Figure 1. Geography and place names in the eastern Bering Sea. The location of the two mooring sites is indicated by bold numerals. The hydrographic transect is shown as a solid line. Depth contours are in metres.
Figure 2. Time series for ENSO (the NINO3 index), the PDO8 (after Mantua et al., 1997), and the Aleutian Low.
Figure 3. Times series of wind speed cubed (an indicator of the strength of wind mixing) measured at St Paul Island, 1995-1998. The bold line in each panel is the smoothed (3 day running average) daily mean value established from the 48 year long data set.
Figure 4. The timing of arrival and departure of sea ice at Site 2 is indicated by the dark bars. Dotted vertical lines indicate periods when an El Niño was occurring on the equator.
Figure 5. Contours of the number of weeks that sea ice was present over the eastern Bering Sea shelf. The average ice coverage during (a) cold period, (b) warm period, (c) cool period, and (d) 1972-1998. Solid circles denote Sites 2 and 3.
Figure 6. Contours of temperature (near the transect shown in Fig. 1) from CTD casts collected during (a, upper) July 1982 and (b, lower) June 1997. Cast locations are indicated by arrows at bottom of each panel. Contour intervals are 0.5°C.
Figure 7. Temperature-salinity diagrams at Site 2 during (a, upper)
May and (b, lower) September/October. Lines of constant density are at intervals
of 0.25 
. The
circles represent temperature and salinity at 5 m and the squares at 60 m.
Figure 8. Temperatures measured at Site 2 (depth 70 m). Temperature was measured about every 3 m over the upper 30 m of the water column and then about every 5 m to the bottom. Each year there were three deployments of the instruments. Typically a subsurface mooring was deployed in September and recovered the following February. At this time two subsurface moorings are deployed. In April (after retreat of sea ice), a surface mooring is deployed and then recovered in September. The yellow line is fluorescence or chlorophyll at a depth of ~10 m. Each year the fluorescence is normalized to the maximum value of that year.
Figure 9. (a. upper) The seasonal signal of near-surface temperature at Site 2. Data from years when moorings were located at this site are indicated by coloured lines. Crosses represent data from hydrographic surveys between 1966 and 1994 collected within 25 km of Site 2. (b, lower) The depth-averaged temperature for the same data used in panel a.
Figure 10. The depth-integrated salinity at Site 2 and at Site 3 from historical hydrographic casts. The casts from 1995 to 1998 are included. (a, upper) Measured near Site 2. (b, lower) Measured near Site 3.
Figure 11. Temperatures measured at Site 3 (depth 125 m). Temperature
was measured every ~3 m in the upper 30 m and every 
10 m below that. During 1995-1997, two moorings were
deployed in each year; during 1998, only a single mooring was deployed. The
yellow line is fluorescence or chlorophyll at a depth of ~10 m. Each year the
fluorescence is normalized to the maximum value of that year.
Figure 12. A schematic of flow on the eastern Bering Sea shelf in the upper 40 m of water column generated from a synthesis of moored current meters, satellite-tracked drift buoys and inferred geostrophic flow. Depths are in metres. (After Schumacher and Stabeno, 1998; Stabeno et al., 1999).
Figure 13. Time series of low-pass filtered currents as measured at Site 2 at (a) a depth of 14 m and (b) near the bottom at a depth of 68 m.
Figure 14. Maximum daily wind speed cubed (unbroken line) and 3 day average wind speed cubed (broken line) during May of each year. Winds were measured at St Paul Island.
Table 1. Hydrographic characteristics of the physical oceanographic
features on a section across the south-east Bering Sea shelf. The dates on which
each section was made are shown at the top. The upper mixed layer is defined
to be the depth of constant temperature and salinity equal to that near the
surface (3-5 m). The top 3-5 m is excluded to eliminate the effects of daily
warming during stable periods. The midpoint depth of the thermocline is located
and the density difference across it is defined in units of (103
kg m-3). The lower water column is defined with respect to temperature
of the cold pool (2°C, 3°C and 4°C), its central salinity (psu),
the width (km) of the zone and the latitude of its centre. The width of the
inner front is defined from the position where temperate contours begin to diverge
to the nearshore location where the water column becomes well mixed. The central
position of the middle transition zone is defined as the bottom mid-point of
the tight contours plunging from 40 m to the bottom. Asterisk (*) indicates data not available;
None indicates cold pool not present.
Table 2. Statistics of currents at 15 m near Site 2.
Table 3. Statistics of currents at 60 m near Site 2.
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