Through the advent of mobile cellular networks the number of radio base stations installed in urban environments has increased exponentially. As a consequence, the level of the electromagnetic (EM) ...field has increased at the same pace, sometimes approaching the limits set by the national rules. The first step of a compliance test campaign is the field estimation, mainly close to the base stations. In this article, the estimation of EM field generated by UHF base station is presented. A rephrasing of the COST 231 - Walfisch-Ikegami model is used to evaluate the path loss at distances greater than 20 m from the base station. Then, the knowledge of the full antenna pattern allows to estimate the field level. Since antenna manufacturers measure, and publish, only the patterns on the principal planes, an extrapolation procedure is also presented. A measurement campaign in the specific small urban and irregular environments of Dorgali (NU), Cala Gonone (NU) and Lunamatrona (CA), Italy, done in the context of Onde Chiare project, has been used to assess the approach presented here.
This study presents a global explanatory analysis of the interplay between the severity of flood losses and human presence in floodplain areas. In particular, we relate economic losses and fatalities ...caused by floods during 1990–2000, with changes in human population and built‐up areas in floodplains during 2000–2015 by exploiting global archives. We found that population and built‐up areas in floodplains increased in the period 2000–2015 for the majority of the analyzed countries, albeit frequent flood losses in the previous period 1990–2000. In some countries, however, population in floodplains decreased in the period 2000–2015, following more severe floods losses that occurred in the period 1975–2000. Our analysis shows that (i) in low‐income countries, population in floodplains increased after a period of high flood fatalities; while (ii) in upper‐middle and high‐income countries, built‐up areas increased after a period of frequent economic losses. In this study, we also provide a general framework to advance knowledge of human‐flood interactions and support the development of sustainable policies and measures for flood risk management and disaster risk reduction.
Key Points
We analyzed the interplay between the severity of flood losses and human presence in floodplains using freely available global data sets
Despite the frequent flood losses in the period 1990–2000, human presence and built‐up areas in the floodplains increased between 2000 and 2015
In low‐income countries, population in floodplains increased after a period of high flood fatalities
Ultrafine particles (UFPs) dominate the particle number population in the urban atmosphere and revealing their chemical composition is important. The thermal desorption chemical ionization mass ...spectrometer (TDCIMS) can semicontinuously measure UFP composition at the molecular level. We modified a TDCIMS and deployed it in urban Beijing. Radioactive materials in the TDCIMS for aerosol charging and chemical ionization were replaced by soft X-ray ionizers so that it can be operated in countries with tight regulations on radioactive materials. Protonated N-methyl-2-pyrrolidone ions were used as the positive reagent ion, which selectively detects ammonia and low-molecular weight-aliphatic amines and amides vaporized from the particle phase. With superoxide as the negative reagent ion, a wide range of inorganic and organic compounds were observed, including nitrate, sulfate, aliphatic acids with carbon numbers up to 18, and highly oxygenated CHO, CHON, and CHOS compounds. The latter two can be attributed to parent ions or the decomposition products of organonitrates and organosulfates/organosulfonates, respectively. Components from both primary emissions and secondary formation of UFPs were identified. Compared to the UFPs measured at forest and marine sites, those in urban Beijing contain more nitrogen-containing and sulfur-containing compounds. These observations illustrate unique features of the UFPs in the urban environment and provide insights into their origins.
The city of London, UK, has seen in recent years an increase in the number of high-rise/multi-storey buildings (“skyscrapers”) with roof heights reaching 150 m and more, with the Shard being a prime ...example with a height of ∼310 m. This changing cityscape together with recent plans of local authorities of introducing Combined Heat and Power Plant (CHP) led to a detailed study in which CFD and wind tunnel studies were carried out to assess the effect of such high-rise buildings on the dispersion of air pollution in their vicinity. A new, open-source simulator, FLUIDITY, which incorporates the Large Eddy Simulation (LES) method, was implemented; the simulated results were subsequently validated against experimental measurements from the EnFlo wind tunnel. The novelty of the LES methodology within FLUIDITY is based on the combination of an adaptive, unstructured, mesh with an eddy-viscosity tensor (for the sub-grid scales) that is anisotropic. The simulated normalised mean concentrations results were compared to the corresponding wind tunnel measurements, showing for most detector locations good correlations, with differences ranging from 3% to 37%. The validation procedure was followed by the simulation of two further hypothetical scenarios, in which the heights of buildings surrounding the source building were increased. The results showed clearly how the high-rise buildings affected the surrounding air flows and dispersion patterns, with the generation of “dead-zones” and high-concentration “hotspots” in areas where these did not previously exist. The work clearly showed that complex CFD modelling can provide useful information to urban planners when changes to cityscapes are considered, so that design options can be tested against environmental quality criteria.
Display omitted
•Validation of novel LES model, using an adaptive, anisotropic eddy viscosity model.•Effect of tall buildings on velocity as well as pollution concentration fields is clearly seen.•Presence of tall buildings leads to pollution remaining locally within the building area.•Location and extend of newly-formed concentration hotspots depend on the height of the tall buildings surrounding the “source” building.
This study shows how the presence of tall buildings affects the dispersion of air pollutants within a small neighbourhood, and how concentration hotspots can be generated in areas which were previously pollution-free.
