Detection of “Shingles” in CZCS and AVHRR Images East of Cape Hatteras

Abstract

“Shingles” (filaments) are ejections of Gulf Stream water which occur at the crest of meanders, and are opposite in direction to the flow of the stream. Evidence from AVHRR images of sea-surface temperature off the US eastern coast clearly shows the occurrence of numerous “shingles” flowing shoreward within any single image. Ocean color images (CZCS) show pockets of high pigment content located between the “shingles” and the north wall of the Gulf Stream. Coastal Zone Color Scanner images are available from 1978–1986, albeit on an irregular basis. AVHRR images for sea-surface temperature are available twice daily since 1982; before this, only radiance values were obtained. Nonetheless, the features of interest, i.e. “shingles”, can still be detected from these data. Phytoplankton growth along the north wall of the Gulf Stream is sustained by the recycling of essential nutrients, as well as by nutrient transport resulting from upwelling. CZCS and AVHRR images off the northeast US coast were examined to determine the spatial/temporal occurrence of “shingles” in relation to upwelling mechanisms along the shelf break.