The role of sea ice in Arctic coastal dynamics and nearshore processes H. Eicken 1, J. Brown 2, L. W. Cooper 3, T. C. Grenfell 4, K. M. Hinkel 5, A. Mahoney 1, J. A. Maslanik 6, D. K. Perovich 7, C. Tweedie 8 1: GI-UAF, 2: WHOI, 3: DE&EB, UT, 4: DAS, UW, 5: DG, UCi, 6:CIRES, UCo, 7: CRREL, 8: DBPP, MSU Introduction: The Arctic coastal zone as a large-scale multi-phase boundaryIntroduction Far-field effects: Reduction in sea-ice extent, coastal erosionFar-field effects Nearshore effects: - Sediment export by sea iceSediment export by sea ice - Ice-push and break-out eventsIce-push and break-out events - Bottomfast ice and coastal morphologyBottomfast ice and coastal morphology Conclusions: Changes in sea-ice regime enhance fluxes of energy and matter across coastal zoneConclusions The Arctic coastal zone as a multi-phase boundary Changing ice cover Comiso, 2002 Lengthening of open water season in coastal Alaska Days Year PB ice free PB 15 km) Photo: Craig George Ice push and ride-up events Bottomfast ice: Ice bonding and coastal morphology Reimnitz, 2002 Changes in the bottomfast ice regime: Laptev Sea Changes in bottomfast ice regime Changes in bottomfast ice regime: Reduced ice thickness Conclusions: Changes in sea-ice regime enhance fluxes of energy and matter across coastal zone Decrease and thinning of sea ice cover with increased cyclone activity Changes in sea ice regime result in substantially enhanced fluxes of heat, freshwater, particulates through the coastal zone Ice-associated impacts include: (1) increased exposure to wave action during open water season with receding ice edge, (2) sea-ice entrainment and export of sediments in shallow water environments, (3) seafloor/coast-ice interaction through ice gouging and ice push events, (4) thermal subrosion and reduced ice-bonding in bottomfast ice zone, (5) larger scale land-ocean heat and moisture exchange Fast ice schematic Sea Ice Index Monitors Summer MinimaLast years minimum ice extent was a record low Sept 2003 also low Remarkably similar pattern both years We attribute to large scale circulation patterns anomalously warm southerly winds advecting ice poleward in spring enhanced cyclonic activity in summer resulting in greater ice breakup and melting 2002 Fetterer, Serreze, Maslanik et al. 1 Feb Feb Feb Feb 2002 Fast-ice morphology