Guam Dive Calibration Complete

915 seafloor surveys. 131 dives. 10-15 foot seas. The Guam dive calibration is complete — and the data covers the entire CNMI.

GAO/Hawaii MERC team conducting reef surveying in Guam
Status
Complete
Mission Start
June 27, 2026
Mission End
July 15, 2026
Region

Guam Reef Calibration Complete for 2026 Pacific Mission

On July 15, the dive team wrapped up two weeks of field calibration surveys across Guam’s reef systems under some of the most demanding conditions the project has faced.

Operating through the Hawaiʻi Marine Education and Research Center (Hawaiʻi MERC) under contract to the Global Airborne Observatory (GAO), a four-person dive team logged 915 individual survey points across 131 dives. Their work mapped coral cover, biodiversity, and reef condition from the surface down to the seafloor. This ground-truth data directly calibrates the aerial imagery collected during the mapping phase, allowing GAO to validate high-altitude sensor readings against real-world seafloor conditions.

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Distribution of the 131 dive sites completed by the Hawaiʻi MERC team across Guam’s northern, western, and eastern reef systems.

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Why Guam Calibrates the Entire CNMI

Ecologically, Guam is part of the broader Mariana Archipelago, sharing the same baseline mix of coral species found throughout the region. The data from Guam will work to calibrate all of CNMI, extending the reach of these calibration models across the entire island chain from Rota in the south all the way to Uracas in the far north.

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What the Reefs Revealed

Guam’s reefs presented a striking contrast, ranging from severely degraded and nearly dead to remarkably vibrant and healthy:

  • Western Coast: Reefs on the west side showed heavy degradation, stemming from decades of coastal development and extensive damage sustained during World War II.
  • Eastern Coast: Reefs on the east side proved notably more intact. Positioned slightly deeper and in harder-to-access waters, these systems were largely spared from major WWII landing operations that permanently altered western shorelines.

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Operating in Heavy Seas

The team pressed forward through Typhoon Bavi, contending with sustained 10- to 15-foot seas for nearly the entire two-week deployment after only two initial days of calm weather.

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Satellite View of Super Typhoon Bavi: Visible satellite imagery (left) and enhanced infrared imagery (right) tracking the storm's eye as it passed between Guam and Rota. The infrared scan shows cloud-top temperatures plunging to -71°C in the eyewall, triggering weeks of 10- to 15-foot seas during the team's July calibration mission.

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Next Steps & Local Impact

With primary aerial and aquatic data collection for Guam and the CNMI now substantially complete, the focus turns to data processing and laboratory analysis at Arizona State University. Final maps are expected in the coming months, with a potential targeted re-flight planned for October to refine coverage in key areas.

The mission is already making a strong impression with regional conservation leadership. Upon receiving early imagery covering the remote northern islands of Uracus and Maug, Kalani Reyes, Coral Reef Lead for the CNMI government, shared:

"MAHALO GREG!! That is SO COOL man, thank you so much for sharing! I have never seen all of my islands before. So this is a big first for me, and the CNMI!"

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Mission Gallery

Guam Dive Calibration Complete

Underwater view looking up toward the ocean surface showing 15.5 meter depth and 27.5 degree Celsius water temperature readings
Hawaiʻi MERC diver setting up a calibration transect line along a sandy coral seafloor during Global Airborne Observatory research in Guam.
Hawaiʻi MERC diver surfacing in open ocean waters off Guam, viewed from the research vessel.
GAO Pacific Mission diver conducting a coral reef calibration survey in Guam while a school of fish swims overhead.
Hawaiʻi MERC diver conducting ground-truth mapping over an encrusted WWII artifact on a Guam coral reef.
GAO Pacific Mission boat crew member throwing a shaka sign inside the vessel cabin alongside scuba diving equipment in Guam.
A hand holds a white, waterproof dive slate covered in handwritten time and depth logs for Guam dive sites 13 and 14 during the GAO Pacific Mission.
Two Hawaiʻi MERC divers in the ocean, one wearing bright orange, manage equipment during choppy, overcast conditions on the GAO Pacific Mission in Guam.
A research vessel motor leaves a wake while transiting out of a marina at dawn or dusk during the GAO Pacific Mission in Guam.
A Hawaiʻi MERC team member watches from a research boat as they pass a brightly lit container ship and port cranes at night in Guam.
A Hawaiʻi MERC crew member in a bright orange shirt checks his phone inside a well-equipped research vessel cabin with scuba tanks in Guam.
Heavy seas and dark storm clouds over the ocean near Guam's coastline during the GAO Pacific Mission.
Rough, choppy waters at sunset with waves crashing against a rocky breakwater in Guam during Typhoon Bavi weather conditions.
Large waves breaking against Guam’s shoreline under dramatic golden sunset clouds during field calibration work for the Global Airborne Observatory.
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