The CNR realised over 138 experiments in the Mediterranean basin with surface Lagrangian drifters in 12 years, not continuously, between July 1998 and April 2022 (month of the last recovery), at coastal and offshore level. Lagrangian drifters produced and sold by 4 different enterprises have been used in the years, with different characteristics in data transmission, structure, repeatability of the experiments, dimensions, batteries, management of the experiments. The four drifters were used in different periods (see the table): - in 1998-1999 the Coastal Lagrangian Drifter (CLD), by Italian company InnoTech S.c.r.l., designed just for coastal use with GPS transmission of its position, by a Trimble Lassen™ SK8, at a frequency of 5 minutes by a GSM mobile phone. The CLD had a housing in PVC with electronic unit, rechargeable battery pack and antennas at its top. Its dimensions were 140 cm high x 27 cm in diameter with a weight of 12.5 Kg. A drogue was used below the CLD; - in 2009-2010 the ArgoDrifter or CODE drifter by Technocean (FL, USA) consisting in a white cylinder of 110 cm height x 15 cm in diameter with four blue sails placed at 90°, for a total area of about 25 m2. Its not rechargeable batteries permitted transmissions till a year by an ARGOS satellite transmitter, a GPS for its localisation and a temperature sensor. Its position at sea was given by both satellite triangulation and GPS; - in 2014 the Iridium Ocean Drifters (ODi) by the Spanish Albatros Marine Technology SA were small, low-cost, and compact surface buoys localised by a GPS module based on Iridium satellite data transmission system (Short Burst Data - SBD). Its housing were two identical halves of a spherical drifter, sealed with an O-ring of 20 cm in diameter and 3 Kg of weight. Drogues were used below drifters; - in 2015-2022 coastal and offshore Nomad drifters by the Spanish SouthTEK Sensing Technologies S.L. were coastal GPRS, namely the Coastal Nomad, and offshore satellite, namely the Offshore Nomad. Both types were made in plastic, yellow colour, 72 cm in height x 22 cm in diameter and 2.895 Kg of weight. The lithium rechargeable batteries allowed operations up to 7 days to the GPRS and several months to the satellite drifters. In the water, only 16 cm of the cylindrical head were over the sea surface. The Nomad drifters were of different types: LCA (GPRS), LCE (satellite), LCH (hybrid, GPRS and satellite), LCF (satellite with temperature sensor). See the list of experiments per year in the Table Immediately any acquisition drifter data were pre-processed and repeated positions or wrong date/time, usually a failure of GPS receiver and visible on plotted tracks, were manually deleted. This was followed by an editing procedure implemented at OGS (Gerin and Bussani, 2011; Menna et al., 2017) starting with the retrieve of the deployment information then filled into the OGS PostgreSQL database, enriched with other important metadata as the type and characteristics of the instruments, the owner, the principal investigator. Here location errors were also replaced with NaNs based on the evaluation of different potential origins of error like positions outside the Mediterranean or on land, duplicated data or data acquired outside the date/time of the experiment or wrong velocities. Further erroneous data remained were then manually removed through a visual check. In some cases, the drifter trajectory was considered as two different deployments and split into more segments due to important temporal gaps or acquisition frequency modifications during the experiment. A new recovery/deployment information were included in the database and the automatic editing procedure is relaunched. A following step was the interpolation of edited data at uniform intervals using a kriging optimal interpolation method (Hansen and Poulain, 1996): at 1-hour intervals data with a frequency in acquisition between a few minutes and 2 hours; at 3-h intervals with frequency till 6 hours; at 6-h intervals with frequency higher than 6 hours. The velocities were calculated as finite differences of the interpolated position. At the end, from the 366 drifter tracks the shortest (just a few data long) were deleted, not permitting a good interpolation, then a final dataset of 204 interpolated drifter tracks is finally available. The presented dataset is composed of the interpolated data in NetCDF files which include the time, latitude, longitude, zonal and meridional speed, and metadata. To be coherent with other dataset released by OGS other 3 variables (Drogue, SST and Volt) are included in the files although they are all set to NaNs as the related information is not available for this dataset. Image Reference: https://www.seanoe.org/data/00793/90537/illustrations/illustration-157.gif. Bibliography Gerin, R. and Bussani, A.: Nuova procedura di editing automatico dei dati drifter impiegata su oceano per MyOcean e prodotti web in near-real time e delay mode, REL. OGS 2011/55 OGA 20 SIRE, Trieste, Italy, 13 pp., 2011 Hansen, D.V. and Poulain, P.-M.: Quality control and interpolations of WOCE-TOGA drifter data, J. Atmos. Ocean. Technol., 13, 900–909, http://dx.doi.org/ 10.1175/1520-0426(1996)013<0900:QCAIOW> 2.0.CO;2,  1996. Menna, M., Gerin, R., Bussani, A., Poulain, P.-M.: The OGS Mediterranean Drifter Dataset: 1986-2016, Rel. OGS 2017/92 OCE 28 MAOS, Trieste, Italy, 34 pp., 2017. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

GlobCurrent is an analysis that linearly combines the geostrophic and Ekman components. Drifters respond locally to a combination of geostrophic, Ekman, tidal, inertial, Stokes, and wind drift processes, including processes on scales smaller and faster than the GlobCurrent grid can resolve. Collocations of drifters (whose drogues move roughly with the 15-m current) and GlobCurrent (also at 15 m, with additional samples at daily intervals from two days before to two days after collocation) are included in this dataset. Six-hourly drifter velocity has been estimated following Hansen and Poulain (1996). We restrict attention to drifters whose continuous drogue presence was confirmed by objective or subjective means (Rio et al. 2012, Lumpkin et al. 2013). The resulting geographic distribution for 1993-2015 (Fig. 1) yields more than eleven million drifter and GlobCurrent zonal and meridional velocity estimates. (A comparable number of drifters lost their drogues and, being more responsive to surface wind forcing, are omitted.)

