Today I had the opportunity to visit the crew that was working on the bridge of the ship. I ran into Jim McGill, the ship’s Able-Bodied Seaman (in the picture to the right), who was on duty at the time. We noticed, off in the distance, a dark sky. The clouds ahead of us were the darkest I had seen in my short time on the ship. “A squall is headed this way”, said Jim, “it’ll be here in 10 minutes”. It was amazing to see the sky continue to darken, and to actually watch the storm system approach the ship. Within a couple of minutes, the ship was surrounded by clouds (there was almost no visibility), rain was pouring down, and the wind-speed went from a breezy 10 to a strong 34 knots.

All of this peaked my curiosity and I began to ask Jim more questions about weather. Apparently, 9ºN (our study site on this research cruise) is in the middle of an oceanic phenomenon known as the Inter-Tropical Convergence Zone, an area where cool northern currents collide with warmer southern currents. The result is rather “swelly” water and the occasional storm system.

To help keep track of any potentially alarming weather, the ship receives internet and/or internet weather updates from NOAA (National Oceanic and Atmospheric Administration) and the United States Navy every 6 hours. In addition, any weather warnings that are announced go directly to the bridge via the NAVTEX receiver, which will print out a report.

I was also curious about the implications of weather on the ship while sailing at sea and on the Alvin submersible. In general, the R/V Atlantis handles weather conditions quite well. It’s a strong vessel and quite stable on the water. Jim indicated to me that the crew appreciates the occasional rainfall because it helps to clean and cool the ship. Jim did mention, however, that when conditions are severe, there is concern for the safety of the ship and crew. The effect of weather on Alvin is a completely different story. The ship can’t launch Alvin in winds over 30 knots. Likewise, if Alvin submerges in strong weather conditions, it would be too dangerous to retrieve. Having a good idea about weather conditions makes sure that everyone is safe, including the ship and Alvin.

It is amazing how complex weather can be. The Captain and crew carefully analyze all of the main elements of weather monitoring: wind direction, wind force, swell direction, air temperature, water temperature, general weather conditions (such as visibility, rain, etc.), and sea state (using the Beaufort scale: observations of the appearance of the water, mostly focusing on “white caps”).

So my question to you is the following: which piece of weather information do you think is the most important while at sea, and why?

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