Linz (AT) suffers from heat waves
Sweating, sweating, sweating. That is what ZAMG meteorologists forecast for the upcoming summer. Temperatures rise up to 35 degrees celsius in the Upper-Austrian Metropolis. In the ranking of the hottest measured spots 2017 Linz was frequently at the top. In contrast to Stockholm, Jönköping and Salvador where flooding is the main issue, the problem in Linz is the exact opposite: Heat waves. Adaptations are required to provoke a cooling by local measures.
Linz is a great example of how the population is suffering from heat exposure. Due to the common urban structures and large-scale climate change impacts, this Austrian demo case is relevant for a number of cities in Central Europe and can serve as a base for development of operating procedures and climate services in other regional centres.
So how can we face this problem?
Urban climate adaptation goes along with applying spatial planning instruments related to climate adaptation in Linz. Here risk and adaptation measures are required to cope withheat exposure as well as extreme precipitation.
The solution is cost-efficient climate-resilient planning for the urban space and infrastructure in two operational scenarios concentrating on resilience to heat exposure and flooding effects in Linz. Urban climate- and microclimate-simulations assess the local measure application against the increase of the urban heat island effect. Greening measures in existing settlement areas are an example. Setting the optimal greening measures (from a microclimatic perspective) makes existing settlement areas better and more climate-resilient in the future.
Can heat exposure be reduced?
The population should suffer less from heat exposure. If the required adaptations are made, heat exposure can definitely be reduced. But of course, city planners aren't the only ones responsible - the whole population can face the problem and adapt to it.
First, it is important to have a map showing the general microclimatic patterns in the city, especially sensitive areas. If end-users can see indicators or maps showing the general microclimatic patterns in the city, especially revealing microclimatic sensitive areas, they are able to carry out climate sensitive city planning based on thoroughly analysed indicators, which are commonly accepted and comparable among cities.
With that map it will then be possible to do efficient city planning while still minding microclimatic patterns. For city planners it is important to get recommendations on how to plan climate resilient new settlement areas, in order to be able to provide guidelines and clear instructions for developers to build high quality settlement areas, which are liveable even in 50 years.
Particularly important for microclimate in existing settlement areas are the effects of building heights and density. In hot spot areas in Linz refurbishment on densification measures will be assessed respecting to effects on microclimate: urban heat islands have to be identified and different scenarios considering building adaptations discussed. The microclimatic stituation will be calculated, results interpreted and made ready to be implemented.
How can ventilation work?
If city planners implement ventilation patterns for Linz based on the current urban fabric and the expected changes over time through an increase of building density. This could adapt the masterplan coping better with air conditions in the city under future climate conditions. Further, the wind situation will be calculated in real-time. The objective is to increase ambient air quality. This requires an adaptation of urban fabric to cope better with air conditions. Also building heights and density have great effects on ventilation patterns.
As a result, CLARITY suggests to use the German VDI “Klimatopen” concept for Linz. Climatopes designate spatial units in a city. In these units the so called microclimatic factors are relatively homogenous, which means that also their characteristics do not differ considerably. If all of the mentioned content is provided, city planners can still build high quality and durable settlement areas, yet not provoking heat waves. [Modest/PF]