Many cirrus clouds produce hair like filaments made of the heavier ice crystals that precipitate from them. These "fall streaks", a form of virga, often indicate the difference in the motion of air (wind shear) between the upper part of the cirrus cloud and the air below it. Sometimes the top of the cirrus cloud is moving rapidly above a slower layer of air, or the streak is falling into a faster moving lower layer. The directions of these winds can also vary.
Cirrus clouds trap and reflect infrared radiation (heat) beneath them (greenhouse effect), but also reflect sunlight to some extent (albedo). It has not yet been determined whether the net effect of cirrus clouds is to warm or cool the earth. Much of the difficulty lies in modeling the albedo effect of clouds composed of various size and shape crystals. Older models tend to underestimate the albedo effect of cirrus. Refinements of these models will improve climate predictions.
Cirrus cloud radiative and microphysical properties from ground observations and in situ measurements during FIRE 1991 and their application to exhibit problems in cirrus solar radiative transfer modeling
Sep 15, 1997; ABSTRACT Measurements from the FIRE 1991 cirrus cloud field experiment in the central United States are presented and analyzed....
Cirrus cloud microphysical property retrieval using lidar and radar measurements, Part I: Algorithm description and comparison with in situ data
Mar 01, 2002; ABSTRACT A retrieval algorithm is described to estimate vertical profiles of cirrus-cloud ice water content (IWC) and general...