Mountain City Research Articles

Design of Special-shaped Interchange between Expressway and Urban Road in Mountainous Cities

Driven by the rapid economic development, the development of transportation in China has begun to move towards mountainous areas. The climate environment, topography and landform of mountainous cities are different from those of plain areas. In mountainous cities, the area of opposite interchanges between expressways and urban roads is generally large, which has a certain contradiction with the topographic conditions of mountainous cities. Therefore, it is necessary to reasonably design the opposite interchanges between expressways and urban roads in mountainous cities. The author explores and analyzes the factors restricting the special-shaped interchange between expressway and urban road in mountainous cities and the main forms of special-shaped interchange, and puts forward a reasonable design scheme, hoping to make a smooth development of the special-shaped interchange in mountainous cities.

Combining Satellite Data and Spatial Analysis to Assess the UHI Amplitude and Structure within Urban Areas: The Case of Moroccan Cities

Landsat-8 surface temperature and the European Space Agency land cover are used to assess the impact of land cover on the Urban Heat Island (UHI) and Urban Heat Sink (UHS). We analyzed five Moroccan cities selected for their different local climate, size, and typology during summer at three different spatial scales. The results show multiple causes defining the different forms and amplitudes of the UHI, namely: the ambient climate, the proximity to the sea, the presence of landscaped areas, and the color of building roofs and walls. Contrary to what was expected, the vegetation was not systematically an island of coolness, either because of its typology or its irrigation status. In the coastal cities of Tangier and Casablanca, UHIs around 20 °C are observed on the seaside, whereas a UHS of up to 11 °C is observed between the city center and the southern periphery of Casablanca. A moderate amplitude UHI of 7 °C is formed in the mountainous city of Ifrane. For cities built in desert-like environments, well-defined UHSs between 9 °C and 12 °C are observed in Smara and Marrakech, respectively. At a finer scale, towns recorded lower temperatures than their immediate surroundings, which are attributed to evaporation from irrigated plants.

Observation of Surface Displacement Associated with Rapid Urbanization and Land Creation in Lanzhou, Loess Plateau of China with Sentinel-1 SAR Imagery

Lanzhou is one of the cities with the higher number of civil engineering projects for mountain excavation and city construction (MECC) on the China’s Loess Plateau. As a result, the city is suffering from severe surface displacement, which is posing an increasing threat to the safety of the buildings. However, up to date, there is no comprehensive and high-precision displacement map to characterize the spatiotemporal surface displacement patterns in the city of Lanzhou. In this study, satellite-based observations, including optical remote sensing and synthetic aperture radar (SAR) sensing, were jointly used to characterize the landscape and topography changes in Lanzhou between 1997 and 2020 and investigate the spatiotemporal patterns of the surface displacement associated with the large-scale MECC projects from 2015 December to March 2021. First, we retrieved the landscape changes in Lanzhou during the last 23 years using multi-temporal optical remote sensing images. Results illustrate that the landscape in local areas of Lanzhou has been dramatically changed as a result of the large-scale MECC projects and rapid urbanization. Then, we optimized the ordinary time series InSAR processing procedure by a “dynamic estimation of digital elevation model (DEM) errors” step added before displacement inversion to avoid the false displacement signals caused by DEM errors. The DEM errors and the high-precision surface displacement maps between December 2015 and March 2021 were calculated with 124 ascending and 122 descending Sentinel-1 SAR images. By combining estimated DEM errors and optical images, we detected and mapped historical MECC areas in the study area since 2000, retrieved the excavated and filling areas of the MECC projects, and evaluated their areas and volumes as well as the thickness of the filling loess. Results demonstrated that the area and volume of the excavated regions were basically equal to that of the filling regions, and the maximum thickness of the filling loess was greater than 90 m. Significant non-uniform surface displacements were observed in the filling regions of the MECC projects, with the maximum cumulative displacement lower than −40 cm. 2D displacement results revealed that surface displacement associated with the MECC project was dominated by settlements. From the correlation analysis between the displacement and the filling thickness, we found that the displacement magnitude was positively correlated with the thickness of the filling loess. This finding indicated that the compaction and consolidation process of the filling loess largely dominated the surface displacement. Our findings are of paramount importance for the urban planning and construction on the Loess Plateau region in which large-scale MECC projects are being developed.

Dual challenges of heat wave and protective facemask-induced thermal stress in Hong Kong

