Koen De Ridder

Flemish Institute for Technological Research | VITO · Environmental Modelling / Climate Impacts (CLIM)

This study evaluates the cost of heat-related mortality using economic impacts and mortality data from the COVID-19 pandemic in Belgium as a proxy. By examining the economic loss measured by gross domestic product (GDP) decline and excess mortality during the first COVID-19 wave (March–June 2020), a new estimate for avoided heat-related mortality i...

Cities in the Sahel are heavily impacted by heat stress. Climate change, growing population rates and urbanization will increase the magnitude and intensity of urban heat stress towards the future. This study provides a comprehensive analysis of the current status of heat stress in Niamey (Niger) and future impacts by combining the results of two m...

Heat stress is an important threat for human health and urban areas are affected at higher rates compared to rural environments. Additionally, climate change will increase the vulnerability towards urban heat stress in the future. Current high-resolution urban heat stress assessments are limited in time and space due to the high computational costs...

Climate change and other anthropogenic threats are increasingly imperilling the diverse biomes of Central Africa, which are globally important for biodiversity, carbon storage and people's livelihoods. The objectives of this paper were to: (i) map the vulnerability of 100 socio-ecologically important priority tree species in Central Africa to clima...

The Climate-fit.City service ( https://www.climate-fit.city ) provides the best available scientific urban climate data and information for public and private end users operating in cities. Within the Climate-fit.City H2020 project, the benefits of urban climate information for end user communities was demonstrated, considering services in diverse...

Urban analysis at different spatial scales (micro- and mesoscale) of local climate conditions is required to test typical artificial urban boundaries and related climate hazards such as high temperatures in built environments. The multitude of finishing materials and sheltering objects within built environments produce distinct patterns of differen...

Today, the vast majority of meteorological data are collected in open, rural environments to comply with the standards set by the World Meteorological Organization. However, these traditional networks lack local information that would be of immense value, for example, for studying urban microclimate, evaluating climate adaptation measures, or impro...

This research project aims to predict the potential shifts in the distribution of the endangered Golden-headed lion tamarin (Leontopithecus chrysomelas) in the Atlantic forests of Brazil, by modelling the species’ climatic suitability under scenarios of future climate change. Through this case study within the framework of the Copernicus Climate Ch...

In urban areas, high air temperatures and heat stress levels greatly affect human thermal comfort and public health, with climate change further increasing the mortality risks. This study presents a high resolution (100 m) modelling method, including detailed offline radiation calculations, that is able to efficiently calculate outdoor heat stress...

As urban environments have a specific climate that poses extra challenges (e.g. increased heat stress during heat waves), gaining detailed insight into the urban climate is important. This paper presents the high-accuracy MOCCA (MOnitoring the City's Climate and Atmosphere) network, which is monitoring the urban climate of the city of Ghent since J...

UrbClim, the urban climate model, is used for short- and long-term projections of climate for Delhi. The projections are performed for RCP8.5 using an ensemble of 11 GCM model outputs. Various heat stress indices were employed to understand the role of urban heat island (UHI) in influencing the present and future urban climate of the city. UHI inte...

Introduction: Direct health effects of extreme temperatures are a significant environmental health problem in Lithuania, and could worsen further under climate change. This paper attempts to describe the change in environmental temperature conditions that the urban population of Vilnius could experience under climate change, and the effects such ch...

People living in cities experience extra heat stress due to the so-called Urban Heat Island (UHI) effect. To gain an insight into the spatial variability of the UHI for the Netherlands, a detailed map (10 m horizontal resolution) has been calculated that shows the summer-averaged daily maximal UHI situation. The map is based on a relationship betwe...

The CORDEX.be project created the foundations for Belgian climate services by producing high-resolution Belgian climate information that (a) incorporates the expertise of the different Belgian climate modeling groups and that (b) is consistent with the outcomes of the international CORDEX (“COordinated Regional Climate Downscaling Experiment”) proj...

