City climate digital twin

In recent years, heat waves have become a recurrent event, with temperatures skyrocketing in the summer months. The heat waves pose an increasing problem for cities, which are often not built to handle the increasing temperature levels.

Heat can endanger health, lower energy efficiency and workforce efficiency and potentially cause loss of revenue in heat-exposed areas. Simply because people are not comfortable being there. It can be an unsafe and costly affair to have a city running too hot. 

Ramboll’s city climate digital twin allows us to map and visualise the climate impact and heat patterns of an entire city and identify problematic areas, where the heat gets too intense and can cause heat stress. Using the solution to visualise future scenarios, we also get detailed insights on where to focus the efforts of mitigation, and on how intense the mitigation needs to be to make a real impact on the urban climate. 

Here, the digital twin can also be used to test different mitigation strategies and quantify the efficacy. Combined with our expertise in sustainable city climate solutions, we can monetise the best possible strategies for reducing the climate impact, bringing the temperatures down, and enable evidence-based decisions for city development. 

What makes it cool? 

The digital twin is a precise virtual city model, which computes wind flow, temperature and solar radiation every day, to provide a detailed map of a given city’s climate over time. 
Within the same city, the effects of high temperatures – the felt temperature – can vary greatly. 

When the climate digital twin was used in a study of Copenhagen, the lakes in the city proved to be relatively cool havens, as trees, shade, water and wind keep the temperatures down – and mostly within the thermal comfort zone. 

In contrast, the meatpacking district, with its asphalt, concrete buildings and limited shade, is close to a sauna when temperatures spike, even though the air temperature is the same in both areas. 

This might sound like a pretty straightforward analysis, but a wide range of factors determine the felt temperature. Wind flow, air temperature, humidity, shade, the interaction with the material of the surfaces, ground, greenery, direct sunlight, reflected sunlight – the list goes on. 

When the assessment and scenarios need to include a city-wide perspective and find holistic solutions, it quickly becomes complicated. However, using High Performance Computing, the digital twin makes it possible to factor all of it in and make the processed data accessible through visualisation and actionable through solution testing.