Earth Institute News
Contact: Mary Tobin
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Reports From the Field
The Antarctic CORC/ARCHES Expedition
April 5 through May 8, 2003
Dr. Gerd Krahmann, of the Lamont-Doherty Earth Observatory, is aboard the Research Vessel Laurence M. Gould heading to Antarctic’s Weddell Sea. Krahmann is leading a group of five scientists and technicians from Lamont (Dr. Robin Robertson, Dr. Deborah LeBel, Dee Breger, and Tim Newberger) on an expedition to replace moored instruments deployed on the northern rim of the Weddell Sea. These three moorings have been observing the strength and properties of the outflow of Weddell Sea Bottom Water for the past four years. The instruments need to be recovered every one to two years to exchange batteries and download the data.
Because it is very cold and salty, Weddell Sea Bottom Water is one of the densest water masses in the world oceans. As such, it and similar dense water masses formed in other locations around Antarctica spread throughout the deep part of the world’s oceans. The goal of the project, dubbed CORC/ARCHES, is to observe changes of the properties and strength of the outflow of Weddell Sea Bottom Water over a period of ten years. Since the Weddell Sea is a major source of deep water, changes in the outflowing waters formed there will in turn affect the global circulation of deep water. Another group of Lamont Scientists is concurrently investigating the processes involved in the formation of deep water in the Antarctic’s Ross Sea (See the Antarctic AnSlope expedition).
Reports from previous weeks:
This Week's Reports (Week 4)
Morning May 7, 2003, from Dr. Gerd Krahmann
Aboard the R/V LAURENCE M. GOULD...
Latitude: 53S 05.5
Longitude: 70W 42.9
Wave height: 0.3m
Air temperature: 6.9C
Wind Speed: 5kn
We are back in Magellan Strait, 8 nautical miles from Punta Arenas. One more hour and our cruise will end. The trip across Drake Passage was fine. We were lucky that we passed between two storms. Only the first day had some swell (the big long rolling waves of the high ocean) left from the first storm. We had already packed partially at Palmer Station. For all our gear, including the instruments we intended to deploy, we have our own 20 foot container. Everything but our seawater samples, which are not allowed to freeze, could be loaded early. First thing this morning was loading the 20 leftover boxes into the container.
Unfortunately, we were delayed a few hours due a head wind on the last part of the passage. Thus we took over the pilot at the entrance of Magellan Strait around midnight. Had we been earlier we would have had a chance to observe dolphins which in this area frequently follow and apparently play in the ship's wake.
The weather here in Punta Arenas is just fine for this time of the year (late fall, compare it to early November in the northern hemisphere). In an hour or so we will dock, and after the customs and other administrative procedures (which usually take 1 to 2 hours) we will be allowed to go into town. As fresh vegetables and fruits were getting scarce on board (they usually don't last much longer than 3 weeks) we will be happy to enjoy the local food. Most of us are leaving Punta Arenas tomorrow around noon for a 24 hour journey back home. Everybody will be happy to get back to their own beds. And then after a few weeks back home we will wish to be out at sea again.