1. The Marine System Modelling group (MSM) at the UK's National Oceanography Centre (NOC) maintains and runs various NEMO configurations. Global, ocean-only, tripolar configurations at 1/4o (ORCA025) and 1/12o (ORCA_R12) resolutions are used in studies coordinated under the long-running DRAKKAR project. Increasingly, these same ocean configurations are being employed in coupled simulations under collaborative programmes with the UK Met Office. NOC also specialises in developing and running biogeochemical models within the NEMO framework and studying shelf-sea processes in regional configurations.
One recent scientific study using ORCA025 identified large near-inertial oscillations in the Atlantic Meridional Overturning which are forced by Near-Inertial Gravity Waves (NIGWs; Blaker et al. 2012, see poster #2899). Here we illustrate how the field of equatorward propagating NIGWs differs between the ORCA025 and ORCA_R12 configurations. At 1/4o, outside of the Gulf Stream region, the waves are smooth and coherent over tens of degrees. At 1/12o the same general features are visible, although the wave crests are more broken. The depth profile of vertical velocity (lower panels) indicates that ORCA_R12 is resolving some higher modes of variability not present at 1/4o resolution. An animation of the simulated NIGWs can be viewed at:
Blaker, A. T., et al., Large near-inertial oscillations of the Atlantic meridional overturning circulation, Ocean Modelling, 42, 50–56, doi: /j.ocemod , 2012.
Drakkar project:
Vertical velocity (m/day) at 2km depth from (top left) NEMO ORCA025 and (top right) NEMO ORCA_R12. Sections of vertical velocity at 55oW (shown as a solid black line in both plots) are shown below in the bottom row.