As a continuation to the shortwave phase of the third Intercomparison of Radiation Codes in Climate Models (ICRCCM III) by Barker et al. (2003), this study establishes longwave benchmarks for inhomogeneous cloud fields and compares the performance of three approximate, one-dimensional (1D) radiation models. The benchmarks are calculated using a correlated-k three-dimensional Monte Carlo (3DMC) algorithm that is validated via comparisons to line-by-line calculations for simple atmospheres. The approximate methods include an independent pixel approximation (IPA) and two cloud-overlap schemes: maximum/random (MRO) and random (RO). The test cases are the same as those used in the shortwave ICRCCM III, and were generated from various cloud resolving models (CRMs). These cases represent a variety of inhomogeneous cloud types that are important radiative forcing mechanisms of general circulation models (GCMs). Domain-averaged fluxes and heating rates from these six "real cloud" atmospheres show that the IPA is consistently more accurate than the cloud-overlap models with respect to the benchmarks. For example, comparisons of model results for the ATEX case yield a maximum cloud layer heating rate error of -20 K/day from using cloud-overlap models, whereas the IPA error is only -2.5 K/day. These differences can be attributed to the 3D effects of cloud radiation, and indicate the need to refine longwave 1D climate radiation codes so that they compensate for unresolved clouds. / A Thesis submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester, 2008. / July 8, 2008. / Includes bibliographical references. / Robert G. Ellingson, Professor Directing Thesis; Ming Cai, Committee Member; Guosheng Liu, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_181708 |
| Contributors | Kablick, George P. (authoraut), Ellingson, Robert G. (professor directing thesis), Cai, Ming (committee member), Liu, Guosheng (committee member), Department of Earth, Ocean and Atmospheric Sciences (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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