4.3.1 Atlantic M2 TACs

Figure 13a–c show the M2 results. In North America (Figure 13a), the M2 TACs show a dipole-like pattern. Both sides of the Florida Peninsula show TACs that are consistently positive. However, they are moderately negative in the Western Gulf of Mexico. Farther north along the US Atlantic coast, a strong concentration of negative TACs are seen from the Florida panhandle to Virginia in the Sargasso Sea, with the strongest correlation in Wilmington, North Carolina (211 mm m<sup>1</sup> ; labeled "WIL" in Figure 13). Positive TACs are seen in the Chesapeake and Delaware Bays, New York City, New York ("NYC"), and Bar Harbor, Maine ("BH"). Finally, TACs in the Gulf of Maine and into the Bay of Fundy are strongly negative, reaching a magnitude of 259 mm m<sup>1</sup> at St. John, Canada ("STJ"). In Europe, the TAC patterns are somewhat more consistent (Figure 13b, c). Negative TACs are seen in most of the English Channel and the Irish Sea, and in the eastern parts of the North Sea. Conversely, positive TACs are found at inland semi-enclosed locations in England such as the Severn estuary; being largest at Avonmouth ("AVON"), farther north at Liverpool ("LIV"), and along the southern coast of the North Sea.
