33N, 19N: Atlantic Explorer **ae1623**
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This cruise shows two small (40km) deep (550m to over 750m)
eddies at similar latitudes, just north of Bermuda (33N),
and another larger (100km) deep (550m-750m) eddy just north of
Bermuda (19N).

.. -------------------------------------------------------
.. |big_eddy_midwater| image:: big_eddy_midwaterT.png
            :alt: ALTERNATE-TEXT
.. _big_eddy_midwater: big_eddy_midwater.png
.. -------------------------------------------------------



.. -------------------------------------------------------
.. |big_eddy_northbound| image:: big_eddy_northboundT.png
            :alt: ALTERNATE-TEXT
.. _big_eddy_northbound: big_eddy_northbound.png
.. -------------------------------------------------------



.. -------------------------------------------------------
.. |big_eddy_southbound| image:: big_eddy_southboundT.png
            :alt: ALTERNATE-TEXT
.. _big_eddy_southbound: big_eddy_southbound.png
.. -------------------------------------------------------



.. -------------------------------------------------------
.. |bowditch_cont| image:: bowditch_contT.png
            :alt: ALTERNATE-TEXT
.. _bowditch_cont: bowditch_cont.png
.. -------------------------------------------------------



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.. |eddies_1-2| image:: eddies_1-2T.png
            :alt: ALTERNATE-TEXT
.. _eddies_1-2: eddies_1-2.png
.. -------------------------------------------------------



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.. |eddy3_zonal| image:: eddy3_zonalT.png
            :alt: ALTERNATE-TEXT
.. _eddy3_zonal: eddy3_zonal.png
.. -------------------------------------------------------



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.. |little_eddy2| image:: little_eddy2T.png
            :alt: ALTERNATE-TEXT
.. _little_eddy2: little_eddy2.png
.. -------------------------------------------------------



.. -------------------------------------------------------
.. |little_eddy2_cont| image:: little_eddy2_contT.png
            :alt: ALTERNATE-TEXT
.. _little_eddy2_cont: little_eddy2_cont.png
.. -------------------------------------------------------



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.. |little_eddy2_cont1| image:: little_eddy2_cont1T.png
            :alt: ALTERNATE-TEXT
.. _little_eddy2_cont1: little_eddy2_cont1.png
.. -------------------------------------------------------



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.. |little_eddy3_cont| image:: little_eddy3_contT.png
            :alt: ALTERNATE-TEXT
.. _little_eddy3_cont: little_eddy3_cont.png
.. -------------------------------------------------------



.. -------------------------------------------------------
.. |little_eddy3_vect| image:: little_eddy3_vectT.png
            :alt: ALTERNATE-TEXT
.. _little_eddy3_vect: little_eddy3_vect.png
.. -------------------------------------------------------



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.. |near-intertial30N| image:: near-intertial30NT.png
            :alt: ALTERNATE-TEXT
.. _near-intertial30N: near-intertial30N.png
.. -------------------------------------------------------



Big eddy north of Bermuda
^^^^^^^^^^^^^^^^^^^^^^^^^^^

The Atlantic Explorer left Bermuda and sailed 350km north crossing through
the center of a large, strong eddy.  The eddy's vertical extent was
greater than the 750m range of the shipboard ADCP.  Zonal velocities
were 0.35-0.4m/s and meridional velocities were 0.6m/s.

The northbound leg sliced through the center of the eddy.  The southbound
leg was offset to the east and the velocities were smaller, but the eddy
was still visible.


**northbound leg** (click image to enlarge)

As the ship passed into deep water just north of Bowditch Seamount,
the ADCP picked up the signal of a small deep eddy, visible from about
550m down to the 750m range of the instrument.  The core could have
been 600-650m deep; we cannot know the actual vertical extent of the
eddy.  It was about 40km across.

The eddy is circled in the lower left corner of the following figure.
Also visible is a scar at about 500m in the 'v' component, due to
side-lobe interference and/or beam spreading and the existence of a
strong scattering layer at about 500m.  It is not uncommon for ADCP
data to have an along-track bias at the shallow side of a deep
scattering layer.  It is only visible when the ship is moving.  `This
diagram
<http://currents.soest.hawaii.edu/docs/adcp_doc/codas_doc/edit_doc/underway_bias/scattering_layer_toon.png>`_
illustrates the phenomenon.


|big_eddy_northbound|_


**small eddy #1**  (click image to enlarge)

Below is a zoomed in view of the small eddy north of Bowditch Seamount.


|bowditch_cont|_


**southbound leg** (click image to enlarge)

The southbound leg included CTDs.  Ship speed is included in the
figure.  At about 33N, there was a nother deep eddy, also about 40km
across, at a similar latitude to the first one.  This second eddy is
circled in the bottom right of the velocities.


|big_eddy_southbound|_


**two cross-sections of the big eddy**


The following figure shows the averaged velocities from 265m-410m for the
northbound and southbound legs.


|big_eddy_midwater|_


**little eddy #2**


The second eddy is shown below in the box.  A brief stop took place in
the middle of the eddy.

|little_eddy2_cont1|_

The scar at 500m is visible as a negative
(because the ship is heading sought) bias in the otherwise northward flow,
resulting in a light stripe (shown below).


|little_eddy2_cont|_

Both eddies are shown together in the plot below

|eddies_1-2|_



======================

Just as the ship as pulling into Puerto Rico, the ADCP picked up the
signal for a third eddy.  This one was larger, measuring more like 100km
across.

The next three figures show (1) the eddy as the ship passed through it
from north to south, (2) a vector plot with the average velocity from
560m-660m, amd (3) the velocities from 560m-660m plotted as a function
of latitue.



|little_eddy3_cont|_
|little_eddy3_vect|_

|eddy3_zonal|_