Circulation in the “Freshwater Switchyard” of the Arctic Ocean Michael Steele Polar Science Center, APL/UW Peter Schlosser & Bill Smethie Lamont-Doherty Earth Observatory, Columbia Univ. Ron Kwok Jet Propulsion Laboratory, NASA/Caltech Michael Steele Polar Science Center, APL/UW Peter Schlosser & Bill Smethie Lamont-Doherty Earth Observatory, Columbia Univ. Ron Kwok Jet Propulsion Laboratory, NASA/Caltech
The “Canadian/Greenland Data Hole”: …perhaps the most poorly sampled region of the Arctic Ocean! The “Canadian/Greenland Data Hole”: …perhaps the most poorly sampled region of the Arctic Ocean! Freshwater outflows EWG winter SSS obs. (200 km bins)
The “freshwater switchyard”: A good place to detect the origins of freshwater that’s about to leave the Arctic Ocean The “freshwater switchyard”: A good place to detect the origins of freshwater that’s about to leave the Arctic Ocean 3 project components: 1.Large-scale hydrochemical sections (Schlosser/Smethie/Swift) 2.Boundary current section at the shelf break (Steele) 3.Sea ice transport studies (Kwok) Large-scale sections Boundary current section …based on Jones et al. (1998); Steele & Boyd (1998); Proshutinsky et al. (2002); Rigor et al. (2002)
Details Alert-NP survey : Twin Otter aircraft, 6-9 stations “ THICR ” = TH rough- I ce C TD- R osette, measuring T, S, O 2, oxygen isotopes, tritium/ 3 He, CFC’s, barium, & nutrients. Samples to be drawn at Alert. Boundary current survey : helicopter, 6-9 stations CTD-O, XCP, surface layer bottles. …modified from Newton & Sotirin (1997) Sea ice transport studies : satellites u ice : AMSR passive μwave, ENVISAT SAR; h ice : altimeters on IceSAT (laser) & ENVISAT, CryoSAT (radar)
Switchyard’03 + NPEO’03 NPEO stations Switchyard stations
Switchyard’04 Helo ops 2004: We plan to repeat the main section centered at 84N, 65W. If time allows, we will make a second section centered at about 84N, 55W. Twin Otter ops 2004: We plan to repeat the Alert- NPEO 2000/2003 section. Additional stations may be taken in coordination with helo ops.
Switchyard’03 results T max : a water mass tracer summer Bering Sea Water just below the mixed layer. Atlantic water at depth Oxygen extrema: a new discovery! Low resolution bottle data have often shown these extrema, but Seabird’s new continuously profiling sensor has defined them as never before. We propose that there exist 2 minima formed via biological processes on arctic shelves; the upper one from the Chukchi/ESS, and the lower from the Barents/Kara seas. Falkner, K., M. Steele, et al., Dissolved oxygen extrema in the Arctic Ocean halocline, in prep. for DSR, Oxygen (ml/L) Salinity Temperature (°C) summer BSW Atlantic water oxygen extrema
Switchyard remote sensing Ice transport in the Switchyard (here, across 45°W) anomalously eastward in the 1990’s anomaly is small recently, but westward in the Lincoln Sea Anomalies of ice motion (vectors) and surface air pressure (contours), relative to means. Ice motion is OI blend of buoys and passive microwave.
Timeline & Linkages Linkages with FWI: (a) observations: Proshutinsky, Falkner, Lee, other Canadian Archipelago & Fram Strait activities, river discharge & chemical signature data (e.g., Peterson) (b) modeling: Vörösmarty, Lettenmaier, Tremblay, other ice-ocean-river modelers (c) logistics: NPEO, other Alert-based activities Linkages with ARCSS: SBI: Pickart and other boundary current studies (SBE) Burning question: What is the fate of freshwater in the Arctic Ocean and downstream into the N. Atlantic Ocean? spring, ) THICR development; NPEO does Alert-NP 2) bdry. current survey 3) prelim. satellite anal. 1) THICR deployed for Alert-NP section(s) 3) ENVISAT, AMSR, IceSAT Share helo logistics 2) Share helo logistics w/ Falkner? 3) CRYOSAT Share helo logistics 2) Share helo logistics w/ Falkner? We are here!