P. Clemente-colon et Xh. Yan, Observations of East Coast upwelling conditions in Synthetic Aperture Radar imagery, IEEE GEOSCI, 37(5), 1999, pp. 2239-2248
Citations number
24
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
Seasonal coastal upwelling in the U.S. Mid-Atlantic coastal ocean normally
occurs during the summer months because of generally alongshore southerly w
ind episodes. Southerly winds force an offshore surface Ekman flow over the
inner continental shelf. Colder and nutrient-rich waters from below upwell
toward the surface replacing offshore-homing surface waters. Synthetic Ape
rture Radar (SAR) observations from the European Remote Sensing (ERS) satel
lite ERS-2 before and after upwelling-favorable mind episodes in early summ
er 1996 along the New Jersey coast are presented here. Lower backscatter co
nditions appearing in the SAR imagery after the onset of upwelling demonstr
ate the influence of the upwelling regime on the sea surface roughness. Sat
ellite sea surface temperature (SST) observations and in-situ sea temperatu
re vertical profiles confirm upwelling conditions, Three key mechanisms are
suggested to explain the lower radar returns observed under upwelling cond
itions, an increase in the atmospheric marine boundary layer stability, an
increase in the viscosity of surface waters, and the presence of biogenic s
urfactants in the upwelling region.