1 April

Long-Term Ocean Climate Observations (LOCO) – D301/302

Cruise Diary – 1^st April 2006

Filling the containers

Saturday - Yesterday we had a big ‘joke’ with our search for a drifting mooring. Today, no such jokes happened although it was the first of April.

The Dutch team was partly busy with packing instrumentation into containers and partly with analyzing samples and data that was gathered during the cruise. For the English team the scientific work started. On our way to the moorings to the south-east of Madagascar, we cross a large feature that is present in satellite images. It is very interesting to see whether this feature is a circulating gyre and, if so, where it comes from. That is the reason why we do not follow a straight course to the moorings. Presently we are crossing this feature. On one side of it vertical temperature profiles are measured by launching so-called XBT’s (see picture).

These XBT’s are thrown in the sea while the ship sails and measure the temperature up to 1800 m depth. A big advantage is that the ship does not need to stop to do these observations, that’s why these XBT’s are used also on some commercial vessels. However, the disadvantage of course is that only temperature is observed. That’s why also 3 CTD stations are occupied in the gyre. It is rather deep here, some 3000 m, thus these CTD stations take some 3 hours.

Preparing an XBT

Launching an XBT