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Weather or Not

May 2, 2013
storm in the distance

Light breaks through the clouds before the next squall arrives.
Image courtesy of Liz Baird, Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Red sky at night, sailors’ delight,
Red sky in the morning, sailors take warning.

Our activities are dictated by the sea and sky. The conditions have to be right to launch the ROV, to put the CTD in the water, and even for some of us to be comfortable writing on a computer! Mariners are the origin of much of the weather lore and legend. In general, these rhymes and sayings are based on observations, and handed down over the ages, as a way of making weather predictions.

Ship’s crews still make weather observations. More than 1,000 ships around the world, including the R/V Ron Brown, participate in the “Voluntary Observing Ship Program”  (VOS) where they submit weather data every 6 hours. On land, we find thousands of weather stations, from the amateur meteorologist who has a station in her backyard, to the high tech National Weather Service Forecast Offices across the country, such as the one in Newport, NC. At sea we don’t have many places to get weather observations, so we rely on these volunteer reports to get an accurate picture of what is really happening. As the VOS website says “Only YOU know the weather at your position.”

barometer

The barometer on the bridge records the air pressure.
Image courtesy of Liz Baird, Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Weather observations were not always collected in such an orderly fashion. Sailors would return to port with their logs, describing the weather they had experienced. However one sailor’s “stiff breeze” might be another’s “strong gale.” Admiral Francis Beaufort developed the “Beaufort Scale” as a way of standardizing ship’s logs for the Royal Navy in the 1930s. Initially the descriptions were based upon the behavior of the sails of a “man-of-war,” ranging from “enough wind to steer” to “will tear any canvas.”  With the arrival of steam-powered vessels, the scale was changed to reflect the sea surface (white caps, spray etc.) and wind speed, as well as land observations (smoke rising, branches breaking). Other scales have since been developed, such as the Saffir-Simpson scale for hurricanes.

As part of VOS, ships submit information on clouds (height, type and amount), visibility, wind speed and direction, dew point, pressure, sea surface temperature, waves and swell, general weather and ship’s course. All of this information adds to the data collected by satellites by “ground truthing” (sea truthing?) what the satellite is reporting.  This makes for more accurate predictions.

The ship receives weather data from a variety of sources. With the current ability to access the Internet nearly 24 hours a day, the latest forecast from the National Weather Service is available at any time. The Navy sends a daily forecast as well.  The sources are not always in agreement, just as our local meteorologists might provide differing forecasts on any day. Using the information provided, the Captain, ROV crew and science team can decide whether or not to launch the ROV or to put some other piece of equipment in the sea.

A series of 4 images of one wave breaking over the bow of the R/V Ron Brown.

A sequence of shots of a waves breaking on the bow of the R/V Ron Brown.
Image courtesy of Liz Baird, Deepwater Canyons 2013 Expedition, NOAA-OER/BOEM/USGS

Yesterday we had seas with 4-6 foot swells and 3-4 foot waves that varied over the course of the day.  Occasionally waves would hit the bow and cover it with spray, as we steamed northward.  We experienced several small squalls, demonstrating the weather rhyme:

Short notice, soon to pass,
Long notice, long will last

We could usually see the rain on the horizon from a distance, and it hardly lasted long enough for us to get our raingear out.

The forecast for the next few days appears quite varied.  Today we are expecting 15-20 knot winds with 5- 8 foot seas, which will decrease later in the day. Tomorrow the seas are predicted at 6-10 feet which might influence which gear goes in the sea. However research will always go on — “weather or not.”

5 Comments leave one →
  1. diane mcclain permalink
    May 2, 2013 1:59 pm

    do you tie yourselves to anything when waves or bad weather comes across so you are not swept off ship?

    • lizbaird permalink
      May 2, 2013 2:19 pm

      Jennie says “No, on this ship we would stay inside if the waves were such that we might worry about being swept away. On other ships you wear a tether to stay safe. And if the weather was REALLY bad we would head to port.”

  2. Lisa Garrison permalink
    May 2, 2013 7:25 pm

    Liz,
    My second graders are studying weather right now! We have been talking about the Beaufort Scale and learning to use the anemometer (standard tool) and the Kestrels to measure wind speed. We also have been learning about wind vanes. What does the weather station look like on the ship? Is it all digital/ electronic? What other factors (besides wind) effect launching?

    • lizbaird permalink
      May 3, 2013 9:55 am

      Dear Ms. Garrison’s class

      I am so glad to hear that you are studying weather right now! At sea the weather, and weather forecasts, determine what we do every day.
      The ship has an anemometer on the bow that measures wind speed and direction but it is a little more complicated than the wind vanes and anemometers on land. As the ship moves forward it generates its “own” wind (like the way it feels windy when you put your hand out a car window while it is moving). In order to figure out how fast the wind is blowing we have to take the reading from the anemometer and subtract the speed of the ship to get an accurate wind speed. We also have to take into account the direction that the ship is moving to figure out the direction of the wind.

      There are several “weather stations” set up on the ship including sensors down near the water. Some of them are digital, while others are analog, such as the barometer pictured in the blog. This allows us to confirm our measurements as well as giving us a back up in case something breaks.

      Besides wind, we have to take into consideration the currents, waves and swells before we launch. The biggest challenge is when we launch and recover the ROV (putting it in the ocean and taking it out). If the seas are too rough and the ship is too rocky it can be dangerous for the people trying to get it on board. It can also be dangerous for the ROV because it might hit the side of the ship if it rocked too much. During the dive the ROV is influenced by the currents underwater. The ship tries to stay in the perfect spot while Jason is down, and if the current or wind is too strong it makes it hard for the ship to maintain position.

      The NOAA Corps officers on watch have been very helpful as I have searched for the answers to your questions. They encourage you to figure out what you love doing and then pursue a career in that field. For them, they enjoy being at sea and being a part of the team that runs the ship.

    • May 3, 2013 10:39 am

      There is a nifty illustration of the Beaufort Scale on Howtoons: http://www.howtoons.com/?page_id=150.

      Nik Swain, Web Editor

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