RESEARCH HIGHLIGHT

NABOS/CABOS in 2005: Progress in Science, Outreach, and International Collaborations

November 14, 2005

History :   Many researchers agree that major changes are taking place in the Arctic Ocean, but data from this vast region on top of the world has been scarce. In an attempt to add to our knowledge of the Arctic Ocean, the International Arctic Research Center (IARC) at the University of Alaska Fairbanks (UAF) initiated a large-scale, international Arctic Ocean mooring-based observational program in cooperation with our Canadian colleagues from the Institute of Marine Sciences in British Columbia. The first mooring (see Figure 1 for standard NABOS/CABOS mooring schematic; NABOS=Nansen and Amundsen Basins Observational System and CABOS=Canadian Basin Observational System) was deployed at the Beaufort Sea slope in September 2001. The Russian ice-breaker Kapitan Dranitsyn (Figure 1) has provided the operational base for NABOS cruises since 2002.   Further, the project has been incorporated into major observational programs like NSF-led SEARCH and EU-led DAMOCLES. Since then, our growing project NABOS/CABOS has become an internationally recognized Arctic Ocean observational program. With carefully chosen mooring sites, advanced pioneering technologies, and cooperative spirit, our observational program targets long-term large-scale Arctic Ocean climate change and variability. Our intention is to make NABOS/CABOS a key element of the international Mooring-based Arctic Ocean Observational System (MAOOS) proposed for the International Polar Year.

2005 Operations:   In 2005, IARC field experiments were conducted in three different parts of the Arctic Ocean (Figure 1). The core NABOS program includes collection of data in the eastern part of the Eurasian Basin, where we work in cooperation with our Russian, US, Canadian, and German colleagues. Our new project is a joint program with our Norwegian colleagues in which we conduct observations in the vicinity of Svalbard, Norway (Figure 1), together with observations in the Canada Basin. These three parts together comprise our cooperative, coordinated approach planned for the growing large-scale mooring-based observational program of the Arctic Ocean.

Highlights: The first major results from the moorings were published in GRL (Polyakov et al, 2005) with 20 authors from 7 countries.   Using mooring records, we have found evidence that the Arctic Ocean is in transition toward a new warmer state (Figure 2). For example, the mooring records show two rapid Atlantic water temperature increases in February and August of 2004 totaling 0.8 ° C. By September 2005, the Atlantic water temperature had slowly increased by 0.15 °C. The Russian r/v Akademik Fedorov CTD survey conducted in September 2005 has shown that some portion of this warm water has turned northward along the Lomonosov Ridge. The Atlantic water temperature increase recorded in the Laptev Sea in 2004 is associated with the Atlantic water warm pulse through Fram Strait observed in 1999 (Polyakov, et al, 2005). Our record shows that the next warm Atlantic pulse, which passed through Fram Strait in the winter of 2000-01, has not yet reached the northern Laptev Sea.

Outreach:   In September 2005, IARC, in cooperation with Laval University (Canada), the Arctic and Antarctic Research Institute (Russia), and the Obukhov Institute of Atmospheric Physics (Russia), conducted a summer school with the theme of "Climate Change in the Arctic Ocean," aboard the Kapitan Dranitsyn during its fourth scientific cruise to the Arctic Ocean (Figure 3). Leading invited scientists addressed a wide spectrum of polar disciplines, from oceanography and meteorology to biology, chemistry, and arctic paleoclimate. In addition to the opportunities for learning and professional training, the students aboard the icebreaker had a unique opportunity to experience arctic exploration, to acquire invaluable skills in fieldwork under harsh arctic conditions, and to gain a better understanding of how scientific observations are organized in practice. Students learned first-hand about oceanographic, biochemical, ice, and meteorological observations. For example, they observed a substantial difference between satellite-based and visual ice observations (the ship encountered thick ice where satellite images showed no ice. See Figure 3).

Reference: Polyakov, I., Beszczynska, A., Carmack, E., Dmitrenko, I., Fahrbach, E., Frolov, I.,    Gerdes, R., Hansen, E., Holfort, J., Ivanov, V., Johnson, M., Karcher, M., Kauker, F.,   Morison, J., Orvik, K., Schauer, U., Simmons, H., Skagseth, Ø., Sokolov, V., Steell, M.,    Timokhov, L., Walsh, D., Walsh, J. (2005): One more step toward a warmer Arctic. Geophys. Res. Lett ., 32, L17605, doi:10.1029/2005GL023740.

Figure 1: Researchers from Canada, Norway, Russia, Germany, and the United States participated in the 2005 NABOS and CABOS research cruises in the Arctic Ocean. Additionally, Japan is collaborating on the project. This effort contributes to the comprehensive study of the Arctic as part of the world climate system. The overall purpose of the observational program is to provide a quantitative, observationally based assessment of circulation, water mass transformation, and their mechanisms in the Arctic Ocean.

Figure 2: Moored profiler record of the Atlantic water temperature from the continental slope of the Laptev Sea from September 2003 to February 2005. Isotherm 0 °C (black line ) shows the boundaries of the Atlantic water layer. Note a strong warming signal starting from February 2004.

Figure 3: Top left:   the NABOS-2005 cruise research and summer school team aboard the Russian icebreaker Kapitan Dranitsyn on the ice camp at the Severnaya Zemlya Islands continental slope; top right:   photo of ice taken from the icebreaker on September 14, 2005, at mooring recovery in position marked by red dot on both of the lower panels; lower panels:   show satellite ice information for September 14, 2005, obtained from the Danish Technological University (left) and the University of Bremen (right) based on Advanced Microwave Scanning Radiometer   (AMSR) satellite data.