Experimental Determination of Cover Surface Temperature Functions at MSW Landfills

Cover temperatures were measured at four MSW landfills located in different climatic regions in North America: Michigan, New Mexico, Alaska, and British Columbia. Temperature measurements were made on a weekly basis throughout the depth of the cover profiles extending from the surface into the top layers of the underlying wastes. Bias was produced in the surface temperature data due to the combined effects of the time of day that weekly surface measurements were taken and the high diurnal variations at the surface. Analytical methods were used to obtain representative surface temperature functions for the covers from experimental data. Mean cover surface temperatures were estimated by extrapolating near-surface temperatures using exponential functions and by interpolating between air and belowsurface cover temperatures using weighting factors. Surface temperature amplitudes were estimated by extrapolating near-surface amplitudes using conventional earth temperature theory. Analysis of data indicated that mean cover surface temperatures and cover temperature amplitudes can also be obtained directly from temperature measurements at 150 to 300 mm depth, when such data are available. Surface parameters obtained in this study can be used at other sites with similar climatic conditions for thermal analysis of cover systems.