Abstract
The New England Seamount Chain (NESC) has physical influences on the Gulf Stream (GS) meanders and rings. As the GS flows northeastward towards Europe and crosses the NESC it becomes increasingly more unstable, and its anticyclonic meanders often become isolated anticyclonic Warm Core Rings (WCR). While the WCRs form throughout the span of 75oW - 55oW from the Gulf Stream, a significant portion of them are formed to the east of the NESC. Many of these rings finally interact and/or cross the seamounts during their westward journey – the subject of our investigation. Out of a total of 1186 warm core rings formed during 1980-2021 between 75oW and 55oW, 780 rings formed to the east of NESC region. Of these 780 rings, only 129 rings eventually reached the seamount region and only 62 rings finally crossed the NESC completely. We call this set of 129 rings the ‘seamount crossing rings’. This study focuses on seamount crossing rings’ path, propagation speed, size, spatial distribution of formation/demise, and lifespan characteristics. The five seamounts of interest are Bear, Physalia, Retriever, Picket, and Balanus. Seamount crossing rings that directly cross Balanus display a unique mean path while all other seamount crossing rings follow the mean path described by Silver et al. (2022). WCR propagation speed analysis showed that rings speed up as they cross the NESC, which is supported by theoretical studies that show a coupling of the baroclinic and barotropic wave modes causing Rossby waves and associated pycnocline anomalies to “jump” across the seamounts. The warm core rings significantly decrease in size while interacting with the NESC. The WCRs that form on top of the NESC tend to be larger, occupy the seamounts longer, and live shorter lifespans compared to rings that form farther to the east and interact with NESC later in its lifespan. Lifespan analysis also showed that the farther a WCR formed east of the NESC, the more likely it would live longer. For rings that formed on top of the seamounts, the larger WCRs had longer lifespans. Finally, a preliminary analysis based on ARGO floats derived vertical profiles is presented to shed light on the rings’ vertical structure.