Abstract: By using the fluid stratification technique in experimentalfluid dynamics, the neutral atmosphere, in which the atmospheric potentialtemperature is constant with respect to height, is simulated with uniform water ina water channel. Then the density of salt water is stratified to simulate thestable atmosphere, in which the potential temperature increases withheight.The similarity theory and experimental method of atmospheric simulation byusing water as the medium are introduced in the present paper. Theinfluences of the terrain in Beijing area on the urban atmosphericenvironment are studied to illustrate the problems which should be solved inthe treatment of the capital urban air pollution. The water channelexperiments combined with the field observation and numerical computation aresuccessfully used to study the influences of terrain on the atmospherictransport and diffusion of the radioactive airborne effluents released froma nuclear power plant in operation, in Fujian Province.