Ellis, Todd Douglas, authorStephens, Graeme L., advisor2024-03-132024-03-132008https://hdl.handle.net/10217/237708The overall purpose of this study is to examine the characteristics of precipitation as they are predicted to change in a typical climate change scenario and as they exist now and how well model reproduces those observations. The first part of this study examines the controls on global precipitation evident in a transient carbon dioxide doubling experiment conducted using coupled climate models collected for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4). As noted in other studies, the ensemble mean changes in water vapor occur at a rate more than three times that of precipitation. A simple ratio of these changes is introduced as a type of measure of the efficiency of the atmospheric hydrologic cycle in responding to changes in moisture, and varies between about 0.09 and 0.25 for the models studied. It is shown that the change in precipitation sensitivity is primarily governed by how emission of radiation from the clear-sky atmosphere increases as water vapor increases. This relationship closely matches one derived from simple energy balance arguments involving changes to water vapor emission alone. The study also presents the precipitation incidence over the global oceans as calculated from the CloudSat satellite, showing precipitation into the high latitudes and calculating that precipitation occurs 11% of the time over the oceans. These data are verified using ship-based (ICOADS) and island-based (GSOD) data. This study then extends the use of these data to an analysis of the observed cloud structures that are associated with rainfall over the oceans and then comparing them to special runs of the ECMWF weather forecast and HadGAM1 climate prediction models. These comparisons show that the models don't predict shallow precipitation nor layered precipitation structures as often as they are observed, and predict incorrect global precipitation incidences.born digitaldoctoral dissertationsengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.climate changehydrologic cycleprecipitationradiation budgethydrologic sciencesatmospheric sciencesTextPer the terms of a contractual agreement, all use of this item is limited to the non-commercial use of Colorado State University and its authorized users.