James Clark Ross (on which much of the ORCHESTRA fieldwork will take place) - Mike Meredith
A major new UK contribution to SOOS is the recently-launched ORCHESTRA project, which aims to “advance our understanding of, and capability to predict, the Southern Ocean’s impact on climate change via its uptake and storage of heat and carbon.” The programme includes major ship expeditions (including to the Drake Passage, the Weddell and Scotia Seas, and across the South Atlantic), autonomous vehicle deployments, tagging of marine mammals, and research aircraft campaigns. Data collected will be used to improve model schemes and validate model outputs, and the improved capability will be fed through to UK climate model development.
The ORCHESTRA programme runs from 2016 – 2021, and focuses on three main questions:
Q1. What controls the exchange of heat and carbon across the air-sea-ice interface, and how well are these exchanges constrained by observations and reproduced by models?
Q2. What are the leading-order processes that control the rate at which heat and carbon enter the Southern Ocean interior in its different layers, and how will these rates change in future?
Q3 What are the size, variability and controls on basin-scale heat and carbon fluxes throughout the Atlantic sector of the Southern Ocean and outwards to the global ocean, and how will these change in the future?
ORCHESTRA will address these three questions through a co-ordinated programme of targeted observations and modelling across six institutes funded by the UK Natural Environment Research Council (NERC), namely the British Antarctic Survey (BAS), the National Oceanography Centre (NOC), the Plymouth Marine Laboratory (PML), the British Geological Survey (BGS), the Sea Mammal Research Unit (SMRU), and the Centre for Polar Observation and Modelling (CPOM). The project represents the first fully-unified activity by NERC institutes to address these challenges. In addition to this, national and international partners, including the UK Met Office, will be drawn in to provide community coherence, and to build a legacy in knowledge and capability that will transcend the timescale of the programme itself.
CTD being deployed in a blizzard - Mike Meredith
The research will be structured in three scientific work packages, with each using different combinations of scientific tools and infrastructure in order to best address the questions above. The packages are as follows:
WP1: Interaction of the Southern Ocean with the atmosphere (NOC, BAS, PML, CPOM). - WP1 will make and use new observations of surface fluxes and their controlling parameters - conducted across a range of conditions, including the open ocean, partially ice-covered regions such as leads and polynyas, and solid pack-ice - to better constrain the exchanges of heat and carbon across the surface of the Southern Ocean.
WP2: Exchange between the upper-ocean mixed layer and the interior (BAS, NOC, SMRU) - WP2 will combine observationally-derived data and model simulations to determine and understand the exchanges between the ocean mixed layer and its interior in unprecedented detail.
WP3: Exchange between the Southern Ocean and the global ocean (NOC, BAS, PML, BGS, Met Office) - WP3 will conduct analyses of both observational and modeling data to constrain past, present and future heat and carbon fluxes on the scale of ocean basins. It will determine the role of large-scale circulation in transferring heat and carbon through the Southern Ocean and exporting them to lower latitudes, and it will ascertain the impact of these transfers on climate.
The five-year, £8.5M ORCHESTRA programme will significantly reduce current uncertainties concerning how the uptake and storage of heat and carbon by the ocean influences global climate, thanks to both a series of unique fieldwork campaigns, and innovative modeling developments.