the search for the elusive giant iceberg A52

Satellite image of Iceberg A52 taken 16 October 2005
for the (US) Defense Meteorological Satellite Program (DMSP).
Upper Left corner is nearest to the South Pole;
Lower Right corner is nearest to southern tip of South America.
Click twice for larger, clearer.

BULLETIN FROM NEPHEW ICE CUBE
aboard the R/V Laurence M. Gould
in Antarctic waters off Palmer Station

Date: 12/8/2005 7:41:29 AM
Subject: From Clarence Island

I haven't sent out a report to you all in a week, and that's because we've been busy hunting icebergs. I think that I mentioned the purpose of this cruise is to see how icebergs affect the bio ... phyto ... krill ... well how they affect the critters. So after leaving Palmer station we searched for an iceberg which had been identified on satellite imagery. This berg is so big it has a name, iceberg A52. We went to where it was last spotted from space, but no berg, you might think it would be real easy to spot a 25 km long iceberg, but we cruised in the expected track direction for about 12 hours at 10 knots until finding it on radar and finally by visual. Approaching the thing was amazing. As we got to within 0.1
nautical miles the face of it stretched to the horizon on the left and the right. The face was taller than the bridge, which is probably 40 or 50 feet off the water. Later on someone used a laser rangefinder and estimated that the face was 100 feet tall, which puts the bottom at about 900 feet down.

We spent three or four days circling the berg and throwing every bit of geophysical and oceanographic instrumentation at it that we could including a fancy side pointing sonar mounted to a 30 foot pole bolted to the side of the ship (until the current broke a shackle holding it in place), laser rangefinding, expendable temperature probes which look like shoulder mounted torpedoes, a cage with temperature, conductivity, depth, oxygen and fluorescence meters and water sampling bottles (I get to run that show, giving the crane operator commands and firing the bottle closures), a robot
submersible with a video camera, and a 10 foot by 10 foot trawling net which can actually open 8 different nets in succesion to sample at different depths. Some of the stuff worked great and some just didn't work at all.

Then came the clash of the titans. OK, maybe that's a bit over the top, but I think I did witness the most dramatic sight of my life this morning. The 25 km long by 400 meter thick iceberg drifted straight into Clarence Island. Now it didn't smash into the cliffy shore of the island sending up water and rock into the lower atmosphere, but there we were next to the BFB (that's big F'ing Berg) watching it drift at 1 knot toward this stark island of steep peaks and jagged cliffs dropping right into the ocean. It appears that (much to my dissapointment) the berg grounded and started spinning rather than drift right into land. And then what happens? The damn biologists announce that we have to leave now since the project is to study free floating icebergs, not grounded ones. I considered emailing Ted Stevens and getting orders from the top to hold our ground and observe something that I would be willing to bet that nobody has ever seen before, but I bit my tongue mostly and went to bed.

So now after steaming around looking for a smaller iceberg we are circling around a cute little 1 nautical mile wide iceberg and doing a new set of measurements. Hopefully the MOCNESS (the net thingy) works this time.

On the way home, I hope to pass by Clarence Island again and see that berg plastered halfway up the sice of the cliffs with pengiuins taking advantage of an awesome sledding opportunity,

--dan

Dan Elsberg
Marine Computer/Instrument Specialist
Antarctic Research/Supply Vessel L.M. Gould

Current Position (Lat +N/-S, Lon +E/-W):

-61.11, -50.62