| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | February 13, 2012 |
| Latest Amendment Date: | February 13, 2012 |
| Award Number: | 1155257 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Eric C. Itsweire
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | February 15, 2012 |
| End Date: | January 31, 2016 (Estimated) |
| Total Intended Award Amount: | $485,424.00 |
| Total Awarded Amount to Date: | $485,424.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
874 TRADITIONS WAY TALLAHASSEE FL US 32306-0001 (850)644-5260 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
FL US 32306-4320 |
| 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): | PHYSICAL OCEANOGRAPHY |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Fundamental to an understanding of El Nino/Southern Oscillation climate fluctuations is an understanding of the interannual equatorial Pacific surface flows which advect the surface waters and change the sea surface temperature. Through the advent of accurate satellite altimeter measurements from late 1992 to the present, we now have long records of estimated sea levels and surface currents that are spatially well resolved and available not just in the Pacific, but also in the Indian and Atlantic Oceans. These records are long enough to study the observed interannual surface flows and their dynamics. While we have some knowledge of the observed interannual flows in the equatorial Pacific, less is known about the structure, strength and variability of the interannual flows in the equatorial Indian and Atlantic Oceans. The main goal of the project will be to describe the interannual equatorial surface flows in all three ocean basins and understand major aspects of them using theory and the dynamically consistent high resolution ECCO2 numerical model results. The scientific community is beginning to take advantage of the ECCO2 global ocean model, and a secondary benefit of the analysis will be the evaluation of the accuracy of this model and its dynamics near the equator in all three ocean basins.
Broader Impacts: Accurate, long satellite altimeter records from 1992 to the present day provide an unprecedented opportunity to examine the detailed spatial and time-varying structure of low frequency surface equatorial flows, flows which play a key role in changing equatorial sea surface temperature and climate. As noted above, surprisingly little is known about the structure and dynamics of these flows, so investigating these flows, and understanding their physics in all three equatorial ocean basins, will make a significant impact on our knowledge of equatorial ocean and climate dynamics. This fundational knowledge will be helpful to the many scientists who will analyze future long records of equatorial climate data gathered in the multinational Atlantic Ocean PIRATA and Indian Ocean RAMA observational programs. It is important to the future of oceanography that new young scientists develop their careers, and this project will support a junior researcher who recently completed her postdoctoral 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.
Although generated in the equatorial Pacific, El Nino gives rise to the largest year-to-year climate variability on earth. In the US, among other things, it affects the number of hurricanes in summer, the amount of heating oil needed in winter, and drought in California.
Fundamental to understanding El Nino, its opposite La Nina, and associated climate variability, are equatorial Pacific currents, for these transport the upper ocean heat and warm water that heat the overlying atmosphere. Despite their importance, little is known about these flows. One thing that is known is that they have the strange property that they occur about 3 months BEFORE the wind that apparently generates them. They also typically change about 3 months in advance of El Nino, and so can be used to predict it. We developed and tested theory to understand these flows, and found that they were linked to long ocean Rossby waves. Ocean currents involve south to north gradients in sea level, and in these waves such gradients are related to trends in time and hence predictability. Theory also shows how these flows are related to non-equilibrium variability and warm water volume (WWV).
During the 1980s and 1990s equatorial Pacific warm water volume (WWV) was shown to be an excellent predictor of El Niño with a lead time of about 8 months. But since about 1998 its lead time has greatly shortened. Using theory and observations, we have established that this failure is real and not a statistical fluke, since it also occurred during 1955-1973. Consistent with recent theory, we have suggested a physically-based reason for this decadal varying prediction lead. We hope to be granted funding to test this idea rigorously in the future, and thus better predict El Nino.
Last Modified: 04/30/2016
Modified by: Allan J Clarke
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