Friday, September 28, 2012

Scientist at Work Blog: Loading Up and Heading Out

Jim Thomson is principal oceanographer at the Applied Physics Lab at the University of Washington. He studies ocean surface waves and coastal processes.

Wednesday, Sept. 26
32.715 degrees north latitude, 117.156 degrees west latitude

It?s been a rough start. The team flew to San Diego over the weekend to meet the ship and load our equipment. On Friday, before we left, someone e-mailed from the Marine Facility to say that our shipping container had not arrived yet ? and did we know when to expect it? We expected it Friday, that?s when.

That container was filled with more than $500,000 worth of equipment, the result of countless hours in the lab and many late nights writing grant proposals. It was filled with everything we need for this expedition, and in large part what we need for many more years of wave research.

Then, on Saturday, the Waverider buoy at Station P missed its daily satellite transmission. Was the battery finally dead? If so, we would spend eight days traveling across the North Pacific to go find a needle in a haystack.

The Waverider buoy is 1 meter in diameter, and nearly invisible amid 10-meter waves. Sure, it?s moored at a specific location, and we have those coordinates, but the ?watch circle? that the mooring moves within is almost a mile across. (The large watch circle results from the 4,200-meter depth of the mooring, since even a small change in mooring angle results in large horizontal displacement.)

I have been expecting this cruise to be challenging. I did not expect the challenges to occur while we were still on land.

On Monday, we arrived at the pier and found our shipping container right there waiting for us ? the e-mail on Friday had just been a miscommunication and there had been a mislabeling. Relieved, we began to unload and, with the help of the ship?s crew, transfer our equipment onto the ship.

Transferring onto the ship is simple: Wire shipping crates, four feet on a side, are pulled out of our steel container and lifted aboard with a crane. While helping us load, the ship?s crew is equally busy with maintenance, safety checks and gathering provisions. (To feed 20 people for three weeks, the boxes of butter alone are staggering.)

More complicated than loading is the installation of our instruments. In addition to the autonomous Swift buoys we will deploy, we will make several measurements from the ship, and these instruments must be well secured before we leave. Once we are offshore, it will be too rough to make any adjustments.

At the bow of the ship, we have a specialized anemometer to measure the turbulence in the wind, complete with motion compensation for the pitch, roll and heave of the ship. Above the pilot house, we have a camera system (also motion compensated) to record the statistics of the breaking waves that we drive through.

At the stern of the ship, we have a tethered balloon, or aerostat, that we will fly above the ship to get a better view of the breaking waves. With a long day on Monday, we installed all of these systems, only to find that the camera system wasn?t working. It was too heavy, relative to the mount, for the stabilization motors.

On Tuesday, we successfully modified the camera system and then laid out the new Waverider mooring on the deck. The new mooring will replace the current one (the one without any recent satellite communications) when we arrive at Station P. We spooled 4,200 meters of mooring line from the dock to the ship?s winch. It took only four hours.

Now, it?s early Wednesday morning, and we are setting off at 7 a.m. We?re ready, and the ship is ready, but the Waverider buoy hasn?t made a satellite call in five days. That?s too long for just bad reception; the battery must be dead. That means a big search lies ahead at Station P. But first, we hope for some wind and waves to measure on the way there. One thing at a time.

Source: http://scientistatwork.blogs.nytimes.com/2012/09/27/loading-up-and-heading-out/?partner=rss&emc=rss

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