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浅層砂土の地温日変化の一表現法


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Title: 浅層砂土の地温日変化の一表現法
Other Titles: An Expression of Diurnal Change in Temperature in Uppef Layer of the Sandy Soil.
Authors: 武政, 剛弘 / 薦田, 広章
Authors (alternative): Takemasa, Takehiro / Komoda, Hiroaki
Issue Date: Jan-1988
Publisher: 長崎大学工学部 / Faculty of Engineering, Nagasaki University
Citation: 長崎大学工学部研究報告, 18(30), pp.47-54; 1988
Abstract: The dry surface layer in sandy soil appears due to the amount of solar radiation in summer season. The both of the soil temperature variation in the wet zone of lower layer located just bellow the dry surface layer and the atmospheric temperature variation of the near ground surface are remarkably affected by the soil temperature variation in the dry surface layer. The application of the harmonic analysis is usual to evaluate the diurnal changing of the soil temperature near ground surface. As is well known, the diurnal changing of the soil temperature is sufficiently expressed with the diurnal term and semi-diurnal term in the harmonic terms. In this paper, a simplified expression on the diurnal change in the soil temperature is derived from the solution of the heat flow equation with the consideration of the diurnal variation of the thermal diffusivity K. The obtained results are summarized as follows. 1) The diurnal changing of the soil temperature in the dry surface layer is sufficiently expressed with the only term of θ=θ0+R1sin(ωt-γ sin ωt+ε1) Where θ0 is mean temperature, R1, ε1; amplitude and phase of the diurnal temperature variation, respectively, ω=2π/P; the angular frequency of the Earth's rotation, and γ; constant. 2) The solution of the heat flow equation tells that the diurnal variation of the thermal diffusivity is characterized by the additional term of "-γ sin ωt".
URI: http://hdl.handle.net/10069/24268
ISSN: 02860902
Type: Departmental Bulletin Paper
Text Version: publisher
Appears in Collections:Volume 18, No. 30

Citable URI : http://hdl.handle.net/10069/24268

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