Collaborative Research: Southern Ocean Current Observations from the U.S. Antarctic Research Vessels, 2010-14

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

"This Award is funded under the American Recovery and Reinvestment Act 0f 2009 (Public Law 111-5)." Researchers from Scripps Inst of Oceanography (UCSD) and the University of Hawaii will continue an effort commenced in 1999 to use underway current profiling capabilities of the Antarctic Research Ice Breakers, Nathaniel B Palmer and Lawrence M Gould. Hull mounted shipboard acoustic Doppler current profilers (ADCPs) enable the acquisition, processing and archiving of upper ocean current velocities and also the structure of the acoustic backscatter signal of Southern Ocean waters through which these vessels ply their transects. The high density of the repeat cruise tracks of the lengthening time series in the Drake Passage (RVIB Gould), a major choke point of the Antarctic Circumpolar Current (ACC), is of interest in providing a record of the effects of climate change in the remote and under observed Southern Ocean. Global circulation models suggest that the Southern Ocean is sensitive to climate change, and likely to warm much faster than other parts of the global ocean. Seasonal to interannual variability of the ACC, the balance of eddy induced exchange compared to mean current mixing, the vorticity balance of the Drake passage and the interaction of circumpolar winds with the planet?s largest ocean current system under changing climate regimes are some of the fundamental questions informed by these measurements. The variability of the backscattering parameter serves additionally as an integrating signal of diurnally migrating zooplankton populations such as Euphausia superba, a key Antarctic food chain species.