A Global Eulerian Observatories (GEO) Pilot Project

Uwe Send, IfM Kielfor the

GEO Science Team

EGS-AGU, April 2003

Some of our most important knowledge about the functioning of the oceans comes from long timeseries of data

Salinity at BRAVO in Labrador Sea

(J.Lazier 1980)

Zooplankton and NAO in subpolar N.Atlantic

(courtesy C.Reid)

Some of our most important knowledge about the functioning of the oceans comes from long timeseries of data

TAO temperatures in eastern Pacific

(courtesy M.McPhaden)

Mixed-layer carbon parameters at HOT

(Keeling et al.)

Need to assure continuation and extension of global timeseries observations to address the needs of research, climate change detection, operational applications, and policy makers.

Science applications (monitor, detect, understand and predict):• CO2 uptake by the ocean• biological productivity, biomass, ecosystem variables and fluxes• air-sea fluxes• thermohaline changes, water mass transformation• rapid or episodic changes (mixed-layer, blooms, convection, MOC, etc)• mass/heat transports (boundary current, over/throughflows, MOC)• geophysics

Operational applications:• input data for forecasting systems (in-situ biogeochemical)• constraints (e.g. transports) for assimilation runs• detection of events• validation of products

Technical applications (reference/calibrate/verify/...) :• air-sea fluxes• remotely sensed variables (SST, wind, color)• sensor calibration (VOS, T/S of floats, ...)• model statistics, physics and parameterizations (and their variability)• providing sound signals for float naviation, acoustic tomography • testbed for new instrumentation

baroclinic transport south of Australia from XBT and CTD

(courtesy S.Rintoul)

With this scope, timeseries observations complement naturally the other elements of the global observing system (satellites, floats, VOS, sealevel, coastal buoynetworks), filling a gap that no other system can provide.

GOAL: Build a global network of multidisciplinary timeseries sites

• Use autonomous moored sensors where possible

• “advanced quantities“ still require ship-board sampling

• resolve variability of interest, avoid aliasing

same transport estimated from altimetry

Example: transport sites for the thermohaline circulation

Benefits and added value of a coordinated global system:- linking up changes at different locations - harmonize/share technologies- detecting patterns - cross-community synergy, linked variables- understanding differences between regimes - common data management and access - spreading/propagation of signals/changes - common advocacy

(from N.Gruber)

(Takahashi et al 1995)

Net CO2 flux

Example: variability in carbon uptake

Example: Coordinated ecosystem changes (Chavez et al)

A global ocean timeseries observatory system is now under development

• A GOOS/CLIVAR/POGO sponsored (via OOPC/COOP) activity

• The system is multidisciplinary in nature, providing physical, meteorological, chemical, biological and geophysical timeseries observations

• Goal is to make the data are publicly available as soon as received and quality-controlled by the owner/operator

• An international Science Team provides guidance, coordination, outreach, and oversight for the implementation, data management and capacity building

• A pilot system (2001-2006) has been defined consisting of all operating sites and those planned to be established within 5 years, subject to evaluation in terms of the qualifying criteria by the Science Team.

Definition of an ocean timeseries site in the global system (requirements):

• Sustained in-situ observations at fixed geographic locations of ocean/climate related quantities at a sampling rate high enough to unambiguously resolve the signals of interest.

• Transport sections using whatever technique are included in choke points and major boundary current systems (moorings, gliders, ship ADCP, tomography, etc)

• Coastal timeseries are included when they are instrumented to have multidisciplinary impact on the global observing system and if they are not part of a national coastal buoy network.

• Any implemented site fulfilling criteria will become part of the system but has to deliver its data into the system and to demonstrate successful operation and value after 5 years.

• Real-time data telemetry of operational variables will be pursued, i.e.make effort if technically feasible

• Data should be made public in near real-time for real-time data or as soon as processed and post-calibrated for other data

• develop a common data format for multidisciplinary timeseries data (2003)

• establish global data centers (1-2 US, 1 Europe, 1 Japan) (2004)

• start by merging data from TAO/TRITON/PIRATA, Bermuda, Hawaii, MBARI, ANIMATE, HiLats

• define quality control standards

• work with programs/P.I.´s to gradually include real-time and delayed-mode data from all sites

Common data access:

Initial map of the pilot timeseries observatory system

Mooring status and plan for Indian Ocean

(Masumoto et al)

www.oceantimeseries.org (next week)

Contacts:

rweller@whoi.eduusend@ifm.uni-kiel.de