|Mutziger, A. - U.C. RIVERSIDE|
|Gan, J. - U.C. RIVERSIDE|
|Ernst, F. - U.C. RIVERSIDE|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 5, 1996
Publication Date: N/A
Technical Abstract: Recent interest in characterizing methyl bromide emission has focused on field and laboratory measurements. Estimating fate and transport, including atmospheric emission, of methyl bromide with numerical or analytical models has been limited to idealized situations without considering environmental conditions such as diurnal temperature changes. To characterize temperature effect on methyl bromide emission under field conditions, we adopted a two-dimensional numerical code that can solve simultaneous equations of water, heat, and solute transport (including both liquid and vapor phases). Functional relationships were established between temperature and methyl bromide liquid-gas phase partition and diffusion coefficients. Soil properties and surface boundary conditions from Yates et al. (1996abc) were used as an example to illustrate the ability of the model for depicting diurnal variations in methyl bromide emission. Comparison between simulated and measured methyl bromide concentration in the soil was also made at selected times after application. The model simulation with the consideration of diurnal variations of soil temperature agreed well with the methyl bromide concentration distributions in the soil. Based on the temperature effect on temporal variations of methyl bromide emission flux, we believe that small sampling intervals (~ 2 h) are needed to accurately determine the actual emission rate of methyl bromide under field conditions.