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Ocean Surface Topography from Space
Eastern Mediterranean Altimeter Calibration Network - e-MACnet (Continuation of DynMSLaC & GAVDOS)
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Erricos Pavlis
(University of Maryland Baltimore)

D. Paradisis
P. Milas
B. Massinas
(National Technical University of Athens, Greece)
Stelios Mertikas
(Technical University of Crete)


NASA's strategic goal to "study Earth from space to advance scientific understanding and meet societal needs", prompted "GAVDOS", a joint NASA-EU R&D project that over the past ten years evolved into a regional network of tide gauges monitored with continuous GPS in Western Crete, Greece. Unique in the area, it collects continuous precise monitoring of sea level and environmental parameters. Its data and our analysis products help answer strategic questions about Earth system changes, their cause and how Earth responds to these, NASA research objectives 2, 4, 5, and 7.

While e-MACnet offers a wide range of existing, in-place hardware and facilities, we are continuously expanding, improving services, products, quality-control and near-real-time information dissemination. This research will: extend operations and maintenance of the facility; continue the combination, analysis and interpretation of all radar altimeter data in the area; prepare for the upcoming Jason-2 launch and calibration phase; and integrate our facilities with IOC's Tsunami Warning System network (ICG/NEMTWS).

The research builds upon the original GAVDOS project's legacy and relies on collaborations with other European groups, e.g. the French group at the western Mediterranean calibration facility in Corsica, and contributes to other projects, e.g. GOOS, GGOS, MedGLOSS, ICG/NEMTWS, ESEAS, etc.

We support a vital aspect of NASA's ocean science program: the collection of in situ data in support of satellite missions and contribution to regional environmental monitoring of a poorly instrumented area. The offshore buoy will extend the network utility and contribute to the tsunami hazard mitigation goal and coastal science for the region. Our original network of two sites, one situated under a cross-over of two tracks, i.e. two calibrations per repeat cycle, and one at Kasteli, provides a total of three observations per repeat cycle. This network has already been expanded and will continue to in the next three months, with the addition of six more tide gauges at strategically selected locations (green triangles in the above figure), so that we can sample 5 to 6 different tracks of JASON-2 in every 10-day cycle. The addition of ancillary instrumentation on existing HCMR buoys (red circles in the above figure) in the near future, will further enhance the utility of this network to monitor the performance of altimeter instruments with great redundancy and in near-real-time.

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