OCS Saildrone Mission Blog - TPOS Mission 3
This mission is supported by NOAA GOMO (formerly OOMD), NOAA OMAO, and Saildrone, Inc.
Four Saildrones were launched from Hawaii on June 8, 2019, initiating a six-month research mission in the tropical Pacific Ocean. This is the third mission of a series intended to test Saildrones in the Tropical Pacific Observing System (TPOS).
April 30, 2020
On December 21, 2019, after six long months at sea, 20,000+ collective miles traveled, and one close call with a tropical storm, all four Saildrone unmanned surface vehicles (USV) returned safely to Hawaii, successfully completing the third research mission to the tropical Pacific (and second to 0°, 140°W). Throughout the mission, the drones proved capable of performing adaptive sampling – adjusting tracks and sailing formations in near-real time – to achieve science goals against ever-changing background conditions. While strong ocean currents and low wind conditions prevailed at times, as in previous missions, the modified fifth generation Saildrone USVs demonstrated improved navigational control and maneuverability in the field. The treasure trove of data collected on these autonomous platforms (in all three missions) will be studied by scientists for years to come, aiding in the development of a more resilient and integrated observing system under the Tropical Pacific Observing System project.
Before I conclude the 2019 OCS Saildrone Mission Blog, I wanted to share some thoughts on autonomous technology in the midst of a global pandemic. Autonomous technologies – such as Saildrone USVs – offer our science community the ability to monitor the ocean and collect data with minimal human involvement. In this respect, we are able to pursue missions and conduct research while working remotely around the world, in essence reducing our carbon footprint. As we take this time to slow down and reevaluate current structures during the current COVID-19 pandemic, we have the unique opportunity to turn disadvantage into future advantage.
Creatures of the Sea
October 31, 2019
Bird's-eye view from Saildrone vehicle 1066.
As the four Saildrone unmanned surface vehicles (USV) continue their northward transit to intercept the ITCZ in the eastern tropical Pacific, there have been a few visitors from the animal kingdom along the way! Likely due to bio-fouling (i.e., barnacle growth) on the side of the vehicles, as seen in the photo above, there has been an increased presence of fish around the drones. In particular, a large dorado (or mahi-mahi) was recently seen cruising alongside Saildrone vehicle 1066. Given that the length of the drone is approximately 7 meters (i.e., ~23 feet) long, it is safe to say that is one big fish! With these food sources available, it is unsurprising that many birds (not shown) have also been attracted to the Saildrone USVs. Unfortunately, this added weight has resulted in slower navigation speeds. Nonetheless, the drones continue to sail on!
Sailing the ITCZ
October 10, 2019
To escape the low-wind and high-ocean current conditions near the Equator, the Saildrone USVs are heading north along 140°W to intercept and explore the Intertropical Convergenze Zone (ITCZ). The ITCZ is a region of the tropics where the trade winds converge and thunderstorm activity is strong, yielding large quantities of rainfall and freshwater input into the ocean surface. Given the short-lived nature of an individual thunderstorm, in-situ measurements obtained by the Saildrone USVs will provide valuable information for better understanding how cold pools and outflow boundaries associated with these storms interact with the surrounding environment.
'Cause you can't stop the motion of the ocean
September 11, 2019
Mission 3 Saildrone USV tracks through August 19 overlaid on background surface ocean currents.
Since launching from Honolulu in June 2019, the four Saildrone unmanned surface vehicles (USV) are approximately halfway through their Mission 3 journey! After a long transit to the Equator, in which the USVs narrowly avoided the remnants of Tropical Cyclone Barbara, the vehicles arrived at the target area on August 1, 2019. Over the past month and a half, the USVs have been sailing around 0°, 140°W performing surface CO2 intercomparisons, mapping zonal and meridional scales of air-sea fluxes, and crossing sea surface temperature fronts along the edges of the equatorial Cold Tongue. Given the season, conditions along the Equator have been challenging, with Tropical Instability Waves and strong surface ocean currents impacting vehicle navigation. Nevertheless, the Saildrone USVs have successfully sailed multiple test patterns and transects throughout the region, providing valuable observational data from this remote region of the eastern tropical Pacific.
June 24, 2019
Saildrone science vehicle 1066 in transit to the Penguin Bank. Photo credit: Saildrone, Inc.
As a pilot study of the Tropical Pacific Observing System 2020 Project (http://tpos2020.org), four Saildrone science vehicles were launched from Hawaii on June 8, 2019 to begin a six-month research mission to study air-sea interaction in the central equatorial Pacific Ocean.
This is the third mission in a three-part series of planned Saildrone missions to the tropical Pacific to study specific targeted phenomena for different phases of the El Niño-Southern Oscillation (ENSO) cycle. Mission 1 (September 2017 – May 2018) occurred during the “Recharge” phase of ENSO, where the cold tongue was developed. Mission 2 (October – December 2018) occurred during the beginning of the “Discharge” phase of ENSO, where warm tropical sea surface temperature (SST) anomalies developed in the Central and Eastern Pacific. On this Mission 3, the Saildrones will likely capture the end of the “Discharge” phase of ENSO, when the warm tropical water is spread to its easternmost extent.
Saildrones are unmanned surface vehicles (USV) developed by Saildrone, Inc. and NOAA/PMEL that use wind and solar energy to transit the ocean and power a variety of mounted scientific instruments. Saildrone measurements during this mission will be used to investigate exchanges of heat and carbon dioxide between the ocean and atmosphere associated with ENSO and other processes that affect SST anomalies in the tropics. With the cluster of four Saildrones, we will better understand the horizontal scales of variability affecting these air-sea interaction processes. Ultimately, through these missions, we hope to learn how Saildrone may best be utilized within the Tropical Pacific Observing System.
Please stay tuned for more updates on this third mission as the four Saildrones journey through the tropical Pacific Ocean!
This blog page is maintained by Samantha Wills.