Transition Handbook for Cities

Background: Excessive summer heat is a serious environmental health problem in several European cities. Heat-related mortality and morbidity is likely to increase under climate change scenarios without adequate prevention based on locally relevant evidence. Methods: We modelled the urban climate of Antwerp for the summer season during the period...

Indoor climatic conditions are strongly influenced by outdoor meteorological conditions. It is thus expected that the combined effect of climate change and the urban heat island effect negatively influences working conditions in urban office buildings. Since office buildings are particularly vulnerable to overheating because of the profound interna...

Urban areas are usually warmer than their surrounding natural areas, an effect known as the urban heat island effect. As such, they are particularly vulnerable to global warming and associated increases in extreme temperatures. Yet ensemble climate-model projections are generally performed on a scale that is too coarse to represent the evolution of...

Heat waves are projected to become more frequent, longer-lasting, and intense. At the same time, urban areas are confronted with the urban heat island (UHI) phenomenon, which adds to the thermal stress experienced during hot spells. Focusing on the Paris area during the hot summer of 2003, we investigated the influence of heat waves on UHI intensit...

http://www.lse.ac.uk/GranthamInstitute/publication/climate-change-heat-stress-and-labour-productivity-a-cost-methodology-for-city-economies/

Background Excessive summer heat is a serious environmental health problem in Skopje, the capital and largest city of the former Yugoslav Republic of Macedonia. This paper attempts to forecast the impact of heat on mortality in Skopje in two future periods under climate change and compare it with a historical baseline period. Methods After ascertai...

UrbClim is an urban climate model that simulates the Urban Heat Island (UHI) effect and other urban climate variables at the local scale with spatial resolution of few hundred meters. It is designed to generate results at finer resolutions consuming minimal amount of computational power and time. UrbClim has been successfully validated for various...

Background: Excessive summer heat is a serious environmental health problem in Skopje, the capital and largest city of the former Yugoslav Republic of Macedonia. This paper attempts to forecast the impact of heat on mortality in Skopje in two future periods under climate change and compare it with a historical baseline period. Methods: After ascert...

This presentation shows hindcasts, projections and the climatic drivers of future urban heat-stress in Belgium based on high-resolution regional land-use and climate modelling.

TERRA_URB introduces an urban land-cover parametrization for the atmospheric system COSMO-(CLM) and allows for the representation of cities in both the COSMO consortium as well as the CLM community. TERRA_URB has been evaluated extensively for many European cities both in offline (Basel, Toulouse) and in online mode (Belgium, Berlin and Zürich). It...

This paper assesses the seasonality of the urban heat island (UHI) effect in the Greater London Area. Combining satellite based observations and urban boundary layer climate modeling with UrbClim model, we are able to address the seasonality of UHI intensity, based on both land surface temperature (LST) and 2m air temperature, for four individual t...

This study examines the urban heat island (UHI) of Brussels, for both current (2000-2009) and projected future (2060-2069) climate conditions, by employing very high resolution (250. m) modelling experiments, using the urban boundary layer climate model UrbClim. Meteorological parameters that are related to the intensity of the UHI are identified a...

The urban heat island effect, in which air temperatures tend to be higher in urban environments than in rural areas, is known to exacerbate the heat impact on population health. We introduce a new urban climate model, further referred to as UrbClim, designed to study the urban heat island effect at a spatial resolution of a few hundred metres. Desp...

As most of the population lives in urban environments, the simulation of the urban climate has become a key problem in the framework of the climate change impact assessment. However, the high computational power required by these simulations is a severe limitation. Here we present a study on the performance of a Urban Climate Model (UrbClim), desig...

As most of the population lives in urban environments, the simulation of the urban climate has become a key problem in the framework of the climate change impact assessment. However, the high computational power required by high-resolution (sub-kilometre) fully coupled land–atmosphere simulations using urban canopy parameterisations is a severe lim...

