| 项目编号: | 1701278
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| 项目名称: | Forced and Natural Turbulence Allowing Studies of Turbulent anIsotropic Conditions (FaNTASTIC- 1) |
| 作者: | Eugene Takle
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| 承担单位: | Iowa State University
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| 批准年: | 2017
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| 开始日期: | 2017-09-01
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| 结束日期: | 2020-08-31
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| 资助金额: | 258928
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| 资助来源: | US-NSF
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| 项目类别: | Continuing grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Atmospheric and Geospace Sciences
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| 英文关键词: | objective
; study
; coherent eddy
; abl
; turbulence
; stratified condition
; research team
; local turbulence
; natural turbulence
; large coherent turbulence eddy
; mesoscale
; high-resolution near-surface turbulence-measurement tower
; stable condition
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| 英文摘要: | The lower part of the atmospheric boundary layer (ABL) - the part of the atmosphere extending ~300 m from Earth's surface - undergoes rapid transitions with nocturnal cooling, resulting in rapidly evolving temporal and spatial properties of coherent eddies. Using a unique and highly instrumented observation region, this project will observe these variations (eddies) in detail. One set of in-situ and remote sensing instruments will be sited inside a 200-turbine wind farm (forced turbulence) and another set ~22 km away in a matched landscape of natural turbulence. The research team will build on prior modeling and measurement experience to produce new understanding of the boundary layer by comparing forced and natural turbulence.
Intellectual Merit:
The innovativeness of this study derives from the fact that turbulence generated by turbines or other landscape structures has a distinctly different spectral signature and subsequent distinct influence on atmospheric exchange processes than do natural landscapes, such as fields of corn/soybean. Coherent eddies, known to be the central feature of the ABL, are not represented correctly by Monin-Obukhov Similarity Theory (MOST). The high-resolution in situ measurements will provide a physical alternative
to MOST for stable conditions, which in turn will improve the skill of weather forecasts and simulations, particularly under stably stratified conditions. The project has three objectives: Objective 1. Characterize anisotropic and large coherent turbulence eddies (natural and forced) by use of a high-resolution near-surface turbulence-measurement tower, strategically placed two tall towers, and a sodar. How are they initiated during and after the early evening transition (EET)? What are the contributing factors to energy conservation as the ABL evolves under stably stratified conditions? Objective 2. Employ multi-resolution decomposition (MRD) and wavelet transform methods to identify events of coherent structures that show minimal low frequency (e.g., mesoscale) compared to high frequency (local turbulence) influences on turbulent covariances. How can these methods help refine descriptions of surface fluxes driven purely by local turbulence from those influenced by uniquely forced (turbines) or mesoscale (e.g., gravity waves, surface heterogeneities, and terrain) influences? Objective 3. Combine measurements and analyses of Objectives 1 and 2, together with mesoscale and LES simulations with WRF and other models, to develop new understanding of coherent eddy evolution and the role of turbulent potential energy (TPE) near the surface in response to radiative changes in the EET of the ABL. What is the model sensitivity to the relative magnitudes of TKE and TPE under various levels of stratification? What principles should guide the choice of coherent eddy length scales for simulating flow in stable stratification?
Broader Impacts:
1) Improved Scientific Understanding from this research will have broad scientific, societal and economic ramifications. The research results will cross-cut many STEM disciplines and provide new fundamental understanding in research areas of high national priority.
2) Student Learning and Training. Results from the study will enhance the education and experience for students at all levels, with emphasis on developing scientists with disciplinary depth and ability to reach across disciplinary boundaries, capable of working effectively in teams.
3) Outreach to Underserved Populations. At the graduate level the research team will take advantage of the Iowa State University's NSFIGERT award's aggressive plan for recruiting students from the University of Puerto Rico. At the undergraduate level, the team will collaborate with the IINSPIRE-LSAMP Alliance, of which ISU is a partner institution.
4) K-14 Engagement. The research team will partner with ISU's new Wind Energy Student Organization (WESO) that has active outreach to both the K-12 and community college level.
5) Bi-Directional Mentoring Hierarchy. Built on current and recent ISU NSF-funded wind energy projects under EPSCoR, IGERT, MRI, and REU, the research team has established near-peer mentorships recognizing roles of gender, ethnicity, personal interests, and temperament in pairing-for-success. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/89102
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Eugene Takle. Forced and Natural Turbulence Allowing Studies of Turbulent anIsotropic Conditions (FaNTASTIC- 1). 2017-01-01.
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