This is the second segment of a three-part series on the monsoon. View the first part here.
Have you ever wondered what triggers the rain to fall from the sky, especially during the Southwest’s summer monsoon season? The answer lies in the fascinating world of atmospheric science, where tiny particles play a crucial role.
Rain is the result of water molecules in the atmosphere coming together to form either ice crystals or water droplets that are heavy enough to descend to the earth. The process begins with “ice-nucleating particles,” which are small bits of matter that facilitate the formation of ice crystals high in the freezing upper atmosphere. Once initiated, these crystals can grow rapidly as more water molecules attach to them.
In regions with dry climates, such as the Southwest, atmospheric dust is a common catalyst for ice crystal formation. However, recent scientific investigations have revealed that biological entities can also contribute. Bacteria, fungal spores, and minuscule fragments of plant material can be carried high into the atmosphere by strong winds and updrafts, where they remain suspended for extended periods.
A compelling illustration of this phenomenon was observed in a study by the University of California, San Diego, in conjunction with the National Center for Atmospheric Research. Researchers collected cloud samples high above Wyoming, analyzing them in flight. Their findings indicated that most ice particles contained nuclei of either dust or biological material.
As climate scientists delve deeper into understanding how variations in atmospheric concentrations of these particles might influence future precipitation patterns, the implications for the Southwest monsoon and climate change become increasingly significant.
This Earth Note was written by Peter Friederici and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.
—
Read More Arizona News
