Kuroshio Extension System Study (KESS)

1. KEO Surface flux buoy Atmospheric Soundings Kuroshio Extension System Study (KESS) KESS GOAL Identify and quantify the processes governing the variability of, and interactions between, the Kuroshio Extension, its recirculation gyre, and the North Pacific storm track.

2. Atmospheric Sounding Cold cross-frontal advection under northerly winds on R/V Roger Revelle T Td Stratus cloud with an elevated base capped by a primary inversion Warm advection under southerly winds SST 6/17 – 7/17/2005 Fog capped by a surface inversion Slide provided by S.-P. Xie

3. Kuroshio Extension alternates between stable and meandering states on decadal time scales. Qiu and Chen, 2005 • During “elongated state” (1993, 1994, 2002, 2003, 2004), the KE is stronger and more stable, its path is shifted northward, and recirculation is elongated. • During “contracted state” (1996, 1997, 1998, 1999), KE is weaker and more variable, its path is shifted southward, and recirculation is contracted. • What sets the state? • KESS measured both states.

4. Agenda for Ocean Model Metrics Workshop, Honolulu, Hawaii, February 25, 2006 8:30 Greeting and opening remarks, LuAnne Thompson and Julie McClean, Jim Potemra 9:00 Plenary talks 9:00 Kathleen Donohue Metrics from a process-oriented experiment (KESS) 9:30 Bruce Cornuelle ECCO and a representation of the ocean 10:00 Eric Chassignet GODAE, HYCOM and the next generation of Ocean models 10:30 to 11:00 break 11:00 Matt Maltrud High Resolution Ocean modeling using POP: What have we learned? 11:30 Peter Gleckler: Metrics for coupled and atmospheric GCMs Discussion and charge to working groups 12:15 Lunch 1:30 Working Groups Climate Metrics: Leader Bill Large Operational Metrics: Leader Greg Jacobs Process studies metrics: Leader Sarah Gille 3:30 Break 4:00 Presentation by working groups (10 minutes each) 4:30 Discussion and future efforts 5:15 Closing remarks

5. KESS will provide metrics for: • Sub-Tropical Mode-Water formation • mesoscale potential vorticity fluxes • upper-ocean heat budget • air-sea fluxes • eddy energetics (including abyssal fields) • KESS offers detailed well-resolved case studies that can serve as benchmarks against which eddy-resolving models can be evaluated. Slides provided by K. Donohue & R. Watts

6. Case Study: Two deep anticyclones and a deep cyclone intensify as meander crests and a trough steepen. Strong barotropic currents cross the baroclinic front. Gray contours denote upper streamfunction. Deep streamfunction: cyclone/low/blue anticyclone/high/red Bottom current Deep flow == barotropic uniform full water column

7. Barotropic eddies are generated during the baroclinic instability process. • The phasing of these eddies with respect to the upper jet determines cross-frontal fluxes. • The bulk of the cross-frontal exchange happens episodically in large events. • Measurements throughout the water column are crucial to quantify the mesoscale dynamics.

8. End of PSMIP presentation Remaining slides are for joint PSMIP (Process Studies and Model Improvement) and POS (Phenomena, Observations, Syntheses) Panels Session

9. The KE System appears to be transitioning from the stable “elongated” state to the more variable “contracted” state. KESS observations have captured both states. Preliminary results show that these vortices have signatures well below the thermocline

10. KEO Surface flux buoy KESS Timeline NSF KEO is both an element of the Kuroshio Extension System Study (KESS)… KEO Timeline NOAA Funding Begins Turnaround Cruise ? ? … and an element of the global network of OceanSITES time series reference sites.

11. As an OceanSITES time series reference site,KEO data is being used to assess satellite, NWP and GCM products. Kubota et al., 2006 NCEP/NCAR Reanalysis summertime Solar Radiation appears to be too weak.