Visiting the DIAL
Today we drove to the top of Hornisgrinde to see the water vapor DIAL. Hornisgrinde is a mountain in the black forest. It stands 1.1 km (3,609 feet) above sea level, and about 1 km (3,281 feet) above the valley floor. The DIAL sits on top of Hornisgrinde where it can get a good view all around. DIAL stands for "Differential Absorption LIDAR", and LIDAR stands for "LIght Detection And Ranging". So this instrument works with lasers and mirrors. Most of the instrument is inside the truck in the picture, but you can see the biggest mirror on top of the truck, behind the scientist.
The DIAL measures water vapor - the amount of water suspended in the air. There is always some water in the air. We call that humidity. When the air feels really dry, the humidity is low, and when it gets muggy and you sweat more easily, the humidity is high. The scientists are interested in measuring pockets of increased humidity - the places where there is alot more water vapor so clouds are more likely to form. While the DIAL measures water vapor, the DOW's measure how the air is moving, and the two together should help the scientists figure out why clouds form where they do, and what causes them to turn into thunderstorms.
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Postcards from the Field: COPS