| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | February 25, 2011 |
| Latest Amendment Date: | May 27, 2014 |
| Award Number: | 1112938 |
| Award Instrument: | Standard Grant |
| Program Manager: |
edward bensman
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | August 16, 2010 |
| End Date: | April 30, 2016 (Estimated) |
| Total Intended Award Amount: | $425,565.00 |
| Total Awarded Amount to Date: | $474,960.00 |
| Funds Obligated to Date: |
FY 2014 = $49,395.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
240 FRENCH ADMINISTRATION BLDG PULLMAN WA US 99164-0001 (509)335-9661 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
240 FRENCH ADMINISTRATION BLDG PULLMAN WA US 99164-0001 |
| 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 & Dynamic Meteorology, EPSCoR Co-Funding |
| Primary Program Source: |
01001415DB NSF RESEARCH & RELATED ACTIVIT |
| 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
The Monin-Obukhov similarity theory (MOST) provides numerical weather and climate models with a basis in formulating the turbulent exchange of momentum, energy, water vapor, and other scalars between the Earth's surface and the lower atmosphere. However, several recent studies have identified some features that are not fully consistent with predictions by MOST and attributed these departures to the disturbance of outer-layer, large-scale coherent structures (hereafter referred to as coherent eddies) on locally-generated active turbulence in the atmospheric surface layer (ASL). Although some studies have presented alternative theories to describe these discrepancies, turbulence structures in the disturbed ASL are still poorly understood. The objectives of this project are to study turbulence structures in the stable and unstable ASL beneath a convective boundary layer where a strong interaction between coherent eddies and active turbulence occurs. The datasets from the already completed Energy Balance Experiment will be used. More specifically, this project aims to:
1. Quantify turbulence structures under the influence of large-scale coherent eddies and characterize the deviations of turbulence structures from predictions by MOST under two atmospheric stratifications during the daytime in the disturbed ASL.
2. Investigate how coherent eddies interact with the ASL turbulence and their contributions to flux exchange of momentum, heat, and water vapor under two atmospheric stratifications.
3. Study the spatial structures and temporal evolutions of coherent eddies from time-series data in the ASL to elucidate the origins and sources of coherent eddies.
4. Enhance the Jackson State University Micrometeorology Laboratory and enrich meteorological courses through incorporating research activities and findings of this project in the classroom and teaching laboratories.
5. Involve a large number of African American undergraduate and graduate students and encourage them to take part in the research activities.
This program will provide an excellent education and training opportunity for undergraduate and graduate students and will greatly enhance atmospheric sciences education in Jackson State University, one of the nation's largest historically black colleges and universities.
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.
In numerical weather and climate models, turbulent transfer of heat, water vapor, and other greenhouse gases in the atmospheric surface layer (ASL) is formulated using the so-called Monin-Obukhov similarity theory (MOST). The MOST assumes that flows in the stationary ASL depend on only local mechanical mixing and thermodynamic processes. Since the MOST is framed in terms of local parameters and is only applied for locally-generated, active turbulence, therefore, it implies that the non-locally generated atmospheric motions in the atmospheric boundary layer (ABL) have no significant effects on flows in the ASL. However, studies have identified some features not fully consistent with the MOST, attributed largely to the influence of non-local, large coherent eddies on the locally-generated active turbulence in the ASL. The research supported by this award was designed to study how large coherent eddies disturb the ASL, thus affecting turbulence structures, flux exchange, and unclosure of the surface energy balance in the ASL. The results of our study gave us a number of new insights into the interactions between large coherent eddies and the ASL, small-scale turbulence. Specifically, our results indicate that spatial scales of large coherent eddies are related to those of soil moisture heterogeneity; large coherent eddies modulate time-series of vertical velocity and scalars (e.g., air temperature and humidity) in different ways leading to temporal variations in fluxes; the increased phase shifts between vertical velocity and scalars of large eddies, leading to the decreased fluxes and thus an increase in unclosure in the surface energy balance.
Six undergraduate students including five African-American students and one Latino student participated in the research in this project; two master students were supported by this project and graduated; Two Ph.D. students have been supported by this project: one graduated in July 2015 and the other is expected to graduate in July 2017. Eleven peer-reviewed journal articles were published, three manuscripts are in preparation and will be submitted to peer-reviewed journals in the next few months, and seventeen conference presentations were made to disseminate our research outcomes to broad communities. Our research results were reported in public media and also cited in the Top Story of the NSF Science360 News. The two courses taught by the PI incorporated the findings of this project in the syllabi, lectures, and field experiments for both undergraduate and graduate education.
Last Modified: 08/01/2016
Modified by: Heping Liu
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