Collaborative Research: Eurasian and Makarov Basins Observational Network Target Changes in the Arctic Ocean

The pan-Arctic boundary current provides the largest input of water, heat, and salt into the Arctic Ocean. Recent hydrographic sections and mooring-based observations captured a Eurasian and Makarov basins (EMB) transition from warming to cooling; understanding the transition requires tracing the intensity of this major subsurface transport system. Responding to urgent needs for a long-term observation system for understanding rapid high-latitude climate change, an EMB observational network is proposed as an element of the Arctic Observing Network (AON).

This international, multidisciplinary effort will explore the Arctic Ocean’s EMB. Three August-September cruises, one every two years, are proposed, with extensive measurements along continental margins, a boundary current conduit; cruises will cover vast areas from Svalbard to the East Siberian Sea. The program ties together oceanographic, chemical, and ice observations using moorings, repeated oceanographic sections, and Lagrangian drifters to provide vital information about Arctic Ocean changes.

Intellectual merit: The overarching goal of the proposed study as an AON element is to compile a cohesive picture of the state and transformations of Atlantic Water (AW) in the EMB, with particular focus on three major observational targets:

  • Target #1: Along-slope AW transport by the boundary currents.
  • Target #2: Interaction of AW branches with shelf waters, deep basin interior and upper ocean.
  • Target #3: EMB indications of changes in the upper ocean circulation.

The proposed targets are broad in scope and pose a wide range of challenges to modern high-latitude observational oceanography. Vital boundary-current observations maintained since 2002 will be continued (Target #1). Recent observations suggest an increasing role of shelf-basin interactions under a changing high-latitude marine climate and a shift to cyclonic circulation in the EMB; observational Targets #2 and #3 are therefore critical to the observational network. Highly coherent changes of multi-year sea-ice area and AW warming/cooling suggest that the AW heat may be a contributor to the observed changes of the arctic ice cover; therefore, sustained, dedicated measurements are critical for understanding the role of ocean interior heat in shaping arctic ice (Target #2). The EMB’s size and location mean that this part of the Arctic Ocean is representative of pan-arctic conditions and processes, and therefore appropriate for long-term observing. Therefore, the proposed program is an important element of the pan-AON.

Relevance to AON and SEARCH: This program is vital for interpreting and assessing polar climate change; it contributes to the AON and the interagency Study of Environmental ARctic CHange (SEARCH) programs via maintaining important, critically-needed AON elements. The project’s observational targets are closely linked to SEARCH science questions and address all three observational priorities specified in the SEARCH Implementation Plan. Proposed mooring sites and oceanographic cross-sections are closely related to SEARCH priority areas for distributed ocean and sea-ice observations; these observations are highly relevant to AON and SEARCH goals. Years of accumulated PI experience from the NABOS (Nansen and Amundsen Basins Observational System) and NPEO (North Pole Environmental Observatory) programs, two SEARCH projects, insure the ability to achieve these goals.

Broader impacts: Better understanding of the Arctic’s future course will have direct economic and social benefits. Climate change is very important to Arctic people, impacting infrastructure, food gathering, and survival. The project will disseminate information about observed Arctic Ocean changes via various channels (web pages, mass media, lectures). Strong existing links with several AON projects will foster synergy and interdisciplinary dialog. International cooperation will be enhanced, resulting in shared research infrastructure, updated databases, and knowledge synthesis. Graduate students will be supported; female and Alaska Native students will be encouraged to participate. Program outreach will culminate in 2013 with a shipboard summer school. Data and products, critically-needed benchmarks for Arctic satellite sea-ice and altimeter measurements, will be available per AON data policy.