Ocean latent (LHF) and sensible (SHF) heat flux products developed by several scientific groups have been examined in the European Space Agency (ESA) Ocean Heat Flux (OHF) project. This dataset is the collocations of nine OHF products with in situ surface marine observations of the International Comprehensive Ocean–Atmosphere Data Set (ICOADS Version 3). Required for inclusion are that a) valid collocations exist with all OHF products and their ensemble and b) all ICOADS variables required to calculate a COARE flux estimate are within 2.8 estimated standard deviations of their respective smoothed monthly climatology. All values (including ICOADS flux estimates by the COARE 3.0 algorithm) are considered at the daily, 0.25-degree resolution of the project’s reference grid. The nine product collocations include additional samples at daily intervals from two days before to two days after ICOADS collocation. Further information about the nine standardized products can be found in Bentamy et al. (2018).

GPS Measurements of surface drifters

The deployment was part of the IMPACT project ( http://interreg-maritime.eu/web/impact ) and performed in collaboration with the CMRE-NATO under the framework of a LOGMEC (Long-term glider missions for environmental characterization) experiment. 40 CARTHE-type drifters were deployed in the open sea, in front of the Gulf of La Spezia Gulf (Italy) on May 2, 2019. CARTHE-type drifters are biodegradable drifters, spanning the first 60cm of the water column (Novelli 2017, 2018, 2020). The deployment strategy consisted of releasing drifters on a regular grid (about 6km side and 1km step, with some 500m nesting) in a time window of about 2-3 hours. 5 drifters were released in line after passing by the Portovenere Channel, while exiting the Gulf of La Spezia. 5 drifters were collected nearby Toulon (France) on May 17, 2019 and 4 of them were redeployed in the same area on June 24, 2020 (logistical support by University of Toulon). Each file contains a drifter trajectory in the NetCDF format (ex: 001.nc, 002.nc, etc...). Trajectories of those drifters that were collected and re-deployed are splitted in different files (ex: 001_a.nc, 001_b.nc). Nominal drifter transmission rate: 5 minutes. Positions available until June 28, 2019. The dataset includes raw positions; outliers were removed.   References: • Novelli, G., C.M. Guigand, C. Cousin, E. Ryan, N. Laxague, H. Dai, B. Haus, and T.M. Özgökmen (2017). A biodegradable surface drifter for ocean sampling on a massive scale. J. Atmos. Oceanic Technol., 34(11), 2509-2532. • Novelli, G., C.M. Guigand, T.M. Özgökmen (2018). Technological Advances in Drifters for Oil Transport Studies. Marine Technology Society Journal, 52(6), 53-61. • Novelli, G, C.M. Guigand, M. Boufadel, T.M. Özgökmen (2020). On the transport and landfall of marine oil spills, laboratory and field observations. Marine Pollution Bulletin, 150, 110805. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

PLOCAN is a multipurpose technical-scientific service infrastructure that provides support for research, technological development and innovation in the marine and maritime sectors, available to public and private users. PLOCAN offers both onshore and offshore experimental facilities and laboratories, operational throughout the whole year thanks to the Canary Islands excellent climatic conditions. PLOCAN also brings a broad experience in large national and EU marine/maritime projects. As part ot its activitites, PLOCAN manages a variety of Observation Platforms in order to provide a continuous and real-time in-situ monitoring of the ocean. These platforms can be both fixed or mobile, providing information about the ocean surface and/or the water column. Different sensors are placed in PLOCAN Observation Platforms allowing access to physical, biochemical and climatological data.

PLOCAN is a multipurpose technical-scientific service infrastructure that provides support for research, technological development and innovation in the marine and maritime sectors, available to public and private users. PLOCAN offers both onshore and offshore experimental facilities and laboratories, operational throughout the whole year thanks to the Canary Islands excellent climatic conditions. PLOCAN also brings a broad experience in large national and EU marine/maritime projects. As part ot its activitites, PLOCAN manages a variety of Observation Platforms in order to provide a continuous and real-time in-situ monitoring of the ocean. These platforms can be both fixed or mobile, providing information about the ocean surface and/or the water column. Different sensors are placed in PLOCAN Observation Platforms allowing access to physical, biochemical and climatological data.

PLOCAN is a multipurpose technical-scientific service infrastructure that provides support for research, technological development and innovation in the marine and maritime sectors, available to public and private users. PLOCAN offers both onshore and offshore experimental facilities and laboratories, operational throughout the whole year thanks to the Canary Islands excellent climatic conditions. PLOCAN also brings a broad experience in large national and EU marine/maritime projects. As part ot its activitites, PLOCAN manages a variety of Observation Platforms in order to provide a continuous and real-time in-situ monitoring of the ocean. These platforms can be both fixed or mobile, providing information about the ocean surface and/or the water column. Different sensors are placed in PLOCAN Observation Platforms allowing access to physical, biochemical and climatological data.

PLOCAN is a multipurpose technical-scientific service infrastructure that provides support for research, technological development and innovation in the marine and maritime sectors, available to public and private users. PLOCAN offers both onshore and offshore experimental facilities and laboratories, operational throughout the whole year thanks to the Canary Islands excellent climatic conditions. PLOCAN also brings a broad experience in large national and EU marine/maritime projects. As part ot its activitites, PLOCAN manages a variety of Observation Platforms in order to provide a continuous and real-time in-situ monitoring of the ocean. These platforms can be both fixed or mobile, providing information about the ocean surface and/or the water column. Different sensors are placed in PLOCAN Observation Platforms allowing access to physical, biochemical and climatological data.