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This is our route since we left Mahe, coloured with SST (laft) and SSS (right). I haven't made precise comparisons with sattelites and climatologies, but it seems that we had slightly warmer SST than usual on our way to 67°E, 3°S. At the location of the ATLAS mooring (67°E, 8°S) and at the location where we're doing the 12 day station (67°30'E, 8°S), we are right in the middle of a hot spot (as suggested by TMI satellite pictures). What we're observing since the begining of the cruise rather looks like a break pahse of the intraseasonal convective activity. We still have 4 weeks until the end of the intensive observations of leg 2, and I hope that we'll have the oportunity to see active convection at work!
Above is the first XBT section produced between Mahe and 67°E, 3°S by Jacques Grelet. The thermocline is deeper than usual with subsurface anomalies up to 6°C, and this is consistent with the diipole mode conditions experienced earlier this year indeed, that result in a anomalously high sea level over a large portion of the southern tropical Indian Ocean.
Above are the positions of the 10 PROVOR floats that have reported up to now. We should hear about the remaining ones today or tomorrow. They should give us a relatively high temporal resolution (about 2 days) meridional section and allow to foolow the changes in the ocean further north, at least during the next few weaks, before they spread apart too far.
This is the route of the three WHOI drifters with temperatures measurements in the miwed layer (every 50cm down to 12m and every 5m from 15 to 60m) and a 1000m nylon rope as a drag. We might have to recover the one to the north at the end of the first leg, unless it bends back into westward currents. The advantage is that it moves very slowly (less than 0.1 m/s). The two other drifters are quicker (about 0.2 to 0.3 m/s) but at least they go towards Seychelles and it won't cost us much additional time to retrieve them.
This is a first quicklook of the 220 CTD profiles and of the flux data we have collected so far. The situation so far has almost always been a gain of heat for the ocean (few clouds, weak wind). Rain events or advection has sometimes brought shallow freshwater puddles, resulting in the creation of transient wrm layers. The high resolution of the CTD casts allows to see detailed high frequency fluctuations in the thermocline. We still have much to do to quality control and process all the data, but there already seems to be interresting features to look at!
Finally, so far, the ATLAS buoy works like a charm. We'll start comparing it with our CTD data soon.