- Introduction -
Surface energy balance is a fundamental issue in boundary layer climatology. In recent years, numerous studies have analyzed data from a global array of micrometeorological towers that are measuring flux densities of carbon dioxide (CO₂), water vapor, and energy between vegetation and the atmosphere (FLUXNET, see Baldocchi et al. 2001) to increase our knowledge of surface energy balance and CO₂ fluxes. Urban areas are one of the few remaining surfaces where the energy and CO₂ exchanges are still not well understood. Although a number of short campaigns over urban areas have reported water and energy exchange (e.g., Oke 1988; Grimmond and Oke 1999; Kanda et al. 2002), the current understanding of energy budgets in these environments have been mainly focused on the variation of the fluxes that occur over several days in summer season. Urban observations of carbon dioxide (CO₂) flux are more limited (e.g., Grimmond et al. 2002; Nemitz et al. 2002). A long-term monitoring of fluxes of radiation, heat, and CO₂ in an urban area is required for further understanding of the seasonal variability of energy and CO₂ exchange.

The purpose of this study is to gain an understanding of the diurnal, seasonal, and annual energy and CO₂ fluxes for a suburban surface. We also investigate the turbulent transfer processes such as flux-profile relationships of momentum, heat, water vapor, and CO₂. We will discuss and compare them with data from natural ecosystems.