Urban climate under change [UC]²

Urban areas are highly sensitive to changes in climate such as extended periods of heat, heavy storms or floods. The consequence: Cities must already prepare for climate change. At the same time, cities are a special place for conflicting goals, for example between the increasing pressure of settlement on the one hand and the necessary adjustments to the consequences of climate change on the other. Correct handling of nitrogen oxide pollution is also a challenge for cities.

Shown is the turbulence intensity in the Berlin government district, simulated with the PALM-4U model. PALM-4U stands for Parallelized Large-Eddy Simulation 4 (for) Urban Applications. — High-resolution computer simulation for the Berlin government district with the new urban climate model PALM-4U.© Leibniz Universität Hannover / Björn Maronga, Siegfried Raasch

The funding measure Urban Climate Under Change [UC]² has been dedicated to the burden of heat and pollutants on cities. The aim was to provide cities with a scientifically sound, practical set of instruments that can be used to design measures for improving urban climate and air pollution planned. Together with future users a new, building-resolving computer model for urban climate modeling was to be designed.

In the first phase of the measure, the basic framework for the new urban climate model PALM-4U was developed. Important milestones were the elaboration of the requirements for such a model, several measurement campaigns and the publication of the first version of the model.

Building on these results, the paramount goal for the second phase is to further develop the urban climate model into a practical product that meets the needs of municipalities and other users not only in research.

At the same time, the model is to be used for scientific research and to be further developed accordingly. In particular, a complete evaluation of the model and the resulting necessary further developments, a user interface and significantly expanded tests in practical applications were necessary for this. The established module structure from the first phase was essentially retained. The work was therefore again organized in three modules, which were devoted to the sub-aspects of model development, evaluation and scientific application, as well as practicability and continuation strategy.

Within the modules, three joint research projects (MOSAIK-2, 3DO+M, ProPolis) worked together with a total of 25 sub-projects. The second phase of the funding measure was financed by the Federal Ministry of Education and Research (BMBF) for three years with around € 13 million. The funding measure was at the same time the first component of the flagship initiative "Local climate and environmental models" of the BMBF digital strategy and the action plan "Natürlich. Digital. Nachhaltig." The flagship initiative aims to support cities and regions with the help of digital applications to achieve sustainability goals such as resilience, climate protection and environmental protection. To this end, BMBF is creating digital tools that make data and models from research usable for users in cities and regions.