International Polar Year 2007–2008 - WMO

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IPY 20 07–20 08
ocean circulation have taken place in the Antarctic
Circumpolar Current. The IPY therefore provided both
a unique near-synoptic assessment of the physical,
biogeochemical and biological state of the Southern
Ocean and insight into the extent, drivers and impacts
of Southern Ocean change.
Many aspects of the Southern Ocean were
measured for the first time during IPY. Examples
include measurements of trace metals like iron and
mercury; patterns of pelagic and benthic biodiversity
from near-shore Antarctic waters to the deep sea; and
the circulation and water mass properties beneath
the winter sea ice. A summary of the observations
completed in the Southern Ocean during IPY and
research highlights from this work are presented in
Chapter 2.3.
The IPY Science Plan called for development of
ocean observing systems in both the Arctic and the
Southern Ocean. In 2006, at a meeting in the margins
of the SCAR Open Science Conference in Hobart, an
international consortium of scientists spanning all
disciplines of Southern Ocean research started to
develop a strategy for sustained observations of the
Southern Ocean. One of the greatest achievements
of Southern Ocean science during IPY was the
demonstration that sustained observations of
Fig. 3.3-1. Repeat
hydrographic
sections proposed
for SOOS. Each of
these lines has been
occupied previously
during the World
Ocean Circulation
Experiment and the
Climate Variability
and Predictability
Program.
the Southern Ocean were feasible, cost-effective
and urgently needed. IPY in this sense served as a
demonstration or pilot project for the Southern Ocean
Observing System (SOOS). Commitment to resource
and implement the SOOS will leave a significant and
long-lasting legacy of Southern Ocean IPY.
The scientific rationale and implementation
strategy for the SOOS is summarised in Rintoul et al.,
(2010) and described in detail in Rintoul et al., (2010).
As discussed there, sustained observations of the
region are needed to address key research questions
of direct relevance to climate and society, including
the global heat and freshwater balance, the stability of
the overturning circulation, the future of the Antarctic
ice sheet and its contribution to sea-level rise, the
ocean uptake of carbon dioxide, the future of Antarctic
sea ice, and the impacts of global change on Southern
Ocean ecosystems.
The limited available observations suggest the
Southern Ocean is changing: the region is warming
more rapidly, and to greater depth, than the global
ocean average; salinity changes driven by changes in
precipitation and ice melt have been observed in both
the upper and abyssal ocean; the uptake of carbon
by the Southern Ocean has slowed the rate of climate
change but increased the acidity of the Southern