There and back again: NOAA Ship Gordon Gunter journeyed away from Pascagoula, Mississippi for 90+ days and 12,700+ nautical miles to conduct the PIRATA Northeast Extension cruise.
A NOAA ship that traditionally sails in the Gulf of Mexico embarked on a 90+ day journey into international waters and successfully completed its mission in support of a key tropical Atlantic observing system.
Crew and officers of NOAA Ship Gordon Gunter set sail from Pascagoula, Mississippi, on January 22, 2024, and returned to the same location over three months later after traveling more than 12,700 nautical miles (. During parts of the long voyage, NOAA researchers, academic partners, and students joined them to service moorings in the tropical Atlantic for the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) project and collect oceanographic and atmospheric samples in support of the PIRATA Northeast Extension.
PIRATA is a collaborative project between Brazil, France, and the United States to study and improve the predictability of air-sea interactions in the tropical Atlantic Ocean. Air-sea interactions, such as heat exchange between the ocean and atmosphere, exert changes in weather and climate. Measuring and observing how these interactions function improves our understanding and predictive capabilities of extreme weather and climate variations. PIRATA Northeast Extension is a joint project between NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) and NOAA’s Pacific Marine Environmental Laboratory (PMEL) that expands the PIRATA array of moored buoys into the northern and northeastern sectors of the tropical Atlantic Ocean. It is important for PIRATA scientists to collect measurements in this part of the ocean because this is the main development region for Atlantic hurricanes.
Due to the global class NOAA Ship Ronald H. Brown undergoing maintenance this year, the cruise took place aboard NOAA Ship Gordon Gunter (a capable but smaller NOAA fisheries vessel) and was split into four legs. Legs 1 and 4 were transits and provided open ocean training opportunities for NOAA officers and crews, while legs 2 and 3 had researchers onboard from AOML, PMEL, NOAA’s National Environmental Satellite, Data and Information Service (NESDIS), and University and Cooperative Institute partners.
During legs 2 and 3, the science team completed the recovery and redeployment of four PIRATA Northeast Extension moorings and one additional PIRATA mooring that is typically serviced by our partners in Brazil. During the early stages of Leg 2, the ship diverted to the south to serendipitously recover another buoy that had gone adrift. Moorings are recovered onto the ship for data to be collected, meteorological and oceanographic sensors refreshed with new instruments and batteries, and the surface buoy cleaned before being redeployed to continue collecting data. Biological growth is common on the upper ~80 meters of moorings after being in the ocean for ~1 year. The surface float and sensors often have Saharan dust on them and sometimes are damaged or missing due to their interactions with the elements (winds and waves) or fishing vessels.One PIRATA mooring located within the Atlantic oxygen minimum zone was augmented with 15 additional current meter sensors (normally there is only one current meter at 12 meters depth). These sensors measure ocean currents in the upper 100 meters of the water column as part of the Tropical Atlantic Current Observations Study (TACOS). TACOS is focused on advancing the understanding of ocean circulation and mixing and their impact on sea surface temperatures and air-sea interactions.
A PIRATA Northeast Extension mooring is recovered onto the deck of NOAA Ship Gordon Gunter.
The team also conducted 59 CTD (Conductivity, Temperature, and Depth) casts and 22 expendable CTD casts that collected data from the ocean’s surface to about a mile deep. The CTD rosette was augmented by total dissolved oxygen and Lowered Acoustic Doppler Current Profilers to provide a more detailed view of the water column by detecting how salinity, temperature, dissolved oxygen, and velocity change relative to depth. When weather conditions were suboptimal or time did not permit, expendable CTD casts were collected. An expendable CTD is like an expendable bathythermograph (XBT) but has an added conductivity sensor. Expendable CTD profiles measure temperature and salinity from the surface to depths of more than a half mile.
Scientists and crew deployed five vertical profiling floats, including two Core Argo floats, one Biogeochemical Argo float, and two ALAMO floats, and five surface drifting buoys at various locations to collect profiles of ocean temperature, salinity, and depth. These ocean observing instruments deployed throughout the global ocean have improved weather forecasts and advanced our knowledge of climate fluctuations.
PIRATA Cruises are a Platform for Collaborative Research and Pilot Studies
The annual PIRATA Northeast Extension cruise serves as a platform for collaborative research projects to take place concurrently with the main cruise operations. Researchers from NOAA’s NESDIS, University of Wisconsin, Arizona State University, and University of Maryland Baltimore collected aerosol measurements throughout leg 2, performed approximately six radiosonde launches in coordination with satellite overpasses, and collected Saharan dust samples from the moorings, in support of the Aerosols and Oceanographic Science Expeditions project. This project’s goal is to gain an understanding of the weather and climate impacts of long-range transport of mineral dust and smoke aerosols over the tropical Atlantic.
Scientists from Woods Hole Oceanographic Institution collected 84 nutrient samples and 94 Sargassum samples from the Great Atlantic Sargassum Belt to study the environmental conditions that affect Sargassum growth, its species diversity, and how its spatial distribution and abundance change from month to month and year to year. This is the sixth PNE cruise where some form of Sargassum-related research was conducted, although the research partners have changed over time.
Dennis McGillicuddy (WHOI) collects Sargassum samples from the Great Sargassum Belt.
The annual PIRATA Northeast Extension cruise allows for academic and international collaboration to advance the understanding of the ocean and to work towards improved prediction of weather and climate variability. Although this year’s cruise looked a little different, NOAA Ship Gordon Gunter researchers and the crew facilitated a successful science mission. This PNE cruise is funded by NOAA Marine and Aviation Operations and NOAA’s Global Ocean Monitoring and Observing Program, with personnel support from NOAA’s AOML, NOAA’s PMEL, and University and Cooperative Institute partners.
Meet Ms. Denise Kester, Chief Scientist for Leg 2 of the cruise
Denise Kester is a mooring instrumentation technician at NOAA’s PMEL. With a background in Marine Science, Denise has gained over 14 years of experience supporting oceanographic research aboard research cruises all over the world. She currently works with the Global Tropical Moored Buoy Program at PMEL and regularly leads moored buoy operations in the Atlantic and Indian Oceans. Denise is also an avid swimmer and enjoys films. She swims year-round with a group in the frigid waters of Puget Sound.
Meet Dr. Renellys Perez, Chief Scientist for Leg 3 of the cruise
Dr. Perez is an oceanographer at NOAA’s AOML. She was the Principal Investigator for the PNE project from 2017-2021 and is now the Co-Principle Investigator for the project. Renellys has served as the Co-Chief Scientist or Chief Scientist on five PIRATA Northeast Extension cruises, including this one. She also designed the TACOS project, which adds additional sensors to PIRATA moorings to advance the understanding of ocean circulation and mixing and their impact on sea surface temperatures and air-sea interactions.
“Thanks to the hard work and dedication of the entire team, including the crew, technicians, engineers, scientists, officers, and students, NOAA was able to collect meaningful oceanographic and atmospheric observations in the tropical Atlantic ocean environment and refresh moored instrumentation in support of a key long-term observing system,” said Renellys Perez.
