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Understanding 20th Century Antarctic Pressure Variability and Change in Multiple Climate Model Simulations

Dusselier, Hallie E.
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1469189473

Abstract Details

2016, Master of Science (MS), Ohio University, Geography (Arts and Sciences).
The CAM5 non-coupled Community Atmospheric model version 5 (CAM5) is used to study the role that natural and anthropogenic forcings (ozone forcing, radiative forcing, tropical forcing) play in the Antarctic pressure pattern in the last century. Seasonal pressure reconstructions at key Antarctic stations through the 20th century are employed as the best estimates of Antarctic pressure variability since 1905, especially as it is shown here that pressure reanalyses are unreliable in the early 20th century. Three experiments are conducted with the CAM5 model; the first of these experiments allows radiative forcings to vary in time with prescribed, time-varying tropical sea surface temperatures, with the goal being to isolate the role of radiative forcings on the pressure pattern over the continent (when compared with another simulation), and to act as the control, as this is most like the real world. The second experiment that is performed with the model has time varying ozone forcing and climatological sea surface temperatures. The goal of this experiment is to isolate the role of ozone forcing on the Antarctic pressure pattern. The final experiment has fixed radiative forcing at 1990 values, but time-varying prescribed tropical sea surface temperatures. The goal of this experiment is to isolate the role of tropical sea surface temperature variability, or aid in isolating the role of radiative forcing when compared with the first experiment. While each of the simulations of the model results contained interanual variability as expected, the results of the model in each experiment were well within the range of the pressure reconstructions, demonstrating reliability. Additionally, when smoothed, similarities between experiment trends and reconstructions trends were clearly identifiable. Model trends showed that tropical sea surface temperatures have a marked influence on the negative pressure trends in Antarctica, particularly near the Peninsula and West Antarctica and near the Amundsen and Bellingshausen Seas. It is also seen that tropical forcing has the most significant impact during MAM, JJA, and SON during the 20th century. During DJF, a stronger influence from ozone is seen, particularly after 1957. In this season, ozone influenced the negative trends across the continent more uniformly, with more positive trends seen in the southern midlatitudes in DJF after 1957.
Ryan Fogt (Advisor)
Jana Houser (Committee Member)
Dorothy Sack (Committee Member)
185 p.
Atmosphere; Atmospheric Sciences; Climate Change; Geography; Meteorology
20th century; Antarctica; Climate; Antarctic pressure variability; MSLP; Ozone; Sea surface temperature; CAM5; SAM; ASL

Recommended Citations

Citations

  • Dusselier, H. E. (2016). Understanding 20th Century Antarctic Pressure Variability and Change in Multiple Climate Model Simulations [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1469189473

    APA Style (7th edition)

  • Dusselier, Hallie. Understanding 20th Century Antarctic Pressure Variability and Change in Multiple Climate Model Simulations. 2016. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1469189473.

    MLA Style (8th edition)

  • Dusselier, Hallie. "Understanding 20th Century Antarctic Pressure Variability and Change in Multiple Climate Model Simulations." Master's thesis, Ohio University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1469189473

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Ohio University and OhioLINK.