An assessment of WRF-urban schemes in simulating local meteorology for heat stress analysis in a tropical sub-Saharan African city, Lagos, Nigeria.

Megacities, such as Lagos, Nigeria, face significant challenges due to rapid urbanization and climate change, resulting in a higher intensity of the urban heat island effect, coupled with high population density, making the city fall under the category of moderate to high heat stress/risk. Despite this, very few studies have analyzed the urban impact on heat stress over the coastal city, albeit with poor resolution data. In this study, we assessed the performance of an integrated high-resolution WRF-urban scheme driven by the readily available urban canopy information of the local climate zone (LCZ) to simulate local meteorological data for analyzing the spatiotemporal pattern of heat stress over the megacity.

Thermal-irradiant performance of green infrastructure typologies: Field measurement study in a subtropical climate city.

Greenery infrastructure (GI) is an important design strategy for sustainable cities and communities' development, as it brings multiple benefits including mitigating urban heat island. Based on the implementation locations, three typical GI typologies, namely green roof, green wall, and ground tree, are widely adopted in urban communities. As previous studies focused on one single GI and mainly studied their thermal features, this study aims to fill the gap by investigating three GI typologies within one site; their thermal-irradiant performance was compared for four typical summer days in a subtropical city.

Right tree, right place (urban canyon): Tree species selection approach for optimum urban heat mitigation - development and evaluation.

The re-integration of trees into the urban landscape is a veritable strategy for urban climate mitigation and adaptation. However, dysfunctional trees in terms of urban heat mitigation are dominant in many sub-tropical cities' landscapes due to the lack of scientific basis of tree selection. Therefore, this study proposes and evaluates a methodological framework as an approach for "right tree, right place" for urban heat mitigation through parametric ENVI-met simulations that involve the combination of 54 generic tree forms and 10 characteristic urban morphology - Sky-View Factor (SVF).

Quantifying the effect of rain events on outdoor thermal comfort in a high-density city, Hong Kong.

Rainfall events often cause a modification to atmospheric conditions. The impact of this phenomenon on human thermal comfort has however been less well studied. Therefore, this paper quantifies the effect of rainfall events on human thermal comfort in a hot-humid subtropical city, Hong Kong.

Evaluating the role of green infrastructures on near-road pollutant dispersion and removal: Modelling and measurement.

To enhance the quality of human life in a rapidly urbanized world plagued with high transportation, the masterful contribution of improved urban and local air quality cannot be overemphasized. In order to reduce human exposure to near-road air pollution, several approaches including the installation of roadside structural barriers especially in open street areas, such as city entrances are being applied. In the present study, the air quality around real world and idealized green infrastructures was investigated by means of numerical simulation and a short field measurement campaign.

Study of traffic-related pollutant removal from street canyon with trees: dispersion and deposition perspective.

Numerical experiments involving street canyons of varying aspect ratio with traffic-induced pollutants (PM) and implanted trees of varying aspect ratio, leaf area index, leaf area density distribution, trunk height, tree-covered area, and tree planting pattern under different wind conditions were conducted using a computational fluid dynamics (CFD) model, ENVI-met. Various aspects of dispersion and deposition were investigated, which include the influence of various tree configurations and wind condition on dispersion within the street canyon, pollutant mass at the free stream layer and street canyon, and comparison between mass removal by surface (leaf) deposition and mass enhancement due to the presence of trees. Results revealed that concentration level was enhanced especially within pedestrian level in street canyons with trees relative to their tree-free counterparts.

Simulation study of dispersion and removal of particulate matter from traffic by road-side vegetation barrier.

Well-positioned and configured vegetation barriers (VBs) have been suggested as one of the green infrastructures that could improve near-road (local) air quality. This is because of their influence on the underlying mechanisms: dispersion and mass removal (by deposition). Some studies have investigated air quality improvement by near-road vegetation barrier using the dispersion-related method while few studies have done the same using the deposition-related method.

Multi-purpose rainwater harvesting for water resource recovery and the cooling effect.

The potential use of rainwater harvesting in conjunction with miscellaneous water supplies and a rooftop garden with rainwater harvesting facility for temperature reduction have been evaluated in this study for Hong Kong. Various water applications such as toilet flushing and areal climate controls have been systematically considered depending on the availability of seawater toilet flushing using the Geographic Information System (GIS). For water supplies, the district Area Precipitation per Demand Ratio (APDR) has been calculated to quantify the rainwater utilization potential of each administrative district in Hong Kong.