Irminger Rings Project Overview
|Enlarge ImageMooring materials and instruments are being prepared for the September cruise. In the background, Dr. Bower looks over an upright float-releasing platform. Another platform lies on its side. The long yellow cylinder in the foreground is a float. (Terry McKee)
|Enlarge ImageSr. Engineer, Jim Valdes, discusses features of a new profiling float with Dr. Bower in WHOI's high bay area. Before the mooring is lowered into the water, twelve floats will be attached to the platforms. (Terry McKee)
|Enlarge ImageTwo Submerged Autonomous Lagrangian Platforms (SALP) will be moored at a depth of 500 meters for two years. During that time, they will release twelve profiling floats into eddies that pass by. (Terry McKee)
|Irminger Rings Mooring|
Animation of the proposed Irminger Rings Project mooring, to be deployed in September 2007.
Jack Cook, WHOI Graphics
|» View Video (Media Player) |
Impact of Irminger Rings on Deep Convection in the Labrador Sea
Deep ocean convection is limited
to a small number of isolated regions worldwide, including the Labrador Sea, but it has a profound impact on the ocean’s
thermohaline circulation and climate. While the convection process
itself has been studied intensively over the last decade , the restratification
of the water column after convection, which will directly impact convection during
subsequent winters, is not as well-studied.
It has recently been suggested
that the decay of coherent, long-lived, anticyclonic eddies shed from a surrounding
warm boundary current are potentially important in restratifying convection
regions. This idea is most developed in the Labrador Sea, where anticyclonic
eddies containing a core of warm, salty water from the Irminger Current (a
remnant of the Gulf Stream) have been observed.
The goal of the proposed research is to advance
our understanding of the role of Irminger Rings in deep convection by
collecting new information on their initial structure and on the evolution of their
core properties as they propagate across the Labrador Sea.
To meet this goal, we plan to deploy one densely instrumented mooring in the
northeastern Labrador Sea near, but offshore of the eddy formation site to
document the full water column hydrographic and velocity structure of about 12 new
rings where they detach from the boundary and enter the interior. The mooring
will also serve as the “launch pad” for the automatic release of a profiling
float each time an eddy sweeps by the mooring. Trapped within the eddies by the
strong azimuthal velocities, the floats will track the eddy trajectories and
measure changes in eddy core properties as they move from the formation site
toward the convection region. When this
research program is completed, we will have unprecedented information on the structure
and heat and salt content of nascent Irminger Rings that have separated from
the boundary, improved estimates of the heat and freshwater fluxes associated
with rings, and new information on where and how their anomalous core
properties are spread within the Labrador Sea.