Search Results (13)

Urban morphology, including land surface, building heights, vegetation, water bodies, and terrain, exerts a significant influence on the urban thermal environment. The complex and nonlinear pathways through which these factors exert influence present significant challenges in urban climate studies. However, existing studies of statistical approaches to the urban thermal environment have primarily focused on linear relationships, often overlooking the complex and nonlinear effects of these factors. Additionally, previous research on those approaches has not adequately addressed the seasonal and diurnal variations in land surface temperature, nor has it examined the extent to which urban morphology influences these variations. While simulation-based approaches can address these nonlinearities and temporal variations, they require large parameter sets and extensive high-resolution input data, making them computationally demanding. This gap limits the ability to develop targeted and effective urban heat mitigation strategies. Recent advancements in remote sensing technologies have revolutionized our ability to analyze these complexities using medium-resolution data products. In this study, we apply a polynomial regression model with an elastic net to represent the impact of terrain and urban morphological factors on the urban thermal environment, considering its seasonal and diurnal variations, taking the case of the Osaka Metropolitan Area. This approach is unique in terms of capturing the nonlinearity of the impacts based on earth observation data by remote sensing and efficiently captures complex relationships while maintaining interpretability and reducing computational overhead. The study leverages MODIS Terra thermal infrared data from 2018, supplemented by Sentinel-2 and Copernicus Land Cover data. The results reveal significant seasonal and diurnal variations in the thermal environment, indicating that building height influences LST non-monotonically, with daytime cooling effects in dense urban areas (0.12 to 0.19 °C decrease) but nighttime heat retention in suburban zones (0.06 to 0.13 °C increase). Similarly, vegetation coverage reduces nighttime LST more effectively, particularly beyond a critical density threshold (NDVI > 0.4). These findings suggest that by optimizing urban design by considering building height effects, strategic design of vegetation coverage can help mitigate heat/cold stress and improve thermal comfort throughout seasons. These findings contribute to sustainable urban development and heat mitigation efforts by providing data-driven insights into urban morphology’s impact on the thermal environment. Full article

The Hokuriku Shinkansen is among the five main Shinkansen lines in Japan. It starts from the capital, Tokyo, and passes through the Hokuriku region (Nagano City, Toyama City, and Kanazawa City) before reaching the Kansai region (Kyoto City and Osaka City). In Japan, the Hokuriku Shinkansen is being developed to increase the number of visitors in the area by shortening travel times and ensuring transportation networks in the event of a disaster; the Kanazawa–Tsuruga extension was opened on Saturday, 16 March 2024. The shortened travel times with this opening are expected to increase the number of visitors to the Hokuriku region and other regions, such as the Tokyo metropolitan area. The Tsuruga extension opening will connect the Hokuriku region with the Tokyo metropolitan area through direct service; however, travel between the Kansai and Chukyo regions will require transfers at Tsuruga Station, which would reduce convenience. Consequently, the flow of people in the Hokuriku region is expected to change significantly after spring 2024. Therefore, this study conducted a questionnaire survey of Kanazawa residents in Ishikawa Prefecture prior to the opening of the Tsuruga extension to analyze its effect on the choice of modes of transportation for travel to the Kansai region. The Hokuriku Shinkansen was found to be the most popular route for travel to the Kansai region after the opening of the Tsuruga extension, and the Hokuriku Shinkansen users prioritized comfort during travel and shorter travel times. Moreover, a high proportion of Hokuriku Shinkansen users were unemployed and received pensions, whereas a high proportion of private automobile users were students, housewives, or other people with no income. Full article

This study analyzes the differences and similarities between Tier 1 (Tokyo) and Tier 2 (Kansai) metropolitan areas due to shrinking city problems. Both metropolitan areas will see a dramatic decrease in the housing asset value (HAV). Kansai is declining at a faster pace than Tokyo: it is projected that HAVs will register a further decrease of around 38% by 2045, and the decline will be quantitatively more important in the northern suburbs of Osaka. These results raised the question of whether Kansai would be more impoverished by HAV deflation. By focusing on the income multiplier of HAV per household, we find that Tokyo has a higher income multiplier of around 4 (against 2 for Osaka), thus causing much greater HAV deflation per household in Tokyo. Greater HAV deflation per household entails more severe problems for elderly households that need to finance their retirement. Considering our findings, despite earlier and faster trends of HAV deflation in the Tier 2 metropolitan area, the Tier 1 metropolitan area could face big socioeconomic challenges in the future. We conclude that HAV deflation leads to problems of different nature depending on metropolitan rank, rather than just knowing which one is losing more through HAV deflation. Full article

