Urban Measurements and Their Interpretation

Abstract

Urban environments create distinct challenges for successful atmospheric measurements primarily due to their complex surface structure (i. e., presence of buildings, a wide variety of construction materials, and heterogeneous land cover). In addition, human-generated emissions of heat, water, or pollutants may be considerable and can often vary dramatically in both space and time. Observational techniques have been adapted and theoretical frameworks developed to address some of these challenges of the urban environment. This chapter provides an overview of commonly used approaches to measure the urban atmosphere (including observations of temperature, humidity, wind, precipitation, radiation, the surface energy balance, and boundary layer height and dynamics), plus the key parameters used to quantify the urban environment (e. g., roughness length, surface cover fraction). Additional considerations that need to be made when measuring or interpreting urban measurements are discussed, alongside open issues that are the subject of ongoing research. Examples of various applications are given.