Maßnahmen zur Hitzestress-Reduzierung anhand Verdunstungsabkühlung

Großflächig versiegelte und hoch verdichtete Stadtstrukturen mit einer geringen Begrünung lassen aufgrund des Klimawandels und zunehmend heiße Tage sogenannte Hitze-Inseln in der Stadt entstehen (Urban-Heat-Island Effekt). Wasser, das verdunstet, kühlt das Mikroklima. Daher sind Maßnahmen günstig, die Regenwasser nicht abführen, sondern längere Zeit speichern, damit es in Hitzeperioden verdunsten kann. Feuchte Böden, Feuchtvegetation, bewässerte Fassaden und gut mit Wasser versorgte Bäume haben die höchsten Verdunstungswerte und kühlen damit am besten. Intelligente Techniken und Verfahren für eine dezentrale Regenwasserbewirtschaftung können im Zusammenspiel mit anderen Maßnahmen einen Beitrag für ein gesundes Stadtklima und die Hitzevorsoge leisten. Sie tragen auch zu einem naturnahen Wasserhaushalt bei und dienen der Überflutungsvorsorge, sind bislang allerdings keine gängige Praxis. Measures for heat stress reduction by evaporative cooling: Due to climate change and increasingly hot days, so-called urban heat islands are being created in the city due to large-scale sealed and highly dense urban structures with poor vegetation cover (urban-heat-island effect). Water which evaporates cools the microclimate. Measures that do not drain rainwater away but store it for a longer period of time so that it can evaporate during heat periods are therefore favourable. Humid soils, wet vegetation, irrigated facades and trees that are well supplied with water have the highest evaporation values and therefore cool best. Intelligent technologies and processes for decentralised rainwater management can, in combination with other measures, contribute to a healthy urban climate and heat prediction. They also contribute to a near-natural water balance and serve to prevent flooding, but are not yet common practic

New methods for local vulnerability scenarios to heat stress to inform urban planning—case study City of Ludwigsburg/Germany

Adaptation strategies to climate change need information about present and future climatic conditions. However, next to scenarios about the future climate, scenarios about future vulnerability are essential, since also changing societal conditions fundamentally determine adaptation needs. At the international and national level, first initiatives for developing vulnerability scenarios and so-called shared socioeconomic pathways (SSPs) have been undertaken. Most of these scenarios, however, do not provide sufficient information for local scenarios and local climate risk management. There is an urgent need to develop scenarios for vulnerability at the local scale in order to complement climate change scenarios. Heat stress is seen as a key challenge in cities in the context of climate change and further urban growth. Based on the research project ZURES (ZURES 2020 website), the paper presents a new method for human vulnerability scenarios to heat stress at the very local scale for growing medium-sized cities. In contrast to global models that outline future scenarios mostly with a country-level resolution, we show a new method on how to develop spatially specific scenario information for different districts within cities, starting from the planned urban development and expansion. The method provides a new opportunity to explore how different urban development strategies and housing policies influence future human exposure and vulnerability. Opportunities and constraints of the approach are revealed. Finally, we discuss how these scenarios can inform future urban development and risk management strategies and how these could complement more global or national approaches.Universität Stuttgart (1023

New methods for local vulnerability scenarios to heat stress to inform urban planning—case study City of Ludwigsburg/Germany

<jats:title>Abstract</jats:title><jats:p>Adaptation strategies to climate change need information about present and future climatic conditions. However, next to scenarios about the future climate, scenarios about future vulnerability are essential, since also changing societal conditions fundamentally determine adaptation needs. At the international and national level, first initiatives for developing vulnerability scenarios and so-called shared socioeconomic pathways (SSPs) have been undertaken. Most of these scenarios, however, do not provide sufficient information for local scenarios and local climate risk management. There is an urgent need to develop scenarios for vulnerability at the local scale in order to complement climate change scenarios. Heat stress is seen as a key challenge in cities in the context of climate change and further urban growth. Based on the research project ZURES (ZURES 2020 website), the paper presents a new method for human vulnerability scenarios to heat stress at the very local scale for growing medium-sized cities. In contrast to global models that outline future scenarios mostly with a country-level resolution, we show a new method on how to develop spatially specific scenario information for different districts within cities, starting from the planned urban development and expansion. The method provides a new opportunity to explore how different urban development strategies and housing policies influence future human exposure and vulnerability. Opportunities and constraints of the approach are revealed. Finally, we discuss how these scenarios can inform future urban development and risk management strategies and how these could complement more global or national approaches.</jats:p&gt

Building-resolving large-eddy simulations for entire Berlin (Germany) – first results using the high-performance urban microscale model PALM-4U

