ABSTRACT
Solar radiance and heat affect buildings and landscapes. Heat gain occurs when heat enters a building from outside. Anthropogenic heat refers to sources of heat from surfaces and materials in the landscape. Solar radiation occurs on a continuum known as the electromagnetic spectrum. Heat from the sun falls in the infrared range of the electromagnetic spectrum. Infrared waves are detected using thermal imaging or thermography. Albedo (surface reflectivity and solar reflectance) is a measure of solar radiance reflected from a surface. These terms describe radiative properties.
Energy has thermal properties, which is felt as heat. Thermal emittance measures the ability of a material to emit heat it has absorbed, and is expressed as emittance or emissivity. Heat capacity is the ability of a material to store heat. The Solar Reflectance Index (SRI) expresses the effects of both reflectance and emittance in one number. Thermal conductivity is the ability of a surface to transfer heat through it. Convection is the transfer of heat by air movement.
Urban heat island occurs in cities in which temperatures are higher than they are in surrounding rural areas. Plants lose moisture through transpiration. The loss of moisture from soil and plants to the air is evapotranspiration. Whitetopping is applied to asphalt, and has a solar reflectance similar to that of concrete. Microsurfacing increases the albedo of asphalt.
