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Henson Conducts Oceanography Survey Demonstrations for Brazilian Navy

Navy NewsStand

Story Number: NNS100326-05
Release Date: 3/26/2010 11:57:00 AM

By Mass Communication Specialist 2nd Class Lily Daniels, U.S. Naval Forces Southern Command and U.S. 4th Fleet Public Affairs

USNS HENSON, At Sea (NNS) -- Military Sealift Command (MSC) oceanographic survey ship USNS Henson (T-AGS 63) demonstrated deep water physical oceanographic and bathymetric surveys March 24-25, for nine Brazilian sailors from the Directorate of Hydrograph and Navigation.

Henson is engaged in Oceanographic-Southern Partnership Station (O-SPS) 2010 with the Brazilian Navy. O-SPS is an exercise focused on military oceanographic surveying capabilities and the exchange of information between hydrographic experts from U.S. Southern Command's (USSOUTHCOM) partner navies.

"It's very good to have this experience. We do similar work in the Brazilian Navy, so it's nice to see different options on how to do the same task," said Capitão-de-Fragata Izabel Jeck, survey division chief at the Center of Hydrography of the Brazilian navy.

Henson is one of the seven Oceanographic Survey Ships in MSC's Special Mission Ships Program. The ship is equipped with two hydrographic survey launches, multi-beam sonar system, sidescan sonar and GPS systems.

Civilian scientists attached to Naval Oceanographic Office (NAVOCEANO) used an autonomous underwater vehicle (AUV) and a shipboard survey system for physical oceanography data collection for their demonstrations.

The shipboard survey system, also known as CTD, measures conductivity, temperature and density of the water, which impact the changes in the speed of sound and allows for accurate acoustic and bathymetric measurements. Data from the CTD is sent directly to the Integrated Survey System (ISS-60) to correct for variations in sound speed.

"We need physical oceanography data for bathymetry correction. It's not a simple problem," said Bruce Stier, senior NAVOCEANO representative. "We use sound waves to measure the depth of the water (bathymetry). Since sound changes a lot depending on temperature, we also collect the physical properties of the water column, and we use supercomputers to record the data real-time."

After the CTD measurements were conducted, the NAVOCEANO scientists used the multi-beam sonar system to characterize a seamount to demonstrate how the U.S. Navy conducts surveys from shallow to deep water.

"The equipment and procedures are similar with some little differences," said Capitão-de-Corveta Alexandre Ramos, geodesy section chief of survey division at the Center of Hydrography of the Brazilian Navy. "What's important during this exchange is making a network of contacts to discuss methodology when you have questions."

Another demonstration using the AUV highlighted the differences between it and the CTD. The AUV can be sent out for four to six months to gather data in time and space. The CTD has to be launched and recovered by the ship in one geographic location, limiting the amount of launches it conducts. The AUV also sends the measurements directly to NAVOCEANO via an iridium satellite for immediate incorporation into ocean circulation models.

"Models determine where variations in major currents like the Gulf Stream occur. These currents meander, so the models let us know where, why, and how they move," explained Danielle Bryant, an oceanographer for NAVOCEANO. "They can also be used for finding wreckage from downed aircraft. NAVOCEANO recently predicted the accurate location of a black box using an ocean circulation model."

Southern Partnership Station is a recurring deployment conducted by Commander, U.S. Naval Forces Southern Command (COMUSNAVSO) and U.S. 4th Fleet with a variety of different objectives.

COMUSNAVSO is the naval component command for USSOUTHCOM and is responsible for all naval personnel and assets in the area of responsibility. COMUSNAVSO conducts a variety of missions in support of the Maritime Strategy, including theater security cooperation, relationship building, humanitarian assistance and disaster response, community relations, and counter-illicit trafficking operations.