Project Title

High resolution underway air-sea observations in Drake Passage for climate science

Summary

Event Number:
O-317-L

Program Director:
Dr. David Porter

ASC POC/Implementer:
Kenneth Vicknair / Bruce Felix

Principal Investigator(s)

Dr. Teresa Chereskin
tchereskin@ucsd.edu
University of California San Diego
Scripps Institution of Oceanography

Project Web Site:
http://adcp.ucsd.edu/lmgould/

Location

Supporting Stations: ARSV Laurence M. Gould
Research Locations: Drake Passage

Description

On frequent crossings of the Drake Passage by the ARSV Laurence M. Gould (LMG), a range of underway measurements are taken. These data represent one of the few repeating year-round shipboard measurements in the Southern Ocean, with more than two decades of data now available. The primary science objectives of this project are to continue to analyze this Drake Passage time series. Some of the analyses are: (1) Describe and relate the seasonal and long-term ocean energy distribution to wind, buoyancy and topographic forcing and sinks; and (2) Describe and relate seasonal and long-term changes in the Antarctic Circumpolar Current (ACC) fronts, water masses, and upwelling to biogeochemical and climate variability. High-resolution, near-repeat Expendable Bathythermograph (XBT) and Acoustic Doppler Current Profiler (ADCP) transect sampling in Drake Passage is used to study modes of variability in ocean temperature, salinity, currents and backscatter in the ACC on seasonal to interannual time frames, and on spatial scales from current cores to eddies. This project is a continuation of the longstanding support for collecting the ADCP and other underway data on United States Antarctic Program vessels, such as the LMG.

Field Season Overview

The O-317-L component will collect ocean current and acoustic backscatter measurements from hull-mounted shipboard acoustic Doppler profilers (ADCPs) onboard the LMG. Data will be collected on all cruises with support from the shipboard electronic technicians (ETs). The operational support from LMG ETs will be similar to that required during previous years of the project, and consists of starting/stopping data acquisition, monitoring, and archiving data at sea. During cruises, ET or IT support may be required, as time allows, in the event that system maintenance or software changes need to be made while underway. Once daily email transmissions (40KB) sent from the ADCP computer to allow for shore monitoring of data quality. ADCP data are archived via an external UHDAS USB drive connected to the logging computer.