'To what extent is climate change already visible in Flanders and Belgium?’ and ‘What are the expectations for the future?’, these are the central questions in the MIRA Climate Report 2015. An analysis of existing environmental indicators, supplemented with new indicators for drought and the urban heat island effect, provides the answer to the fir...

De temperatuur in steden is doorgaans hoger dan in de nabijgelegen plattelandsgebieden; naar dit fenomeen wordt verwezen als het stedelijk hitte-eiland. Terwijl dit temperatuurverschil gemiddeld enkele °C bedraagt, kan het in bepaalde omstandigheden oplopen tot 7-8 °C en meer. Internationaal onderzoek heeft aangetoond dat, tijdens hittegolven, deze...

[Report in Dutch] ‘In welke mate is de klimaatverandering nu al zichtbaar in Vlaanderen en België?’ en ‘Wat zijn de verwachtingen voor de toekomst?’, dat zijn de belangrijkste onderzoeksvragen van het MIRA Klimaatrapport 2015. Analyse van bestaande milieu-indicatoren, aangevuld met nieuwe indicatoren voor droogte en het stedelijk hitte-eilandeffect...

A new dynamical downscaling methodology to analyze the impact of global climate change on the local climate of cities worldwide is presented. The urban boundary layer climate model UrbClim is coupled to 11 global climate models contained in the Coupled Model Intercomparison Project 5 archive, conducting 20-year simulations for present (1986–2005) a...

In order to improve the representation of the water balance in urban land-surface models, we present a new impervious water-storage parametrization that assumes a distribution of water reservoirs. It has been implemented in TERRA-URB, a new urban parametrization for COSMO-CLM’s standard land-surface module TERRA-ML. The water-storage capacity and t...

A simple numerical experiment to evaluate the influence of model resolution on estimates of ambient air quality and associated human exposure is presented. This is done based on annual mean NO2 concentration fields for the agglomeration of Brussels and surroundings, simulated by the deterministic urban/regional-scale AURORA model at a resolution of...

A simple numerical experiment to evaluate the influence of model resolution on estimates of ambient air quality and associated human exposure is presented. This is done based on annual mean NO2 concentration fields for the agglomeration of Brussels and surroundings, simulated by the deterministic urban/regional-scale AURORA model at a resolution of...

Changes in the landscape by urbanization have lead to drastic climate modifications, which ranks among the most significant human impacts on the environment. Most remarkable is that cities are exposed to higher air temperatures than those in the natural surroundings. This phenomenon - known as the urban heat island - causes serious health risks for...

Belgium is one of the areas within Europe experiencing the highest levels of air pollution. A high-resolution (3 km) modelling experiment is employed to provide guidance to policymakers about expected air quality changes in the near future (2026–2035). The regional air quality model AURORA (Air quality modelling in Urban Regions using an Optimal Re...

Dit rapport bevat de analyse van het stedelijk hitte-eiland effect en het voorkomen van hittestress in Gent. De hoofdstukken 1 t.e.m. 4 beschrijven in detail een experimentele meetcampagne die heeft plaatsgevonden tijdens de zomer van 2012, een modelleerstudie aan de hand van het URBCLIM stedelijk klimaatsmodel en de verwerking van een aantal satel...

We studied and compared different operational modeling techniques that are used to generate regional scale concentration maps for PM10, PM2,5, NO2 and O3 over Belgium. The various techniques and resulting maps were analyzed, validated and compared aiming at identifying the best possible regional scale concentration map for each pollutant. A distinc...

The LIFE C Environmental Policy & Governance project ATMOSYS has the objective to implement an advanced and comprehensive air quality modeling system as a web-based service used by policy makers. The ATMOSYS system is based on advanced technology, including prognostic 3-D atmospheric computer models, data assimilation techniques, CFD modeling, and...

Belgium is one of the areas within Europe experiencing the highest levels of air pollution. To provide insight to policy makers about expected changes in the air quality towards the near future (2026-2035), a high resolution (3 km) modelling experiment is set up. The regional air quality model AURORA (Air quality modelling in Urban Regions using an...

