Data from drifting buoys, also known as drifters, are used in a variety of ways by scientists and operational agencies all around the world. Information from drifting buoys has been helpful not only in understanding ocean currents and temperatures, but in solving problems that arise when hurricanes, oil spills, tsunamis, and other ocean-related disasters occur. Today, scientists continue to develop new uses for drifters, as well as new technology to make these applications possible. With the combination of improving technology and the occurrence of events that demand information from drifting buoys, drifters have become an indispensable tool in oceanic and atmospheric research.
Dr. Luca Centurioni plays a significant role in the drifting buoy community. The Global Drifter Program (GDP) is a scientific project in which he works alongside colleagues at the National Oceanic and Atmospheric Administration (NOAA) to define the scientific direction and goals of the program. Dr. Centurioni poses insightful scientific questions about the ocean’s currents for the benefit of the oceanographic, meteorological and climate science communities and the better understanding of the interactions between the ocean’s surface and the atmosphere. Within the GDP, Centurioni has several resposabilities, including finding out what the observations gathered by GDP instruments teach us about ocean circulation and climate. Centurioni also oversees the development of drifters at the Scripps Institute of Oceanography (SIO). Dr. Centurioni directs a lab where engineers work to improve and expand the capabilities of drifting buoys in the exploration of new sensors and measurements of ocean currents.
With his highly qualified background and current position, Dr. Centurioni was able to provide an immense amount of insight into the recent uses and developments of drifting buoys, specifically in detailing the involvement of drifters in response to several major ocean-related disasters of the past decade.
According to Dr. Centurioni, special hurricane drifters have been air-deployed by the 53rd Weather Reconnaissance Squadron “Hurricane Hunters” in more than ten hurricanes and typhoons since 2003. The “Hurricane Hunters” are part of an Air Force squadron that flies into hurricanes to take measurements and deploy scientific equipment, like drifting buoys, before a storm. Hurricane drifters are unique in their structure as they have a series of temperature sensors that extend down into the ocean to provide information about how hurricanes affect the temperature of the ocean’s surface which in turn can affect the intensification of the storm. Although a variety of instruments are used to collect as much information about hurricanes as possible, drifters are unique in their ability to measure temperature and atmospheric components as in-situ instruments. With the combination of hurricane drifting buoys’ measurements and that of other scientific instruments and sensors comes an invaluable ability to understand and track these rapidly changing, fast-moving storms.
Hurricane drifters have proven to be sources of information that are integral to the understanding of tropical storms. For Hurricane Isaac in 2012, drifters were able to successfully collect wind data in real time for the first time, making accurate measurements more accessible than ever before. However, NOAA hurricane drifters cannot be used in every hurricane, as, in some cases, they are limited by their location at Keesler Air Force Base in Mississippi. Because deployment of hurricane drifters require a special aircraft, a C130-J, a storm like Hurricane Sandy, that hit along the Northeastern seaboard, may be too far away for the drifters to be efficiently and effectively deployed. For this reason, engineers are working on developing more compact, air-deployable drifters that could be released by smaller, more accessible aircraft.
Aside from studying ocean currents and the interaction of hurricanes with the ocean, drifting buoy data have also helped scientists solve problems related to oil spills, tsunamis, and other ocean-related crises. Following the Deepwater Horizon Oil Spill in 2010, drifters were used to track the spread of oil as they revealed information about currents in and around the Gulf of Mexico. The buoys allow scientists to verify simulations of potential outcomes, in this case anticipating the spread of oil. Similarly, drifting buoys were used to validate predictions about the path of debris that was floating in the ocean after the Japanese tsunami and Fukushima Nuclear Crisis happened in 2011.
Drifters have even offered information in cases of disaster like that of the missing Malaysia Airlines Flight 370 in the spring of 2014. Had the investigation been able to identify debris from the plane, assuming it crashed in water, ideally such evidence could have assisted the process of locating the crash by retracing the ocean currents’ paths. However, the likelihood of a drifter being in the same area of suspect debris is very slim, so, theoretically, more drifters would be necessary in different parts of the ocean to prepare for investigations like this.
What can be learned from drifting buoys is ever expanding as technology improves. Aside from the aforementioned plan to make hurricane drifters more compact in order to ease the process of deployment, developments are underway to release wave and pH sensors in the near future, according to Dr. Centurioni. Wave sensors measure the energy in the water, and this information can be used in practical ways such as informing sailors of rough waters ahead. By measuring the amount of certain substances in the ocean, such as carbon dioxide, scientists can use pH sensors to understand more about the interactions between the sea’s surface and the atmosphere.
As with any useful equipment, the structure and application of drifting buoys are constantly evolving and adapting. Even the optimal number of drifters in the global array is subject to change from 1,250 buoys. This is because the array is currently determined by a demand for SST (Sea Surface Temperature) measurements, which are used to verify the information being collected by satellites and to do so in near-real time. As drifter technology becomes more capable and last longer, fewer buoys may need to be deployed each year; however, the melting ice that is exposing unexplored regions of the ocean may lead to an increase in drifter demand. Clearly, the array of drifters is subject to fluctuate as the abilities of drifting buoys change as well.
Ultimately, Dr. Centurioni asserts that the Global Drifter Program is an extremely rewarding project with which to be involved. Drifters are important for science, climate, and daily applications such as search and rescue, emergency response, and weather forecasting. This system offers “incredible infrastructure to exploit new sensors and technologies to monitor the ocean surface and the way it interacts with the atmosphere.” Thanks to the vision of Peter Niiler, the founder of the GDP, and with the primary support of NOAA and of the US Office of Naval Research, this project has become a significant source of cutting-edge information regarding our oceans’ surfaces and their impact on climates around the world.