Globally unique measurements in Enschede to improve the prediction of urban heat stress

During the 'Twente Enschede Olé 2026' measurement campaign, unique data on urban heat stress were collected this month in and above the city of Enschede, creating a dataset of global significance. Members of the 4TU.HERITAGE programme carried out the campaign, complemented by several international experts. Data were acquired from multiple viewing and solar angles, at different times of day, and across various parts of the electromagnetic spectrum, using measurements taken from the ground, within the atmosphere, from an aircraft, and by satellites. The campaign was coordinated by UT's researcher Wim Timmermans of the Faculty of Geo-Information Science and Earth Observation (ITC).

The collected data cover a wide range of urban land cover types (built-up areas, vegetation and water), urban structure (morphology) and land use, to improve our understanding of urban heat and the associated physical processes. The initiative focuses, among other things, on the development and validation of algorithms for current and future satellite missions, including LSTM, TRISHNA, SBG, Landsat and Constellr, to support urban climate modelling, environmental modelling and evidence-based policy making.

From 40 centimetres to satellite imagery

The simultaneous use of multiple remote sensing platforms enables urban heat stress in Enschede to be mapped with an accuracy of up to 40 centimetres. The ultimate objective is to use these high-resolution data to develop algorithms that can exploit lower-resolution imagery from current and future operational satellites. These satellites typically provide images with a spatial resolution of 30 to 50 metres. However, the new algorithms are designed to retrieve information at the sub-pixel level. This will make it possible not only to map urban heat stress at the required level of detail, but also, supported by urban climate models, to predict heat stress, enabling timely warnings and appropriate mitigation measures.

Next step: algorithms and new satellites

In the coming months, ITC researchers will begin developing the algorithms. This work will be carried out in close collaboration with the international partners listed below. At the same time, under the leadership of the University of Valencia, the consortium is working on the development of a new satellite specifically designed to capture nighttime imagery over urban areas.

A unique dataset made possible through broad collaboration

The satellite, airborne and atmospheric observations collected during the campaign were complemented by an extensive network of ground-based measurements. These included a network of meteorological stations, solar radiation and heat measurements in ten different neighbourhoods, measurements in and on the homes of volunteer residents, as well as observations from several high-rise buildings across Enschede.

"None of this would have been possible without the excellent collaboration with the Municipality of Enschede, housing association Domijn, and the volunteer residents of Enschede," says Wim Timmermans. "The fact that all of this took place during the warmest and most extreme early summer period ever recorded in Northwestern and Western Europe makes this dataset truly unique."

Participants in the Twente Enschede Olé 2026 campaign

Centre for the Study of the Biosphere from Space (CESBIO) – French National Centre for Scientific Research (CNRS), Toulouse, France (Jérôme Colin); Czech Globe – UVGZ AV CR, Brno, Czech Republic (Jan Hanuš, Karel Holouš); French Aerospace Lab (ONERA) – Optics and Associated Techniques Department (DOTA), Toulouse, France (Laure Roupioz); Delft University of Technology, Faculty of Civil Engineering, Delft, the Netherlands (Xuan Chen); University of Strasbourg – French National Centre for Scientific Research (CNRS), Strasbourg, France (Françoise Nerry); University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC), Enschede, the Netherlands (Srinidhi Gadde, Jonathan Hempenius, Heet Joshi, Camilla Marcatelli, Wim Timmermans); University of Valencia, Faculty of Physics, Department of Thermodynamics, Global Change Unit, Burjassot, Spain (José Sobrino); Wageningen University, Meteorology and Air Quality Section, Wageningen, the Netherlands (Luuk Eijkelkamp).

dr.ir. W.J. Timmermans (Wim) Researcher

+31534874488

 w.j.timmermans@utwente.nl

Building: Langezijds 1115

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