We finished the first dye release experiment today. It lasted a little under 24 hours, and was very successful. We were able to stay with the dye despite strong currents 40 cm/s. The goal for the glider survey was to fly a coherent pattern relative to a translating drifter. While we were piloting the glider I thought we were doing horribly, but when I plotted the relative trajectory I was pleasantly surprised (see the two figures). We ran right over the drifter!
Drifter tracks, glider doug's trajectory (thick blue line) and last route (aiming for the red waypoint).
Glider doug's trajectory relative to the pink drifter in the previous figure. Units are kilometers.
We recovered doug around 1 pm today – blazing hot sun, but nice and calm. The recovery went smoothly, and when we lifted the glider out of the water a dozen fish took off swimming every which way! They were hiding out under our glider. I’ve heard of this happening, but it was still cool to see it.
We found a new survey site and started pumping dye around 6:30, finished around 8pm and deployed the glider at 9pm. We used Chris’s quick release – not because we needed to, but because we had brought it with us, so why not use it. It worked great.
Doug was deployed at 17:32 today (dinner time: spaghetti with meatballs and sausage!).
We deployed in the “normal” fashion from doug’s cart off the starboard side of the ship; the Hatteras is pretty low to the water and it is very calm. I slid doug off and Chris kept doug away from the side of the ship with the pole.
We are conducting a 24-hr survey, after which we will recover and prepare to redeploy tomorrow evening.
Doug is struggling to stay in position relative to the drifters – currents are surprisingly strong (20 cm/s dive-averaged), but we are in the general vicinity!
Doug is on three hour call ins now to try to make some headway on the drifters. Chris will pilot starting at midnight. I will help him get started and nap between calls.
Other ops are going well. Brian Guest (WHOI Tech) had an under water camera and filmed the dye being deployed at 25 m depth – very cool! The water is so clear you could also see it from the surface.
Kipp
As part of the Lateral Mixing Project, Glider Doug and Glider Russ set sail out of Beaufort NC on the R/V Cape Hatteras Monday morning. During the vessel’s seven day cruise the multi-organization science team will run several trial experiments characterizing the way upper ocean waters mix laterally. Experiments will utilize dye to trace the currents, sensors to follow the dye’s path and Lagrangian floats to ride the current. Gliders will run survey lines relative to one of the floats characterizing the water properties that move the float and the mixing currents.
Results from this trial cruise will prepare for the team for the full run next summer that will include three coordinated research vessels, airplane-based LIDAR and our Slocum gliders. Results from the experience will help us understand a fundamental feature of energy transmission through the ocean and help us create better computer models.
Chris Ordonez