3.5. Environmental context
As regards to the distribution of near-surface temperatures,
salinity, and limits of mixed and stratified waters during sampling
in early June 2008, 2009 and 2010, the eastern and western parts of
the Irish Sea exhibited contrasting inter-annual variability (Fig. 4).
For example, temperature was higher in the west in 2010 compared
with 2009, but in the east, the differences of SST were not as
marked. Conversely, there was a marked difference in salinity in the
east between 2009 and 2010, but it was only moderate in the west
(Fig. 4). These variations of temperature and salinity influenced the
delimitation of mixed and stratified waters (Simpson Stratification
Index > 20). The apparent increase in the stratified area during the
2010 campaign in the western part of the Irish Sea can be linked to
the more pronounced gradient of near surface temperatures and a
wider distribution of near surface salinities >34 in that region in
2010.