1. Eastern WP Gap winds April 2013 Dec 2013 SST warmest coldest Local gap wind effect Regional conditions, comments by Gordon and Sprintall SST 6 April 2014

2. Aquarius Satellite February 2014 water vapor Spurs 1 Spurs 2 Gap winds water vapor flux ~0.3 Sv, a bit larger than the Amazon! Amazon limited water vapor flux x

3. 1 2 ERA-40 ERA Interim Satellite measurements of surface winds (Quickscat 10-m) and sea surface temperature (from a satellite microwave radiometer, TMI) averaged for January 2000. Vertical integral of eastward (red) and northward (blue) water vapor flux from ECMWF ERA-40 and ERA-Interim. Color lines represent the 12-month running mean and the thinner line the annual averages. 3 3 zonal meridional Gap 2 is largest, interannual variability Local gap wind effect Total ~0.3 Sv water vapor flux

4. Climatological annual SSS (upper 20 m), 1°x1° lat/long World Ocean Atlas. Ekman transport vectors in Sv, within 2.5°x2.5° cells using long term mean wind stresses based on ECMWF ERA-40 monthly data). Contours of mean ocean dynamic topography (MDOTMaximenko (IPRC) and Niiler (SIO). 1958-2001 average of the divergence of water vapor flux (color; kg m -2 s -1 x 10 3 ) monthly ECMWF ERA-40. E-P (contours; m yr -1 ) estimated from ERA-40

5. 2013, Aquarius SSS + OSCAR Winter freshness in Panama Gulf; ITCZ freshness in summer

6. 2013, Aquarius SSS + OSCAR Winter freshness in Panama Gulf; ITCZ freshness in summer Where to site SPURS-2? What months? Specific Objectives; experiment components and design

7. Regional Scale Variability in Eastern Pacific: Relevance to SPURS-2 Campaign Janet Sprintall, Scripps Institution of Oceanography MoorSPICE Cruise, Solomon Sea SIO La Jolla Westpac Vietnam Sorry I can’t join you today but I am on travel!

8. Wind Forcing Kessler, W. The circulation of the eastern tropical Pacific: A review, PiO, 2006. Positive Curl: Upwelling in NH Note significant meridional component Surface layer variability in the eastern Pacific is influenced by the seasonal migration of the ITCZ (most northerly in ~November). In the far eastern Pacific, the ITCZ interacts with wind jets that blow through gaps that produce strong wind stress curl dipoles (+ve on left flank; -ve curl on right). Gap winds are strongest in winter; vary on short (weekly) time scales and generate coastal eddies

9. Precipitation Fiedler and Talley. Hydrography of the eastern tropical Pacific: A review, PiO, 2006. ITCZ: P>> E with a maximum slightly west of Gulf of Panama Also, high river runoff off western slope of Andes Also, MJO intraseasonal variability high in winter drives heavy rainfall Also, “temporales”, week-long periods of continuous rain but weak winds maybe related to interaction of ITCZ and Caribbean systems.

10. Questions of Interest Focus is on understanding the role of the regional scale forcing and circulation in driving the seasonal patterns of salinity in SPURS-2 area. How does the regional ocean circulation (i.e. NECC; SEC) impact the local coastal circulation including eddy variability? What interplay between regional currents, local upwelling driven by gap wind and/or regional wind forcing, eddy variability and precipitation causes the distinctive SSS “bumps” in the far eastern Pacific? What mix of local (wind-driven upwelling, precipitation, background stratification etc.) and remote (Kelvin waves, regional advection etc.) forcing drives the seasonal variability in barrier layer formation?

11. Approach Addressing these links of the regional/large-scale circulation to the local circulation will consist of analysis of existing remotely sensed (winds, SSS, SST, precip etc.) and in situ (Argo, XBT/CTD etc) data sets to map the climatological local and regional fields Field work (CTD, TSG, hull-mounted ADCP and side-mounted high- freq. ADCP to resolve near-surface currents) required to examine the T-S-V characteristics of the upper ocean stratification (incl. MLD, barrier layer etc.) and circulation (incl. the very near-surface wind- driven Ekman transport) I look forward to future discussion and interaction Contact me at jsprintall@ucsd.edujsprintall@ucsd.edu me too: agordon@ldeo.columbia.edu