ICES Report on Ocean Climate 2019

Long time-series of ocean properties are rare in the surface ocean and even more uncommon in the deep ocean. The North Atlantic region is unique, 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 ICES Report on Ocean Climate (IROC) combines decades of ocean observations across the North Atlantic ICES region to describe the current status of sea temperature, salinity, and atmospheric conditions as well as observed trends and recent variability. The IROC is produced by ICES Working Group on Oceanic Hydrography (WGOH; Gonzalez-Pola et al., 2019).

Section 1 synthesizes information from a selection of the longest available time-series into an overview of changes across the ICES Area. The main focus of this report is the observed variability of 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 Argo float data, distributed by the Coriolis data centre in France, while Section 2.4 continues to provide an estimate of the Subpolar Gyre Index. Sections 4 and 5 contain short regional summaries on the variability of North Atlantic upper ocean, and intermediate and deep waters, respectively. A new section has been added this year, reporting for the first time on the conditions in the Gulf of St Lawrence (Section 4.4). The focus of the report is on temperature and salinity measurements. However, additional complementary datasets are included throughout the report, such as sea level pressure (SLP), air temperature, and ice cover.

The data presented here represent an accumulation of knowledge collected by many individuals and institutions over decades of observations. A list of contacts for each dataset is provided in Annex 1, 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 the IROC web tool. 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 WGOH annual meeting reports.

WGOH met via video conference on March 26, 2020 to review oceanographic conditions in the North Atlantic in 2019. The following highlights emerged from the joint analysis of the available hydrographic time-series.