Evaluating the wind cooling potential on outdoor thermal comfort in selected Iranian climate types

Wind is one of the main factors affecting people's outdoor thermal sensation. Ongoing urbanization and urban densification are transforming the urban climate and complicating the pedestrian-level wind environment. Therefore, the main aim of this research is to evaluate the potential wind-cooling effect on human outdoor thermal conditions. Accordingly, the current research attempts determine the best wind directions for thermal comfort at the studied stations and how these factors will be changed under the effects of global warming. Outdoor thermal conditions were modeled based on the physiologically equivalent temperature (PET) thermal index using RayMan software for the decades of the 2000s and the 2040s in different climate types of Iran (Csb, BWh, Csa, and BSh) To estimate the potential cooling effect of wind, the PET was calculated (1) under actual wind conditions, and (2) under calm wind (0.05 m/s) conditions. Then, the ΔPET for these two conditions, which indicates the cooling potential effect (CPE) of the wind, was calculated for four representative stations (Ardebil, Bandar Abbas, Gorgan, and Shiraz). In comparison with the 2000s, the results indicated that by the 2040s, the predicted wind cooling potential will have increased in Ardebil, Shiraz, Bandar Abbas and Gorgan (CPE of 13.2 °C, 13.1 °C, 11.2 °C, and 11 °C, respectively). Based on the overall average of two climate change scenarios (A2 and B1) used in this study, the occurrence of “comfortable” conditions by the 2040s will have increased in Bandar Abbas, Shiraz, and Ardebil by 1.1%, 0.4%, and 0.3%, respectively, while it will have decreased in Gorgan by 1.5%. Accounting for the cooling effect of wind, the comfort cooling potential of wind is predicted to rise by an average of 1.6 °C in the 2040s compared with the 2000s in all the studied stations. Therefore, this will affect the microclimates positively and could reduce the urban heat island effects.     

城市典型绿化植物释氧与降温的生态效应:贵州安顺城区实例研究

城市绿化植物是城市生态系统的重要组成部分,在美化城市、保持其生态平衡及维持其可持续发展等方面作用不可低估。本研究以贵州省安顺市城区为研究实例,在对绿化植物种类和数量进行调查的基础上,对香樟等16种典型植物的释氧和降温的生态效应进行分析。结果表明:贵州安顺城区内绿化植物种类较少,结构单一,物种均匀度低;不同植物在不同月份的释氧能力虽有差异,但都表现出6月和8月上升,7月和9月下降的规律;8月份各种植物的降温效果与释氧规律相一致,乔木以法国梧桐降温0.32℃最明显,灌木以小叶女贞降温0.26℃最明显,攀援植物以爬山虎降温最强,达0.46℃。本研究可以为同类型城市的生态建设、改善人居环境以及生态可持续发展提供基础性的研究参考。     

Assessing the current status of urban forest resources in the context of Parco Nord, Milan, Italy

During the early part of the 1980s, a major project called Parco Nord was undertaken by the Lombardia Region to establish forest resources within an industrial area located in the northern part of the city of Milan. Since 1983, more than 60 ha of formerly industrial land has been converted into urban forest plantations, thus creating large patches of trees with the potential to sustain a wide range of functions and services. This paper describes an integrative study aimed to assess the current status of forest resources in Parco Nord. It focuses on the actions taken to determine whether forest resources significantly changed their status 20 years after their establishment, considering historical field data and records of management practices. Analyses have been conducted at both stand and tree level by collecting quantitative and qualitative parameters. Stand-level analysis gave a quantitative estimation of the response of species to ecological conditions and management practices while tree-level analysis provided evidence of species renovation after thinning operations.     

