NOAA Teacher at Sea
Onboard NOAA Ship Gordon Gunter
June 5–24, 2013
Mission: Ecosystem Monitoring Survey
Geographical area of cruise: The continental shelf from north of Cape Hatteras, NC, including Georges Bank and the Gulf of Maine, to the Nova Scotia Shelf
Weather Data from the Bridge: Time: 21.00 (9 pm)
Latitude/longitude: 3734.171ºN, 7507.538ºW
Barrometer: 1023.73 mb
Speed: 9.6 knots
Science and Technology Log:
This week we launched a Global Drifter Buoy (GDB) from the stern of the Gordon Gunter. So what is a GDB? Basically it is a satellite tracked surface drifter buoy. The drifter consists of a surface buoy, about the size of a beach ball, a drogue, which acts like a sea anchor and is attached underwater to the buoy by a 15 meter long tether.
Drifter tracking: The drifter has a transmitter that sends data to passing satellites which provides the latitude/longitude of the drifter’s location. The location is determined from 16-20 satellite fixes per day. The surface buoy contains 4 to 5 battery packs that each have 7-9 alkaline D-cell batteries, a transmitter, a thermistor to measure sea surface temperature, and some even have other instruments to measure barometric pressure, wind speed and direction, salinity, and/or ocean color. It also has a submergence sensor to verify the drogue’s presence. Since the drogue is centered 15 meters underwater it is able to measure mixed layer currents in the upper ocean. The drifter has a battery life of about 400 days before ending transmission.
Students at the Howard Gray School in Scottsdale, Arizona designed stickers that were used to decorate the buoy. The stickers have messages about the school, Arizona and NOAA so that if the buoy is ever retrieved this will provide information on who launched it. In the upcoming year students at Howard Gray will be tracking the buoy from the satellite-based system Argos that is used to collect and process the drifter data. You can follow our drifter here, by putting in the data set for the GTS buoy with a Platform ID of 44932 and select June 19, 2013 as the initial date of the deployment.
Why are drifter buoys deployed?
In 1982 the World Climate Research Program (WCRP) determined that worldwide drifter buoys (“drifters”) would be extremely important for oceanographic and climate research. Since then drifters have been placed throughout the world’s oceans to obtain information on ocean dynamics, climate variations and meteorological conditions.
1. Maintain a 5×5 worldwide degree array (every 5 degrees of the latitude/longitude of world’s oceans) of the 1250 satellite-tracked surface drifting buoys to maintain an accurate and globally set of on-site observations that include: mixed layer currents, sea surface temperature, atmospheric pressure, winds and salinity.
2. Provide a data processing system of this data for scientific use.
EcoMon survey: We are continuing to take plankton samples and this week we started taking two different Bongo samples at the same station. Bongo mesh size (size of the holes in the net) was changed several years ago to a smaller mesh size of .33 mm. However, they need comparison samples for the previous nets that were used and had a mesh size of about .5 mm. They had switched to the smaller net size because they felt that they were losing a large part of the plankton sample (basically plankton were able to escape through the larger holes). We are actually able to see this visually in the amount of samples that we obtain from the different sized mesh.
It’s hard to believe that my Teacher at Sea days are coming to a close. I have learned so much about life at sea, the ocean ecosystem, the importance of plankton, data collection, and the science behind it all. I will miss the people, the ocean and beautiful sunsets and the ship, but I’m ready to get back to Arizona to share my adventure with my students, friends and family. I want to thank all the people that helped me during this trip including: the scientists and NOAA personnel, the NOAA Corps and ship personnel, the bird observers and all others on the trip.
Did you know? Drifters have even been placed in many remote locations that are infrequently visited or difficult to get to through air deployment. They are invaluable tools in tracking and predicting the intensity of hurricanes, as well.
Question of the day? What information would you like to see recorded by a Global Drifter Buoy and why?