Seasonal variability of sea-surface temperature fronts on Georges Bank

Sea-surface temperature (SST) fronts, extracted from archived (1985–1996) advanced very high-resolution radiometer (AVHRR) data, are determined in the Georges Bank region. Resulting frontal locations clearly show the tidal mixing front on Georges Bank. The probability of detecting an SST front at an individual pixel on Georges Bank is presented as a monthly climatology. Variations in the probability, position, and associated water depth of SST fronts in the Georges Bank region show the development of the tidal mixing front during the summer, as well as the presence of a persistent front near the shelfbreak. he 12-yr time series of fronts, 144 individual monthly frontal probability images are decomposed into the mean frontal position and empirical orthogonal functions (EOF) using singular value decomposition (SVD). Spatial and temporal information from the first EOF mode reveals the seasonal development of the tidal mixing front. Spatial patterns associated with the first mode also reveal the winter occurrence of fronts on the Northeast Peak area of Georges Bank, which is most likely associated with Scotian Shelf Water flow across the Northeast Channel. The second mode also indicates the development of the “hot spot” often observed over Georges Bank during the late summer and early fall. r evidence indicates that the mean position of detected SST fronts on southern Georges Bank changes approximately 10 km on-bank from late-spring to mid-summer. Monthly mean positions are also compared to the distribution of Simpson and Hunterʹs (1974) tidal mixing parameter, with resultant positions compared to historical stratification at those locations. Comparison of detected SST fronts to historical hydrographic data on Georges Bank points to the fronts being located in increasingly stratified water from May through August.