Gopalakrishna V.V. auteur aut IRD Durand Fabien auteur aut IRD Nisha K. auteur aut IRD Lengaigne Mathieu auteur aut IRD Boyer T. P. auteur aut IRD Costa J. auteur aut IRD Rao R. R. auteur aut IRD Ravichandran M. auteur aut IRD Amrithash S. auteur aut IRD John L. auteur aut IRD Girish K. auteur aut IRD Ravichandran C. auteur aut IRD Suneel V. auteur aut IRD text journalArticle eng text/pdf born digital access The southeastern Arabian Sea (SEAS), located in the Indian Ocean warm pool, is a key-region of the regional climate system. It is suspected to play an important role in the dynamics of the Asian summer monsoon system. The present study reports the salient features derived from a newly harvested observational dataset consisting of repeated fortnightly XBT transects in the SEAS over the period 2002-2008. The fortnightly resolution of such a multi-year record duration is unprecedented in this part of the world ocean and provides a unique opportunity to examine the observed variability of the near-surface thermal structure over a wide spectrum, from intra-seasonal to interannual timescales. We find that most of the variability is trapped in the thermocline, taking the form of upwelling and downwelling motions of the thermal stratification. The seasonal variations are consistent with past studies and confirm the role of the monsoonal wind forcing through linear baroclinic waves (coastally-trapped Kelvin and planetary Rossby waves). Sub-seasonal variability takes the form of anomalous events lasting a few weeks to a few months and occurs at two preferred timescales: in the 30-110 day band, within the frequency domain of the Madden-Julian oscillation and in the 120-180 day band. While this sub-seasonal variability appears fairly barotropic in the offshore region, the sign of the anomaly in the upper thermocline is opposite to that in its lower part on many occasions along the coast. Our dataset also reveals relatively large interannual temperature variations of about 1 degrees C from 50 to 200 m depth that reflect a considerable year-to-year variability of the magnitude of both upwelling and downwelling events. This study clearly demonstrates the necessity for sustained long-term temperature measurements in the SEAS. specialized XBT data Arabian Sea Lakshadweep Sea Interannual variability Intra-seasonal variability WICC 032 021 57 6 739-754 2010 0967-0637 https://www.documentation.ird.fr/hor/fdi:010049602 10.1016/j.dsr.2010.03.010 0967-0637 [F B010049602] https://www.documentation.ird.fr/hor/fdi:010049602 https://www.documentation.ird.fr/intranet/publi/2010/07-2/010049602.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2010-08-03 2017-08-23 fdi:010049602 fre