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**Figure 1. Depths and locations of the time series used in this study. (Top) Record
lengths of the velocity ( u) and temperature (T) time series at 0°, 110°W.
(Bottom) SST and wind record lengths at the measurement locations along 110°W. SST was
measured at 1 m depth except at 5°S for January-August 1986, when the 20 m temperature
record was used.**

**Fig. 2. Time series of zonal and meridional surface wind, SST, and depth
of the 20°C isotherm at 0°, 110°W for the 3 years 1986-1988. Solid lines are
the measured values, and dotted lines are the monthly mean climatological values
based on the historical data from the mooring at this location [ McPhaden
and Hayes, 1990].**

**Figure 3. Low-pass-filtered (91-day Hanning filter) time series of the SST ( T, solid line), surface wind speed (U, short-dashed line), and total surface heat flux
(Q, long-dashed line, see text) at
0°, 110°W for the period indicated. The mean value has been removed from each series
prior to plotting. Scales for Q are
on the left-hand axis; T and U are indicated on the right.**

**Figure 4. Components of the surface heat flux (see equation (1)).**

**Figure 5. Contour plots of ( a) isotherm depth (contours are in degrees
Celsius), (b) zonal velocity (centimeters per second), and (c) meridional
velocity (centimeters per second) in the upper 100 m at 0°, 110°W, based on the 91-day
low-pass-filtered time series. The dashed line superimposed on the isotherm contours
indicates the mixed layer depth computed as discussed in the text. Contour intervals are
1°C, 20 cm s, and 5 cm s for temperature, zonal velocity, and meridional velocity,
respectively.**

**Figure 6. Time series plots of various terms in equation (1). All time series have
been low pass filtered with a 91-day Hanning filter. ( a) Change in the mixed layer
heat content, Q; the solid line was
computed with variable h, and the
dashed line has a constant h = 25 m.
(b) Zonal advective heat flux, Q; the solid line was computed with T/x estimated
from moorings at 110°W and 140°W, dashed line assumes a constant . (c) Vertical entrainment, Q. (d) Vertical diffusive heat flux, Q. (e) Superposition of Q (dashed line) and Q (solid line) as defined in the text.**

**Figure 7. Low-pass-filtered (91-day Hanning filter) time series of the mixed layer
depth h and Richardson number Ri
at the base of the mixed layer at 0°, 110°W, estimated as described in the text.**

**Figure 8. Time series of the winds, SST, and depth of the 18°C isotherm for boreal
spring of ( a) 1986, (b) 1987, and (c) 1988 at the latitudes indicated
along 110°W. Wind sticks point in the direction toward which the wind is blowing. The
length of the sticks is such that 20 m s is equivalent
to the monthly tick marks on the time axis. For SST and 18°C depth, the light line
indicates the daily data and the heavy line indicates a 21-day Hanning low-pass filter.
The 5°S SST in 1986 is actually the 20-m temperature record. The SST and 18°C depth
scales are correct for the equatorial time series. The SST time series at the other
latitudes have been offset as follows: 5°N and 2°N are offset by 6°C and 3°C for all 3
years shown, 2°S is offset by -3°C in 1987 and by -6°C in 1988, and 5°S is offset by
-6°C in 1986 and 1987 and by -10°C in 1988. The 18°C time series offsets are the same
in all years: 5°N is offset by -125 m, 2°N by -50 m, 2°S by 50 m, and 5°S by 75 m.**

**Figure 9. Meridional structure functions and time series of the first EOF of surface
relative to 300 dbar dynamic height constructed from the temperature time series along
110°W in 1987 and 1988. For comparison the meridional structure of a first-vertical-mode
equatorial Kelvin wave with a phase speed of 2.1 m s
is also shown.**

**Figure 10. Time series of zonal and meridional velocity on the equator at 110°W at
depths of 10 m (light line), 45 m (heavy line), and 120 m (dashed line) for boreal spring
of 1986, 1987, and 1988. Units of velocity are centimeters per second.**

**Figure 11. The top panel for each year shows time series (45-day low-pass Hanning
filter) of Q (dashed) and Q (solid; see text for definition).
The bottom panel for each year shows meridional diffusive heat flux Q (dashed) and meridional advective heat flux Q (solid). Records for boreal spring 1986, 1987,
and 1988 are shown.**

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ryan.layne.whitney@noaa.gov