A study of the effect of variable surface conditions on the outdoor heat stress using a mathematical model of the atmospheric boundary layer

A one-dimensional model of the atmospheric and soil boundary layers is used to study the climate near the ground (micro-climate) under variable surface conditions. The model is based on the assumption that at any given moment a balance of energy exists at the interface separating the atmosphere from the ground. The solar and sky radiation are specified, and the temperature, wind, and humidity at 300 meters, and the temperature 32 cm under the soil surface are given as upper and lower boundary conditions. The surface conditions (e.g., vegetation cover) are simulated by specifying the surface albedo, α, the roughness parameter, Z₀ and a parameter related to the nature of evaporation from the surface. The model produces results of temperature and humidity as a function of time and height. These results are used to derive a simple comfort index which is compared under different surface conditions.