| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | May 13, 2015 |
| Latest Amendment Date: | June 6, 2017 |
| Award Number: | 1443328 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Paul Cutler
pcutler@nsf.gov (703)292-4961 OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | June 15, 2015 |
| End Date: | May 31, 2018 (Estimated) |
| Total Intended Award Amount: | $260,000.00 |
| Total Awarded Amount to Date: | $260,000.00 |
| Funds Obligated to Date: |
FY 2016 = $91,959.00 FY 2017 = $78,997.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
3100 MARINE ST Boulder CO US 80309-0001 (303)492-6221 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
3100 Marine Street, room 479 Boulder CO US 80309-0572 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ANT Glaciology |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
This project will develop a record of the stable-isotope ratios of water from an ice core at the South Pole, Antarctica. Water-isotope ratio measurements provide a means to determine variability in temperature through time. South Pole is distinct from most other locations in Antarctica in showing no warming in recent decades, but little is known about temperature variability in this location prior to the installation of weather stations in 1957. The measurements made as part of this project will result in a much longer temperature record, extending at least 40,000 years, aiding our ability to understand what controls Antarctic climate, and improving projections of future Antarctic climate change. Data from this project will be critical to other investigators working on the South Pole ice core, and of general interest to other scientists and the public. Data will be provided rapidly to other investigators and made public as soon as possible.
This project will obtain records of the stable-isotope ratios of water on the ice core currently being obtained at South Pole. The core will reach a depth of 1500 m and an age of 40,000 years. The project will use laser spectroscopy to obtain both an ultra-high-resolution record of oxygen 18/16 and deuterium-hydrogen ratios, and a lower-resolution record of oxygen 17/16 ratios. The high-resolution measurements will be used to aid in dating the core, and to provide estimates of isotope diffusion that constrain the process of firn densification. The novel 17/16 measurement provides additional constraints on the isotope fractionation due to the temperature-dependent supersaturation ratio, which affects the fractionation of water during the liquid-solid condensate transition. Together, these techniques will allow for improved accuracy in the use of the water isotope ratios as proxies for ice-sheet temperature, sea-surface temperature, and atmospheric circulation. The result will be a record of decadal through centennial and millennial scale climate change in a climatically distinct region in East Antarctica that has not been previously sampled by deep ice coring. The project will support a graduate student who will be co-advised by faculty at the University of Washington and the University of Colorado, and will be involved in all aspects of the work.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The goal of this project is the development of a complete, ultra-high-resolution record of the water isotope ratios on the South Pole ice core (SPICEcore). Our goal is to improve the resolution of the measurements such that all of the potential information in the isotopes will be available and none will be lost by the need to average or sample at lower than desirable resolution. The tradeoff is the time and expense to make such detailed measurements, a problem we have solved by using continuous flow isotope analysis. This technique, developed by our labs and applied only for the second time here to an entire ice core, significantly reduces the costs of the measurements by reducing the time required to make the measurements by a factor of four or more while increasing the resolution by a factor of six or more. All three water isotope ratios (D/H, 18O/16O and 17O/16O are measured. These will be used in concert with other measurements to obtain the following: 1) a record of temperature changes over the past 50,000 years, 2) a better understanding of how the ice sheet in that location has thinned or thickened over time, which relates to the potential for this part of the ice sheet to contribute to rising and falling sea levels, and to constrain the magnitude of the offset between the age of the ice and the age of gases within the ice, a key parameter required in linking changes in the atmosphere with changes in the climate system.
Last Modified: 07/06/2018
Modified by: James W White
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