WP3 – Task 3.6

Surface drifters

Author: Pierre Blouch (EUMETNET)Date: 10th June 2015Version:1.0

Surface driftersSurface drifters

From May 17th to June 2nd, 2015

Eumetnet barometer buoysNon-Eumetnet barometer buoysNon barometer buoys

What are surface drifters?

•SVP global network• Lagrangian buoy (fitted with a drogue centered at 15-metre depth)• Part of the WMO Integrated Global Observing System (WIGOS)• One of the component of GOOS (taget of 1,250 drifters met)• Managed by the Global Drifter Programme of JCOMM/DBCP)• Dropped by any kind of ships (from up to 10-metre high, 18 knots)• Real-time data transmission onto the GTS (WIS)

=> GEOSS compliant• Several operators in the world: Eumetnet/E-SURFMAR in Europe

•SVP drifter family• Basic SVP (SST, “surface current” (15 metres))• SVP-B (same, plus sea level pressure). The most common drifter now.

=> essential to numerical weather analysis• SVP-BS (SVP-B fitted with a conductivity sensor)• SVP-BW (SVP-B fitted with wind measurement capabilities)• SVP-BTC (SVP-B fitted with a thermistor string)

Network improvement in South Atlantic

•Proposed deployments– In Guinea and Angola Basins where a lack

of buoys is obvious

– Budget allows to purchase/deploy about 13 buoys per year thanks to MSC container carriers operating between Le Havre and Cape Town

– Drifters will be standard SVP-B similar to those operated by E-SURFMAR in North Atlantic

– First deployment (4 buoys) occurred on last mid-April

– Coordination with NOAA and Met Office to avoid duplication in deployments

– Sustainability of the network possibly borne by EUMETNET after the 4-year period

Moored buoys Existing drifters(August 2014)

AtlantOS drifters(plans)

Development of new salinity drifters

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•Evaluation by CNRS

Study of drifters fitted with thermistor strings

•These drifters may fill a gap up in sea temperature measurements (EOV)

SVP-BTC Drifter

•Initial proposal– was to improve existing SVP-BTC drifters made

by a SME partner: Marlin-Yug (Ukrain)

– Unfortunately, Marlin-Yug being now a Russian company, it can no longer be an AtlantOS partner

– Satellites sample the sea temperature with a good accuracy and good spatial and temporal resolutions but… in surface only

– Argo floats measure temperatures in depth but with a too poor temporal resolution for air-sea interaction sudies

•Revised proposal– Evaluation study by CNRS, of existing buoys

fitted with a thermistor string