WP3 – Task 3.6 Surface drifters Author: Pierre Blouch (EUMETNET) Date: 10 th June 2015 Version:1.0

Surface drifters Surface drifters From May 17th to June 2 nd, 2015 Eumetnet barometer buoys Non-Eumetnet barometer buoys Non 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 jhjh –jhj –lklkl 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