Between September 2003 and December 2007, and
including a single mission in September 2002, Seaglider
visited the offshore terminus of the V-shaped transect on 50
occasions, each time collecting between 5 and 20 (median 5
11) dive-climb pairs of profiles within 25 km of the
terminus (Fig. 1). These observations have been almost
continuous since September 2003, with only a few minor
gaps in the time series. Waterfall plots were constructed for
all Seaglider measurements; density and Chl a are shown
for example for September 2003 to December 2004 (Fig. 2).
Variability among individual profiles within a single
monthly visitation was due to internal waves and some
spatial heterogeneity in water mass composition along the
50-km section of the transect. The rationale for averaging
the data from each monthly sampling was to produce an
average record for identifying seasonal and interannual
changes, rather than to focus on variability within a 3-day
sampling period.