On Origins of the Cold Water Inflows to the Mid-Atlantic Bight Cold Pool in Late Spring

During late spring each year, after the Mid Atlantic Bight (MAB) Cold Pool has been defined by vernal restratification, there is a continuing flow of even colder water from the Georges Bank/Gulf of Maine (GB/GoM) region the northeastern end of the MAB. The cold inflow water forms a distinctive minimum temperature “cold patch” that is subsequently advected southwestward down the shelf during the summer. An explicit reanalysis of the Nantucket Shoals Flux Experiment (NSFE) data shows a westward temperature transport of sub-10^oC water, which peaks at about 600 x 10⁵ m^{3 o}C in early April 1979 and exponentially decays to near zero by the end of June. This evidence begs the question about the origins of the springtime cold water inflow to the MAB Cold Pool. Between 2007 and 2012, the Mid Atlantic Regional Association Coastal Ocean Observing System (MARACOOS) ocean gliders conducted a series of along-shelf zigzag trajectory hydrographic surveys that included full cross-shelf transects off of Massachusetts (Leg-1) and New Jersey (Leg-2). Subsequent MARACOOS multiple glider missions in 2013-2015 add to the data archive. These data have been used to locate the transect temperature minima TT_min or core of the Cold Pool water mass; as well as define the extent of the MAB Cold Pool in 2007 and 2013-2015. The T-S diagram signatures from the Leg-1 TT_min and most seaward stations are very similar to the T-S signatures hydrographic transects that intersect the north slope of Georges Bank. The latter evidence suggests the western GoM as the origin of the MAB Cold Pool’s “cold patch” water. Results of an integrated analysis of the MARACOOS glider-inferred transports and high frequency radar surface current maps in terms of the variability of cold water inflow structure to the MAB will be discussed