Gonzâlez-Pola et al.
ICES-WGOH Assessment on Ocean Climate
Frontiers In Marine Science | www.frontlersln.org
2
March 2019 | Volume 6 | Article 103
1. INTRODUCTION
Since its founding in 1902, the International Council for
the exploration of the Sea (ICES) has aimed to increase the
scientific knowledge of the marine environment and its living
resources and to use this knowledge to provide unbiased, non
political advice to competent authorities 1 . Primarily focused in
the North Atlantic, ICES consists of a network of marine
scientists that seek to coordinate on ocean monitoring and
research, with the aim of providing the best available science to
decision-makers.
ICES internal coordination relies on a complex structure that
builds on the work carried out by up to 150 Expert Groups
(EGs). EGs gather scientists from different countries to address
specific topics within the broad spectrum of marine science.
EG members work throughout the year, typically meeting in
person once per year to work through a series of assigned tasks.
No financial support is provided by ICES for EGs, so members
need to find funds from their home institutions or projects.
This presents a challenge to members and can compromise
engagement, especially in periods of scarce resources. However,
the long-term continuity of most EGs indicates that the funds
invested in their activities are beneficial.
ICES established the Working Group on Ocean Hydrography
(WGOH) within this framework in 1976 (ICES, 1977) to
further the work done by the Hydrography Committee on
data management and to coordinate cooperative hydrographic
research within the framework of the World Meteorological
Organization (WMO). At that time, 15 years ahead of the
creation of the Global Ocean Observing System (GOOS), ICES
represented a major partnership within the ocean community
and a valuable opportunity for international networking, thereby
inspiring several physical oceanographers to join the group.
A review of the WGOH activity up to 2009 is given by
Holliday et al. (2010) within the framework of the Oceans09
Conference. Currently, the WGOH is composed of nearly 50
members from 35 institutions and 18 countries around the North
Atlantic region.
The WGOH has been active, meeting on a yearly basis, for
more than 40 years. During these four decades the way we
observe ocean hydrography has changed profoundly, evolving
from primarily traditional vessel-based in-situ sampling to
progressive incorporation of remote autonomous observation
technologies. Also, the ocean observing community has grown,
initiatives promoting international coordination have emerged,
and comprehensive near-realtime ocean state analyses have
been established as a public service. Meanwhile, the WGOH
has continued to evolve while preserving the essence of its
work aimed at providing ICES with information on ocean
hydrography as a basis for marine ecosystems research and
resources evaluation. Next we present our view on the future of
the WGOH, highlighting its long-standing foundation which is
rooted in international cooperation.
1 from www.ices.dk/explore-us/what-we-do/Pages/default.aspx
2. OCEAN CLIMATE STATUS. THE I ROC
A central component of WGOH annual meetings since its
formation has been a session devoted to regional reviews
of ocean climate. These reviews are based on data from
existing monitoring programs run by individual countries or
as international collaborations, sometimes in the framework
of fisheries management programs. Considered together, the
detailed regional reviews inform our understanding of North
Atlantic variability and may be used to develop joint strategies
for global monitoring.
Over time it became clear that this joint review of ocean
status was valuable to other expert groups working on topics
related to marine environment and ecosystems under the ICES
umbrella. In 1999, the WGOH published the first review
of previous year ocean climate conditions as an Annex of
the WG official Report (Turrel, 1999), naming it Annual
ICES Ocean Climate Status Summary (IAOCSS). A year later,
the IAOCSS became a standalone document. In 2004 major
formatting changes were introduced that helped homogenize the
presentation (Hughes and Lavin, 2004), and key illustrations
were included summarizing changes observed across the North
Atlantic. In 2006 the IAOCSS was renamed ICES Report on Ocean
Climate (IROC) (Hughes and Holliday, 2006). That report first
incorporated the ISAS large-scale gridded fields produced by the
LOPS laboratory and Coriolis operational oceanography center,
a product which exploits the expansion of Argo autonomous
profilers array (Gaillard et al., 2016).
In 2013 the WGOH implemented an interactive web version
of the IROC 2 in collaboration with the ICES Data Center
(Figure 1). Now the regional timeseries are updated as soon as
observations are available during the year and the data can be
freely downloaded. An archive of IROC reports is available on
the website and summary highlights for current year conditions
are posted immediately following the WG annual meeting. A
recent improvement is the inclusion of newly developed indices,
such as the Subpolar Gyre Index (Berx and Payne, 2017; Hatun
and Chafik, 2018), which serves as a proxy for the strength
and extent of the large scale circulation in the North Atlantic.
Current efforts are focused on further standardization with
regards to data processing (i.e., anomaly computation) and report
layout (presentation of regional circulation maps, timeseries
display, etc.).
WGOH analyses are based predominantly on existing
repeated long-term in-situ hydrographic observations at stations
and sections around the North Atlantic, the Nordic Seas and
adjacent shelf seas, including the coastal, shelf and deep ocean.
The idea behind the IROC is that regional experts perform
analyses applying their specialized knowledge of a region to
identify the most relevant available observational timeseries
that support their assessment of hydrographic change. In this
sense it is important to highlight that the IROC web is not
a data repository but a heterogeneous collection of specialized
timeseries. Most series are derived from CTDs deployed at fixed
stations or along sections, with data extracted from either a single
2 https://ocean.ices.dk/iroc/