Waves during 2D fieldwork

Below are data from the offshore rider buoy for the period between September 14 and 21, 2012. Graphs taken from Instituto Hidrográfico.

Significant wave height (blue) and maximum wave height (red).

Average  wave period (blue) and maximum period (red).

Less than 1 m significant wave height, with 5 s average wave period is not enough, even during equinoctial tides that reach 1.5 m above MSL (mean sea level).
Nevertheless, for those of us who stayed at the beach during those long hours, the parameter below was very important!

Water temperature.

Yes, yes, the ADP, PTs and our bodies confirm: 23 degrees water temperature during the afternoon. GREAT!

2D fieldwork on Ancão

The meeting was at 5:30 AM (ouch!!!) to load the boat and transport the team to the study site.

Station 1 was already on site (PT moored offshore, click here for more information).

Station 2 included the ADP (Acoustic Doppler Profiler) and a PT, on an aluminium frame, located lower on the profile.

ADP (on top) and PT (on the leg) on station 2.

Station 3 included an EMC (Electro-Magnetic Current meter) and a PT.

EMC (middle of the frame) and PT (rigth pole of the frame) on station 3.

Station 4 included an ADV (Acoustic Doppler Velocimeter) and a PT.

ADV being deployed on the metal frame by Óscar, Maria and Bruno.

On station 5, 6, and 7 the equipment was not fixed since we didn't know if overwash was going to occur or not.

Poles to fix PTs on stations 5, 6, and 7.

Some people got excited about fixing the frames.

Erwan hammering the pole.

Then we had a lot of waiting for the tide to rise... From 8:00 until 15:00 nothing to do............

For 7 long hours we rested, read, dip, chat, slept, took a walk. Thanks guys for keeping the good  mood!

And at the end of the day, this was the highest water level we got.

Our last action was to retrieve the PT that was moored offshore.On September, 19, the divers were Zapa and Nuno and RUSH team was Ana and Carlos.

Nuno, Ana and Zapa.

The location of equipment was precise and we recovered the PT smoothly.

Here it is. Safe and sound.

Mooring the PT

The first action of the 2D fieldwork was mooring a PT (Pressure Transducer) offshore the study site at about -14 m, below the closing depth of the beach profile (around -12 m in this area).

The mooring structure is a car tire filled with concrete and metal  bars,  with a stainless steel structure on top to attach the PT.

The PT was deployed by two divers (Zapa and Inês), on September 13, at a depth during diving of 16 m.

Daniel is passing the PT to Zapa. Inês is behind the boat in this photo.

The skipper was Daniel and the RUSH team was Ana and André, who did the location of the equipment with the GPS.

Plans for the first 2D fieldwork

The first 2D fieldwork is planned for September, 15th and 16th.
The equinoctial spring tide will (hopefully) provide some extra centimeters to the water level which may be enough to overwash the barrier.

What we are asking Poseidon is to provide us the oceanogaphic conditions to keep the area to the right (photo below) wet, with the instruments measuring overwash flow; and the area to the left dry with the base station, tents, computers, ...

Small elevation in the backbarrier , suppose to be 'safe', where the base station will be set.

Top of the barrier, where instruments will be deployed.