This 90-day mission is supported by NOAA OMAO and Saildrone, Inc.

Two Saildrone uncrewed surface vehicles (USV) departed the 10°N, 125°W launch site on June 22, 2022, initiating the fifth in a series of Saildrone missions to the eastern tropical Pacific as part of a multinational effort to enhance the Tropical Pacific Observing System (TPOS).

Want more up-to-date information? You are in luck! Follow the drones on their 2022 TPOS journey and access real-time data on the PMEL Saildrone dashboard.

Go with the Flow

August 29, 2022

With approximately one month remaining in the TPOS 2022 Mission to the eastern tropical Pacific, the two drones have made impressive strides as they continue to sample the air-sea environment across the region. During their first month, the drones successfully completed two buoy intercomparisons against the Tropical Atmosphere Ocean (TAO) array moorings located at 8°N, 125°W and 5°N, 125°W. These intercomparisons involve the drones circling around a buoy for 12 - 24 hours in order to evaluate the sensors on both types of observing platforms and ensure that we are collecting climate-quality measurements.

In the second month of the mission, as the drones traveled south toward the equatorial study region, they once again encountered strong ocean currents associated with the westward expanding equatorial Cold Tongue and tropical instability wave (TIW) activity. As in previous missions, strong ocean currents coupled with weaker winds pose navigational difficulties for the drones, as the vehicles are not motorized and instead rely on environmental conditions for sailing. Using past lessons learned, the drones were directed to use the currents to their advantage, sailing clockwise around a TIW crest to enter more favorable conditions for reaching the study region. While sailing this clockwise trajectory, the drones successfully crossed a weak sea surface temperature (SST) front associated with a convergence zone on the backside of the TIW crest, maintaining a zonally-oriented east-west formation as they collected observations.

Unfortunately, given degradation in the sailing performance of drone 1052, the drones will likely become separated for the remainder of the mission as they continue south across a region of powerful westward-flowing ocean currents. Nevertheless, the drones will continue in an attempt to cross the strong meridional SST front separating the warm sub-tropical waters from the cold, upwelled water along the Equator, yielding important information on the air-sea interface. 

The Sun Rises on TPOS 2022

July 6, 2022

Photo taken on SD1033 en route to the 8°N, 125°W TAO buoy in the eastern tropical Pacific Ocean. Photo credit: Saildrone, Inc.

The day after the (boreal) summer solstice, Saildrone USVs SD1033 and SD1052 began their mission in the middle of the eastern tropical Pacific Ocean, having launched from Alameda, CA about one month prior. As in previous missions, the drones are fully equipped with oceanic, atmospheric, and biogeochemical sensors to collect climate-quality air-sea measurements over data sparse regions of the tropical ocean, with the overarching goal to address gaps in the current Tropical Pacific Observing System array. As we enter into the fifth TPOS Saildrone mission to the eastern tropical Pacific, we continue to explore the feasability of USVs as observing platforms within different regimes, such as the low-wind environment of the ITCZ (i.e., "the doldrums"), the low-wind, high-ocean current environment of the equatorial Pacific Cold Tongue, and the warm, biologically-active waters of the tropical Pacific Ocean.

This blog page is maintained by Samantha Wills.