During the COVID-19 pandemic, wearing protective facemasks (PFMs) can effectively reduce infection risk, but the use of PFMs can amplify heat-related health risks. We studied the amplified PFM-induced human thermal stress via both field measurements and model simulations over a typical subtropical mountainous city, Hong Kong. First, a hot and humid PFM microenvironment has been observed with high temperature (34–35 °C) and high humidity (80–95%), resulting in an aggravated facial thermal stress with a maximal PFM-covered facial heat flux of 500 W/m2 under high-intensity activities. Second, to predict the overall PFM-inclusive human thermal stress, we developed a new facial thermal load model, SPFM and a new human-environment adaptive thermal stress (HEATS) model by coupling SPFM with an enhanced thermal comfort model to resolve modified human-environment interactions with the intervention of PFM under realistic climatic and topographical conditions. The model was then applied to predict spatiotemporal variations of PFM-inclusive physiological subjective temperature (PST) and corresponding heat stress levels during a typical heat wave event. It was found wearing PFM can significantly aggravate human thermal stress over Hong Kong with a spatially averaged PST increment of 5.0 °C and an additional spatial area of 158.4% exposed to the severest heat risks. Besides, PFM-inclusive PST was found to increase nonlinearly with terrain slopes at a rate of 1.3–3.9 °C/10°(slope), owing to elevated metabolic heat production. Furthermore, urban residents were found to have higher PFM-aggravated heat risks than rural residents, especially at night due to synergistic urban heat and moisture island effects.

Crosswind Stability of Metro Train on a High-Pier Viaduct under Spatial Gust Environment in Mountain City

To ensure the ride quality of metro system in mountain cities, the characteristics of the wind-train-bridge system with high-piers are studied, and the corresponding safety threshold is calculated in this paper. The improved spatial gust model considering the wind speed-up effect in mountainous terrain and spatial correlation is established. The time series of the wind loads are input to the dynamic system. The finite element method is used to model the bridge and the track, the multi-rigid-body system connected with the suspension spring and the damper is used to model each vehicle in the train. The whole process of the metro train running on the three-span high-pier viaduct is simulated. The study shows that both amplitude and frequency components of fluctuating wind have greater influence than the average wind, which can make the calculation result tend to be conservative and more conducive to analyze the vehicle running performance. Due to the comprehensive effect of the correlation of gust in spatial distribution, different vehicle parameters and aerodynamic coefficient differences, the response of each vehicle is different. The windward side of the high-pier bridge is the conservative calculation condition to evaluate the running performance. The wind barrier weakens the wind resistance of the bridge, but greatly improves the wind environment for the train. Metro train is less sensitive to increased wind speed with the wind barrier, but exceeds the limit under the same condition without any measures. When wind speed reaches 30 and 32 m/s, the ride comfort and running safety cannot be guaranteed respectively. The corresponding value for with single-side and bilateral barrier are 0.063 g and 0.061 g, decrease by 37% and 39% than that without barrier, and the value with two barriers are 0.216 and 0.211, decrease by 73% and 74%.

Improving awareness of energy conservation: Rocky Mountain City

Purpose The purpose of this research project was to improve public awareness to improve public awareness of the importance of energy conservation and to improve the use of simple conservation strategies. A thorough evaluation of the net gain from the numerous energy campaigns rolled out to the public every year is lacking. This study conducted pre- and post-campaign surveys and focus groups to evaluate one campaign’s impact on self-reported energy behaviors. Design/methodology/approach The campaign used television public service announcements and a website to improve awareness of the city’s efforts to conserve energy and to increase individual energy conservation practices. Focus groups (n = 40) were used to identify common barriers to conservation, and pre- and post-surveys (n = 533, 479) were conducted to evaluate the campaign’s effectiveness. Findings Results indicated that the campaign increased positive changes in changing light bulbs and confidence in taking action to turn down thermostats, unplug devices and turn off lights. While follow-up research is needed on the precise mechanism of the psychological process at work, the findings are consistent with the concepts of self and response efficacy as needed components of any behavior change. The authors advocate the adoption of research-informed message design to maximize communication campaign effects. Originality/value This paper demonstrates how the combination of three prominent persuasion theories can be used to develop behavior change campaigns. Also, it is one of the few studies to evaluate the effectiveness of the Energy Star campaign.

Optimization of Green Space Planning to Improve Ecosystem Services Efficiency: The Case of Chongqing Urban Areas.

This paper applied landscape indexes to evaluate the size, form, and structure of green spaces in the mountainous city of Chongqing and found that green spaces benefit from certain advantages in size, but the network suffered from low heterogeneity and limited interconnectivity. To ensure the integrity and continuity of ecological processes and improve the efficiency of ecosystem services (ES), the authors used Geographic Information System (GIS) software to conduct adaptability evaluation and adjacent buffer analysis for the existing green spaces, wetlands, rivers, and other landscapes with relatively high capacity for ES. We designed a comprehensive map of potential areas for UGS expansion by superimposing the maps obtained from adaptability evaluation and buffer analysis. We also proposed some strategies that respect, consider, and evaluate aspects and special features of urban environment to optimize green space planning and improve ES efficiency, such as protection of important areas, development of green corridors, and careful consideration of ecological processes and complex functions in urban areas. Based on these strategies, the paper put forth suggestions for green space planning to improve ES efficiency that can function as foundation for subsequent green space planning.

