Eulerian time series form an important element of the modern oceanographic toolbox. As part of the North Pole Environmental Observatory (NPEO; Morison et al., 2002; http://psc.apl.washington.edu/northpole), we therefore maintained a bottom-anchored, instrumented mooring within ~ 55 km of the North Pole from 2001 to 2010 (Aagaard et al., 2008). The mooring site was over the Pole Abyssal Plain in water ~ 4,300 m deep, a location that illuminated boundary current evolution along the Eurasian flank of the Lomonosov Ridge and events in the interior ocean away from the boundary. Standard measurements have included velocity, temperature, salinity, and pressure at various depths, as well as ice thickness (Morison et al., 2002). In 2005 and 2006, sensors for bio-optics and nutrients were added.

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2. Aagaard, K., R. Andersen, J. Swift, and J. Johnson. 2008. A large eddy in the central Arctic Ocean. Geophysical Research Letters 35, L09601, https://doi.org/10.1029/2008GL033461.
3. Morison, J.H., K. Aagaard, K.K. Falkner, K. Hatakeyama, R. Mortiz, J.E. Overland, D. Perovich, K. Shimada, M. Steele, T. Takizawa, and R. Woodgate. 2002. North Pole Environmental Observatory delivers early results. Eos, Transactions, American Geophysical Union 83:357–361, https://doi.org/10.1029/2002EO000259.

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