The paper concerns an investigation of the atmospheric diffusion processes by means of experimental, analytical, and numerical methods. Experimental momentum transfer and heat transfer analyses are presented. Shear stresses in the surface layer are measured directly by means of a shear meter; momentum eddy diffusivities and drag coefficients over flat ground are determined from shear stress and wind velocity data. Convective heat transfer rates in the surface layer are measured indirectly by means of a heat flow meter and a radiometer; convective conductances are determined from the convective heat flow and air temperature data. Two new, analytical, periodic, convective heat flow solutions for the atmospheric system are derived. One solution pertains to an eddy diffusion system in which the boundary temperature varies sinusoidally with time and the eddy diffusivity varies sinusoidally with time but is independent of height. The other solution pertains to an eddy diffusion system in which the boundary temperature varies sinusoidally with time and the eddy diffusivity varies sinusoidally with time and linearly with height. A simple heat-momentum transfer analogy for the surface layer was developed which relates some of the pertinent heat and momentum transfer variables in the atmospheric diffusion system.