FN Archimer Export Format PT J TI Wind-induced upwelling in the Kerguelen Plateau region BT AF GILLE, S. T. CARRANZA, M. M. CAMBRA, R. MORROW, R. AS 1:1;2:1;3:2;4:2; FF 1:;2:;3:;4:; C1 Univ Calif San Diego, Scripps Inst Oceanog, San Diego, CA 92103 USA. Observ Midi Pyrenees, Lab Etud Geophys & Oceanog Spatiale, F-31400 Toulouse, France. C2 UNIV CALIF SAN DIEGO, USA LEGOS, FRANCE IN DOAJ IF 3.978 TC 15 UR https://archimer.ifremer.fr/doc/00291/40207/39014.pdf https://archimer.ifremer.fr/doc/00291/40207/62142.pdf LA English DT Article CR MD 188 / KEOPS 2 SURVOSTRAL BO Marion Dufresne AB In contrast to most of the Southern Ocean, the Kerguelen Plateau supports an unusually strong spring chlorophyll (Chl a) bloom, likely because the euphotic zone in the region is supplied with higher iron concentrations. This study uses satellite wind, sea surface temperature (SST), and ocean color data to explore the impact of wind-driven processes on upwelling of cold (presumably iron-rich) water to the euphotic zone. Results show that, in the Kerguelen region, cold SSTs correlate with high wind speeds, implying that wind-mixing leads to enhanced vertical mixing. Cold SSTs also correlate with negative wind-stress curl, implying that Ekman pumping can further enhance upwelling. In the moderate to high eddy kinetic energy (EKE) regions surrounding Kerguelen, we find evidence of coupling between winds and SST gradients associated with mesoscale eddies, which can locally modulate the wind-stress curl. This coupling introduces persistent wind-stress curl patterns and Ekman pumping around these long-lived eddies, which may modulate the evolution of Chl a in the downstream plume far offshore. Close to the plateau, this eddy coupling breaks down. Kerguelen has a significant wind shadow on its downwind side, which changes position depending on the prevailing wind and which generates a wind-stress curl dipole that shifts location depending on wind direction. This leads to locally enhanced Ekman pumping for a few hundred kilometers downstream from the Kerguelen Plateau; Chl a values tend to be more elevated in places where wind-stress curl induces Ekman upwelling than in locations of downwelling, although the estimated upwelling rates are too small for this relationship to derive from direct effects on upward iron supply, and thus other processes, which remain to be determined, must also be involved in the establishment of these correlations. During the October and November (2011) KErguelen Ocean and Plateau compared Study (KEOPS-2) field program, wind conditions were fairly typical for the region, with enhanced Ekman upwelling expected to the north of the Kerguelen Islands. PY 2014 PD NOV SO Biogeosciences SN 1726-4170 PU Copernicus Gesellschaft Mbh VL 11 IS 22 UT 000346356800016 BP 6389 EP 6400 DI 10.5194/bg-11-6389-2014 ID 40207 ER EF