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Global Drifter Program: Activities and Future Plans

This report provides an overview of the current activities of the Global Drifter Program (GDP) and discusses future plans. It includes information on the status of the global drifter array, drifter evaluations, and data analysis.

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Global Drifter Program: Activities and Future Plans

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  1. Global Drifter Program NOAA/AOMLMiami, Florida, USAISABP – 13Buenos Aires, ArgentinaApril 19, 2010Mayra Pazos

  2. The Global Drifter Program Report Present activities and Future plans

  3. Some of the activities of the Global Drifter Program (GDP) are: • Maintain an active array of 1250 surface drifter throughout the world with the cooperation of participating countries • Assemble, apply quality control and interpolation procedures to drifter data • Disseminate and monitor real time data on the GTS • Web access, archival and distribution of the datasets • Perform drifter evaluations

  4. Status of the Global Drifter Array The Global Drifter Program

  5. Global Drifter Program (GDP) Drifter Evaluations • The GDP has continued the comparison study of drifters from 4 different manufacturers, deployed in clusters of 4, at the same time and at the same location, to evaluate : • How well these drifters’ transmitters are surviving to the design lifetime of 450 days • How well we can detect drogue presence • How long are drogues lasting compared to the expected lifetime of 300 days • 2005 – 8 clusters were deployed in the Atlantic, all SVPs • 2006 – 8 new clusters were deployed in the Atlantic, all SVPs • 2008 – 5 clusters of SVPs, in different regions of the world • 2010 – 5 clusters of SVPs from 4 manufacturers and • 5 clusters of SVPBs from 5 manufacturers in different regions of the world

  6. ADB 2008 Cluster Deployments -- Clearwater --Technocean --Metocean --Pacific Gyre *Indicates cluster deployment location

  7. grounded grounded Pacific Gyre and Metocean drifters had the best lifetime performance: 3 out of 5 each still alive after >450 days Transmitter and drogue lifetimes Clearwater drifters died more rapidly, only one is still alive after >450 days. None of the drifters failed on deployment but two from Metocean and one from Technocean ceased trasmitting in less than three months. Two Technocean drifters ran aground. Two still alive. Four of Technocean drifters lost their drogues before dying, with a mean drogue lifetime of 120 days. Latest update: July 31, 2009 Lighter shades of colors indicate transmitters’ life Darker shades of colors indicate drogues’ life Both Metocean and Pacific Gyre had large average drogue lifetime

  8. Summary Table of Transmitters’ Life Times (days)9 alive (passing life expectancy of 450days, 11 dead) Clusters Clearwater: One transmitter alive, four quit after 125, 212, 301, 359 days. Technocean: Two transmitters alive, one died after 50 days, two grounded after 236 and 361 days. Metocean: Three transmitters alive, two quit after 34 and 64 days. Pacific Gyre: Three transmitters alive, two quit after 91 and 296 days. * = OK until last update, July 31, 2009

  9. Summary Table of Drogues’ Life Times (days) (drogue life expectancy is 300days) Clusters Clearwater: Two drogues attached until transmitter quit, three drogues lost after 99, 119 and 166 days. Technocean: One drogue attached until transmitter quit at 50 days, other drogues lost after 75, 100, 101 and 200 days. Metocean: Two drogues attached when transmitter quit, 3 drogues lost after379, 385and 400days. Pacific Gyre: One drogue still attached after 506 days, 1 attached when transmitter quit and 3 drogues lost after 12, 250 and 354 days. * = OK until last update, July 31, 2009 (or drifter death)

  10. SST Summary- All good except: • Pacific Gyre: • One SST sensor failed after 30 days in the water. • One drifter had SST too cold by 0.450 (confirmed that correct coefficient was being used). • Metocean: • One SST sensor failed after 5 days in the water. -- Clearwater --Technocean --Metocean --Pacific Gyre SST SST Bad after 30 days Bad after 5 days 0.45 offset was added to correct SST

  11. Jan 23 Jan 23 Jan 12 Mar 6 Plan: 5 clusters each of 4 SVP drifters from 4 different manufacturers, four already deployed 5 clusters each of 5 SVPB drifters from 5 different manufacturers, none deployed yet.

  12. What have we learned from data analysis through March 8, 2010? (55 days after deployment of cluster 1 and 44 days after clusters 2 and 3 deployments) Delayed 31.8 days Delayed 16.8 hours Cluster 1 Cluster 2 Cluster 3 • Technocean drifter in cluster 1 started transmitting 31.82 days later than the other 3 drifters in the cluster • Technocean drifters in cluster 2 and cluster 3 have not transmitted at all, they are considered to have failed on deployment. • Clearwater drifter on cluster 3 started transmitting 16.8 hours later than the other 2 that were successfully transmitting after deployment. • All drifters have their drogues attached. (All drifters had submergence sensor except Clearwater’s drifters that have been using strain gauge drogue detection for several years now). • All SST compare to each other. • Drifters deployed as part of Cluster #4 were successfully transmitting after deployment, but there was still very little data at the time this report was prepared for further analysis. -- Clearwater --Technocean --Metocean --Pacific Gyre

  13. Global Drifter Program (GDP) Drifter Evaluations Strain Gauge Drogue Detection Method • DBCP recommended drifter manufacturers to change drogue detection method from submergence sensor to tether strain. • In September 2008, a pilot study was conducted in the Bay of Biscay, with drifters from 3 US manufacturers that had strain gauge for drogue detection developed on time for the study were deployed and later retrieved. • The manufacturers were: Clearwater Instrumentations, Technocean Inc. and Pacific Gyre Inc. • Results were mixed, indicating that challenges still remain in detecting drogue presence, and making drogues stay attached for longer periods of time. • The Clearwater and Technocean tether strain sensors performed well, clearly indicating drogue lost, but raised concerns over drogue life. The Pacific Gyre sensors malfunctioned. They have already addressed the problem since then.

  14. Tropical Atlantic (30°N – 20°S): 360 drifters (25 SVPBs) These include 25 upgrades by Brazilian Navy • Extra Tropical Atlantic (20°S – 40°S): 100 drifters (75 SVPBs) • South Atlantic (40°S – 60°S): 225 drifters (all SVPBs) These include ~100 upgrades by SAWS These numbers are only Predictions: the actual numbers will vary depending on deployment opportunities. The GDP is trying to increase the number of SVPB drifters deployed world wide, with emphasis in higher latitudes. The GDP continues to encourage and work with interested countries to participate in the barometer upgrade opportunity. GDP Deployment Plans: June 1, 2010 - May 31, 2012

  15. Many thanks to all participants for making this possible!!!

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