DIMES Progress Report
RR0901 - 4 February 2009
We have injected all the tracer (about 80 kg). There were some
adventures in electricity and pressure sensors, and pumps, but we are
finished and it went well. Here is a map of our activities.
The two red lines that make the red cross are our injection streaks.
The 'x' nearby is where we released a shearmeter, 3 RAFOS floats, the
first EM-APEX float and a SOLO float on 3 February. The 9
little circles are a CTD survey planned as the next thing we do (after
another set of floats near the 'x', this time without the EM-APEX
float). Contours are absolute dynamic topography as mapped by Valery Kosneyrev,
in meters. The arrows are geostrophic velocity near the surface from
the ADT map (scale in the lower righthand corner). The geostrophic
velocity at 1500 m depth at the 'x' from the CTD casts at the ends of
our our first injection line is 1.5 cm/s toward the southwest.
This has error bars associated with it, but nonetheless gives us a way
to adjust the position of the various events in the picture to a common
time (displacements are less than 1 km).
The pressure of the injection varied from 1560 to 1590 dbar. Our target
for the injection was potential density = 34.6077, reference to 1500
dbar. Sigma_theta is then approximately 27.6745; neutral
density 27.9. It took us from about 0030 Z on 3 Feb to 0600 Z on 5 Feb
to do this injection. Recovery of the injection system with the
relative motion between sea and Revelle, and high freeboard on Revelle
is not easy. The last recovery was in heavy seas and was flawless,
thanks to Brian Guest and the team working with him. No doubt we have
more adventures before us, but these last two days were probably among
the most challenging and important of the cruise.
photo by Uriel Zajaczkovski