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A technique for the analysis of data from a subsurface moored upward-looking acoustic Doppler current profiler (ADCP) to determine ice coverage, draft and velocity is presented and applied to data collected in Marguerite Bay on the western Antarctic Peninsula shelf. This method provides sea ice information when no dedicated upward-looking sonar (ULS) data is available. Ice detection is accomplished using windowed variances of ADCP vertical velocity, vertical error velocity, and surface horizontal speed. ADCP signal correlation and backscatter intensity were poor indicators of the presence of ice at this site. Ice draft is estimated using a combination of ADCP backscatter data, atmospheric and oceanic pressure data, and information about the thermal stratification. This estimate requires corrections to the ADCP-derived range for instrument tilt and sound speed profile. Uncertainties of ± 0.20 m during midwinter and ± 0.40 m when the base of the surface mixed layer is above the ADCP for ice draft are estimated based on (a) a Monte Carlo simulation, (b) uncertainty in the sound speed correction, and (c) performance of the zero-draft estimate during times of known open water. Ice velocity is taken as the ADCP horizontal velocity in the depth bin specified by the range estimate.

As part of the U.S. Southern Ocean GLOBEC program, moored time series measurements of temperature, conductivity (salinity), pressure, velocity, and acoustic backscatter were made from March 2001 to March 2003 in and near Marguerite Bay, located on the Antarctic Peninsula western shelf. To monitor surface forcing during the moored array observations, two automatic weather stations (AWSs) were deployed on islands in Marguerite Bay and time series of wind, air temperature, pressure, and relative humidity were collected from May 2001 through March 2003. This report describes the individual moorings, their locations and local bathymetry, the instrumentation used and measurement depths, calibration and data processing steps taken to produce final time series, and basic plots of the final time series. The AWS data acquisition and processing are also described and basic plots of the final meteorological time series presented. Directions are given about how to access the raw and processed moored and AWS data via the SO GLOBEC website