Parameters and instruments A. Proshutinsky, Woods Hole Oceanographic

Institution

Science and Education Opportunities for an Arctic Cabled Seafloor Observatory

An NSF-Supported Community Meeting, Barrow, Alaska 7 – 8 February, 2005

In the Arctic, Cabled Observatories have to be among active elements of an Arctic Ocean Observing system and in combination with other observational systems have to monitor processes in the ocean, sea ice, and atmosphere

BACKGROUND:

Major recommendations for Arctic observational strategy and instruments were formulated by two international workshops supported by NSF:

Instrumentation for Arctic Ocean Exploration, October 16-18, 2002, Moss Landing, CA Arctic Observing Based on Ice-Tethered Platforms, June 28-30, 2004, Woods Hole, MA

NOAA Arctic Science Priorities Workshop, February 2-3 2005, Silver Spring, MD

Key Arctic Science Issues Requiring New Instrumentation or Methods of Observation

Physical oceanographic studies primarily seek pressure, temperature, salinity and current measurements to understand the ocean circulation, freshwater and heat contents, vertical structures, water masses and other physical parameters. An improved understanding of surface fluxes, finescale to mesoscale ocean variability, and mixing processes are also considered important to better predict changes in the ice-ocean system.

ArcticArctic Ocean monitoring Ocean monitoring systemsystem

A basin-wide, mobile network of ice-mounted buoys and free-vehicles (i.e.

gliders, drifters, AUVs)

Arctic Ocean Observing System (J-C. Gascard et al)

Principal elements for ocean;

Fast ice pack (or drifting ice)

Surface waters

Pacific waters

Atlantic waters

WIND

““Standard” permanent instrumentsStandard” permanent instrumentsSea level:Sea level:

Sections with bottom pressure gauges in combination with coastal tide gauge

Currents:Currents:

CODAR systems for surface currents

Sections with ADCPs

Sections with moorings equipped with vertical profilers

Sections combining profilers and ADCPs

Water properties (temperture, salinity, and chemistry)Water properties (temperture, salinity, and chemistry)

Sections with vertical profilers measuring water properties

(MMPs, ITPs, acoustic tomography)

Sea ice:Sea ice:

Sections with ULSs (thickness)

Sections with ADCPs (drift)

““Expanded” observation employing:Expanded” observation employing:

AUVs,

Gliders,

And via communication and data exchange with drifters.

• Sea Ice:Sea Ice:

Sea-ice studies focused on measurements of the thermodynamics (growth, decay, and mass balance, including consideration of the snow cover and radiative properties) and the dynamics (deformation, ridging, and failure).

Sea ice parameters

Instruments and methods include:Instruments and methods include: - sections with ULSs, - Airborne methods using AUA’s, helicopters - Direct observations using monthly surveys (snow machines) of ice thickness, ridges, snow thickness, etc. - Ice Mass Balance Buoys deployed in the fast ice to

monitor its thermodynamics, growth and decay

Atmospheric measurements supplemented to the cabled observatory emphasize the need to determine the heat, humidity and momentum fluxes, and variability of radiative and turbulent properties, in addition to obtaining standard meteorological parameters (air temperature, barometric pressure, wind direction and velocity, etc).

Airborne observations using Automated Unmanned Airborne observations using Automated Unmanned Airplanes:Airplanes:

Air temperature profiles

Atmospheric pressure and wind

In addition these AUAs can provide sea ice and ocean surface parameters such as:

Sea ice conditions (concentration, ridges, snow)

Surface water temperature

Wave parameters

•Biological and chemical studies:Biological and chemical studies:

Biological and chemical studies stressed the need to understand processes occurring under the ice during winter, and to evaluate the seasonal and interannual variability of numerous biological and chemical parameters (nutrients, dissolved oxygen and other gases, PAR, fluorescence, optical, etc.) in the ocean on the same temporal and spatial scales as the physical variables. Geochemical tracer studies provide information about freshwater, ocean circulation and mixing processes that cannot be derived from physical measurements alone. While historically these tracer data have primarily been obtained by shipboard collection of water sample and subsequent analysis, it is important to pursue next-generation sensors (such as new sensors based on inline reaction chemistry, optical measurements and microfluidic systems) for integrating geochemical and biogeochemical measurements into autonomous IBOs.

The Monterey Accelerated Research System (MARS) is a cabled-based observatory system, incorporating a benthic instrument node, AUVs, and various other instruments