Are raindrops really shaped like teardrops?
Not really. Raindrops start out as round cloud droplets. As they grow and start falling, they begin to experience the resistance of the air, which causes them to flatten and resemble tiny M&M candy. Further growth leads to thinning in the center of the M&M, until the eventual breakup of the drop.
The flattening of raindrops alters the echo they produce when "illuminated" by radar from the side. But for a space-borne radar such as the GPM DPR, the effect is minimal.
Watch the below video to learn more:
This short video explains how a raindrop falls through the atmosphere and why a more accurate look at raindrops can improve estimates of global precipitation.
This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?11288