by Wendel Brown
An Investigation of Mid-Atlantic Cold Pool Dynamics: Gliderpalooza-2016
Middle Atlantic Bight (MAB) Glider Measurements: May-October 2016
These data will be assimilated by several MARACOOS numerical circulation models which will produce temperature maps that define the Cold Pool. MARACOOS is coordinating an ever-expanding fleet of ocean glider deployments during the May–November Gliderpalooza-2016. Some of the Gliderpalooza-2016 gliders in the Middle Atlantic Bight (MAB) will be flying approximate 500 km triangles – favored by the MARACOOS modelers. We in UMass Dartmouth/SMAST/OCEANOL deployed one of those ocean gliders – Blue – just west of Martha’s Vineyard on May 18th. For the following 3+ weeks, Blue will be sampling the ocean along a triangle in the Southern New England Bight (SNEB) region south of Martha’s Vineyard (see Figure 1). Blue will be one of the MARACOOS glider fleet that is distributed on the Middle Atlantic Bight (MAB)/ of the continental shelf between Cape Cod to Cape Hatteras. Glider Blue’s mission will be guided by the MARACOOS Glider Technical Center – in this case a primary collaboration between people at the Rutgers University (RU) central node and University of Massachusetts Dartmouth (UMassD) secondary node.
Glider Blue, like most of the other Gliderpalooza-2016 Teledyne-Webb (TW) Slocum glider fleet, will measure temperature (T), salinity (S), oxygen (O), optical backscatter (OB), and estimated section-averaged velocity (V). The glider measurements will be complemented by other MARACOOS measurements, including the (a) high frequency (HF)-derived maps of surface current; and (b) satellite SST and color maps.
About Mission 7: May/ June 2016
Glider Blue was deployed around noon (EDT) on 18 May 2016 from SMAST’s RV Lucky Lady (berthed in Fairhaven, MA) at a site west of Gay Head, Martha’s Vineyard, MA [41o 22.11’N (41.3685o); 70o 59.44’N (70.9907o)]. In the first week of what is glider Blue’s Mission-7, it has already traversed the first leg of the triangle depicted in Figure 1 and Figure 2 (waypoints in Table 1).
At about 25 km/day these missions will take 3 to 4 weeks to complete this circuit; slicing through the newly-formed 2016 MAB Cold Pool twice. Blue’s measurements of the first slice through the 2016 Cold Pool temperatures shows a distinctive cold water mass (Figure 2). We had expected the ocean properties that Blue is measuring would be similar to comparable measurements in 23-28 May 2007 (see Figure 3). However, despite the different legend, it is obvious that the 2007 Cold Pool, with its section minimum temperature of 4.78oC, was considerably colder than is the May 24th, 2016 measurement that Blue just took, having reported a section minimum temperature of about 6.5oC.
As we get further into the Gliderpalooza season, more updates from the team will be available on the blog here: maracoos.org/blogs/main