Clivar - Pune The Vasco-Cirene experiment J.Ph. Duvel J. Vialard and R. Molcard J.Ph. Duvel J. Vialard and R. Molcard LMD-ENS Paris, France LODYC, UPMC, Paris, France Support from CNES, CNRS/INSU, CORIOLIS

Clivar - Pune Intraseasonal Variation SST-OLR SST/TMI OLR/NOAA Coherent variations of the TMI-SST and the NOAA-OLR SST more reactive south of the equator

Clivar - Pune Vasco-Cirene calendar Argo floats deployment campaigns February 2005 First Vasco campaign from Seychelles Islands 5 PBs & 5 Aeroclippers JFM 2006 Intensive Vasco campaign ~ 20 PBs & 20 Aeroclippers February 2006 Atalante campaign Ocean measurements (CTD, ADCP…) Flux measurements Radiosondes Mooring deployment at 76°E + Sagar Kanya campaign in the east ? Subsurface mooring (ADCP) at 76°E IX06 SOOP line (TSG + XBT) IOP

Clivar - Pune Argo Floats Deployment Plans Sagar Kanya (August 2004) : 14 floats Marion Dufresne (September - October 2004) : 12 floats For all floats : One profile (0-2000m) of T and S every 10 days At 6°S : High frequency profiles given by three floats lagged by 3 days.

Clivar - Pune Atalante Cruise Feb 2006 Simultaneous cruise of the Sagar Kanya ? Ocean measurements (XBT, CTD, ADCP) Flux measurements Radiosondes Mooring deployment at 76°E

Clivar - Pune The Aeroclipper Measurent of surface atmospheric and oceanic parameters Surface turbulent fluxes using bulk formulas

Clivar - Pune Comparison with ECMWF Zonal Wind: Large differences ! Quasi-Lagrangian Measurements of: - Pressure - Temperature - Humidity In or above the atmospheric boundary layer Example trajectories for balloons 1 and 6 during the INDOEX experiment INDOEX-type balloons

Clivar - Pune Average Wind for January-March NCEP U Aeroclipper trajectories simulated using ECMWF wind for JFM Aeroclippers deployed from Seychelles Islands

Clivar - Pune Summary Role of air-sea interaction in the ISO Role of air-sea interaction in the ISO New experimental concept (Lagrangian and Eulerian measurements at the interface) in a region with very few in situ observations. New experimental concept (Lagrangian and Eulerian measurements at the interface) in a region with very few in situ observations. Experiment open to other international cooperations: Experiment open to other international cooperations: Additional in situ measurements Additional in situ measurements Satellite data processing Satellite data processing … Support from CLIVAR expected Support from CLIVAR expected

Clivar - Pune Scientific Context SST Variability linked to Intraseasonal convective perturbations (Anderson et al, 1996, Jones et al, 1998 ; Shinoda et al, 1998,1999, 2001; Woolnough et al, 2000, Duvel et al, 2004) SST Variability linked to Intraseasonal convective perturbations (Anderson et al, 1996, Jones et al, 1998 ; Shinoda et al, 1998,1999, 2001; Woolnough et al, 2000, Duvel et al, 2004) Role of air-sea interaction in the MJO characteristics? Role of air-sea interaction in the MJO characteristics? Interaction between Intraseasonal and Seasonal/Interannual time scales over the Indian Ocean Interaction between Intraseasonal and Seasonal/Interannual time scales over the Indian Ocean Large scale dynamics -> Thermocline depth -> Mixed Layer reactivity to atmospheric forcing Large scale dynamics -> Thermocline depth -> Mixed Layer reactivity to atmospheric forcing Mean Ocean structure may give elements of predictability of the ISV characteristics for a given season ? Mean Ocean structure may give elements of predictability of the ISV characteristics for a given season ?

Clivar - Pune Intraseasonal Variation SST Underestimate of the Intraseasonal variation of the SST by Reynolds blended dataset (cloud screening, …) SST/TMI SST/Reynolds

Clivar - Pune TMI evaluation Cold event of January 1999 Surface Velocity Program (SVP) drifter* Buoy WMO23589 Confirmation of the strong cooling of January 1999 *Distributed by Drifting Buoy Data Assembly Center, AOML/NOAA, Miami

Clivar - Pune SST comparison ORCA-TMI Forced OGCMTMI Modelling study suggests that: SST Intraseasonal fluctuations are due to surface heat fluxes Mixed layer temperature more reactive south of the equator due to shallower thermocline But Uncertainties due to poor knowledge of the surface fluxes and to model shortcomings (warm layer representation, …) Duvel et al, 2004

Clivar - Pune Experiment objectives Fine scale structure of atmospheric and oceanic parameters Fine scale structure of atmospheric and oceanic parameters SST diurnal cycle SST diurnal cycle SSS horizontal gradient SSS horizontal gradient Boundary layer structure Boundary layer structure Intraseasonal fluctuations of: Intraseasonal fluctuations of: Atmospheric large scale dynamics Atmospheric large scale dynamics Surface heat fluxes Surface heat fluxes Ocean Mixed Layer structure Ocean Mixed Layer structure Seasonal to interannual variations of: Seasonal to interannual variations of: Ocean Mixed Layer structure Ocean Mixed Layer structure Ocean Equatorial Dynamics Ocean Equatorial Dynamics