We have increased our basic CTD station spacing to 60 nautical miles, from the original 30 nautical miles. We kept to 30 over the core (and highest priority) part of the cruise plan. We knew, however, that when we crossed into the Antarctic Circumpolar Current, which we are now sailing in and along, there was little oceanographic damage switching to 60-mile spacing, which helps save time. The station plan includes runs to the continental slope with more closely spaced stations at the ends of the P18 and S4P lines. Ice conditions at the end of the P18 line (see attached file for today’s ice map) may allow us to make it to the shelf break, perhaps a little east of the intended line, within the time we will allot to that portion of the cruise plan.
The pace in the labs is now a little more relaxed. With a plan in place regarding how we intend to complete the measurement program (within the next two weeks), everyone is focused on simply getting the job done.
Temperature and salinity differences with the 1992 Ioffe occupation of S04P continue in a similar vein to those reported earlier: away from the western boundary, the bulk of the water column is a little warmer and possibly slightly saltier now than measured in 1992.
A major activity this week was the deployment of a 4 km string of moored instruments at a specified spot in the ocean for Xiaojun Yuan (Columbia/LDEO) and Janet Sprintall (SIO). Neither PI was on board, but because WHOI mooring expert Jim Ryder was along, they knew - quite correctly - that their project was in great hands. The specifications called for the top float of the mooring to be 100 meters below the sea surface - in ca. 4500 meters of water - plus the mooring needed to be in an area where the bottom was flat, and had to be deployed in reasonably good weather. We used the Palmer’s multi-beam bathymetric mapping system (managed by Chris Linden, RPSC) to map the ocean floor, then we did a CTD cast at the most likely looking mooring deployment spot to measure the water characteristics and verify the bottom depth. There were also a host of XBT casts and one more CTD cast associated with the mooring science program, not to mention the long deployment itself. Add a day of time lost to bad weather before mooring deployment, and you can see why this was quite an operation, and one we are glad to have completed successfully and now have behind us.
A highlight for the science team was tours of the Palmer’s engine spaces this week by Chief Engineer Johnny Pierce (“JP”) and his expert team of engineers. With two of the four large marine diesel engines powered up plus some of the electrical generator diesels, of course hearing protection was needed, and there are hot/dangerous spots to avoid. But ordinary clothes are fine - nothing will get dirty during a tour to the engineers’ nearly spotless work place, as clean and as orderly as can be. Wow!
Holidays can be fun on board, so April 1st got some special attention. Even better, some of us who were “fooled” forgot that it was April 1st, adding to the joy of the conspirators and the fun had by all. Check out Juan’s blog for the fun.
We’re a relaxed bunch, well-fed, tired of stormy weather, happy for the present good weather, and working together to get the job done.
All is well on the Nathaniel B. Palmer.
Jim and Alex
Included with this email:
”” shows the planned P18S track to (and slightly beyond) the shelf break along with the 06April2011 ice conditions. If conditions stay much the same, our “P18S” track would run slightly east of that shown, in more favorable ice conditions. Ice coverage is currently ca. 100% in the area of Stan Jacobs’ moorings. We are not equipped to recover moorings in ice-covered waters.