The urban heat island (UHI) over Paris during summer 2006 was simulated using the Advanced Regional Prediction System (ARPS) updated with a simple urban parametrization at a horizontal resolution of 1 km. Two integrations were performed, one with the urban land cover of Paris and another in which Paris was replaced by cropland. The focus is on a fi...

The average summer temperatures as well as the frequency and intensity of hot days and heat waves are expected to increase due to climate change. Motivated by this consequence, we propose a methodology to evaluate the monthly heat wave hazard and risk and its spatial distribution within large cities. A simple urban climate model with assimilated sa...

Evaporation from the urban impervious surface could have a considerable impact on the surface energy and moisture balance on rainy days. In particular, the ever increasing urbanization could alter the interaction between evaporation from the surface and precipitation within the urban climate (change) in the future. However, uncertainty exists withi...

There exists a large discrepancy between the rural and urban land cover in terms of soil water, aerodynamical, thermal and radiative characteristics, and anthropogenic heat. This results in urban-scale meteorological features such as the urban heat island, reduced wind speed and the city breeze. Some of these effects have a considerable impact on h...

A new non-iterative bulk parametrization for surface-layer transfer coefficients for momentum and heat is presented. It is applicable for a wide range of aerodynamic and thermal roughness lengths, and includes the effect of the roughness sublayer. As a consequence, the non-iterative method is suitable for every surface type, especially for urban su...

Knowledge of the air and land surface temperature and their temporal and spatial variations within a city environment is of prime importance to the study of urban climate and human-environment interactions and to monitoring environmental changes due to urbanization. We present a number of air and land surface temperature products that have been pro...

A combined mathematical model was developed for the regional-scale dynamics of gaseous admixtures and aerosols in the atmosphere. The model incorporates the following modules: thermo-hydrodynamic equations for meso-scale atmospheric processes in the non-hydrostatic approximation; transport of gaseous admixtures and aerosols, with allowance for phot...

The urban heat island (UHI) over Paris during summer 2006 was simulated using the Advanced Regional Prediction System (ARPS) updated with a simple urban parametrization at a horizontal resolution of 1 km. Two integrations were performed, one with the urban land cover of Paris and another in which Paris was replaced by cropland. The focus is on a fi...

In this paper, we describe the implementation of the Semi-Analytical Cloud Retrieval Algorithm (SACURA), to obtain scaled cloud optical thickness (SCOT) from satellite imagery acquired with the SEVIRI instrument and surface UV irradiance levels. In estimation of SCOT particular care is given to the proper specification of the background (i.e. cloud...

Increasingly, mesoscale meteorological and climate models are used to predict urban weather and climate. Yet, large uncertainties remain regarding values of some urban surface properties. In particular, information concerning urban values for thermal roughness length and thermal admittance is scarce. In this paper, we present a method to estimate v...

The Po Valley (Italy) model inter-comparison exercise (POMI) has been carried out in order to explore the changes in air quality in response to changes in emissions. The starting point was the evaluation of the simulated particulate matter and ozone (O3) modelled concentrations against observations for the year 2005 of the six participating chemica...

Located in the semi-arid African Sahel, Lake Chad has shrunk from a surface area of 25000 km2 in 1960 to about 1350 km2 due to a series of droughts and anthropogenic influences. The disappearance of such a large open-water body can be expected to have a noticeable effect on the meteorology in the surroundings of the lake. The impact could extend ev...

The European Commission, in its strategy to protect the health of the European citizens, states that in order to assess the impact of air pollution on public health, information on long-term exposure to air pollution should be available. Currently, indicators of air quality are often being generated using measured pollutant concentrations. While ai...

A new air quality forecast system has been developed in which all the corrections for the air quality model output by assimilating observations have been carried out in post-processing mode. In order to make more accurate forecasts of the air pollutants, time series models have been used in combination with data-assimilation. The approach has been...