Flux Measurements Over Urban Areas

Abstract

 Numerous research projects examining urban surface flux have been conducted during the last two decades.Direct measurements of surface flux using the eddy covariance method facilitated the advancement of quantitative elucidation of the heat balance and CO₂ exchange between urban surfaces and the atmosphere. Results show that the heat balance in cities has unique features differing from those of bare ground, vegetation, and forests. This report addresses the following topics: selection of an appropriate observation site for the flux measurement over urban areas, recommendation of instrumentation height in the urban surface layer, and the “surface” concept in cities. Moreover, fundamental examination is made of urban heat balance and CO₂ flux in Tokyo, obtained mainly based on the author’s experiments. Some recent research trends of flux measurements over urban areas are described, with introduction of the “Urban Flux Network,” launched as a flux community network.