Weather or Not
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.”
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.
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.”