Friday, 7 December 2007

About to start again

We finished our main piece of work - the Drake Passage CTD section - late on Tuesday. This allows an estimate to be made of the rate of flow of water around Antarctica, which is somewhere around 130 million cubic metres per second (over 600 times the flow of the Amazon). This is spread over a wide area, but it also organises itself into two main jets of flow, where the current can be well over 1 knot at the surface. At several stations the CTD package was very noticeably pulled towards aft (the ship faces the current when it stops), on the first one the winchman radioed the bridge to confirm we were actually stopped! We lower the CTD at 1m/s and the angle was sufficient for the horizontal component to create an odd feature in the acoustic current profiler data - though it took quite a bit of searching and thinking to work that out (and some geometry of the ship and instrument to confirm).

After the main section we have been going down the Antarctic Peninsula, past Deception Island (though unfortunately not in, would be hard to justify the time). Due to the delays at Stanley the stop at Damoy (an old base) was reduced to a morning and about 12 people went over to clear the place up - removing chemicals, old flares, two iced in skidoos and putting up health and safety notices. Didn't get asked to go and didn't want to take a place from someone else, after being extremely lucky to land on Crozet. The afternoon saw a call to Vernadsky, formerly the UK Faraday base, now Ukranian. Again, didn't get ashore for same reasons but that mostly saved me from being plied with vodka, so probably no bad thing. Scenery is spectacular, but conditions haven't been ideal for photography.

As of 8.30 this evening we start another CTD transect, to look at the possibility of warm and salty water from the deep ocean coming up a trench near Rothera and affecting the sea ice.

Photos to come

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