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Atmospheric Change in Antarctica since the 1957-1958 International Geophysical Year

Nicolas, Julien Pierre
http://rave.ohiolink.edu/etdc/view?acc_num=osu1397747086

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Atmospheric Sciences.
The Antarctic Ice Sheet holds a volume of ice and snow equivalent to 55 meters of sea level. The melting of only a relatively small fraction of this volume could have dramatic consequences for populations around the world. With this in mind, the research presented here focuses on two atmospheric variables that are key controls of the state of the ice sheet: its surface mass balance (or net snowfall) and its near-surface air temperature. The analysis aims to understand how these two parameters have changed (if at all) since the 1957-1958 International Geophysical Year (IGY), the start of the instrumental era in Antarctica. Particular attention is given to the part of the continent known as West Antarctica, the most vulnerable to atmospheric and oceanic warming, and the one where rapid glacial change is currently taking place. The research is divided into three parts. The first part uses a set of seven global reanalyses to investigate the changes in Antarctic surface mass balance and Southern Ocean precipitation since 1979 (start of the reanalyses). This investigation is also intended to shed light on the reliability of these reanalyses, which often contained artifacts caused by changes in the observing system, particularly in high southern latitudes. Spurious changes in precipitation are found to various degrees in all data sets but with varying characteristics and origins. According to the two reanalyses deemed most reliable, neither Antarctic surface mass balance nor Southern Ocean precipitation have changed significantly over the past three decades. The second part consists of a multifaceted investigation of the near-surface temperature record from Byrd Station, in central West Antarctica. As the only meteorological record in this region to extend back to the IGY, it is a critical data set, but also one with a complicated history and substantial data gaps. A comprehensive revision of the record is undertaken and a novel approach is used to estimate the missing observations. The complete Byrd record reveals a marked increase in the annual mean temperature since the late 1950s. This warming is not only stronger than previously estimated by other studies, but also establishes central West Antarctica as one of the fastest-warming regions on Earth. A review of the atmospheric and oceanic drivers of the temperature trends highlights their strong seasonal dependence and the complex interplay between low-latitude sea surface temperature forcing and high-latitude atmospheric variability. The third and final part of the research builds upon the new Byrd record and the records from 14 other stations to generate an Antarctic-wide temperature reconstruction spanning the IGY to the present time. The spatial interpolation method is adapted from, and improves upon, a kriging technique previously employed for the same purpose. The reconstruction is then used to re-examine the relationship between the Southern Annular Mode (the dominant mode of high southern latitude atmospheric variability) and Antarctic temperatures. The analysis shows how the strengthening of the SAM in austral summer and fall seen in recent decades has mitigated an otherwise stronger background warming of Antarctica.
David Bromwich, PhD (Advisor)
Jay Hobgood, PhD (Committee Member)
Jeffrey Rogers, PhD (Committee Member)
Jialin Lin, PhD (Committee Member)
188 p.
Atmospheric Sciences; Climate Change
Antarctica; West Antarctica; reanalysis; surface mass balance; reconstruction; Byrd; ice sheet; climate change

Recommended Citations

Citations

  • Nicolas, J. P. (2014). Atmospheric Change in Antarctica since the 1957-1958 International Geophysical Year [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397747086

    APA Style (7th edition)

  • Nicolas, Julien. Atmospheric Change in Antarctica since the 1957-1958 International Geophysical Year. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1397747086.

    MLA Style (8th edition)

  • Nicolas, Julien. "Atmospheric Change in Antarctica since the 1957-1958 International Geophysical Year." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397747086

    Chicago Manual of Style (17th edition)

osu1397747086
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