ICES Report on Ocean Climate 2018

Long time-series on ocean properties are rare for the sur­face ocean and even more uncommon for the deep ocean. The North Atlantic region is unique in having a relatively large number of locations where oceanographic data have been collected repeatedly for multiple years or decades; the longest records extend back more than a century. The IROC combines decades of ocean observations across the North Atlantic ICES region to describe the current status of sea temperature and salinity, and atmospheric conditions, as well as observed trends and recent vari­ability. The IROC production focuses the main efforts from ICES WGOH (González-Pola et.al. 2019) Section 1 synthesizes information from the longest time-series into an overview of changes across the ICES Area. The main focus of this report is the observed varia­bility in the upper ocean (upper 1000 m), and a summary of upper ocean conditions is provided in Section 2. Sec­tion 2.3 provides gridded fields constructed by optimal analysis of the Argo float data, distributed by the Coriolis data centre in France, whereas Section 2.4 provides, for the first time, an overview of surface sampling along two shipping routes crossing the Subpolar Gyre. Finally, section 2.5 continues to provide an estimate of the Sub­polar Gyre Index. The next two sections consist of short regional summa­ries on the variability of North Atlantic upper (Section 4), inter-mediate and deep waters (Section 5). Although the focus of the report is on temperature and salinity measurements, additional complementary datasets are included through-out the report, such as sea level pressure (SLP), air temperature, and ice cover. The data presented here represent the accumulated knowl­edge obtained by many individuals and institutions over decades of observations. A list of contacts for each dataset is provided in Section 9, including e-mail addresses for the individuals who provided information, and the data centres at which full archives are maintained. Much of the data included in this report, and additional data, are available to download via a web tool at http://ocean. ices.dk/iroc. A more detailed overview of a particular region, and a full description of some of the datasets used to develop the time-series presented in this report, can be found in the annual meeting reports of the ICES WGOH at http://www.ices.dk/community/groups/Pages/ WGOH.aspx. The ICES WGOH met 19–21 March 2019 in Bergen, Norway, to review oceanographic conditions in the North Atlantic in 2018. The joint analysis of the existing hydro­graphical time-series provided the following highlights.