This is a presentation of my recent work on bathymetric controls on the North Atlantic Current. The MASTS (Marine Alliance for Science and Technology for Scotland) conference allows you to submit e-posters which are displayed on large TVs, thus opening up the possibilities for including animated media. View in Youtube for higher res version.
The ICES Working Group on Ocean Hydrography (WGOH), of which I am a chair-invited member, has just published its annual report on North Atlantic ocean conditions in 2018. The report comprises several dozen multi-year time series of ocean observations around the North Atlantic Basin, which together paint a coherent picture of the current status of the ocean climate: https://www.ices.dk/news-and-events/news-archive/news/Pages/Ocean-climate-2019.aspx
North Atlantic ocean conditions 2018
In 2016, freshening of the upper ocean (0–1000m depth) was observed in the eastern subpolar North Atlantic. This decrease in salinity has since expanded northwards into the Nordic seas, influencing the Greenland Sea and northern Norwegian Sea to Fram Strait, as well as the southern reaches of the Barents Sea. Freshening is also observed spreading westward into the Irminger Sea and eastward into the North Sea.
Throughout the subpolar region, freshening is accompanied by moderate cooling at just a few sites, indicating that the large changes in salinity are dissociated from changes in temperature.
Freshening of central waters in the northeast Subtropical Gyre and intergyre region (Bay of Biscay, West Iberia, Gulf of Cadiz, and Canaries) was enhanced and extended deeper into the water column. In contrast to northern regions, temperatures here decreased in concert with freshening, thereby conserving water mass properties.
Coupled with atmospheric conditions, sea surface temperatures (SST) exhibited a tri-pole pattern, with warm conditions in both the subtropical and Nordic seas regions and cooler conditions in the subpolar region. A cold anomaly observed in the surface and upper ocean of the central subpolar North Atlantic intensified and expanded after weakening in 2017.
The Scotian and Northeast US shelves were warmer than normal, accompanied by notable freshening at several sites.
Extremely warm temperatures were observed near the surface in spring–summer across the Baltic Sea and the North Sea (> 1.5˚C than normal), with less pronounced warming observed from Biscay to Ireland (0.5–+1.0 ˚C).
A computer simulation of the ocean around Greenland was used to study the movement of water in and out of a large fjord. This is important because warm water that gets into the fjord may come into contact with the Greenland Ice Sheet and cause it to melt. The simulation indicates that a significant amount of warm water comes into contact with the ice during the winter. This was previously difficult to measure because of the difficulties in taking direct measurements of the water during the Greenland winter.
This work was based on Dr Neil Fraser’s PhD, but the model was forced using realistic winter wind conditions rather than idealised wind. This was the first time (for me) that using Paraview to analyse model data in 4D has led or contributed to a publication.
Fraser, N. J., Inall, M. E., Magaldi, M. G., Haine T. W. N. and Jones S. C. (2018). Wintertime fjord-shelf interaction and ice sheet melting in southeast Greenland. JGR: Oceans, https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JC014435
- Slope water has been tracked on the European Shelf using drifters and gliders.
- The deflection onto the shelf is not captured in models.
- The slope water has a higher nitrate concentration that the shelf water, and supplies nutrients to the shelf.
Porter, M., Dale, A., Jones, S.C., Siemering, B., Inall, M.E. (2018). Cross-slope flow in the Atlantic Inflow Current driven by the on shelf deflection of a slope current. Deep-Sea Research Part I, in press. doi:10.1016/j.dsr.2018.09.002
Jones, S., Cottier, F., Inall, M., & Griffiths, C. (2018). Decadal variability on the Northwest European continental shelf. Progress in Oceanography, doi: 10.1016/j.pocean.2018.01.012
This paper details one of the key outcomes from my PhD so it was good to get it finished! It describes how wind acting over the shallow seas west of Scotland can change the origin of waters on the inner continental shelf (and the coast). This region typically recieves a mix of salty, nutrient rich water from the Atlantic and fresher, relatively nutrient poor water from the Irish Sea. 1-2 months of sustained easterly winds can block the inflow of Atlantic water and drive a pulse of Irish Sea water into the region, potentially importing much greater abundances of Irish Sea organisms and pollutants than during a typical year. This body of water is detectable on the continental shelf for several months before it it fully displaced northwards. Conversely, sustained winter storms can drive Atlantic water far onto the shelf and block the outflow from the Irish Sea, bringing oceanic conditions to what would normally be considered coastal locations. The strong variability which results is roughly an order of magnitude greater than the changes seen in the adjacent Northeast Atlantic so is thought to mask the well documented decadal changes in these waters.
The model robotic glider I built a few years ago is back in action; this time in the Scottish Parliament for a science and technology forum. Expertly modelled by Professor Mark Inall.
My animation of FVCOM model output won the 2017 ARCHeR image and video competition. ARCHeR is the largest Cray supercomputer in the UK, and its supercomputing service was used by Dr Dmitry Aleynik (SAMS) to run a series of simulations of waters off the west coast of Scotland. I used the output of these model runs to create the animation using Paraview.
Link to the ARCHeR competition gallery here.
Learn more about my work on data visualisation here.
1 Aleynik, D. Davidson, K., Dale A. C., Porter, M. (2016) A high resolution hydrodynamic model system suitable for novel harmful algal bloom modelling in areas of complex coastline and topography. Harmful Algae, 53(3):102–117, 10.1016/j.hal.2015.11.012
There are numerous projects and facilities within SAMS that are a mystery to many staff outside specific departments. I thought it might be nice to have an occasional informal show-and-tell with a general staff invite, whether it be an interesting experiment, piece of equipment or entire enigmatic wings of the building.
For a start, Professor Mark Inall kindly offered to do a demonstration of the fjord tank .
We had a great turnout, with two sittings to accomodate everyone. Based on the success of this session we’ll definitely do another one fairly soon. A couple of photos below showcasing the tank and Mark’s smashed finger!
On the weekend of the 27/28th SAMS organised a series of outreach and public engagement activities. I set up an exhibition based on the SAMS Marine Robotics Facility, and featuring several of our underwater vehicles. It’s rare that the public gets to see the robots in the flesh, so it was nice to show them off and answer a range of interesting questions.
A couple of photos courtesy of Raeanne.