Research on the Rockpile

2013-10-27 19:03:34.000 – Roger Pushor,  Weather Observer/IT Specialist

Sandra setting up for another run

As most of you probably already know our mission here at the MWObs is to ‘Advance understanding of the natural systems that create the Earth’s weather and climate, by maintaining its mountaintop weather station, conducting research and educational programs and interpreting the heritage of the Mount Washington region’. This week we’ve had the pleasure of hosting Researchers Kathy, Kerry and Sandra from the Army Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, NH.

While the picture that’s included in this post may look like Sandra is getting ready to launch a small rocket skyward, that’s not what’s going on at all. Sandra is actually setting up an instrument that was developed here at the Observatory back in the 1940’s called a Rotating Multi Cylinder. The Multi Cylinder is put outside facing into the flow of the wind, with water droplets that make up the fog we spend 60% of our time in. The Multi Cylinder is left outside until the very top element has collected enough ice to be the size of the second, rotating at approximately one revolution per minute. This process can take anywhere from four to twenty minutes. Once sufficient ice has built up, the entire Multi Cylinder is brought inside to the Cold Room where it’s very carefully disassembled so that the ice can be weighted and measured to determine the rate of accretion, droplet size and liquid water content.

So by now you’re probably asking ‘Why does anyone care about how Rime Ice builds up on one of these Rotating Multi Cylinders?’. Well I’m so glad you asked. The data that is being gathered will be used to improve the weather models and predict when, where and how much rime ice will build up on a surface. This is some very important information to have if you’re going to build structures like antennas, power lines, and wind farms or fly airplanes in conditions that are likely to see conditions where substantial amounts or Rime Ice can build up.

Since rime ice forms to differing degrees depending on the temperature, wind speed, and water content you need to make a lot of runs in varying conditions to collect adequate data for the models to be accurate. Between 1990 and 2013 CRREL has made 249 runs at the top of Mount Washington, the most of any location. With the ideal conditions we’ve had since we all arrived Wednesday the CRREL team has been able to make over 70 runs.


Roger Pushor,  Weather Observer/IT Specialist

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