Diagnosis, Design & Managment of urban overheating during heatwaves: cross-fertilization of microclimatic simulation tools and IRT imaging – DIAMS

The project is structured around 5 research Work Packages (WP) to resolve the scientific issues involved in processing and exploiting satellite data:

- The EXPE WP to select and prepare the experimental data available to the consortium on the temperatures of different urban surfaces (roofs, floors, facades, metro stations, building interiors), air temperatures, or airborne images or Lidar measurements. This stage will also enable us to select the most appropriate data to feed into the work of the other components of the project.

- The MODE WP to qualify the models developed or used by the consortium on the basis of the datasets selected in the EXPE component. The results of microclimatic simulation models on a district scale will be compared with each other and with the experimental data selected for various case studies. In this WP, the models will be prepared for forcing surface temperatures using temperatures obtained from satellite images, as an alternative to their calculation.

- The IRT WP to set up methods for exploiting urban IRT images. Two major contributions are targeted. The first is to adapt the method for estimating surface temperature (LST) from satellite images to the particularities of the urban environment (by identifying error-inducing factors: materials, composition of building facades, their orientation, etc.). The second is to estimate the impact on air temperature calculations of using these LSTs under microclimatic model boundary conditions, depending on the spatial and temporal resolution of the satellite data. The methods developed at this stage should make it possible to identify the neighborhoods most sensitive to urban overheating.

- In the PREVI component, the aim is to demonstrate the feasibility of producing a short-term forecasting tool for hot and cool zones at neighborhood level during heatwaves, based on fine spatial and temporal resolution satellite IRT data and weather forecasts. This tool aims to identify sensitive buildings and outdoor spaces, as well as cooler areas. As the composition of each neighborhood, and in particular its materials, is generally unknown, this WP will use deep learning to build a metamodel from previous IRT data, which will then be used to assess the risk of overheating, based on future forecasts.

- The APPLI WP applies the developments made in the IRT and PREVI WPs to validate the possibility of using the tools introduced by the illustration on concrete cases in the design office.

The DIAMS project will develop methods and tools for :

- Estimate surface temperature (LST) in complex urban environments at 50-60 m resolution;
- Use IRT data in conjunction with microclimatic modelling to estimate air temperatures, enabling us to better assess urban overheating and thermal comfort conditions;
- Estimate predictable temperatures a few days ahead based on IRT data.

In addition, the project will provide data sets prepared as a first basis for standardized case studies (Benchmarks) enabling other modellers to validate and compare their urban microclimatology tools.

Other aspects of the project will be the validation and potential improvement of existing microclimatic models, and the creation of validation datasets for microclimatic models, which will be made available to the scientific community.

-

The DIAMS project aims to evaluate the contribution of thermal infrared (TIR) imagery acquired from space for the diagnosis and monitoring of urban overheating from the city to the district scale.
It anticipates the arrival of upcoming TIR satellite missions, such as the Franco-Indian project TRISHNA (launch planned in 2025), expected to provide TIR data with a spatial resolution around 50 m every 2 to 3 days, and later the LSTM mission (ESA) with similar characteristics.

The DIAMS project will set up robust methods adapted to urban environments to exploit remote sensing data acquired in the TIR domain to derive land surface temperatures and study thermal comfort at district scale.

To reach this goal, the project is built around a coordination work-package and 5 research work-packages described below.
The MODE work-package focuses on the qualification of the various models developed or used by the consortium on the basis of the data sets selected in the EXPE work-package. It also analyzes the impact of surface temperature forcing in these models.
The objective of the EXPE work-package is to select and prepare the experimental data available to the consortium in the form of benchmarks for the MODE work-package along with validation data sets for the IRT and PREVI work-packages.
The IRT work-package is dedicated to the implementation of methods for the exploitation of urban TIR images. Two major contributions are intended: an adaptation of the land surface temperature (LST) estimation method to the particularities of the urban environment and the use of these estimated LST in boundary conditions of the microclimatic models of the MODE component.
In the PREVI work-package, the aim is to demonstrate the feasibility of producing a short-term forecasting tool for hot or cool zones at the district scale during heat waves, using satellite TIR data at fine spatial and temporal resolution.
Finally, the APPLI work-package implements developments made in the IRT and PREVI work-packages to validate the possibility of using the tools set up by the illustration on concrete cases.

DIAMS will thus lead to the implementation of methods and tools for:
? The estimation of land surface temperature (LST) in complex urban environments at the resolution of 50-60 m;
? The joint use of TIR data and microclimatic modeling to estimate air temperatures, which will allow a better assessment on urban overheating and thermal comfort conditions;
? The estimation of predictable temperatures a few days after the TIR data.

In addition, the project will provide ready-to-use datasets as the first input for standardized case studies (Benchmarks) allowing modelers to validate and compare urban microclimatology tools.