Urban Energy Balance Climatology: A Preliminary Investigation of the City-Man System in Downtown Los Angeles

M SOST studies in urban climatology have been conducted by measuring traditional parameters, especially air temperature, on a rather small scale.' Apparently no major attempts have been made to determine the energy-balance climatology of cities,2 except for estimates of the ratio of artificial heat generation to radiational heat3 and investigations of the relationship between solar radiation and air pollution.4 But with relation to energy-balance climatology, the urban interface and its atmospheric boundary differ from natural surfaces in several major aspects. (1) Albedoes are generally higher because vegetation is largely replaced by concrete or other more reflecting surfaces. In winter, however, the high albedo of snow is less prevalent because of melting (owing to the greater heat of the city), removal, and soot cover. (2) The existence of numerous vertical surfaces changes considerably the patterns of incidence