摘要：Air temperature trends (1960–2009) based on stations in cities; minus those based on global surface temperature datasets; are defined herein as urban heat island (UHI) trends. Urban climate was examined globally by comparing UHI trends with indices of geophysical factors; including background climate; latitude; and diurnal temperature range (DTR) and indices of artificial factors; including anthropogenic heat emission (AHE) and population indices. Surprisingly; a better relationship was found between UHI trends and DTR—an integrated geophysical index representing thermal inertia—than with the indices of artificial factors. Thus; while an increase in sensible heat (mechanism 1) triggers UHI formation; this study infers that large thermal inertia (mechanism 2) contributes significantly on UHI. The correlation of UHI trends with other indices can be explained by both mechanisms.
