文档介绍：Interannual variability of the Tropical Indian Oceanmixed layer depthM. G. Keerthi?M. Lengaigne?J. Vialard?C. de Boyer Monte′gut?P. M. MuraleedharanReceived: 2 November 2011/ Accepted: 16 January 2012?Springer-Verlag 2012AbstractIn the present study, interannual ?uctuations ofthe mixed layer depth (MLD) in the tropical Indian Oceanare investigated from a long-term (1960–2007) eddy per-mitting numerical simulation and a new observationaldataset built from hydrographic in situ data including Argodata (1969–2008). Both datasets show similar interannualvariability patterns in relation with known climate modesand reasonable phase agreement in key regions. Due to thescarcity of the observational dataset, we then largely relyon the model to describe the interannual MLD variations inmore detail. MLD interannual variability is two to fourtimes smaller than the seasonal cycle. A large fraction ofMLD interannual variations is linked to large-scale climatemodes, with the exception of coastal and subtropicalregions where interannual signature of small-scale struc-tures dominates. The Indian Ocean Dipole is responsiblefor most variations in the 10?N–10?S band, with positivephases being associated with a shallow MLD in the equa-torial and south-eastern Indian Ocean and a deepening inthe south-central Indian Ocean. The El Nin?o signature israther weak, with moderate MLD shoaling in autumn in theeastern Arabian Sea. Stronger than usual monsoon jets areonly associated with a very modest MLD deepening in thesouthern Arabian Sea in summer. Finally, positive IndianOcean Subtropical Dipoles are associated with a MLDdeepening between 15 and 30?S. Buoyancy ?uxes gener-ally appear to dominate MLD interannual variations exceptfor IOD-induced signals in the south-central Indian Oceanin autumn, where wind stirring and Ekman layer?Interannual variability?Indian Ocean?Indian Ocean Dipole?El Nin?o/SouthernOscillation?Monsoon1 IntroductionAlmost any ocean pro?le disp