The Biologic Origin of Snowflakes and Raindrops
This article is reposted under Free Access as a public information courtesy from the now defunct Suburban Emergency Management Project
Biot Report #506: March 15, 2008
Much of Earth’s precipitation begins its journey from the atmosphere to the ground in the form of ice. The miniscule nucleus of a snowflake may form de novo by sublimation of pure water vapour directly into solid ice at very, very cold temperatures (-42 degrees Celsius). These temperatures exist in the upper troposphere. Recall that the troposphere is the lowest portion of Earth’s atmosphere (closest to the Earth where all storm activity resides); averages about 11 km, or 7 miles in height; and contains almost all of the atmosphere’s water vapor and aerosols. What is the range of temperatures in the troposphere that envelops Earth?
|Snowstorm. Source: http://nyc.metblogs.com/archives/images/2006/02/02…; accessed March 11, 2008.|