| 54 | 56 | The conventional approach to assess biometeorological aspects in urban areas is an Eulerian approach, i.e., the area-wide evaluation of relevant parameters and indices, and subsequent mapping and zoning of these parameters. In this approach, socio-economic aspects of urban residents, such as resident characteristics like age, skin sensitivity, wealth, or population density and the typical behavior and movement patterns of these residents are usually neglected. In order to account for these additional parameters, a multi-agent system is implemented in PALM-4U that allows a new quality of biometeorological assessment studies. The multi-agent system is a Lagrangian approach in which groups (from hundreds to several thousands) of individual agents (i.e., residents) are released at selected locations of interest in the model domain (see e.g. Bruse, 2007; Chen and Ng, 2011; Gross, 2015, for further reading). Each agent can have individual characteristics (age, clothing, speed, starting points, targets, etc.) so that typical population groups can be statistically represented and released in the model. Each agent is able to move according to a path-finding algorithm that takes into account not only the agent’s characteristics, but also the atmospheric conditions in its surroundings, like sun/shaded area, searching for an optimal compromise between the fastest and most convenient path. The path-finding algorithm will be based on a potential field scheme where the direction of movement is determined from the sum of forces acting upon the agent. The potential itself can be regarded as the result of a force towards the target area and additional forces due to sloped terrain, forbidden areas (buildings), shaded and non-shaded sites, or the occupation of areas by other agents. |
