Cirrus clouds have been classified by height since studies on these clouds began. Unfortunately, this method of classification does not take into account condensation trails, or contrails. As a result, there is no consensus concerning whether contrails can be categorized as a type of cirrus cloud or are a different phenomenon altogether. Cirrus cloud formation differs from contrail formation, but other properties, such as their thickness and occurrence, are very similar. Although contrails usually disappear without significantly impacting the atmosphere, occasionally contrails may act as a generating mechanism for cirrus clouds. The nuclei used for cirrus clouds and contrails originate from different sources, but both phenomena go through similar freezing processes as they develop.
Updating the current cloud classification model might allow contrails to be classified as cirrus clouds. Further studies are also needed in order to better understand the net radioactive properties of both contrails and cirrus clouds.
"Cirrus Clouds and Contrails: A Comparative Analysis,"
McNair Scholars Research Journal: Vol. 1
, Article 9.
Available at: http://commons.erau.edu/mcnair/vol1/iss1/9