ABSTRACT

Annual springtime, large-scale airborne surveys of the Arctic Ocean will be conducted in two regions: the central Arctic Ocean (annual surveys), and the southern Beaufort Sea (odd-year surveys). The surveys will sample the two main circulation features of the Arctic Ocean, the Transpolar Drift Stream and the Beaufort Gyre. The total number of stations will reach a maximum of about 25 at each location during IPY, decreasing to a lower level after IPY as part of a long-term Arctic Observing Network (AON). The proposed surveys have two main goals: (a) observe Arctic Ocean change by taking sea ice and ocean sections across frontal features, and (b) advance understanding of seasonal variability in the sea ice - upper ocean system to map the growth and melt of ice and to reduce seasonal bias in comparisons of past and future hydrographic records.

Five meridional sections will be done during IPY from the North Pole south to 85N, with possible extensions. Pairs of sections will be done annually after IPY. In the Beaufort Sea, the work will include two meridional sections extending to 78N and two nearly zonal sections that will pre-sample summertime icebreaker cruise tracks. After IPY, subset of sections will be done in in odd-numbered years. To resolve seasonal change, station locations will be chosen to provide end-of-winter comparisons with end-of-summer measurements made by Ice Tethered Platforms (ITPs) and icebreakers. At each station a variety of physical and chemical ocean data, including temperature, salinity, and dissolved oxygen will be collected using proven methods. A new nitrate sensing system will expand the high-resolution chemical profiling. Bottle samples of tracers such as dissolved oxygen, barium, phosphate, silicate, nitrate, nitrite, ammonium,
alkalinity, and oxygen isotopes will be taken. In collaboration with US and European sea ice scientists, snow and sea ice thickness data will be acquired both along our flight tracks using remote sensing and in situ while on station. In collaboration with US, European, and Canadian scientists, we will extend our section data from the central Arctic toward the coastlines.

Together with information from ITPs, this project will give the most comprehensive, synoptic view of springtime, Arctic Ocean sea ice - ocean conditions since the Soviet airborne survey programs in the 1970s. This proposed component of the AON will effectively track Arctic Ocean change, and, with corresponding summer measurements, will provide seasonal coverage with which to test system models and their ability to capture system variability. We will help to ensure continuity in the US capability to undertake and remain at the forefront of such science efforts by training two graduate students and so directly engage the next generation of polar scientists. The public will be engaged in polar discovery through a range of activities including, giving public lectures, communicating with the press, giving K-12 presentations, being on the Advisory Board for the Earth & Sky NPR radio program's proposed IPY Polar Heroes project, being a science advisor for the San Francisco Exploratorium proposed IPY project, being on the
Science Advisory Team of MacGillivray Freeman Films' proposed IPY "Polar Quest" IMAX movie, and contributing to the annual Seattle Pacific Science Center-Polar Science Weekend.

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