MURI Glider Sampling

One of the primary components of the MURI project is a strong occupancy of the shelf with an ONR fleet of coastal gliders. Those gliders carry a wide variety of physical and optical sensors, being able to measure in situ temperature, salinity, density, chlorophyll concentration, Colored Dissolved Organic Matter (CDOM) and backscatter at several channels.

Although sustained glider observations have been collected off New Jersey since late 2003 (blue transects in Figure 1), only recently (since early 2007) with the implementation of the MURI the observations were expanded to span the entire Middle Atlantic Bight (red lines in Figure 1). This MURI effort has produced monthly/bi-monthly observations extending from Cape Cod, Massachusetts to Chesapeake Bay. This 1000 kilometer footprint will be occupied monthly in coming years and forms the subsurface backbone for the Mid Atlantic Regional Coastal Ocean Observing System (MARCOOS).

 
Figure 1: Glider transects on the Middle Atlantic Bight. The blue transects off New Jersey are the Rutgers University Glider Endurance Line, with sustained observations since late 2003. The red lines show new glider transects that are occupied bi-monthly since early 2007. On the right panel, the temperature cross-sections for one of the deployments are overlain on surface velocities measured with CODAR.

The usefulness of optical data to help identify physical phenomena is clearly seen on Figure 2. A resuspension of benthic particulate material associated with a storm is clearly seen on the optical data (right panel), extending up 40 meters in the water column. Although this event is a dramatic feature on the shelf, it is completely invisible for traditional simultaneous hydrographic observations (e.g., temperature, left panel). By helping discriminate such features, the optical data will allow for an improvement of the physical models currently being used and to a better understanding of the interactions of ocean physics and optics on the Middle Atlantic Bight.

Figure 2: Temperature and backscatter at 470 nm measured with gliders along the Middle Atlantic Bight. Note that the strong resuspension event seen in the optical data near the 80-m isobath is completely invisible in the temperature section.

The complete set of glider observations on the Middle Atlantic Bight can be found at
http://www.marine.rutgers.edu/mrs/