bond, Frankignoul, Nakamura, Qiu, 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/B) Cross Scale Interactions (F/B) Assessment of current IPCC-Class models (B) Discuss outstanding issues (F/B) Conducted new analyses in support of papers Papers were submitted to J. Climate July 2009

8. Atlantic SST & LHF March averages of SST for (left) 2003 and (right) 2007. Latent heat fluxes using the COARE bulk formula (Fairall et al. 1996). Inputs to the COARE algorithm were microwave SST, QuikSCAT scatterometer winds, and ECMWF for other atmospheric variables.

9. SST impact on high wind events Winter (DJF) climatology of the frequency of high wind events (20m/s) from QuickSCAT (color, in %) and AVHRR climatological mean SST (white contours at an interval of 2C). Topography higher than 500, 1000, and 1500m altitudes is shaded (see color bar). From Sampe and Xie (2007, BAMS).

10. Kuroshi and Oyashi Fronts Latitude-Depth sections of five-winter mean fields of temperature (black contours) and its meridional gradient for OFES (0.1 model) and Obs Contour intervals for temperature are 1 °C. Unit for the gradients is °C (100 km) −1. Nonaka et al. 2006 1968- 1972 1984- 1988 Difference

11. Impact of SST Fronts on Atmosphere Vertically averaged eddy kinetic energy (EKE) (m 2 s –2 ) for the spring of 2004 in a mesoscale atmospheric model with (left) observed Sand (right) artificially smoothed SST as boundary conditions. The SST black contours at 1K interval (Taguchi et al. 2009).

12. Composite Niño - Niña SST (°C; shaded) Yr 0: Nino 87, 91, 97, 02, 06; Nina 88, 98, 99, 05 ASO (yr 0) FMA (yr 1) Mean Con Int 4°C

13. WBC Workshop Logistics Phoenix, AZ 15-18 January 2008 ~60 participants (many international) One day overlap with Annual AMS meeting Sponsored joint session on WBCs with AMS Air-Sea Interaction at the annual meeting Description/Agenda/links to presentations at: http://www.usclivar.org/WBCWorkshop2009.php 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

14. Special WBC Volume “Virtual” special J.Climate issue of papers on Air-Sea Interaction over Western Boundary Currents Submission deadline is August 29, 2009 ~25 papers proposed including 2 review papers –Wide array e.g small scale in situ measurements of fluxes to AGCM response to frontal scale SSTs –~10 in review process already (submittted, accepted etc.) Additional Workshop Publications Climate Variations Article (April 2009) Based on 3 presentations at WBC workshop Atmospheric Sciences AGU Newsletter (vol3 issue 1) Mar 2009 Summary Document/BAMS article (in preparation)

15. Workshop Questions & Future Directions What are the cutting-edge science issues for the WBC air-sea interaction? Processes involved in boundary layer response to frontal- scale SST anomalies (e.g. wind mixing, pressure gradient, baroclinicity) Large-scale response to these anomalies/ Recent idealized studies show atm responds to mean WBC SST fronts but unclear for more realistic SSTAs Identify requirements for ocean and atmospheric observing systems in WBC regions Development of an ocean obs 09 white paper: Monitoring ocean-atmosphere interactions measuring in western boundary current extensions (Cronin et al).

16. II Workshop Questions/Future Directions What WBC metrics are most relevant for the modeling community? Close scrutiny of WBCs in Climate models and their possible errors => WBC CPT (LuAnne Thompson) What modeling experiments should be considered; e.g. impact of frontal SST anomalies, on the free atmosphere anomalies on atmosphere?

17. * Note images may appear vertically for narrower display