| Summary: | 碩士 === 國立中興大學 === 環境工程研究所 === 81 === The purpose of this research is to develop a technique to
measure water vapor flux and methane flux from land surface.
This technique is based on the similarity theory. Water vapor
flux from Tseng-wen reservoir,water vapor flux from a grass
land at Tungao, and methane flux from Taichung land-fill site
have been explored by using this technique. The average
water vapor flux at Tseng-wen reservoir was measured to be
0.60 m/year from Dec. 8 to Dec. 13, 1992. The average water
vapor flux at Tungao was measured to be 0.76 m per year from
Mar. 28 to Apr. 2, 1993. The methane flux at Taichung
landfill site was measured to be 0.12 mg per square meter per
second,1.06 kg per ton-waste (wet) from Feb. 26 to Feb. 28,
1993. However, special cares have to be taken to measure
flux at complex terrain such as Taichung landfill site.
This technique of flux measurement has been verified by an
energy budget method.The error of calculated soil heat flux,
which is summation of calculated latent heat flux, sensible
heat flux and measured net radiation, is determined to be
.plmin.65% in comparison with measured soil heat flux. In
addition, numerical sensitivities of calculated exchange
coefficient based on similarity theory have been conducted. It
is found that the most important factor affecting exchange
coefficient is wind speed gradient, the second dominate
factor is air temperature gradient, the third is relative
humidity gradient, and the least important factor is air
pressure.
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