The Study of Soil Heat Flux and Evapotranspiration at The Surface

• Main Authors: Cheng-Wei Huang, 黃丞瑋
• Other Authors: Cheng-I Hsieh
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/63389664988239423067

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 96 === Surface fluxes of momentum, heat, water vapor, carbon dioxide and other scalars (e.g., CH4) are important parameters for understanding of the biosphere-atmosphere interactions. This study focuses on quantifying two of these important parameters: the soil heat flux and water vapor flux. In the first part of this study, long-term estimation of soil heat flux from single layer soil temperature was carried out by the traditional sinusoidally analytical method and the half-order time derivative method of Wang and Bras (1999). Our results pointed that the analytical method did not predict the soil heat flux well due to the sinusoidal assumption for soil heat flux’s temporal variation was not valid. While good agreement between soil heat flux measurements and predictions by the half-order time derivative method was found. In the second part of this study, a two-dimensional Lagrangian analytical dispersion model in conjunction with an inverse approach was proposed for inferring surface evapotranspiration rate from the mean humidity profile under local advection conditions. Our results showed that this approach was able to reproduce the measured downwind evolution of surface evapotranspiration rate (water vapor flux) under local advection conditions.