Maximizing the potential of Arctic Ocean Gateway array

Marie Curie project (EU Horizon 2020)

Duration: July 2015 to June 2017.

Figure 1: Mooring sites maintained during 2008-2009. The four major Arctic gateways (Davis, Fram, Bering Straits and BSO) are highlighted by orange circles. Each box shows length of observations maintained by six different research institutes. Modified Di (Photo: Alfred-Wegener-Institut)

The Arctic boundary has been observed over many years to better understand and monitor the exchanges between the Arctic Ocean and its neighboring oceans. The unique geometry of the Arctic—surrounded by the land masses of North America, Greenland and Siberia—has encouraged researchers to make a joint effort to enclose the Arctic Ocean with hydrographic observation lines (Figure 1).

A method to treat the Arctic as a single box bounded by hydrographic lines and land has been developed recent years. This pan-Arctic approach has produced significant scientific outcomes: the first quasi-synoptic net heat and FW transports in a single month from summer 2005 (Tsubouchi et al. 2012); the dissolved inorganic nutrient budget (Torres-Valdes et al., 2013), and a dissolved inorganic carbon (DIC) budget (MacGilchrist et al. 2014). We have also quantified a full annual (summer-to-summer) cycle of monthly net heat and FW transports during 2005–2006 (Tsubouchi et al. in prep.).

The ARCGATE, funded as a EU Marie Curie project, attempts for the first time to integrate all the individual mooring arrays across the Arctic boundary in order to quantify time variability of ocean circulation and associated heat and fresh water (FW) transports over many years.  During the project, large amount of moored instrument data (c.a. 1,000 moored instruments from 230 mooring sites in total) will be analyzed to quantify the multi-year monthly Arctic heat and FW budgets for the years 2004-2010  (Figure 2).  Moreover, total alkalinity budget in summer 2005 will be calculated to better understand the Arctic Ocean’s role on the carbonate system.

Figure 2: Net oceanic and sea ice FW transport (m3s-1) time series. The transport estimate during 2004-2010 will be quantified under ARCGATE project. (Photo: Alfred-Wegener-Institut)

The ARCGATE also aims to address important questions to design future sustained pan-Arctic observation lines quantifying the uncertainties associated with the results. The specific questions are: (1) Does current configuration of pan-Arctic mooring array monitor the major oceanic heat and FW exchanges between the Arctic Ocean and surrounding Oceans? (2) Where is the most efficient place to add additional instruments to increase the accuracy of measurements?

Acknowledgement:

The Arctic main gateways have been measured by six research institutes in the world: the University of Washington (UW) in the United States (US) for Davis Strait and for the US side of Bering Strait; the Norwegian Polar Institute (NPI) in Tromsø, Norway and the Alfred Wegener Institute (AWI) in Bremerhaven, Germany for western and eastern Fram Strait, respectively; the Institute of Marine Research (IMR) in Bergen, Norway for the Barents Sea Opening (BSO); and the University of Alaska Fairbanks (UAF) in the US and Arctic and Antarctic Research Institute in Russia for the Russian side of Bering Strait. The pan-Artic approach is developed under two UK NERC projects, ASBO and TEA-COSI. 

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Collaborators:

Dr. W.-J. von Appen;  Dr. B. Rabe;  Prof. Dr. T. Kanzow;  Dr. M. Karcher

AWI and Arctic boundary PIs in Davis , Fram, Bering Straits and Barents Sea opening (BSO)