This study aims to clarify the impact of the urban exodus triggered by the COVID-19 pandemic on shrinking cities in the Osaka metropolitan area, where a declining population is caused by population aging. Analyzing the Osaka metropolitan area enables us to clarify how cities are shrinking due to the urban exodus. This study analyzed the monthly population data of three types of municipalities: ordinance-designed/regional hub cities, ordinary cities, and towns/villages. In conclusion, the study clarified that population change due to the urban exodus occurred in the ordinance-designed/regional hub and ordinary cities from summer to autumn 2020. The most significant population increases occurred in the municipalities in the Osaka metropolitan fringe area, which are located more than 30 km away from the center of the Osaka metropolitan area. The conclusion is important because the population increased not only in the ordinance-designed cities but also in the ordinance-designed/regional hub cities, unlike the rest of the metropolitan area. The result is the new insights unique to the Osaka metropolitan area that this study clarified. The urban exodus contributes to the need for the local governments of shrinking cities to maintain the urban services necessary for people’s daily lives. Full article

In Japan, where the population is declining and aging significantly, walkability has attracted attention as a way to improve residents’ lifestyles. Therefore, it is essential to identify the residential clusters where walkability improvement would contribute to the maintenance of the population in order to select urban areas for the implementation of walkable designs. This study aimed to identify the residential clusters in which walkability affects the future population from the perspective of real estate prices. The reason for focusing on real estate prices is that they are expected to be a confounding factor connecting walkability and the future population. The method we used was to analyze the structural equation modeling of the impact of walkability index, real estate prices, and future population change ratio. This analysis was based on the neighborhood association scale. This study clarified that effective residential clusters are the business center cluster and the sprawl cluster. In the business center cluster and the sprawl cluster, the price of apartments for sale is the real estate value, through which the walkability index positively impacts the future population change ratio. This means that it is expected to contribute to the maintenance of the future population through a combination of walkable designs and housing policies that encourage people to change their residence types to apartments for sale when rebuilding old building stock using the location optimization plan policy. Full article

This study aims to clarify the impact of the COVID-19 pandemic on home range. The home range is the area that individuals traverse in conducting their daily activities, such as working and shopping. In Japan, the central government declared the first state of emergency in April 2020. This study analyzed the panel data for mobile phone GPS location history from April 2019 to April 2020 in Ibaraki City, Osaka Metropolitan area. The study applied the minimum convex polygon method to analyze the data. The results show that the home range decreased significantly between April 2019 and April 2020. Specifically, the home range in 2020 decreased to approximately 50% of that in 2019 because of COVID-19 infection control measures, preventing people from traveling far from their homes and only allowing them to step outside for the bare minimum of daily activities and necessities. The results suggest that the emergency reduced people’s home ranges to the neighborhood scale. Therefore, it is necessary to consider designing new walkable neighborhood environments after the COVID-19 pandemic era. Full article

The purpose of this study was to identify the walkable streets where traffic behavior changed according to each residential cluster during the COVID-19 pandemic. By elucidating the changes, it is possible to identify streets that should be redesigned following the changes in traffic behavior in relation to human mobility. This study analyzed Ibaraki City, a suburban city located in the Osaka Metropolitan Area. The analysis compared the panel data of the GPS Location History for April 2020 and April 2019. The analysis method used was Empirical Bayesian kriging. The results show that the speed significantly increased in the dense, sprawl, mountain, and old NT clusters. It was also found that the number of cyclists increased during the COVID-19 pandemic. The results suggest a need to design walkable streets according to each residential cluster for the post-COVID-19 pandemic era. For example, some car lanes need to be converted to bike lanes in the main neighborhood to create walkable streets in the clusters. Full article

This study aims to clarify the statistical causal relationship between the locations of urban facilities and forecasted population changes according to types of residential clusters in the Osaka Metropolitan Fringe areas. This paper’s background is the location optimization plan policy formulated by the Japanese MLIT (Ministry of Land, Infrastructure, Transport, and Tourism) in 2015. The methods combined urban ecological analysis, cohort analysis, and Bayesian network analysis. Using the Bayesian network analysis, the causal relationship between the forecasted population change ratio and the urban facility location was analyzed. The results suggest the location of urban facilities for each residential cluster that will prevent a rapid population decline in the future. Specifically, in the sprawl cluster, this study found that residential areas closer to medical facilities will sustain the future population, while in the old new-town cluster, this study found that residential areas closer to train stations will best sustain the future population. However, in the public housing cluster, residential areas more distant from regional resources will best sustain the future population. Therefore, it is worth considering different urban designs in the old new-town and public housing clusters, rather than the location optimization plan policy. Full article

This study aimed to clarify the effect of walkability on urban sustainability, according to the types of residential clusters in the Osaka Metropolitan fringe area. For this purpose, this study analyzed the statistical causal relationship between the Walkability Index and the Ecological Footprint to Biocapacity (EF/BC) ratio of each residential cluster. The EF/BC ratio is the ratio of the ecological footprint of the biocapacity of the residential clusters. As a result, the effect of walkability on urban sustainability was clarified depending upon the types of residential clusters in the Osaka Metropolitan fringe area. Specifically, it was found that the Walkability Index negatively affects the EF/BC ratio in the sprawl cluster. This suggests that, in the sprawl cluster, active efforts to improve the Walkability Index can contribute to the realization of SDGs (Sustainable Development Goals of the 2030 Agenda). However, Walkability Index has a strong positive effect on the EF/BC ratio in the old new-town cluster, etc. For the residential clusters, the results of this study suggested that there is a necessity to improve urban sustainability through approaches other than improving Walkability. Full article

