Day2: Alaska GNSS-A Deployment-KOD1_Watch Group 1

Working Blog

After departure, we are excited to get on the way to the planning site to deploy the transponder and waveglider. 

The first shift of watch group consistis of two PIs, Dr. Andy Newman and Dr. Surui Xie, and also 4 students, Nathalie, Joaquin, Alex and Guoli.

Dr. Newman is checking the coordinates of planned sites for deployment

We get up early at 2 am to prepare for the verification of planning sites to deploy the waveglider and transponder. Because the original site is chosen by bathymatry map, and now on boat we have higher resolution bathymetry map. We can check the coordinates of all planned sites on Sikuliaq and make sure the 3 transponders are deployed in the similar depths and each one with the same distance to the center of the triangle.

Group member is checking the bathymetry map of the planned coordinates

Map showing bathymetry and planned sites to deploy transponder

Original planned STK1 site

By checking the bathymetry, in the Sikuliaq's map server we found that there is a trench near the planned site for STK1-B(2), which means the deployed transponder may not be stable at the bottom of the seafloor, and the signal quality would be decreased.

In this case, we need to rotate the planned sites to make each of 3 transponders with the similar depth to be deployed and still with the same distance of each one.

Team is working through to resolve the coordinate issues of STK1

We use the bathymetry map in Sikuliaq to generate new coordinates for STK1, basically rotate from the original sites for about 30 degrees. We control the depths difference in 20 meters level with high accuracy. Also we make each side of the triangle with the similar distances of the centroid of the triangle.

The new site for STK1

At the same time, we need to record the log, which is important to get to know how does the research process go on. We arrive at the main lab at 2:00 am, so we take the first record around that time, and after each hour, time(mainly in UTC), coordinates of latitude and longitude of ship, course angle and ocean current speed are recorded.

Ocean Current Speed profile

Log notebook

In transit on Log book means we are still on the way to the planned sites, after that, at 14:11 UTC, 06:11 local, we arrived at the first station KOD1, began to prepare the deployment of waveglider and transponders. 

At 14:32 UTC, 06:32 local, waveglider is deployed successfully to the sea.

Main deck with wavegliders and transponders

Wavegliders

We have 2 wavegliders on Sikuliaq, green one is the older one and orange one is the brand-new one with half a million price. We deploy the green waveglider at KOD1. Waveglider has solar panel to collect electricity, and has two GPS antenna at the front and deck to determine the location precisely. With the transducer on wavegliders, signal will be transmitted to the deployed transponder on seafloor, when the transponders receive the signals from the waveglider, we can calculate the exact locations for transponders based on the two-way travel time and sound speed.

Crew Members Are deploying the transponder with the benchmark

With the connection of floating pack, the transponder is deployed to the seafloor. The floating pack is designed to provide buoyancy for the transponders to make it not go much fast undersea and avoid the potential damage. Acoustic release technology is used to get floating pack back to the surface. When the transponder reaches the seafloor, acoustic signal will be sent to the transponder and floating pack, then the floating pack will be detached with the transponder and go up to the sea surface. This is the process the transponder go down to the seafloor and return back the floating pack. The floating pack will be shown with the orange color on the sea and easily captured. In this case, we can use floating pack many times.

Floating pack on the surface

Crew members are getting the floating pack back to the ship

CTD Profile

With the CTD equipment, we can get salinity, density and temperature of the sea, with the depth becoming deeper, the parameters will change by that. In this way, we can analyze the deep sea conditions precisely.

Landscapes

The below is some landscapes pictured by our group, it was exciting to see the snowy mountains, horizon and pure ice melted water in the gulf of Alaska. And of course, Sikuliaq.