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   Image courtesy of Dr. Robert Wood

From: Dr. Robert Wood
Over the ocean west of Arica, October 28, 2008

Inside the POC!!!!

Wish you were here!

We're flying inside of a weather system called a "pocket of open cells" (POC), which you can see in the photograph. We're flying on the NSF C-130 aircraft. This weather system is huge, about 100 km across and about 1000 km long (so about the same area as the Island of Cuba to the south of the United States). The interesting aspect about this feature is that the processes occurring within the POC are controlled by drizzle. Drizzle is light precipitation that mostly contains very small rain drops that are barely detectable with the human eye when they fall on you. However, even though this precipitation is very light, it can wash out many of the tiny (100 times smaller than human hair) aerosol particles in the atmosphere. Scientists think that this cleansing of the air in the POC helps to sustain this type of weather system. In this way, what we see from space as a huge change in the clouds may be strongly influenced by the tiniest of particles.

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