Finally understanding sub-mesoscale currents

By on December 3, 2014

Ocean currents are streams of seawater that flow in the ocean, and are caused by wind, gravity, earth’s rotation, and differences in density. Currents can carry animals, nutrients, and even pollutants with them as they move. Therefore, it is important for CARTHE scientists to study their movements so we can better predict how the currents will impact the transport of pollutants in the water.

Some currents are large and permanent with a characteristic length of 10s of kilometers up to 100s of kilometers.  We call these mesoscale features. Other currents are small and temporary, lasting only a few hours up to a week, and are referred to as sub-mesoscale. To better understand the difference between mesoscale and sub-mesoscale, let’s imagine the ocean currents are streets…


Major currents are seen in “ribbons” of red, pink, and black (speeds of over 100 cm/s in black).

Mescoscale currents (like the Loop Current Eddy in the Gulf of Mexico and the Gulf Stream in the Atlantic Ocean) are the big highways of the ocean, carrying a lot of cars across large distances. It is a huge road, like I-95, so you cannot easily cross it and you stay on it for awhile (months) going roughly the same speed the whole time. The size and speed can be measured by satellites, allowing us to model it and do the important predictions we mentioned earlier.

Sub-mesoscale features are like the small streets in your neighborhood. Many cars use these streets everyday but only for a short amount of time.  They are so small and narrow, and cars turn to a new street so frequently that we could not observe them by satellite. And to complicate the matter, some of these roads are temporary.  Some are created and reinforced (by wind, river outflows, rain, waves, storms, etc), while others are decaying and being destroyed. The neighborhood is ever evolving. It makes it hard to measure and model…but we did it!

Deploying drifters during GLAD

Deploying drifters during GLAD

During our Grand Lagrangian Deployment (GLAD) experiment, we put over 300 GPS-equipped surface drifters into the Gulf of Mexico simultaneously and within 100m 10km of each other (the drifters are the cars in our analogy). We measured how fast the cars spread in these small streets, compared to how they spread using the highways.

We proved that the sub-mesoscale currents can dominate how a pollutant spreads in the short term. The trajectories of the drifters allow us to draw maps of the diverse routes that can carry floating material like oil at the surface of the Gulf of Mexico. For the first time, we could observe the role of both the temporary and the persistent currents on the dispersion of pollution.


For more information on the GLAD experiment, visit:

For more information on our drifters, watch our video:

To read more about our findings, visit:


Written by: Guillaume Novelli and Laura Bracken


Oil spill simulator makes a splash at Delaware Coast Day

By on October 17, 2014

    The 38th annual University of Delaware “Coast Day” was held on October 5, 2014 in Lewes, Delaware – the home of the UD marine school.  UD faculty shared their research, gave tours of their research vessels, and offered


Using drones in oil spill research

By on October 9, 2014

The use of drones during the Surfzone Coastal Oil Pathways Experiment (SCOPE) helped scientists from CARTHE study how oil moves from offshore onto our beaches! This is an innovate approach to a complex problem with powerful results. Check out this

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The Nova/CARTHE team studying bacteria during SCOPE

By on August 4, 2014

While assisting the SCOPE team conduct experiments on the research vessel, our group was also collecting bacterial samples directly from the sea surface and subsurface water about 20 cm deep. We are especially interested in bacteria that are known to


Intern Reed McDonough – Final Summary

By on August 3, 2014

Summary During the summer months of 2014, I worked under Dr. Shuyi Chen to compare data from OSCAT and TRMM satellites with the UMCM-WMH model for 10-meter wind speed and rainfall forecasts within the Gulf of Mexico. Comparisons of model

Intern Nate Murry – Entry 1

By on July 8, 2014

Intern Nathan M. Murry – senior Oceanography major at Millersville University, working under Drs. Bruce Lipphardt and Helga Huntly at the University of Delaware. Entry 2: I am a senior student in Millersville University’s Physical Oceanography program. I have experience with environmental data analysis and

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Intern Shane Hinton – Entry 2

By on July 3, 2014

Intern Shane Hinton – senior Meteorology major with minors in Mathematics and Electronic Media working under Dr. Shuyi Chen at the University of Miami’s Rosenstiel School. Entry 2: July has just started but I am already submerged in my research with

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Intern Reed McDonough – Entry 2

By on June 26, 2014

Intern Reed C McDonough – freshman Meteorology and Broadcast Journalism major working under Dr. Shuyi Chen at the University of Miami’s Rosenstiel School. Entry 2: It is now late June, and I am about halfway through my summer project. For the


Intern Jonathan Zikos – Entry 1

By on June 24, 2014

Intern Jonathan Zikos – Senior Environmental Chemistry major working under  Dr. Darek Bogucki at Texas A&M University – Corpus Christi’s Harte Research Institute. Entry 1 This summer, I will be analyzing and categorizing data from Dr. Bogucki’s Optical Turbulence Sensor

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Intern Shane Hinton – Entry 1

By on June 19, 2014

Intern Shane Hinton – senior Meteorology major with minors in Mathematics and Electronic Media working under Dr. Shuyi Chen at the University of Miami’s Rosenstiel School. Entry 1: Over the course of the next few weeks, I will be analyzing