Development of the glider system In-Situ Observations MERSEA 3rd annual meeting London, IFM-GEOMAR, Kiel, Germany IMEDEA, Esporles, Spain IFREMER, LPO, Coriolis, CERSAT, Brest, France, LOCEAN, Paris, France, MERCATOR, Toulouse, France SIO, LaJolla, CA, USA

1)Gliders are driven by positive and negative buoyancy created by a change in volume. No propeller is required. 2)Wings convert vertical velocity into forward velocity. 3)Glide downward when denser than surrounding water and upward when buoyant, in a sawtooth pattern. Spray Scripps Institution of Oceanography Seaglider APL-University of Washington Slocum Webb Research Corp. Autonomous Underwater Gliding Vehicle (AUGVs): GLIDERS change of buoyancy and control of internal mass distribution forward movements induced vertical velocity, and control of roll and pitch

Coriolis Data Center IFREMER Brest, France Numerical Models Mercator, MFS,... Ground Station IFM-GEOMAR Kiel, Germany U ~ cm/s W ~ 10-20cm/s Autonomous Underwater Gliding Vehicle (AUGVs): GLIDERS 1k m ~2-5 km between surfacings

North Atlantic Ocean Mediterranean Sea Development of the glider system:  Collection of Physical and Biogeochemical Data during the TOP phase  Data Flow and Quality Control  Data Assimilation  Next operations Spray glider Scripps Institution of Oceanography Slocum glider Webb Research Corporation MERSEA gliders WP3.5: assessment of available long-range glider technologies which meet MERSEA requirements

Mediterranean Sea Operations with 2 Slocums 1) Development of user-fitted lithium batteries for better endurance (x3) Tests during a “virtual mooring“ mission. ~120 profiles (0-1000m, end of Sept. 2005) 2) Trials in coastal environment (0-200m) Poster WP3.5 Virtual mooring off Mallorca To be continued... Potential temperature

North Atlantic Ocean – TOP phase Glider survey around PAP (MERSEA multidisciplinary mooring) Press releases for MERSEA Ouest-FranceTelegramme Proven ~3-months endurance (> 2300 km horiz.) Carried out ~450 dives to 1000m measurements of - Salinity, - Temperature, - Fluorescence (Chl), - Currents averaged over m (green arrows). Preparation at Ifremer (Brest) Deployment from the Argonaute (SHOM) on the still active! +

All profiles in grey. Last profiles in color. [n=last profile] North Atlantic Ocean 5 Dec now ~450 profiles to 1000m [5 profiles/day] Vertical res. ~ 3 m Horiz res. ~ 3-5 km n, n-1, n-2, n-3, n-4, n-5, n-6 Salinity Pot. temperatureChlPot. Density

North Atlantic Ocean Large scale: water mass characteristics and distribution, mixed layer evolution Mesoscale (~50 km): fronts, eddies Small scale (~3-5km): oscillations, filaments – “subgrid phenomena“ Physical constraints on numerical models Potential temperature along the glider trajectory ~ 2300 km - 3 months Mixed layer depth

North Atlantic Ocean Large scale: water mass characteristics and distribution, mixed layer evolution Mesoscale (~50 km): fronts, eddies Small scale (~3-5km): oscillations, filaments – “subgrid phenomena“ Physical constraints on numerical models + PAP 80 km Potential temperature along the glider trajectory U ~ 30cm/s

North Atlantic Ocean Large scale: water mass characteristics and distribution, mixed layer evolution Mesoscale (~50 km): fronts, eddies Small scale (~3-5km): oscillations, filaments – “subgrid phenomena“ Physical constraints on numerical models + Potential temperature along the glider trajectory PAP

North Atlantic Ocean Large scale: water mass characteristics and distribution, mixed layer evolution Mesoscale (~50 km): fronts, eddies Small scale (~3-5km): oscillations, filaments – “subgrid phenomena“ Physical constraints on numerical models Salinity along the glider trajectory

Large scale: biological acitivity (mainly mixed layer), vertical distribution/integral Mesoscale (~50 km): local modulations Small scale (~3-5km): diurnal cycle, filaments North Atlantic Ocean Fluorescence (Chl) along the glider trajectory Vertical integral = bio-activity in the mixed layer validation elements for coupled physical-biogeochemical models

Glider Control from Land Monitoring the health of the glider (Voltage, pump time, waypoints, comms...) Remote steering with information from: 1) model analyses/forecasts 2) satellite imagery “Glider Routing“ in development: use of a glider simulator in NRT to forecast glider trajectories > MERCATOR - SSH AVHRR - SST

Coriolis ftp server Data Access Mersea In-Situ Portal data visualization Coriolis data selection website data visualization and download

Quality Control and Metadata QC procedures at Coriolis like for profiling floats. Profiles are considered as vertical. - T and S outsiders based on historical data - Density inversions are rejected + visual inspection Metadata: Vehicle name, project, PI Waypoint (heading) Angle of ascent/descent Target depth Climb depth Target altitude Time between surfacing Current correction Dive #260 – “dirt“ in the conductivity cell

Assimilation of glider data Temperature differences between MERCATOR North Atlantic 1/15° and the in-situ observations Before data assimilation After data assimilation glider The model trajectory is modified by the data assimilation process, to better fit the observations. development required to better assimilate in-situ data at the moment: correlation criteria for profiling floats 1 profile per 1°x1° per week >> in progress

Achievements and Plans Demonstrated 1) Steering possibility 2) Long endurance 3) Near real time physical and biogeochemical data 4) High density and resolution of the measurements 5) Continuous measurements 6) Impact on operational numerical products Next operations - Deployments in the Western Mediterranean end of March - Deployments in the North Atlantic 1) Maintain surveys around PAP recovery/redeployment 2) Similar survey around CIS June-Sept 2006