Outdoor Thermal Environments of Main Types of Urban Areas during Summer: A Field Study in Wuhan, China

Under the influence of the urban heat island effect, the thermal environments of urban built-up areas are poor, leading to the loss of urban vitality and the extreme deterioration of thermal comfort. In this paper, the outdoor thermal environment in Wuhan’s main urban area is studied via the use of field measurements. From June to August in the years 2015 to 2017, 20 measurement points were selected for monitoring from 08:00 to 19:00 h, which were located in spaces such as residential areas, parklands, commercial streets, and college/university campuses. The measurements for the same types of land and different types of land use are analyzed. A comprehensive thermal environment index is used to quantitatively evaluate the overall situations of thermal environments. The results showed that the cooling effect of vegetation shading was stronger than the effect of water evaporation and the maximum temperature difference between the two cooling methods reached 6.1 °C. The cooling effect of the canopy shading of tall trees was stronger than the effect of grassland transpiration and the maximum temperature difference was 2.8 °C. The streets with higher aspect ratios might improve the ventilation, but the wind speeds remained low, which did not provide a strong cooling effect. This study helps urban planners understand the thermal environment of Wuhan or similar cities with hot summer and diversified urban areas, and puts forward suggestions to reduce the heat island effect from the aspect of building layout, green coverage, shading mode, and street aspect ratio, so as to establish sustainable cities that are climate adaptable and environmentally friendly.

Minimum temperature forecasting by stochastic techniques : An evidence of the heat island effect

This paper deals mainly with the forecasting of minimum temperatures (Tm) from an stochastic viewpoint. Some appropriate theoretical considerations lead to a choice of those variables significant connected to Tm. Modelling has been carried out for two nearby observatories, one in the centre of Madrid, the other one in the border (Barajas airport). The obtained models allow to show that the significant variables are the same for both locations, but performance in the peripheral area is of a rather inferior quality. It is shown, taking into account the characteristics of both places, that the difference between them can be allotted to the heat-island effect in the centre of Madrid.

Cool Materials and the Heat Island Effect: a bibliometric analysis

A current problem triggered by anthropological factors that many cities in the world face is the increase in temperature in urban centres caused by urban heat islands. There is a constant proposal for measures to reduce these effects, which can be harmful to the health and well-being of the population. The purpose of this work is to carry out a bibliometric mapping to analyse the published documents on cool materials regarding the mitigation effects of heat islands and to understand their origin and possible reasons that led to the study of this theme. From the SCOPUS database, searching for “Cool Material AND (Albedo OR Reflectance) AND Heat Island”, the scientific documents (engineering area) published between 1995 and 2021 were selected and analysed: the types of documents, their origin, the year of publication, the main authors and the journals in which they were published. Energy and Buildings and Building and Environment were the two main journals on the subject. 1995 had the first article published and coincided with the year of the first Conference of the Parties (COP1), on climate change. Through a bibliometric survey, it is possible to understand the importance of the beginning of this line of research and that climatic events can trigger interest and bring the scientific view to a certain area. However, because it is a single-base study, the research, despite bringing good information, still needs constant updates.

Ecological specialization, rather than the island effect, explains morphological diversification in an ancient radiation of geckos

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this ‘island effect’. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus . Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent–island systems.