Food selection and predation risk in the Andean white-eared opossum (Didelphis pernigra Allen, 1900) in a suburban area of Bogotá, Colombia

Urbanization is spreading throughout the Andes, and despite it there is still wildlife which survives in these novel environments throughout Colombia and elsewhere. The Andean white-eared opossum (Didelphis pernigra Allen, 1900) can tolerate moderate levels of urbanization in the Andes highlands, and we evaluated its food selection based on optimal patch use theory using foraging stations to measure giving-up densities in a suburban area in Bogotá (∼2600 m a.s.l.). We offered the opossums equicaloric mixtures of protein-rich and sucrose-rich foods, and they preferred the sucrose mixture. However, the magnitude of this preference was influenced by temporal and spatial effects. We suggest that in environments such as the high Andes, where air temperature regularly drops below 10 °C, the opossums prefer foods that provide energy easily. We also assessed the opossums’ perceived risk of predation when domestic dogs (Canis lupus familiaris) are present by sprinkling dog urine in cotton swabs next to foraging stations; we expected opossums to forage more when the predator’s signal was not present. Dog urine indicated a risk for opossum’s at only one of six foraging stations, suggesting a weak predator’s signal effect that depends on location. Both food preferences and perception of risk by the opossum were affected by the spatial heterogeneity of the urban environment. Thus, microhabitat management at the study site, which is part of a recently created reserve to preserve Bogotá’s natural capital, appears to be key to conserve the opossums and their ecological functions in highly disturbed areas of the Andes.     

Selected questions of topical interest in human bioclimatology

This paper deals with the different effects of climate, and the likely impact of climatic change, on the human being, his health and well-being. Those effects follow from consideration of the human energy budget and air pollution, including photooxidants and radiation, the latter especially in the UV-range. The development of tools to produce bioclimate maps, i.e. maps expressed in physiologically significant terms, in different scales up to the high resolution necessary for the microscale urban climate, will be discussed. The most important questions in bioclimate research and its application will be considered.     

中原城市群“三生”空间模拟及生态效应评估——基于未来土地利用模拟模型和共享社会经济路径情景

黄河流域高质量发展背景下,加强该流域典型城市群"三生"空间(PLES)时空演变和生态效应具有重要现实意义。以中原城市群为例,基于2010年、2015年和2020年的土地利用数据,耦合未来土地利用变化情景模拟模型(FLUS)、共享社会经济路径(SSPs)和生态环境效应模型,分析了2025-2100年五种SSPs情景下中原城市群"三生"空间的时空演变特征,以及2035年不同情景下的生态环境效应。结果表明:(1)从2025年到2100年,除SSP4情景外,其余4种情景均表现为生产空间面积持续缩减、生活空间面积明显扩张、生态空间面积略有起伏总体缩减。(2) 5种SSPs情景下,"三生"空间的空间分布格局相对一致。城镇生活用地较为聚集呈片状分布,农村生活用地呈点状零散分布。农业生产用地较大,分布均匀。林地和牧草生态用地主要分布在西部和南部,水域生态用地呈东西向带状分布在中原城市群中北部。(3)2035年,研究区生态环境质量空间分布不均衡,呈现"西南高-中部低"特征。中间发展情景(SSP2),生态环境质量略高于其他情景。研究结果对中原城市群的国土空间规划和生态文明建设具有一定的理论和实践价值。     

Effect of nesting environment on incubation temperature and hatching success of Morelet's crocodile (Crocodylus moreletii) in an urban lake of Southeastern Mexico

Incubation temperature is an important aspect in terms of biological performance among crocodiles, and several controlled experiments have demonstrated a significant relationship between incubation temperature, success in hatching and survival of hatchlings. However, a few studies have tested these relationships in the wild. The objective of this study was to determine the relationship of nest characteristics and environment (hatch year, nest basal area and height, clutch size, distance to shore line, and vegetation cover), to incubation temperature and hatching success among Morelet's crocodile (Crocodylus moreletii). The study was carried out during the nesting seasons of Morelet's crocodile, from 2007 to 2009 in the Laguna de Las Ilusiones, an urban lake located in Villahermosa, Tabasco, Mexico. We physically characterized 18 nests and inserted a temperature data logger in each nest chamber. At the end of the nesting season and prior to hatching, we recovered the crocodile eggs and data loggers and calculated hatching success, under laboratory conditions. We related the environmental variables of the nest with the mean and fluctuation (standard deviation) of nest temperature, using linear models. We also related the environmental variables affecting the nest, to mean nest temperature and fluctuation in incubation temperature and to hatching success, using linear models. Although we found differences in incubation temperature between nests, mean incubation temperature did not differ between years, but there were differences in nest thermal fluctuation between years. The mean incubation temperature for 11 nests (61.1%) was lower than the suggested Female–Male pivotal temperature (producing 50% of each sex) for this species, and all hatchlings obtained were males. There were no differences in clutch size between years, but hatching success varied. Our study indicates that hatching success depends on certain environmental variables and nest conditions to which the eggs are subjected, including season, nest size and clutch size. We also discuss the importance of the fluctuation of incubation temperature on hatching success and sex determination.     

