Assessment of Biophysical Characteristics Over Various Urban Surfaces During the Presence of Oppressively Hot Weather Types

The built environment of cities can have substantive negative societal and health impacts that are due in part to the altered surface types, and can be exacerbated by oppressive weather types. It is important for urban planners/designers to understand the role that different urban surfaces, coupled with an oppressive weather type, play in amplifying extreme temperatures. This knowledge can lead to ways to mitigate the extra heating of the surface and local air temperatures. The current study used a portable weather station deployed over 11 different local surface types in Lubbock, TX (semi-arid climate type), consisting of a cylindrical radiation thermometer (CRT), temperature/relative humidity probe, propeller anemometer, CNR4 net radiometer, and a black globe temperature sensor. Measurements were used to identify the radiational, thermal, and moisture properties affecting the microclimatic conditions of each surface at 30-second averages. Examples of select surfaces include permeable pavement, green roof, asphalt, concrete, and grass. Deployments were carried out between the months of June and September 2014 during peak heating hours on ‘tropical' weather type days, as identified by the Spatial Synoptic Classification (SSC). Hence, the weather station was deployed only on days classified as moist tropical (MT) or dry tropical (DT) for the given location and time of year, as these are the most oppressive weather types in terms of human health, and also result in the greatest urban heating effects. Temperature and relative humidity are common tools used to understand human health in an urban setting, but radiation and wind components are just as important, and result in the most effective alterations to the energy budget within the urban fabric. The simultaneous measurements from the net radiometer, black globe temperature sensor, and CRT present a unique understanding of the radiational microclimate a human would be experiencing over each surface, and further aid in the assessment of the energy budget fluxes. A suite of results will be presented with in-depth comparisons and analysis of the various microclimates, drawing implications to the physiological impacts to urban health. Subsequently, this will aid in identifying, while an oppressive weather type is present, which surfaces are most detrimental to human health, and which can possibly help mitigate urban heating during the hottest times of the day.