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An Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data

Philippoff, Karl Steven
http://rave.ohiolink.edu/etdc/view?acc_num=osu1388793239

Abstract Details

2014, Master of Science, Ohio State University, Geological Sciences.
The interpretation of variations in oxygen isotopes ( d18O) within tropical ice core records have been a subject of much debate. In this study the ice core record from Dasuopu (28 23 N, 85 43 E) in the central Himalayas was compared with two coral composite records derived from Indian (Chagos Islands, Mafia, Mahe, Malindi, and Mayotte) and Pacific (Kiritimati, Maiana, Nauru, Palmyra, and Tarawa) Ocean corals, precipitation data from the Global Precipitation Climatology Center (GPCC) v6 and Indian monsoon subdivisions, the Nino 3.4 index, sea surface temperature (ERSST v3b), and air temperature data (NCEP 20th century reanalysis) to examine its relationship over interannual, 2-8 year, and multi-decadal timescales. Coral records represented reliable, consistent, and highly resolved proxy records of SST variability over the length of their respective records and provided a comparison for the results derived from the SST reconstructions. The results from these analyses indicate that the Dasuopu record can be best understood in a hierarchical manner. Over interannual and 2-8 year timescales, the variability of the Dasuopu oxygen isotopic record is dominated by local and regional rainfall variability which are both strongly associated with the variations in the strength of El Nino-Southern Oscillation (ENSO). However, over decadal and especially multi-decadal timescales, the variation in its isotopic record is strongly driven by long-term trends in air and sea surface temperature in regions upwind of the ice core location. These relationships were highly significant and were observed in both the coral composite and instrumental datasets, making these results more robust. A multi-regression model constructed using the summer monsoon rainfall from the East Uttar Pradesh monsoon subdivision, the summer mean Nino 3.4 index and air temperature anomalies in a region bound by 20-28 N, 80-88 E described 27% of the variance in the Dasuopu d18O record between 1886 and 1996, with temperature the most important parameter. This strongly suggests that these three parameters control a large degree of the variability observed in the Dasuopu d18O record over this time frame.
Lonnie Thompson (Advisor)
Andrea Grottoli (Committee Member)
W. Berry Lyons (Committee Member)
194 p.
Climate Change; Geochemistry; Paleoclimate Science
tropical ice core; coral; Himalaya; El Nino-Southern Oscillation; climate proxy; oxygen isotopes; monsoon; temperature effect; amount effect;

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Citations

  • Philippoff, K. S. (2014). An Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388793239

    APA Style (7th edition)

  • Philippoff, Karl. An Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data . 2014. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1388793239.

    MLA Style (8th edition)

  • Philippoff, Karl. "An Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data ." Master's thesis, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388793239

    Chicago Manual of Style (17th edition)

osu1388793239
469
© 2014, some rights reserved.Creative Commons License An Investigation into the Causes of d18O Variations in the Dasuopu Ice Core, Central Himalayas, using Coral Composites and Instrumental Data by Karl Steven Philippoff is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.