1. 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

2. 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)

3. 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)

4. 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)

5. Switchyard’03 + NPEO’03 NPEO stations Switchyard stations

6. 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.

7. 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, 2004. Oxygen (ml/L) Salinity Temperature (°C) summer BSW Atlantic water oxygen extrema

8. 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 1978-2003 means. Ice motion is OI blend of buoys and passive microwave.

9. 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, 20032004200520062007 1) 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!