Cities are very sensitive to shifts in the climate, while their transformation cycles are usually very slow. In order to design new cities fit for the future or to adapt existing cities to the expected consequences of climate change, planners and decision makers need to consider effective measures already today. Important bases for planning decisions in urban areas are powerful simulation models for the climate on urban environments. For urban planners, the collection and use of climate data is increasingly important. 

For example, year-round data on hours of sunshine and the direction of the sun, intensity and direction of wind flows, weather conditions and other climate-related influences are used. They are essential to develop effective strategies for high quality livable (public) spaces and entire city districts. Advanced urban climate modeling supports modern city planning related to the urban microclimate and climate change.

Research program “Urban Climate Under Change” 

The goal of the research project “Urban Climate Under Change” is the development of an innovative and user-friendly simulation tool for urban climate modelling called the PALM-4U. The German Federal Ministry of Education and Research (BMBF) supports this project (grant number: 01LP1602A) within the Research for Sustainable Development (FONA) program. The newly developed urban climate model PALM-4U is an open-source software tool that can be used to carry out climate change-compatible, interdisciplinary analyses for urban areas and to plan measures to improve air pollution control and the urban climate.

The application possibilities are manifold, ranging from creating small-scale views of individual buildings to scaling entire districts and even big cities like Berlin. Various integrated sub-models of PALM-4U allow tackling typical urban climatic issues such as wind comfort or thermal comfort. Further fields of application are, for example, simulations of the spread of pollutants or assessments of the behavior of individuals by means of a multi-agent model.

In order to meet future users’ requirements, selected application examples and user groups are integrated directly into the model development, measurement and data collection stages. Fraunhofer Institute for Building Physics IBP participates at the subproject “UseUClim” and checks the suitability for practical application. For this purpose, application partners from municipal environmental offices and city planners are trained to use the new urban climate model PALM-4U. Their feedback is essential for verifying the applicability of the model.

First application examples in China 

New visualization technologies allow an even better utilization of calculation results in day-to-day planning and an efficient integration into work and decision processes. Advanced urban climate modelling in combination with new visualization technologies help to give building owners, city representatives as well as non-professionals an understanding of external influences and their effects on buildings and cities. 

An innovative mixed reality solution of a city model, using tablets and augmented reality to visualize urban climate simulation was presented at last year’s FENESTRATION BAU China, which took place in Beijing in November 2018. At its booth, Fraunhofer IBP demonstrated the application of the advanced technology on a 1.5 by 1.5 meter city model of the “Shanghai Jinqiao Sub-Center”, a master plan of its project partner SBA Architektur und Städtebau.

Jinqiao Development Zone is located in the central city of Shanghai and the north-central part of Pudong New Area. It is an important new manufacturing base in Shanghai and an emerging production service cluster. This project has an overall area of 4.5 km² and a core area of 1.5 km², with the urban construction land area of about 4.4 km². The total construction volume is 6.5 million sqm, of which the reserved building area amounts to 2.2 million sqm. 

The high humidity in Shanghai's urban climate results in the sultry of summers and wet cold winters. Urban surface temperature and airflow is decisive for the citizens’ comfort in external spaces. In this project, the planners optimized the relationship between buildings and their external space by analyzing the urban surface temperature and the wind speed of the entire district. The overlay of the city model with dynamically visualized simulation results allowed the planners to experiment with various measures to improve the thermal comfort in public space.

Article Resource: Econet Monitor Special Green Building