Fig. 1. CTD/ADCP section data distribution. Top panel shows latitudes and longitudes of the 172 meridional sections used in this study. Middle panel shows times when these sections crossed the equator. Sections occupied between 1991 and 2001 are shown by (+). Sections occupied between 1985 and 1991 are shown by (O), with 10 years added for compactness. Bottom left panel shows (contoured at intervals of 10 with increasingly dark contours indicating more data) number of sections where ADCP and CTD data are available in the meridional-vertical plane. Bottom right panel follows bottom left but for number of sections with CTD data alone.
Fig. 2. Sections of mean zonal velocity (U) estimated at 10 nominal longitudes and along the equator. Locations marked in the bottom right corner of each section. Contour interval is 10 cm s–1, with heavy contours at 50 cm s–1 intervals. Eastward velocities are shaded.
The SEC(N) is strongest in the central Pacific, building in strength as it flows from 95°W to 140°W, but then declining almost to nothing by 165°E, and continuing to be weak to 143°E. Like the SEC(N), the SEC(S) is surface-intensified in the east where the thermocline is shallow, but it deepens considerably toward the dateline. The SEC(S) also builds in strength from the eastern to the central Pacific, but maintains its strength further west, weakening by 156°E. Both branches of the SEC have deep extensions in the east that extend far below the thermocline (Fig. 3). These deep branches are strongest at 110°W, but are visible from 140°W to 95°W.
Fig. 3. Sections of mean potential temperature (
)
estimated at 10 nominal longitudes and along the equator, following Fig. 2.
Contour interval is 1°C, with heavy contours at 5°C.
Fig. 4. Sections of mean salinity (S) estimated at 10 nominal longitudes and along the equator, following Fig. 2. Contour interval is 0.1, with heavy contours at 0.5.
Fig. 5. Zonal sections of zonal velocity (U) along the equator estimated for 6 months and both phases of the ENSO cycle. Six months of a SOI = 0 (normal) year are shown in the upper six panels as described in the text. SOI = –1 (El Niño) is shown in the bottom left panel and SOI = +1 (La Niña) in the bottom right panel. Details follow Fig. 2.
Fig. 6. Zonal sections of potential temperature ()
along the equator estimated for 6 months and both phases of the ENSO cycle.
Details follow Fig. 3.
Fig. 7. Zonal sections of salinity (S) along the equator estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 4.
Fig. 8. Meridional sections of zonal velocity (U) at 165°E estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 2.
Fig. 9. Meridional sections of potential temperature ()
at 165°E estimated for 6 months and both phases of the ENSO cycle. Details
follow Fig. 3.
Fig. 10. Meridional sections of salinity (S) at 165°E estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 4.
Fig. 11. Meridional sections of zonal velocity (U) at 155°W estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 2.
Fig. 12. Meridional sections of potential temperature ()
at 155°W estimated for 6 months and both phases of the ENSO cycle. Details
follow Fig. 3.
Fig. 13. Meridional sections of salinity (S) at 155°W estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 4.
Fig. 14. Meridional sections of zonal velocity (U) at 110°W estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 2.
Fig. 15. Meridional sections of potential temperature ()
at 110°W estimated for 6 months and both phases of the ENSO cycle. Details
follow Fig. 3.
Fig. 16. Meridional sections of salinity (S) at 110°W estimated for 6 months and both phases of the ENSO cycle. Details follow Fig. 4.
Fig. 17. Zonal current volume transport (106 m3 s–1) for (from top to bottom) the EUC, NECC, SEC(N), and SEC(S). Left panels show the quantity with error bars versus longitude for means (GRAPHIC_HERE joined by solid lines), SOI = –1.5 strong El Niño (GRAPHIC_HERE joined by dashed lines), and raw data (+). Right panels show contours of the seasonal cycle versus longitude. Contour interval in the right panels is 5 × 106 m3 s–1 and the y-axis tick marks on the left panels are at twice that interval.
Fig. 18. Zonal velocity-weighted current latitude (°) for (from top to bottom) the EUC, NECC, SEC(N), and SEC(S). Contour interval in the right panels is 0.5° and the y-axis tick marks on the left panels are at twice that interval. Details follow Fig. 17.
Fig. 19. Zonal velocity weighted current depth (m) for (from top to bottom) the EUC, NECC, SEC(N), and SEC(S). Contour interval in the right panels is 10 m and the y-axis tick marks on the left panels are at twice that interval. Details follow Fig. 17.
Fig. 20. Zonal velocity-weighted current temperature (°C) for (from top to bottom) the EUC, NECC, SEC(N), and SEC(S). Contour interval in the right panels is 1°C and the y-axis tick marks on the left panels are at twice that interval. Details follow Fig. 17.
Fig. 21. Zonal velocity-weighted current salinity (PSS–78) for (from top to bottom) the EUC, NECC, SEC(N), and SEC(S). Contour interval in the right panels is 0.1 and the y-axis tick marks on the left panels are at twice that interval. Details follow Fig. 17.
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