Mary Cook, December 18, 2004

NOAA Teacher at Sea
Mary Cook
Onboard NOAA Ship Ronald H. Brown
December 5, 2004 – January 7, 2005

Mission: Climate Prediction for the Americas
Geographical Area: Chilean Coast
Date: December 18, 2004

Location: Latitude 22°16.32’S, Longitude 86°10.94’W
Time: 8:30 am

Weather Data from the Bridge
Air Temperature (Celsius) 19.46
Water Temperature (Celsius) 19.81
Relative Humidity (percent) 69.46
Air Pressure (millibars) 1016.99
Wind Direction (degrees) 123.54
Wind Speed (knots) 15.73
Wind Speed (meters/sec) 7.20
Sunrise 07:57
Sunset 21:27 (9:27 pm)

Question of the Day

What does a psychrometer measure?

Positive Quote of the Day

For where your treasure is, there will your heart be also. Jesus Christ

Science and Technology Log

Today Diane and I journeyed up to the bridge struggling against the strong winds and the lurching of the ship. We interviewed Ensign Silas Ayers and “Pirate” Jim Melton. Silas gave us instruction on ship safety and navigation. He said the two most important things in navigation are: don’t hit anything and don’t run aground. Silas showed us how they plot the ship’s course on a map/chart and all the navigational instrumentation. The RONALD H. BROWN has radar that ranges up to 96 miles but it is set for 24 miles at this time. The radar is used to detect other ships that might be in our path. He also showed us the autopilot computer and controls. They can set the coordinates and the ship will drive itself!!! Of course someone has to stay on the bridge at all times, because as everyone knows computers have glitches that could cause a malfunction. That could be a disaster. Something that I find fascinating is that this ship can hover in one place! It’s officially called dynamic auto positioning. They set all the thrusters at a specific setting and the ship stays in one place. He then explained the ship’s lights. The ship has a red light on the port side and a green light on the starboard side. These lights reveal our ship’s location to other ships and enable them to ascertain our heading by watching the movement of our lights.

There’s another series of light signals that communicate the ship’s condition. For example, when we hover to do a CTD cast, the ship displays a set of red/white/red lights that tell other ships we are unable to make quick maneuvers. There’s also a set of lights that means man overboard. Another cool thing on the bridge was the spinning window. Yep. I said spinning window. It wasn’t spinning today but it can spin. (I hope they weren’t pulling my leg.) The purpose of the spinning window is to reduce ice buildup on the glass.

“ Pirate” Jim Melton shared with us the lookout duties. He keeps a watch that scans the horizon constantly. Jim uses an alidade. An alidade is a telescopic instrument that has a special swiveling balance that can compensate when the ship rolls, pitches, or yaws.

I looked through the alidade and saw a line across my field of vision. Jim said that they use that line as a reference point and they can determine the size of the ocean swells. Everyone working on the bridge must also report the complete weather data to NOAA every hour.

Before we finished, I sat in the captain’s chair and scanned the horizon for whales and other ships at sea!

Late this afternoon, Diane and I continued working on the children’s book. Bruce Cowden, the illustrator, is producing artwork faster than we’re writing the story! So we’re feverishly trying to catch up. It’s fun writing with Diane. She has a bright mind and she has a genuine excitement for atmospheric and oceanic science.

Tonight at “6:00 Science on the Fantail”, we interviewed meteorologist Dan Wolfe of the Environmental Technologies Laboratory in Boulder, Colorado and Frank Bradley physicist/ meteorologist of Australia’s Commonwealth Scientific and Industrial Research Organization. They have been studying clouds, precipitation and humidity, as well as launching radiosondes (weather balloons) 4-6 times a day. Dan explained how the radiosondes work. The instrument package records temperature, pressure, and humidity as the helium-filled balloon ascends into the sky. The radiosondes have a GPS antenna that transmits its location and another transmitter that communicates the data being collected back to the computer in the lab. All of this information is compiled to help develop a “picture” of the atmosphere in this region which has never been thoroughly studied. This information can then be used in making models for more accurate weather prediction.

Frank Bradley shared with us his work which has been in collaboration with Dr. Bob Weller and Dr. Chris Fairall for the past 20 years. Frank showed us the somewhat “old fashioned” Assman psychrometer that he uses to take the wet bulb and dry bulb temperature readings several times a day. A psychrometer’s temperature readings can be used to determine relative humidity. Frank says that he uses this low-tech instrument because nothing can go wrong. This psychrometer’s readings are then used as a validation of the high tech instruments on board. Frank said that he has studied air-sea interaction, the interface of the ocean and the atmosphere, for many years and considers it a very important area for developing better models to predict the weather.

Personal Log

Wow! I really liked the bridge! It is cool. I don’t know why they wouldn’t let me drive the ship. I mean, come on, we’re out in the middle of the biggest ocean on Earth. What could I run into? And there’s no ground in sight. Actually, there’s nothing in sight. So I’d be satisfying the two most important rules of ship navigation and safety: don’t hit anything and don’t run aground. It seems though, that I remember something about needing a license to drive. I’m not sure.

While on the bridge, I saw that our planned course will take us right by the San Felix islands. It’ll be the first land I’ve seen since December 5! I wonder what that will feel like?

As we near the end of the cruise and it seems almost all the work is done, everyone is reading guidebooks about Valparaiso and planning some excursions. Even though I’m not ready to get off the ship, I am feeling a little excited about seeing a new place. I just love to go to new places and I’ve heard that Valparaiso is one of Chile’s most beautiful cities. Diane and I are deciding what to do during our two days there. One day we want to see the city and another day we want to drive toward the Andes Mountains and get glimpse of Aconcagua, the highest mountain in all of the Americas!

Yeah! Another adventure awaits!

Until tomorrow,


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