The North Atlantic Ocean and Climate Observing System Stuart A. Cunningham Scottish Association for Marine Science Barbara Berx 1, Eleanor Frajka-Williams 2 and Mark Inall 3 1 Marine Laboratory Science, Aberdeen, 2 National Oceanography Centre, University of Southampton, 3 SAMS. MASTS ASM, Herriot Watt, August 2013

Tickling the Dragon’s Tail The Role of the Atlantic in Global Climate

The strategic focus for MASTS Deep Sea Research 1.Sustained observations of the varying and evolving ocean circulation. 2.Analysis and interpretations of observations for comparison with climate models. 3.Focused field experiments to understand ocean processes not resolved in coupled climate models so these processes may be better represented in models. This will rely on: New Technologies (platforms, sensors, power). Enhancement of sustained observation programmes (in time, space and parameters). Multi-disciplinary teams of brilliant scientists focused on strategic research issues. Definition of ocean circulation: Physical, chemical and biological properties (currents, temperature, salinity, sea-surface level, oxygen, nitrate, carbon dioxide, phytoplankton etc.)

Sustained Observations of the Varying and Evolving Ocean Strategic focus of MASTS deep-seas research must be to observe the patterns of climate change in the ocean, to interpret the observations to understand the process of climate change and to improve our ability to accurately predict the course of climate change globally and regionally. 1.Long time series establish the amplitude and variability on sub-annual, seasonal and inter-annual timescales against which climate change on decadal timescales can be assessed. 2.Monitoring establishes the spatial pattern of decadal changes which are essential for assessing the mechanisms of change. 3.Comparing spatial pattern of change of model predictions with and without anthropogenic forcing establishes whether the decadal changes are the result of natural variability or anthropogenically driven change.

Ocean State Estimation Estimating the Circulation and Climate of the Ocean (ECCO) Aim: to produce increasingly accurate syntheses of all available global-scale ocean and sea-ice data at resolutions that start to resolve ocean eddies and other narrow current systems, which transport heat, carbon, and other properties within the ocean. MIT OGCM 0.3-1° resolution 1993-now 1.Monthly, 10-day, daily or 12- hourly ocean model state, adjusted forcing fields and mixing coefficients.

Atlantic-Nordic/Arctic Ocean Inflows & Outflows Atlantic Inflows to the Nordic Seas (e.g. FSC, Marlab) Atlantic Outflows (FBC, Iceland Ridge, Denmark Strait, Davis Strait)

Lab Sea Exit Array Line 35°N 26.5°N 16°N 35°S From 1996 Since 2004 Deep Western Boundary Current Flux Arrays

Sustained Observations of the Atlantic Meridional Overturning Circulation at 26.5°N The RAPID array at 26.5°N Cunningham, S. A. et al. (2007). "Temporal variability of the Atlantic Meridional Overturning Circulation at 26.5°N." Science 317(17 Aug 2007):

Sustained Observations of the Varying and Evolving Ocean Surface to ~1100m 1100m to 5000m

Sub-Tropical Atlantic Ocean Heat Content Cunningham, S. A., et al., (2013). "Atlantic Meridional Overturning Circulation slowdown causes widespread cooling in the Atlantic." Geophys. Res. Letters submitted.

Slowing of the AMOC 1.6 to 2.7 Sv slowdown Smeed, McCarthy and Cunningham 2013: Slowing of the AMOC, Ocean Sci. Discussion, submitted.

Slowing of the AMOC 1.6 to 2.7 Sv slowdown

Slowing of the AMOC 1.6 to 2.7 Sv slowdown

Ocean Observatories Initiative 2014 to Irminger Sea Node 1.Air-sea fluxes of heat, moisture and momentum. 2.Physical, biological and chemical properties throughout the water column. 3.Geophysical observations made on the sea-floor. 1.Horizontally fixed platforms (moorings). 2.Moored profilers to sample the full water column. 3.Mobile platforms (gliders) for spatial and temporal sampling capabilities.

Observing the Sub-Polar North Atlantic Programme The OSNAP line, comprising: (A) German 53°N western boundary array and Canadian shelf-break array; (B) US West Greenland boundary array; (C) US/UK East Greenland boundary array; (D) Netherlands western Mid- Atlantic Ridge array; (E) US eastern Mid-Atlantic Ridge array; (F) UK glider survey (yellow) over the Rockall-Hatton Plateau and Rockall Trough; (G) UK Rockall Trough and Scottish Slope Current array. Red dots: US float launch sites. Blue star: US OOI Irminger Sea global node. Black concentric circles: US sound sources.

Fluxes Across Sloping Topography of the North East Atlantic The use of multiple AUVs in FASTNEt: a study of Ocean Shelf Exchange Mark Inall Internal tide generation at the shelf break And decay and mixing on shelf Exchange drainage in the bottom boundary Internal tide generation at the shelf break And decay and mixing on shelf Exchange drainage in the bottom boundary Internal tide generation at the shelf break And decay and mixing on shelf Exchange drainage in the bottom boundary Standard Glider Pairs + Turbulence Glider + AutoSub Long Range (planned) Internal tide generation at the shelf break And decay and mixing on shelf Exchange drainage in the bottom boundary

Summary Deep Seas needs to have a motivating strategic focus 1.Sustained Observations 2.Analysis and interpretation (for understanding and to compare to climate models) 3.Focused field experiments/process studies Opportunities: New Technologies (platforms and sensors) Enhancement of existing arrays (RAPID, OSNAP, OOI, Argo) Multi-disciplinary teams of brilliant scientists

The research leading to these results has received funding from the European Union 7th Framework Programme (FP ), under grant agreement n NACLIM