Why Do Raindrop Sizes Matter In Storms?

Submitted by JacobAdmin on Thu, 03/31/2016
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Not all raindrops are created equal. The size of falling raindrops depends on several factors, including where the cloud producing the drops is located on the globe and where the drops originate in the cloud. For the first time, scientists have three-dimensional snapshots of raindrops and snowflakes around the world from space, thanks to the joint NASA and Japan Aerospace Exploration Agency Global Precipitation Measurement (GPM) mission.

Diagram of raindrop shape
High in the atmosphere, water collects on dust and smoke particles in clouds. Raindrops start to form in a roughly spherical structure due to the surface tension of water. This surface tension is the "skin" of a body of water that makes the molecules stick together. The cause is the weak hydrogen bonds that occur between water molecules. On smaller raindrops, the surface tension is stronger than in larger drops. The reason is the flow of air around the drop. As the raindrop falls, it lose that rounded shape. The raindrop becomes more like the top half of a hamburger bun. Flattened on the...