AMT25

AMT25 set sail from Immingham on 15th September aboard the British Antarctic Survey vessel the RRS James Clark Ross and arrived in Stanley, Falkland Islands on 3rd November 2015.

The highlights of AMT25 were as follows:

• Eighty-one CTD profiles at stations spaced approximately 200nM apart measuring key physical and biogeochemical parameters including: temperature, salinity, chlorophyll, oxygen, nutrients, total alkalinity, dissolved inorganic carbon, phytoplankton abundance and microbial dynamics;
• Thousands of underway bio-optical and biogeochemical measurements covering a 100° range in latitude and vastly contrasting ocean biomes;
• Underway radiometry combined with hyperspectral in-water Inherent Optical Property measurements, particularly pertinent for satellite calibration validation. Both hyperspectral and multi-spectral data were taken independently;
• Launch of 7 Argo floats, on behalf of the UK and German Met Offices, in the tropical and south Atlantic;
• Recovery a deep (5000m) sediment trap mooring in the South Atlantic Gyre for NOC, which had previously been deployed in October 2014 (AMT24) and the construction and deployment of a single sediment trap mooring at the same location. The entire operation was achieved in less than 18 hours;
• Automated processing chain, partly developed and designed on AMT24/25, to seamlessly send coarse resolution CTD data to the UK Met Office for assimilation into atmosphere/ocean forecasts. Of particular interest was the real-time ingestion to FOAM of a deep CTD cast (>5000m) in the northern Atlantic;
• Continuous operation of acoustic sensors to probe positions of marine creatures;
• Continuous swath bathymetry and ADCP data;

The image shows the AMT25 track overlaid by NEODAAS satellite products provided during the expedition. From top to bottom: VIIRS chlorophyll, AVHRR SST, VIIRS euphotic depth and VIIRS chlorophyll.