Heavy metals in leachate from simulated green roof systems

The contribution of green roofs to urban water quality, either as sinks or sources of pollutants, is an open question. This study examined leaching of Cd, Fe, Ni, Pb, and Zn from simulated green roof systems that had been deployed under field conditions and naturally leached for 22 months. The objectives were to determine if Arkalyte (an expanded clay), when mixed with pine bark as a substrate, leached metals and if so, whether leaching was influenced by the depth of substrate, structural components of the green roof system, or wet/dry deposition. Leachate was collected from each system after wet deposition events in June 2007, October 2007, February 2008, and April 2008 and analyzed. The concentration of four elements routinely exceeded USEPA water quality criteria for chronic and/or acute toxicity and were therefore of possible relevance to water quality, particularly for Pb. The frequency and intensity of local wet deposition influenced the volume of leachate recovered from the systems and in some instances the corresponding metal concentration in the leachate. There were no consistent trends with respect to depth and metal concentration in the leachate, due perhaps to the confounding effects caused by leaching of metals from materials used to construct the built-in-place systems and from inputs from deposition. Further evaluation of this substrate and the structural materials is needed to determine if their use in green roof systems will improve or degrade urban water quality.     

Dendrochronology and dendroclimatology of Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae) exposed to urban pollution in Rio de Janeiro city,Brazil

Nowadays, the biological monitoring through the growth rings has received increasing attention from ecologists and toxicologists. Structural analysis of these rings allows the incorporation of a time component in the study of plant responses to environmental variation. This allows also to evaluate long time series from the woody plants. In this paper, we assessed the dendrochronological characteristics of Ceiba speciosa growing in forest environment and under urbanization impact. Stem samples were obtained with Pressler probe into trees growing the campus of the Oswaldo Cruz Foundation, adjacent to one of the main urban thoroughfares of the city of Rio de Janeiro (Avenida Brasil), and at Tinguá Biological Reserve, an important remnant of Atlantic Forest. The samples were processed and analyzed following usual dendrochronological methods, with COFECHA and ARSTAN softwares. A negative exponential curve was used for standardization of the series. The residual chronologies were correlated with precipitation and temperature indexes obtained from NOAA weather database. Growth rings are distinct and annual, marked by bands of marginal parenchyma, thick-walled and radially flattened fibres in latewood and distended rays in earlywood. In both sites, the intercorrelation between the trees was above 0.40. Ages ranged from 11 to 41 years in the urban site and from 27 to 64 years in the forest site. In urban area, mean annual increment and cumulative average growth rates were 6 mm/year and 142.62 mm, respectively. At the forest site, these rates were 4 mm/year and 173.07 mm, respectively. The comparison between cumulative radial increment of the two sites revealed that trees of the urban site had higher increment rates beginning at the start of their development and consequently, they showed similar diameters despite lower ages. Correlation analysis between the chronologies and climatic factors revealed a positive association between growth and hot and rainy periods for both study sites. However, there is an immediate response of urban trees in relation to the rains and, a late response of forest trees to the same factor. The dry and hot climate, typical of urban environments, and the absence of natural water reserves in urban soil, may explain this more immediate response of urban tree growth to rainfall and temperature indexes. Our results revealed that Ceiba speciosa is a plastic and stress-tolerant species that is able to survive and adapt to polluted urban conditions. These features, along with its wide natural distribution and frequent planting for city landscaping, make this species an important biomarker for environmental monitoring studies.