26 April 2001
N.B. Palmer
 

Hello Jose et al.

We are now at -60 26.430° S; -66 14.442° W (22:34 local) and steaming on a southerly course at about 11.3 kts.

This morning we were greeted with the roll of the ship in a long period swell. Although the sea was only choppy in a 10+ knot wind, but there was a large swell coming at the ship from the west and we were steaming in the trough. At mid-morning, from the main lab, several large swells came by that were at least 8' peak to trough. The sky was heavily overcast all morning with the clouds coming down to the sea surface a few hundred meters out away from the ship. Very gloomy.

Things did not get better. The relatively nice seas and weather disappeared and by early afternoon, the seas were building along with the wind. We had sustained winds around 40 kts out of the southeast for a good portion of the afternoon and early evening, and instead of a long period swell out of the west, we had a shorter period sea coming at us from off the port bow (133 deg.) as we continued to steam nearly due south. The air temperature also dropped from around 4 or 5° C in the morning to -2.6° C in late afternoon, to -3.6° C now. Along with the wind was an occasional mixed precipitation. Although the ride was generally OK (not everyone in the science party thought so as noted by their absence from the work areas), occasionally we bumped up against a good sized wave and the ship slowed abruptly and shuddered. An indicator of the rapid changes in the climate we experienced was the listing on the white board this evening in the galley that read "Outside decks closed due to icing".

The work with the CTD, which was scheduled for this afternoon, was scrubbed because of the wind and seas, but a Sonabuoy was deployed about the time we left the 200 mile limit of Argentina. Although additional work is needed to verify the occurrence, a couple of the Sonabouy recordings had the earmarks of whale calls; the sounds at least initially could not be correlated with any noises that might have been emanating from the ship. Also starting at the 200 mile marker, Eileen Hofmann's group has been shooting XBT's at 10 nm intervals to get temperature/depth profiles to show when and where we crossed the polar front. The north wall of the front is defined as the place where the 2° C isotherm is at 200 m. We crossed that point about 20:55 this evening at -60 10.29° S; -66 10.66° W.

The high winds and seas have now abated, and winds recently have been in the 10 to 15 kt range. The ship's ride is much more comfortable. We will continue the XBT drops at 10 nm intervals, looking now for evidence of the Antarctic Circumpolar current. Once we reach mooring SIOS3, which is positioned just at the Western Peninsula's shelf break , XCTD drops will be made to gather both temperature and salinity profile data as we steam along the shelf edge towards our first survey station. The T/S data will enable sound velocity profiles to be computed, which will be an aid for the Sonabuoy work as well as help us define the ACC boundary along the shelf. No additional Sonabuoy deployments are planned until reaching SIOS3 unless whales are spotted along our transit line.

I hope all is going well with the work on the Gould and the Polarstern.

Cheers, Peter