An extraordinary breach of the Gulf Stream north wall by a cold water intrusion

Abstract

A breach of the Gulf Stream (GS) North Wall by a parcel of cold Middle Atlantic Bight shelf water was observed from October 2 to 5, 2001 by a sequence of NOAA AVHRR sea surface temperature (SST) images. Unlike the warm/cold core rings generated by GS meanders, the path of cold water eventually cuts into the GS. Subsequently, the cold water remained intact and eventually penetrated and transversed the entire width of the GS. This is readily apparent in the 3-day SST sequence. Analysis of wind data from a nearby CMAN station reveals a high (over 12.8 m/s) and persistent (3 days) alongshore wind event occurred prior to the breach. An 11-year time series (1991-2001) of local wind measurements show that this type of strong and persistent wind situation is uncommon, which may explain why the large-scale surface shelf water breach of the GS has not been previously reported.