Field measurement of albedo for different land cover materials and effects on thermal performance

Albedo (or solar reflectivity) plays an important role in the thermal behavior of pavements and other ground surfaces, and their resultant impacts on humans and the environment. This study developed a new albedo measurement system with a dual-pyranometer and automatic data acquisition system, and used it to conduct field measurements of albedo on different pavement materials and for long-term monitoring of albedo. The albedo values were obtained for commonly used land cover materials including asphalt, concrete and interlocking concrete paver surfacing materials with different designs and some other materials. These new data can help reduce the uncertainty in understanding, evaluating and modeling the thermal behavior and environmental impacts of ground surfaces with different albedos. The seasonal effects of albedo on pavement thermal performance were examined through experimental measurements. An empirical relationship between the cooling effect of increased albedo on a pavementʹs high temperature and solar radiation was developed. The cooling effect has a positive correlation with the peak solar radiation intensity. This simple correlation can be used to roughly estimate the cooling or heating effect of changing albedo on pavement for various climates and seasons with different solar radiation intensities.