scholarly journals Towards Winter Seasonal Predictability of the North West European Shelf Seas

2021 ◽  
Vol 8 ◽  
Author(s):  
Jonathan Tinker ◽  
Leon Hermanson

We investigate the winter predictability of the North West European shelf seas (NWS), using the Met Office seasonal forecasting system GloSea5 and the Copernicus NWS reanalysis. We assess GloSea5’s representation of NWS climatological winter and its skill at forecasting winter conditions on the NWS. We quantify NWS winter persistence and compare this to the forecast skill. GloSea5 simulates the winter climatology adequately. We find important errors in the residual circulation (particularly in the Irish Sea) that introduce temperature and salinity biases in the Irish Sea, English Channel, and southern North Sea. The GloSea5 winter skill is significant for SST across most of the NWS but is lower in the southern North Sea. Salinity skill is not significant in the regions affected by the circulation errors. There is considerable NWS winter temperature and salinity persistence. GloSea5 exhibits significant predictive skill above this over ∼20% of the NWS, but for most of the NWS this is not the case. Dynamical downscaling is one method to improve the GloSea5 simulation of the NWS and its circulation, which may reduce biases and increase predictive skill. We investigate this approach with a pair of case studies, comparing the winters of 2010/2011 and 2011/2012 (with contrasting temperature and salinity anomalies, and NAO state). While 2 years are insufficient to assess skill, the differences in the simulations are evaluated, and their implications for the NWS winter predictability are considered. The NWS circulation is improved (where it was poor in the GloSea5), allowing more realistic advective pathways for salinity (and temperature) and enhancing their climatological spatial distributions. However, as the GloSea5 SST anomaly is already well simulated, downscaling does not substantially improve this – in other seasons or for other variables, downscaling may add more value. We show that persistence of early winter values provides some predictive skill for the NWS winter SST, and that the GloSea5 system adds modestly to this skill in certain regions. Such information will allow prospective end-users to consider how seasonal forecasts might be useful for their sector, providing the foundation on which marine environmental seasonal forecasts service and community may be developed for the NWS.

2019 ◽  
Vol 15 ◽  
pp. 142-144
Author(s):  
John Kennedy

Review(s) of: The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors, by MacQuarrie, Charles W., and Nagy, Joseph Falaky Nagy (eds), (Amsterdam: Amsterdam University Press, 2019) hardcover, 212 pages, 1 map, 4 figures, RRP euro99; ISBN 9789462989399.


Author(s):  
R.P. Briggs ◽  
R.J.A. Atkinson ◽  
M. McAliskey ◽  
A. Rogerson

Histriobdella homari is a polychaete annelid belonging to the Order Eunicida and Family Histriobdellidae. Histriobdella homari is normally found in the gill chambers or among the eggs of the lobster Homarus vulgaris from the English Channel (Roscoff) and in the southwestern part of the North Sea (George & Hartmann-Schroder, 1985). Two independent sightings of H. homari living on the pleopods of Nephrops norvegicus from the Irish Sea and Clyde Sea area are reported.


Author(s):  
D. J. Crisp

Material collected prior to 1940 indicates that Elminius modestus was not present on British coasts at that time.Elminius increased in abundance in south-east England from 1946 to 1950 and extended its range as far as the Humber, where it halted.Its advance westwards along the south coast was similarly halted at Portland, but by 1948 independent colonies had been established in several of the river systems of Devon and Cornwall, in Milford Haven, and in the Bristol Channel.The first populations in the Irish Sea were in Morecambe Bay. From there Elminius spread rapidly south and west along the north coast of Wales, and more slowly north and west towards Galloway, eventually bridging the sea to the Isle of Man.Detailed observations showed that Elminius advanced along the uniformly favourable north coast of Wales as a definite front moving at a rate of approximately 20–30 km per year. Around Anglesey where tidal currents were stronger it appeared simultaneously in many scattered centres.A distinction is drawn between marginal dispersal taking place under the influence of normal agencies at the boundary of an existing population, and remote dispersal due to an artificial or freak transport over a long distance. In the case of Elminius the maximum distance that is likely to be bridged by marginal dispersal in the absence of strong residual drifts is about 30 miles.Elminius probably first appeared near Southampton, and was introduced into the Thames estuary area probably by remote dispersal. Thence it spread along the east coast and was transported to Holland. Its extension into south Devon, the Bristol Channel, the Irish Sea, and to the French coast must also be attributed to remote dispersal.The main ecological effects of Elminius result from competition for space with Balanus balanoides. Since Elminius breeds in summer, its dominance has a profound effect on the composition of the summer plankton, greatly increasing the number of barnacle nauplii, presumably at the expense of other larvae.


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