FN Archimer Export Format
PT J
TI Seasonal and intraseasonal biogeochemical variability in the thermocline ridge of the southern tropical Indian Ocean
BT 
AF RESPLANDY, L.
   VIALARD, Jerome
   LEVY, M.
   AUMONT, Olivier
   DANDONNEAU, Y.
AS 1:1;2:1;3:1;4:2;5:1;
FF 1:;2:;3:;4:;5:;
C1 UPMC, CNRS, MNHN, LOCEAN IPSL,IRD, F-75252 Paris 05, France.
   CNRS, UBO, IFREMER, LPO,IRD, F-29200 Brest, France.
C2 IPSL, FRANCE
   CNRS, FRANCE
SI BREST
SE PDG-ODE-LPO
TC 53
TU Centre national d'études spatiales
   Centre national de la recherche scientifique
   Commissariat à l'énergie atomique et aux énergies alternatives
   ELECTRICITE DE FRANCE
   Institut de recherche pour le développement
   Institut français de recherche pour l'exploitation de la mer
   Institut national de la santé et de la recherche médicale
   Muséum national d'histoire naturelle
   Observatoire de Paris
   Université Paris Diderot
   Université Paris-Est Créteil Val-de-Marne
   Université Paris-Sud
   Université Pierre et Marie Curie
   Université de Bretagne Occidentale
   Université de Cergy-Pontoise
   Université de Versailles Saint-Quentin-en-Yvelines
   École nationale des ponts et chaussées
   École normale supérieure de Paris
   École polytechnique
   École pratique des hautes études
UR https://archimer.ifremer.fr/doc/00185/29630/27994.pdf
LA English
DT Article
CR CIRENE 2007
   VT 102 / CIRENE
   VT 75 / CIRENE
BO Le Suroît
   Marion Dufresne
DE ;madden julian oscillation;arabian sea;rossby waves;interannual variability;circulation model;monsoon;temperature;perturbations;nutrients;dynamics
AB The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) time series shows high variability of surface chlorophyll at seasonal and intraseasonal time scales in the oligotrophic southern tropical Indian Ocean thermocline ridge called the Seychelles-Chagos thermocline ridge (SCTR). The SCTR is characterized by an open ocean upwelling due to local Ekman pumping, which annually maintains the mixed layer (ML) shallow and is responsive to atmospheric forcing and in particular to the Madden-Julian Oscillation (MJO) at an intraseasonal time scale. Here we present an overview of SCTR biogeochemistry and investigate the physical processes driving the response observed at seasonal and intraseasonal time scales. Using satellite observations and biophysical ocean simulations, we show that seasonal and intraseasonal SeaWiFS signals (in austral winter and during MJO events, respectively) correspond to wind-induced mixing episodes. During such episodes, entrainment fertilizes the ML and allows phytoplankton production. Increased surface production is compensated by a decrease in the subsurface due to light limitation, leading to no significant change in integrated biomass and carbon export. Satellite observations and model results support the conclusion that the biogeochemical response to MJO is highly dependent on interannual variability of thermocline depth. Following Indian Ocean Dipole events, deepened nutrient-rich waters prevent nutrient input into the ML, decreasing the biogeochemical response to MJO. These results shed light on the physical processes at work in the strong surface temperature response to MJO in this region and suggest that entrainment cooling can play a role in the temperature signature to the MJO but is highly modulated by basin-scale interannual variability.
PY 2009
PD JUN
SO Journal Of Geophysical Research-oceans
SN 0148-0027
PU Amer Geophysical Union
VL 114
UT 000268353700001
DI 10.1029/2008JC005246
ID 29630
ER

EF