Scientists measure sea spray at Mount Desert Rock
By Marie C Darling
Engineer Research and Development Center
CONCORD, Mass.-- Scientists from U.S. Army Corps of Engineers' Cold Regions Research and Engineering Laboratory (CRREL) and NorthWest Research Associates (NWRA) recently braved the wind and cold of the Gulf of Maine to collect data for an Office of Naval Research project on sea spray. The project, "Sea Spray Icing in the Emerging Open Waters of the Arctic Ocean," is an effort to better characterize sea spray formation in high winds and cold temperatures.
CRREL Research Physical Scientist Kathy Jones and Dr. Ed Andreas, a CRREL retiree and now with NWRA, spent a month, from Dec. 29, 2012 to Jan. 28, 2013, on Mount Desert Rock, Maine.
The lighthouse at Mount Desert Rock, established in 1830, is both the farthest offshore and most exposed lighthouse on the east coast. The tiny, remote, treeless island is approximately 25 miles south of Bar Harbor, Maine. Because the island is so small and far from shore, it is an ideal land-based site for open ocean observations.
The decline of the Arctic sea ice cover has increased open water for sea spray generation. Sea spray transfers heat and moisture from the ocean to the atmosphere, and is a component of global climate models. In below-freezing air temperatures, ice from sea spray accumulates on offshore structures and can be a problem for operations, safety and stability. While ships create their own spray, sea spray on fixed structures comes from wind blowing on waves. In very high winds, the wind shears water from the wave crests. In these conditions, ice accumulates on railings, ladders, and equipment; encases lifeboats; and can result in significant additional load on the windward side of the platform.
The College of the Atlantic in Bar Harbor, Maine, owns the lighthouse and associated structures on Mount Desert Rock (it was transferred from the U.S. Coast Guard in 1996).
The college provided logistical and onsite support to the scientists by providing generators and fuel to power equipment and utilities; boat transport of personnel, food and equipment to the island with resupply at pre-set intervals; and maintenance of the generators and utilities. This enabled the scientists to focus their attention on their research.
"The support of personnel from the college made our work possible," said Jones. "They showed us how everything worked and kept all the systems going, so that we didn't have to. That was a major effort on their part."
The college uses the island in the summer for whale, seal and bird observations. However, this year two students were able to take advantage of CRREL's presence and stayed for the month to augment their summer observations with winter data -- grey and harbor seals gather on the island during January and February for their pupping and mating season.
"This was a great opportunity to study sea spray," said Jones. "It was a collaborative effort and we are very appreciative of all the support we received from the College of the Atlantic. We gathered a lot of data for this research project, which will enhance our understanding of the sea spray process. We hope to conduct research at the Rock again next winter."
Learn more about this research at http://onlinelibrary.wiley.com/doi/10.1002/qj.897/full and at http://polar.crrel.usace.army.mil/projects/project-sea_spray_icing.html.