Due to the increasing number of people living and/or working in dense urban environments, the importance of city planning in consideration of human health and comfort has been continuously growing. Health and comfort factors such as thermal comfort, air quality, ventilation and UV exposure, must be considered in a future-oriented development of urban regions. For decision support, urban climate models (UCM) are applied to model the effects of existing and planned building distributions, facade and city greening, etc., based on the above mentioned factors. A highly-efficient microscale UCM, PALM-4U, has been developed allowing simulations of large cities with grid-resolved buildings and vegetation canopy, which consider a large variety of processes important for urban environments. PALM-4U is part of the PALM model system (http://palm-model.org), which is based on the large-eddy simulation code PALM. While there exist numerous UCMs that have been used for over two decades and which are well established in the scientific community, they are difficult to adapt to state-of-the-art parallel computer systems and thus often have limitations in either performance and/or possible number of grid points. PALM-4U is able to compute entire city environments like Berlin (about 1 700 km²) at building-resolving grid spacing (here 10 m) on massively parallel computers, where limitations are mainly imposed by the available computational resources. It offers several features required in urban environments, such as an energy balance solver for urban and natural surfaces, radiative transfer in the urban canopy layer, chemical reactions, biometeorological analysis products, and self-nesting to allow high resolution (e.g. 1 m) in regions of special interest. In this presentation we will focus on an overview of PALM-4U's current and planned capabilities for application in urban environments. Besides, we will demonstrate PALM-4U's performance and features based on microscale building-resolving large-eddy simulation of entire Berlin (Germany, 1700 km²) at a grid spacing of 10 m, with a nested domain of size of 1 km² at a grid spacing of 1 m. The simulation spans a simulated period of a full diurnal cycle during a selected heat wave period and is characterized by low geostrophic winds and a strong solar forcing during daytime. General features of the simulation will be visualized. This presentation is intended to be the first in a series of presentations that all have a more specific focus on single features of PALM-4U and for which abstracts are submitted separately. In this overview talk we will thus focus on the more general features of the simulation

Quantifying the effects of urban stormwater management - towards a novel approach for integrated planning

ABSTRACT Integrated planning of stormwater management requires a quantitative description of positive and negative effects of possible measures. We suggest quantifying these effects with generic performance indicators within eight categories: building physics and services, landscape quality, urban climate, biodiversity, groundwater, surface water, direct costs and indirect environmental costs. First results indicate that the defined performance indicators allow an objective pre-selection of measures based on their ability to reach local stormwater management goals. The final selection of measures should be based on an evaluation for a specific city quarter (to reduce indicator uncertainty) and reviewed by local stake holders

Dreidimensionale Observierung atmosphärischer Prozesse in Städten – 3DOSchlussbericht des Verbundvorhabens 3DOThree-dimensional observation and modeling of atmospheric processes in cities – 3DOfinal report for joint project 3DO

Ziel des BMBF-Programms 'Stadtklima im Wandel' war die Entwicklung, Validierung und Anwendung eines gebäudeauflösenden Stadtklimamodells für ganze Städte. Das Verbundprojekt 3DO übernahm die dem Modul B zugeordneten Forschungsaufgaben: Aufbereitung vorhandener Daten aus der Langzeitbeobachtung (LTO), Aufbau neuer Messstationen, Gewinnung neuer dreidimensionaler atmosphärischer Daten und die Entwicklung neuer Konzepte z.B. zur Modellevaluation. Untersucht wurden der Aufbau der atmosphärischen Grenzschicht, die Charakteristik der meteorologischen Parameter und deren Einfluss auf das thermische Empfinden des Menschen. Ein einheitlicher [UC]2-Datenstandard sowie Analysewerkzeuge wurden entwickelt und in ein Datenmanagementsystem und eine Wissensplattform für den modulübergreifenden Austausch integriert.Aim of the BMBF-Programme 'Urban Climate under Change' was development, validation and application of a building-resolving urban climate model for entire cities. The joint project 3DO took over the research tasks assigned to module B: Preparation of existing data from long-term observation (LTO), deployment of new measuring stations, acquisition of new three-dimensional atmospheric data and new concepts, e.g. for model evaluation. The structure of the atmospheric boundary layer, characteristics of meteorological parameters and their influence on the thermal sensation of humans were investigated. A uniform [UC]2 data standard as well as analysis tools were developed and integrated into a data management system and a knowledge base for cross-module exchange

Dreidimensionale Observierung atmosphärischer Prozesse in Städten – 3DOSchlussbericht des Verbundvorhabens 3DOThree-dimensional observation and modeling of atmospheric processes in cities – 3DOfinal report for joint project 3DO

Ziel des BMBF-Programms 'Stadtklima im Wandel' war die Entwicklung, Validierung und Anwendung eines gebäudeauflösenden Stadtklimamodells für ganze Städte. Das Verbundprojekt 3DO übernahm die dem Modul B zugeordneten Forschungsaufgaben: Aufbereitung vorhandener Daten aus der Langzeitbeobachtung (LTO), Aufbau neuer Messstationen, Gewinnung neuer dreidimensionaler atmosphärischer Daten und die Entwicklung neuer Konzepte z.B. zur Modellevaluation. Untersucht wurden der Aufbau der atmosphärischen Grenzschicht, die Charakteristik der meteorologischen Parameter und deren Einfluss auf das thermische Empfinden des Menschen. Ein einheitlicher [UC]2-Datenstandard sowie Analysewerkzeuge wurden entwickelt und in ein Datenmanagementsystem und eine Wissensplattform für den modulübergreifenden Austausch integriert.Aim of the BMBF-Programme 'Urban Climate under Change' was development, validation and application of a building-resolving urban climate model for entire cities. The joint project 3DO took over the research tasks assigned to module B: Preparation of existing data from long-term observation (LTO), deployment of new measuring stations, acquisition of new three-dimensional atmospheric data and new concepts, e.g. for model evaluation. The structure of the atmospheric boundary layer, characteristics of meteorological parameters and their influence on the thermal sensation of humans were investigated. A uniform [UC]2 data standard as well as analysis tools were developed and integrated into a data management system and a knowledge base for cross-module exchange