Winter Lead Convection The Study of Environmental Arctic Change (SEARCH) and the Barrow Cabled Observatory Presentation at Science and Education Opportunities for an Arctic Cabled Seafloor Observatory February 7-8, 2005 Jamie Morison Polar Science Center, University of Washington

SEARCH Motivation The Arctic has been characterized in recent decades by a complex of significant, interrelated, pan-Arctic changes (Unaami).

Examples Decreased sea level atmospheric pressure, Increased air temperature over most of the Arctic, More cyclonic ocean circulation and rising coastal sea level, Warmer Atlantic waters, Reduced sea ice cover, Warming of permafrost The physical changes of Unaami impact ecosystems and society. Complex of change appears related to a spin up of the Northern Hemisphere atmospheric Polar Vortex. Complex of Arctic change is a possible component of climate change. Motivates a program of long-term observations, analysis, and modeling

Implementation Strategy at SEARCH Web site: Implementation Strategy at SEARCH Web site: Current Activities at Eight SEARCH Activities Areas include: - DTO: Distributed Terrestrial Observatories - DMO: Distributed Marine Observatories - LAO: Large-scale Atmospheric Observatories - DQU: Detecting and Quantifying Unaami and Other Modes of Variability - LGC: Linkages and Global Coupling - ASR: Arctic System Reanalysis - SEI: Social and Economic Interaction - SOR: Social Response SEARCH Implementation

Distributed Terrestrial Observatories

Large-scale Atmospheric Observatories DTO Sites

DMO: Distributed Marine Observatories Make large-scale atmospheric, oceanographic, sea ice and ecosystem observations in the marine environment. SEARCH Implementation Strategy available at

Distributed Marine Observatories

DMO Philosophy Scales are pan-Arctic and decadal. Therefore the DMO emphasis is on: And because startup is urgent: - Use of proven, existing technologies - Basin-wide coverage - Long, relatively low res time-series

So, what role can a high-tech, high- bandwidth cabled observatory at Barrow have in DMO? Two DMO elements near Barrow: Ocean pathway moorings Cross shelf exchange moorings

Role for high-bandwidth, localized measurements particularly in Cross shelf exchange mooring function of DMO, and The Linkages and Global Coupling (LGC) activity area

Processes in the shelf and slope region are important to ventilation of the deep ocean, e.g. These processes tend to be intermittent and spatially variable. Generation of eddies that move into the basin Cross shelf exchange driven by buoyancy flux in the Seasonal Ice Zone (SIZ) and winter shore leads and polynyas

AIDJEX Lead Experiment, 1974

Indication of cross-shelf exchange Example of bottom boundary layer generated by Barrow shore lead (ALEX, 1974)

Consider buoyancy flux and cross shelf exchange.

These processes create density structure parallel to shore and cross shore pressure gradients, which drive alongshore currents.

So where does cross-shelf exchange occur? In the surface and bottom boundary layers where flow moves down pressure gradient.

How would we use the BCO to measure shelf processes?

Supercoolometer: Seamore ROV SBE 39 T Probe Heater SBE-19+ Temperature & Conductivity Optical Backscatter Water In

JAMSTEC UROV 7k Remotely Operated Vehicle Battery Operated Fiber Optic Link KAIKO Hanger UROV

TIC

SonTek ADVOcean (5 MHz) SBE 03 thermometer SBE 07 micro- conductivity meter SBE 04 conductivity meter SonTek Instrument Cluster Ice T-string ROV- CTD 0.6 m 1 m Van Mijen Fjord Instruments Miles McPhee Turbulent Inst Cluster

Autonomous Flux Buoy Tim Stanton Flux Buoy

The Autonomous Microconductivity-Temperature Vehicle (AMTV)

AMTV

AMTV Results SHEBA Summer Lead Study, Day Under Lead S constant? Cooler Back Toward Ice Warmer Fresher S constant & S’ small Cooler & T’ small Under Ice From Hayes Dissertation, 2003

AMTV Turbulence on S’ and T’ Vigorous Under Lead Turbulence Significant Under Lead S’ and T’ Reduced Under Ice Turbulence Enhanced Under Ice? Lower Frequency From Hayes Dissertation, 2003

AMTV Turbulent Fluxes on 219.9, 1998 at SHEBA Summer Lead Turbulent Stress, u * =(  ) 1/2, Increased Under Ice From Hayes Dissertation, W m W m -2 Substantial Turbulent Heat and Salt Flux in the Lead, Reduced Fluxes Under Ice 2.4x10 -5 kg m -2 s x10 -5 kg m -2 s x10 -5

Conclusions:  The BCSO can play an important part in SEARCH.  Focus as an intensive observing point for shelf-basin processes critical for the large scale behaviour of the marine environment

The End