September 2025 | Oceanography
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DATA ANALYSIS
In the final step, students analyzed the drifter observations and
compared them to local bathymetry, wind forecasts, and tides.
They accessed oceanographic data through the Copernicus
Marine Environment Monitoring Service archive, which provides
comprehensive global and regional datasets of ocean currents,
sea level, and meteorological variables. In the following analy-
sis, the bathymetry was obtained from EMODnet Bathymetry
Consortium. Students also accessed wind data from Windy.com,
but these data get deleted after one year. Here, we used surface
wind observations from the NOAA Integrated Surface Database
(ISD) provided through SENSOTO, which contains hourly mean
wind speed (m s–1) and wind direction (°), measured at the Horta
station (WMO ID: 085050-99999; 38.52° N, 28.72° W) near Horta
Airport. This station is the closest meteorological site to the
drifter launch point. The teams were also introduced to the oper-
ational numerical model engine, MOHID Water System, from
+ATLANTIC CoLAB (Neves, 1985; Santos, 1995). This platform
uses a system of models to cover the Azores archipelago with dif-
ferent resolutions by downscaling the Copernicus Marine Global
model. The MOHID modeling systems also provide an accurate
estimate of the local tides.
Figure 7a shows the GPS observations of the deployed drift-
ers. The Team 6 drifter was never able to record any measure-
ments, and some drifters lost GPS connection earlier than others.
Only Team 1 collected data from both GPS units, confirming close
FIGURE 7. Panel (a) shows the drifter trajectories obtained
from each of the individual teams. Snapshots of the obser-
vations from the non-commercial Team 1 GPS are pro-
vided at three timestamps between July 17, 2023, and
July 18, 2023. In panel (b), the orange arrow shows the
speed and direction of the wind at that instant as mea-
sured by a nearby weather station, and the blue contour
lines represent the bathymetry. The tide height is listed in
the header. In panel (c), the arrows represent the surface
velocity field that was determined by the numerical sim-
ulation, but the temporal resolution of the model is three
hours, so the snapshots do not capture the full dynamics
of the drifter. Click on the arrow icons to watch animations
associated with b and c.