2020年7月1日
On the Relationship between the TKE Dissipation Rate and the Temperature Structure Function Parameter in the Convective Boundary Layer
Journal of the Atmospheric Sciences
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- 巻
- 77
- 号
- 7
- 開始ページ
- 2311
- 終了ページ
- 2326
- 記述言語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1175/jas-d-19-0274.1
- 出版者・発行元
- American Meteorological Society
<title>Abstract</title>Under stably stratified conditions, the dissipation rate <italic>ε</italic> of turbulence kinetic energy (TKE) is related to the structure function parameter for temperature <inline-formula />, through the buoyancy frequency and the so-called mixing efficiency. A similar relationship does not exist for convective turbulence. In this paper, we propose an analytical expression relating <italic>ε</italic> and <inline-formula /> in the convective boundary layer (CBL), by taking into account the effects of nonlocal heat transport under convective conditions using the Deardorff countergradient model. Measurements using unmanned aerial vehicles (UAVs) equipped with high-frequency response sensors to measure velocity and temperature fluctuations obtained during the two field campaigns conducted at Shigaraki MU observatory in June 2016 and 2017 are used to test this relationship between <italic>ε</italic> and <inline-formula /> in the CBL. The selection of CBL cases for analysis was aided by auxiliary measurements from additional sensors (mainly radars), and these are described. Comparison with earlier results in the literature suggests that the proposed relationship works, if the countergradient term <italic>γ</italic><italic>D</italic> in the Deardorff model, which is proportional to the ratio of the variances of potential temperature <italic>θ</italic> and vertical velocity <italic>w</italic>, is evaluated from in situ (airplane and UAV) observational data, but fails if evaluated from large-eddy simulation (LES) results. This appears to be caused by the tendency of the variance of <italic>θ</italic> in the upper part of the CBL and at the bottom of the entrainment zone to be underestimated by LES relative to in situ measurements from UAVs and aircraft. We discuss this anomaly and explore reasons for it.
- リンク情報
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- DOI
- https://doi.org/10.1175/jas-d-19-0274.1
- URL
- https://journals.ametsoc.org/view/journals/atsc/77/7/jasD190274.xml
- URL
- http://journals.ametsoc.org/jas/article-pdf/77/7/2311/4979932/jasd190274.pdf
- URL
- https://journals.ametsoc.org/downloadpdf/journals/atsc/77/7/jasD190274.xml
- Scopus
- https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85091562209&origin=inward
- Scopus Citedby
- https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85091562209&origin=inward
- ID情報
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- DOI : 10.1175/jas-d-19-0274.1
- ISSN : 0022-4928
- eISSN : 1520-0469
- SCOPUS ID : 85091562209