The term "prognostic clouds" is usually reserved for numerical models that predict weather and climate
. Prognostic cloud schemes may differ as to the number of prognostic equations and parameterized microphysics processes (the sources and sinks of cloud water), and as to whether or not they advect cloud water. In current climate models
, spectral size distributions of cloud water particles
(and falling condensate) are almost always assumed, rather than predicted, and their (radiative) effective radii are specified. Most often, the cloud volume fraction is parameterized by diagnostic relationships, as in purely empirically based, diagnostic cloud parameterizations, but it can be prognostic. Key cloud radiative properties, such as cloud optical depth
, may be parameterized in terms of the prognostic cloud variables
and the (radiative) effective radii of the cloud particles.
Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact [email protected]. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.