Image Courtesy of Dr. Cynthia Twohy

From: Dr. Cynthia Twohy
Arica Hotel, Chile, South America, October 28, 2008

Sleepless in South America

Well, we haven’t been getting much sleep lately because we’ve been flying night flights on the C-130 aircraft. The photo shows what the airplane looks like when we arrive at the airport, at about 1:00 AM local time. We bring flashlights to walk from the car to the aircraft, so we don’t stumble on rocks and who knows what! The airplane takes off at about 3:00 in the morning and we fly until noon. We catch sleep in the afternoons and evenings when we can.

After three long flights like this, everyone was getting pretty tired, but the flight last night made it all worthwhile. We sampled our first “POC” (pockets of open cells). This is basically a large area within the stratocumulus cloud deck that looks different when viewed by satellite from above. Instead of solid, relatively uniform clouds, clouds in the POC are variable and there are even some completely clear areas. There is lots of drizzle and the air is extremely clean. This is because one drizzle drop forms from many small drops, and these small drops in turn form from small particles in the air. When a drizzle drop falls to the ocean’s surface, it takes these particles out of the atmosphere. It also can collect more aerosol particles on the way down as it falls! You may have experienced something similar when you notice how clean the air seems after it rains—that’s because the rain removes particles that normally scatter and absorb light from the air.

I’m sure you’ll hear more about these POCs and why they’re important from other scientists involved in the project. And now, it’s time to get some sleep!

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