Ocean structure and climate (Eastern North Atlantic): in situ measurement and remote sensing (altimeter)

Abstract

Structure and climate of the east North Atlantic are appraised within a framework of in situ measurement and altimeter remote sensing from 08^608N. Long zonal expendable bathythermograph/conductivityt emperature^depth probe sections show repeating internal structure in the North Atlantic Ocean. Drogued buoys and subsurface £oats give westward speeds for eddies and wavelike structure. Records from longterm current meter deployments give the periodicity of the repeating structure. Eddy and wave characteristics of period, size or wavelength, westward propagation speed, and mean currents are derived at 208N, 268N, 32.58N, 368N and 488N from in situ measurements in the Atlantic Ocean. It is shown that ocean wave and eddy-like features measured in situ correlate with altimeter structure. Interior ocean wave crests or cold dome-like temperature structures are cyclonic and have negative surface altimeter anomalies; mesoscale internal wave troughs or warm structures are anticyclonic and have positive surface height anomalies.

Annual westward propagating anomalies near 26°N and eddy generation south of the Canary Islands: remote sensing (altimeter/SeaWiFS) and in situ measurement

“…Since the annual elevation signal is mainly due to large scale heat or buoyancy storage, local annual changes in elevation due to the azimuthal geostrophic surface current structure of swestylike anomalies are appraised by comparing a local signal with a larger scale annual signal. Most of the mesoscale structure due to eddies and waves in the North Atlantic (between 208^508N) has a spatial scale or wavelength $ 13 Ro (where Ro is the Rossby radius, Ro¼c/f, c is the phase speed for mode 1 internal waves and f is the coriolis parameter (see Pingree, 2002, table 3)) or $ 58 of longitude, so a smoothing scale of about $ 500 km will remove most of the mesoscale structure that dominates a sla map. A background reference or seasonal picture for the North Atlantic derived using a 58longitudeÂ58latitude averaging of the sla data (Figure 1) is e¡ectively without Figure 1.…”

Temperature–salinity distribution in the northeastern Atlantic from ship and Argo vertical casts

“…The latter values compare well with the previous studies in the region. In situ observations suggest eddy radii between 40 and 100 km in the area of the AzC (Gould, 1985;Pollard and Pu, 1985;Pingree and Sinha, 1998;Alves and Verdiere, 1999;Alves et al, 2002;Pingree, 2002;Mourino et al, 2003) and between 10 and 60 km in the northern part of the study region (Arhan and Colin de Verdiere, 1985;Mercier and Colin de Verdiere, 1985;Shoosmith et al, 2005), as well as in the upwelling area near the Iberian Peninsula (Pingree and LeCann, 1992;Oliveira et al, 2004). Derived from the satellite altimetry, the characteristic eddy scales in the study region are estimated to be 40-80 km (Le Traon et al, 1990) and 60-100 km (Stammer, 1997;Jacobs et al, 2001;Chelton et al, 2011).…”

Size-fractionated primary production, bacterial production and net community production in subtropical and tropical domains of the oligotrophic NE Atlantic in autumn

“…For geographical reasons, the North Atlantic subtropical gyre has been extensively studied and its hydrographic characteristics are presently well established (e.g. Pingree 1997Pingree , 2002 and references therein, Garçon et al 2001). Our knowledge of the metabolism of planktonic communities and their spatial and temporal scales of variability is, however, still limited.…”