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A Study of the Probability of Clear Line of Sight Through Single-Layer Cumulus Cloud Fields in the Tropical Western Pacific

The plane-parallel hypothesis (PPH) used to approximate clouds in global climate models neglects the 3-D effects of clouds. Such effects can contribute as much as 20 Wm-2 to the downward longwave flux at the surface. Several investigators have proposed accounting for longwave 3-D cloud effects by using information on the Probability of Clear Line of Sight (PCLoS) to modify the PPH approximation. This study investigates the PCLoS at the Atmosphere Radiation Measurement (ARM) Program's Tropical Western Pacific (TWP) site and its dependence on cloud properties. PCLoS is determined for single-layer cumulus events over 2-hour intervals using Whole Sky Imager (WSI) data at the Nauru and Manus sites simultaneous to numerous observations of the location of cloud boundaries and the downward longwave flux. The WSI PCLoS is compared to calculations from a set of PCLoS models using measured cloud field statistics as input (e.g., cloud fraction and aspect ratio). A PCLoS climatology is also prepared for the observation periods at both sites, and the results are used to investigate the spatial variability of the PCLoS and effects on the downward longwave flux at the surface. Comparisons to similar data obtained at the ARM Southern Great Plains site will also be made. / A Thesis Submitted to the Department of Meteorology in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Summer Semester, 2006. / June 22, 2006. / Cumulus Clouds, Cloud Radiative Effects, 3D Radiation / Includes bibliographical references. / Guosheng Liu, Professor Co-Directing Thesis; Ezra Takara, Professor Co-Directing Thesis; Xiaolei Zou, Committee Member; Paul Ruscher, Committee Member.

Identiferoai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_176159
ContributorsTaylor, Patrick C. (authoraut), Liu, Guosheng (professor co-directing thesis), Takara, Ezra (professor co-directing thesis), Zou, Xiaolei (committee member), Ruscher, Paul (committee member), Department of Earth, Ocean and Atmospheric Sciences (degree granting department), Florida State University (degree granting institution)
PublisherFlorida State University, Florida State University
Source SetsFlorida State University
LanguageEnglish, English
Detected LanguageEnglish
TypeText, text
Format1 online resource, computer, application/pdf
RightsThis 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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