|
|
Observing
Vertical Ocean Fluxes of Heat Salt and Momentum in the Central Arctic.
As the ocean provides a critical “thermal flywheel” in the
Arctic heat balance on seasonal and longer time scales, accurate
measurement of vertical heat fluxes through the upper ocean is critical in
determining the balance between radiative and sensible heat fluxes at the
ice surface, changes in ice cover, thickness and heat content, and ocean
heat content which all interact over seasonal scales to maintain ice cover
in the Arctic. The insulating properties of the Arctic ice cover largely
decouple rapid, strong variations of surface heat fluxes from the ocean
interior. Furthermore, since still water is also a very good insulator,
the vertical transport of heat to and from the salt stratified ocean
interior is determined primarily by the rate at which the upper ocean is
stirred. This stirring occurs when wind blows over the ice and moves,
forming a turbulent boundary layer extending down from the ice toward the
stratified pycnocline, typically at 30m depth. The flux buoy measures
these fluxes within the stirred “mixed” layer below the ice. I have
been funded to develop autonomous, ice-deployed drifting buoys (http://www.oc.nps.navy.mil/~stanton/fluxbuoy/)
capable of measuring vertical fluxes of momentum, heat and salt in the
upper ocean in Polar regions through the NSF “Polar Instrumentation and
Technology Development” program. The first of a series of buoys has been
deployed as a component of the North Pole Environmental Observatory (http://psc.apl.washington.edu/northpole/index.html)
near the North Pole in April 2002 in a cluster of observing systems that
measure the local ocean/ice/atmosphere vertical fluxes. The approach taken
in the buoy design and progress of the program will be discussed.
|
|