Aging in place can be a challenge for seniors living in cities, where the infrastructure and associated services are typically designed for the working population to enhance efficiency and ...productivity. Through surveying community-dwelling seniors, we ask these research questions: How is the neighborhood environment related to the physical and mental health of seniors living in Hong Kong, Singapore, and Tokyo? How can we make cities more age-friendly to encourage aging in place? To answer these research questions, both observational and questionnaire surveys are used. Characteristics of the local neighborhood are captured by individual-based and general local characteristics. Multilevel analysis is used to disentangle the effects of factors operating at different spatial scales. A total of 687 seniors aged sixty-five and older living in Hong Kong, Singapore, and Tokyo in eleven residential neighborhood districts were recruited through local senior community centers. Based on the final models, 17.53 percent and 8.24 percent of the variance in the physical and mental health scores is across general neighborhoods, respectively, and the remaining is at the individual level, including individual-based neighborhood factors. Biological factors are not the most important. Instead, having a normal range of weight and the proper use of a walking aid can allow seniors, even of the oldest-old group of eighty-five and older, to be more active. Policy-wise, neighborhood factors should be carefully planned to promote seniors' health directly through enhancing walkability and fostering supportive peer groups and indirectly through encouraging a more active lifestyle. Promoting a walkable urban environment should be a priority area for supporting aging in place in cities.
The comfort of the urban environment is one of the key factors influencing the quality of life for the population. A particular focus is placed on examining small towns (with a population of up to ...50,000 people) from the perspective of their suitability for local community living. In order to comprehensively study the issue of a comfortable urban environment in the Russian provinces, the dynamics of the urban environment quality index in a number of cities in the Vologda Region were analysed, and survey materials from local residents (n = 1400) were also utilised. It is argued that sociological diagnostics complements and reveals statistical information on problem areas in urban development, allowing for the development of a unified approach to overcoming these issues, taking into account the opinions of the residents themselves. The study concluded that over the past five years, the development of small towns in the region has shown a positive trend, with an increase in the urban environment quality index being observed. However, based on the data for 2022, only 4 out of 13 small towns (Veliky Ustyug, Kharovsk, Totma, Sokol) can be considered as having a favourable urban environment. According to statistical data, the most problematic areas of the urban environment in small areas are social and recreational infrastructure and public business infrastructure. According to the opinions of residents, the quality of medical and educational services and housing availability are also significant issues. More positively, the environmental situation is evaluated in cities (as indicated by the index indicators and local residents’ judgments), as well as the level of safety and crime rates. Despite the presence of problematic areas in the development of small towns and their lag in terms of living comfort, the overall attitude of the local community toward theirplace of residence is positive, with a willingness to take responsibility for the city’s development. The results obtained serve as a basis for the policy of preserving and developing small areas, addressing social contradictions, and establishing promising directions for creating a comfortable living environment in these areas, taking into account the opinions and participation of the local community in these processes.
The problem considered in the article is the systematic lack of data on the objects of the urban environment for management and decision-making. This problem is particularly acute in the lack of data ...on points of attraction, informal and thematic places of interest. At the same time, this kind of information is necessary for the qualitative development of the urban environment. This article discusses an approach to creating new information resources based on the analysis of publications and messages of citizens, which can be used to effectively manage the development of the city and improve the quality of the urban environment. For example, to create new centers of attraction for citizens and tourists and effective landscaping. Currently, there is a public demand for the semantic content of the urban environment, considering historical and cultural associations, informal symbols. Traditionally, this request is met through surveys of the population in urban improvement projects. This article presents an approach to supplementing such surveys with information from Internet social networks processed by natural language analysis methods to extract hidden topics and thematic objects of the urban environment. The approach is demonstrated based on the example of the city of St. Petersburg in the Russian Federation
Long‐term landslide deformation is disruptive and costly in urbanized environments. We rely on TerraSAR‐X satellite images (2009–2014) and an improved data processing algorithm (SqueeSAR™) to produce ...an exceptionally dense Interferometric Synthetic Aperture Radar ground deformation time series for the San Francisco East Bay Hills. Independent and principal component analyses of the time series reveal four distinct spatial and temporal surface deformation patterns in the area around Blakemont landslide, which we relate to different geomechanical processes. Two components of time‐dependent landslide deformation isolate continuous motion and motion driven by precipitation‐modulated pore pressure changes controlled by annual seasonal cycles and multiyear drought conditions. Two components capturing more widespread seasonal deformation separate precipitation‐modulated soil swelling from annual cycles that may be related to groundwater level changes and thermal expansion of buildings. High‐resolution characterization of landslide response to precipitation is a first step toward improved hazard forecasting.
Plain Language Summary
In an ever‐expanding urban environment, we opt to live with the risk of catastrophic natural hazards through a perceived safety net of building codes and engineering solutions. Unfortunately, our concern for these hazards is often focused on their immediate impact to our everyday lives and does not account for imperceptible processes that may become significant over decades in time. Notoriously, some landslides slowly and continuously deform, ultimately causing costly unpredicted damage to homes, lifelines, and other infrastructure. Recent advances in satellite technology allow us to accurately measure these long‐term movements, tracking where and when they occur. We show that the duration and amount of seasonal precipitation and associated water pressure changes determine how fast the landslides move and how recent drought conditions have slowed their advance. The satellite data allow us to differentiate the landslide deformation from normal seasonal changes in unaffected areas, giving us greater predictability of this hazard.
Key Points
Independent component analysis of radar interferometry time series reveals four spatiotemporal deformation patterns on and off landslides
Seasonal and drought‐related pore pressure changes modulate landslide deformation
Precipitation also produces widespread soil shrink/swell and groundwater‐related surface deformation
PDF
