In situ Lagrangian drifting buoy data off East Antarctica for the austral spring of 2012, deployed during the SIPEX II voyage of the Aurora Australis

Progress Code: completed | Statement: Deployment opportunities were compromised due to poor flying conditions (weather) as well as, at some occasions, due to inefficient flight scheduling. Scientific deployment plan was not fully reflected in Service Level Agreement. Standard Operating Procedures for ice-floe work via helicopter makes the realisation of meso-scale ice-physics work difficult. Importantly both helicopters have to work together (within visibility of each other, which for meso-scale work means that each buoy deployment requires two helicopters to be present. Helicopters were only allowed to shut down once safely landed on an ice floe, if they were within 20nm of the support vessel. Having not only one but two helicopters under power sharing ones workspace on often confined ice floes impacts on communication and work efficiency for the deployment team. | Purpose Provide in situ measurements of sea-ice displacement for a defined time span, from which to derive sea-ice motion. | In situ Lagrangian drifter positions were collected from nine expendable sea-ice buoys. Positions were collected by GPS receivers aboard each buoy and relayed via the CLS Argos satellite data system. The scientific proposal for this project was based on the deployment of two meso-scale buoy arrays over the continental shelf break in the SIPEX 2012 experimental region. Resolving of ice motion over the continental shelf and the shelf break is expected to provide crucial information on sea-ice deformation and ice strength. However, due to the unfavourable cruise track and also due to operational issues with helicopter support, it was not possible to deploy any of the meso-scale buoy arrays. Instead buoys were deployed to resolve ice deformation within the wider SIPEX 2012 region. Position data are available hourly from most buoys. CLS Argos transmitted data suffer from a data transmission blackspot just prior to local none, when there will be no data available. Data processing will be carried out as described in Heil et al. [2008] The dataset is build from ASCII files for each buoy with time stamps and observed latitude and longitude. The format (by column [C] for each file is as following: C1: Program ID C2: Buoy ID C3: Year C4: Month C5: Day C6: Hour C7: Minute C8: Second C9: Day-of-year C10: Lat (degN) C11: Lon (degE)