Peri-urban agriculture (PUA) has been widely regarded as a sub-field of multifunctional agriculture for improving the sustainability of urban environments. However, urban sprawl has both negative and positive effects on peri-urban farming, and the research on this issue in Japan is insufficient. This study aims to demonstrate the spatial distribution of farmland parcels in Tokyo and Osaka metropolitan areas and explore the synergistic effect of distance from cities and urban sprawl on the size of farmland parcels and farm-diversified activities such as direct marketing, farming experience, and environmentally friendly practices. Ordinary Least Squares (OLS) and Poisson regression analyses were used with a nationwide agricultural land parcel Geographic Information System (GIS) database (Tokyo metropolitan area = 1,939,162 and Osaka metropolitan area = 1,507,072 parcels), in Japan, to specify the farmland locations and calculate the extent of urban sprawl. The results revealed that more than 50% of farmlands in the targeted areas were located within 4 km from the boundaries of densely inhabited districts (DIDs). Furthermore, with a decreasing distance from a DID, the urban sprawl had more positive effects on farmland parcel sizes and farm-diversified activities. These findings imply that PUA has a wider presence in Japan, and the peri-urban farmers may be capable of utilizing the multifunctional nature of intensively sprawled urban environments. Full article

Plastic debris presents a serious hazard to marine ecosystems worldwide. In this study, we developed a method to evaluate high-resolution maps of plastic emissions from the land into the sea offshore of Japan without using mismanaged plastic waste. Plastics were divided into microplastics (MicPs) and macroplastics (MacPs), and correlations between the observed MicP concentrations in rivers and basin characteristics, such as the urban area ratio and population density, were used to evaluate nationwide MicP concentration maps. A simple water balance analysis was used to calculate the annual outflow for each 1 km mesh to obtain the final MicP emissions, and the MacP input was evaluated based on the MicP emissions and the ratio of MacP/MicP obtained according to previous studies. Concentration data revealed that the MicP concentrations and basin characteristics were significantly and positively correlated. Water balance analyses demonstrated that our methods performed well for evaluating the annual flow rate, while reducing the computational load. The total plastic input (MicP + MacP) was widely distributed from 210–4776 t/yr and a map showed that plastic emissions were high for densely populated and highly urbanized areas in the Tokyo metropolitan area, as well as other large urban areas, especially Nagoya and Osaka. These results provide important insights that may be used to develop countermeasures against plastic pollution and the methods employed herein can also be used to evaluate plastic emissions in other regions. Full article

The Japanese city presents a certain number of peculiarities in the organization of its physical space (weak zoning regulations, fast piecemeal destruction/reconstruction of buildings and blocks, high compacity, incremental reorganization). Compared to countries where urban fabrics are more perennial and easily distinguishable (old centers, modern planned projects, residential areas, etc.), in Japanese metropolitan areas we often observe higher heterogeneity and more complex spatial patterns. Even within such a model, it should be possible to recognize the internal organization of the physical city. The aim of this paper is thus to study the spatial structure of the contemporary Japanese city, generalizing on the case study of Osaka and Kobe. In order to achieve this goal, we will need to identify urban forms at different local scales (building types, urban fabrics) and to analyze them at a wider scale to delineate morphological regions and their structuring of the overall layout of the contemporary Japanese city. Several analytical protocols are used together with field observations and literature. The results, and more particularly the building and urban fabric types and their location within the Osaka-Kobe metropolitan area, are interpreted in the light of Japanese history and model of urbanization. A synoptic graphical model of an urban morphological structure based upon Osaka is produced and proposed as an interpretative pattern for the Japanese metropolitan city in general. Full article

Active travel can contribute to physical activity achieved over a day. Previous studies have examined active travel associated with trips in various western countries, but few studies have examined this question for the Asian context. Japan has high levels of cycling, walking and public transport, similar to The Netherlands. Most studies have focused either on children or on adults separately, however, having children in a household will change the travel needs and wants of that household. Thus, here a household lifecycle stage approach is applied. Further, unlike many previous studies, the active travel related to public transport is included. Lastly, further to examining whether the built environment has an influence on the accumulation of active travel minutes, a binary logistic regression examines the built environment’s influence on the World Health Organization’s recommendations of physical activity. The findings suggest that there is a clear distinction between the urbanized centers and the surrounding towns and unurbanized areas. Further, active travel related to public transport trips is larger than pure walking trips. Females and children are more likely to achieve the WHO recommendations. Finally, car ownership is a strong negative influence. Full article