Climate feedback mechanisms are known to substantially affect the surface temperature response to an external forcing. This study aims to advance our physical and quantitative
understanding of forcing and feedback contributions to the surface temperature response to an external forcing. The dissertation begins with a comprehensive overview of the climate feedback
concept and the frameworks used to interpret the effects of forcing and feedbacks on surface temperature. The climate feedback-response analysis method (CFRAM), a relatively new climate
feedback framework whose advantages over the traditional climate feedback analysis framework are delineated, is then used to study the seasonal surface temperature response to a doubling of
CO2 in a global warming simulation of the NCAR CCSM4. This allows us for the first time to explain the major features of the seasonal warming structure quantitatively. Polar regions, for
example, experience the largest warming and the greatest seasonal variation, with maximum warming in fall/winter and minimum warming in summer. In summer, the large cancelations between the
shortwave and longwave cloud feedbacks and between the surface albedo feedback warming and the cooling from the ocean heat storage/dynamics feedback lead to a warming minimum. In polar
winter, surface albedo and shortwave cloud feedbacks are nearly absent due to a lack of insolation. However, the ocean heat storage feedback relays the polar warming due to the surface albedo
feedback from summer to winter, and the longwave cloud feedback warms the polar surface. Therefore, the seasonal variations in the cloud feedback, surface albedo feedback, and ocean heat
storage/dynamics feedback, directly caused by the strong annual cycle of insolation, contribute primarily to the large seasonal variation of polar warming. Furthermore, the CO2 forcing, and
water vapor and atmospheric dynamics feedbacks add to the maximum polar warming in fall/winter. The CFRAM allows for a process-based decomposition of the temperature response into individual
contributions by the forcing and non-temperature feedbacks, which implicitly include the thermal-radiative coupling (i.e., temperature feedback) effects between the surface and atmosphere. To
uncover this hidden effect in the CFRAM, this study develops and introduces a method known as the surface feedback-response analysis method (SFRAM) to isolate the temperature feedback effects
on surface temperature, allowing for a physical and quantitative understanding of the temperature feedback effects. The temperature feedback effect is found to be the most important
contributor to the surface temperature change, accounting for nearly 76% of the global mean surface warming. From the CFRAM perspective, the temperature feedback effect is just the indirect
effects of the forcing and non-temperature feedbacks. The SFRAM analysis, in conjunction with the CFRAM results, indicates that in general the indirect effects of the forcing and
non-temperature feedbacks on the surface temperature change are larger than the direct effects; thus demonstrating the influence and strength of the temperature feedback effect in the CFRAM
results. By isolating the temperature feedback loop, an understanding of why the indirect effects are generally larger than direct effects is achieved. The SFRAM also serves as a bridge to
the traditional TOA feedback analysis. A comparison of the SFRAM results with those of the traditional TOA feedback analysis indicates the largest disparity in interpretation is given for the
lapse-rate feedback, which is shown to just stem from a misinterpretation of the temperature feedback effects on surface temperature. A better and more intuitive explanation is achieved
through the surface perspective of the SFRAM than the TOA perspective of the traditional feedback analysis. A reconciliation of the surface and TOA perspectives is achieved once the
temperature feedback effects are included with the effects of the forcing and non-temperature feedbacks, as in the CFRAM analysis. / A Dissertation submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Doctor of
Philosophy. / Fall Semester, 2014. / October 28, 2014. / carbon dioxide, climate feedbacks, global warming, surface temperature, temperature feedback / Includes bibliographical references. / Ming Cai, Professor Directing Dissertation; Xiaoming Wang, University Representative; Robert G. Ellingson, Committee Member; Philip Sura, Committee
Member; Zhaohua Wu, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_252888 |
| Contributors | Sejas, Sergio A. (authoraut), Cai, Ming, 1957- (professor directing dissertation), Wang, Xiaoming (university representative), Ellingson, R. G. (committee member), Sura, Philip (committee member), Wu, Zhaohua (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Science (degree granting department) |
| 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 (115 pages), 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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