頁籤選單縮合
題 名 | Estimating Latent Heat Flux from a Vineyard Using Scintillometry=葡園潛熱通量之閃爍計估算 |
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作 者 | Green,Alan E.; Green,Steve R.; Astill,Mark S.; Caspari,Horst W.; | 書刊名 | Terrestrial, Atmospheric and Oceanic Sciences |
卷 期 | 11:2 2000.06[民89.06] |
頁 次 | 頁525-542 |
分類號 | 328.48 |
關鍵詞 | 潛熱通量; 閃爍計估算; 閃爍估算; Scintillation; Line-averaged; Latent heat flux; Large-scale; |
語 文 | 英文(English) |
英文摘要 | The combination of a near-infrared and a microwave scintillometerwere used to estimate the line-averaged, latent heat flux density ( λEs ) froma well-irrigated, vineyard valley during summer. The 2 km scintillometerbeam passed over the valley floor at a height (z) of 30 m. Eddy covariancetowers instrumented at 3 m above the valley surface provided an independent check of vineyard evaporation. A formula for free convective λEscompared favourably to the eddy covariance values, λEe at low wind speedsand under clear skies. As the convective boundary layer (CBL) developedand passed through the scintillometer beam it caused additional scintillations, in which case λEs >> λEe. During unstable conditions the comparisons were in close agreement. However λEs tended to overestimate λEeas the wind speed increased. For near-neutral conditions the scintillometergave unrealistically large values of λEs. The additional scintillations originated from the strong entrainment of advected dry and warm air into thenewly formed surface boundary layer. During calm overcast days, cold days and during the early morningperiods when the surface fluxes were small, the signal strength of the infrared scintillometer approached the system noise. |
本系統中英文摘要資訊取自各篇刊載內容。