Subsidence Monitoring of Fill Area in Yan’an New District Based on Sentinel-1A Time Series Imagery

In recent years, many cities in the Chinese loess plateau (especially in Shanxi province) have encountered ground subsidence problems due to the construction of underground projects and the exploitation of underground resources. With the completion of the world’s largest geotechnical project, called “mountain excavation and city construction,” in a collapsible loess area, the Yan’an city also appeared to have uneven ground subsidence. To obtain the spatial distribution characteristics and the time-series evolution trend of the subsidence, we selected Yan’an New District (YAND) as the specific study area and presented an improved time-series InSAR (TS-InSAR) method for experimental research. Based on 89 Sentinel-1A images collected between December 2017 to December 2020, we conducted comprehensive research and analysis on the spatial and temporal evolution of surface subsidence in YAND. The monitoring results showed that the YAND is relatively stable in general, with deformation rates mainly in the range of −10 to 10 mm/yr. However, three significant subsidence funnels existed in the fill area, with a maximum subsidence rate of 100 mm/yr. From 2017 to 2020, the subsidence funnels enlarged, and their subsidence rates accelerated. Further analysis proved that the main factors induced the severe ground subsidence in the study area, including the compressibility and collapsibility of loess, rapid urban construction, geological environment change, traffic circulation load, and dynamic change of groundwater. The experimental results indicated that the improved TS-InSAR method is adaptive to monitoring uneven subsidence of deep loess area. Moreover, related data and information would provide reference to the large-scale ground deformation monitoring and in similar loess areas.

RETRACTED ARTICLE: Air dust pollution and online music teaching effect based on heterogeneous wireless network

This article first introduces management technology and handover technology in heterogeneous wireless networks and summarizes common network access selection strategies and algorithms. Aiming at the shortcomings of long switching delay in existing fuzzy logic network selection algorithms, a low-complexity fuzzy logic-based heterogeneous wireless network access selection algorithm is proposed. Therefore, this paper uses the WRF-Chem model of the Urban Forest Consortium to carry out a numerical simulation study on the air and dust pollution of mountain city L. Combining the single-layer urban forest model with the WRF-Chem model, this model has an improved simulation function after testing, which can simulate the air pollution process in the L city center and analyze the factors of the urban canopy on the distribution of atmospheric dust pollutants and influences. Finally, we have conducted a comprehensive research on the educational effects of online music education. With the rapid development of Internet communication technology, online education has gradually become popular with the public. As a part of it, online music teaching has also been rapidly developed and promoted. It breaks the time and space limitations of traditional music education and is changing the way and concept of music learners. This article summarizes the background and development of online music teaching, analyzes the advantages and limitations of online music teaching, and briefly introduces future development trends. This paper applies the research results of air dust pollution based on different wireless networks to the research on the effect of online music education, which has successfully promoted the development of online music education.

Forest Transition and Its Dynamics in Subtropical Chongqing, China since 1990s

This research aims to advance our understanding towards forest transition, which is about the shift from net deforestation to net reforestation over a given area during certain period, through a case study of a western city in China from 1990 to 2015. Three main contributions are made to the theory and practice of forest land management. First, this research enriches forest transition theory with a meso-level exploration on forest land change in subtropic Chongqing, which echoes the “U” shape transition rules widely observed in the Euro-American context but was found a time lag of the turning point until 2000s. Second, it intentionally identifies the subtype of forests—the artificial plantation, which is considered influential on performance of forest’s carbon sequestration but not paid sufficient attention to. Third, it adds knowledge on forest transition pathway at an intra-urban scale through the identified significance degree of forest transition dynamics, which implies that economic development matters but is less important than topography in a mountainous city like Chongqing, and different dimensions of economy impact differently on forest transition.

Time Series InSAR Monitoring and Analysis of Spatiotemporal Evolution Characteristics of Land Subsidence in Yan'an New District

Objectives Yan'an New District has attracted much attention because of its large-scale mountain excavation and city construction project. Such mega-scale land creation, rapid urban construction and complex geological conditions has induced wide land subsidence in the region. Methods In this paper, the temporal and spatial evolution of land subsidence in Yan'an New District was assessed using small baseline subset synthetic aperture radar interferometry (SBAS-InSAR) to process the Sentinel-1A images covering the period from May 2016 to October 2019. Then, the mechanism and evolution trend of land subsidence in the new district was analyzed. Results Experimental results suggest that the spatial evolution pattern of land subsidence in Yan'an New District is highly relevant with the process of land creation project. The land subsidence area in the new district gradually expanded from the major urban area to the area of forest along with the land creation project, and its area decreased gradually with the passing of time. The temporal deformation evolution of land subsidence in the new district is related to the thickness of the fill, and all exhibit non-linear subsidence with various velocities. The temporal evolution of land subsidence undergoes three processes of rapid-slow-steady. The greater the thickness of the fill, the larger the amount of sedimentation, the longer it takes for the sedimentation to stabilize. Conclusions The main internal mechanism of land subsidence is the consolidation and compression deformation of the loess fill, which can be divided into three stages: Instantaneous settlement, consolidation settlement, and secondary consolidation settlement. Based on the characteristics of different stages combined with time series deformation, the land subsidence process and development trend can be analyzed. The research results provide a scientific reference for further monitoring and early warning, urban planning, and prevention and control of subsidence disasters in the new district.

Urbanization, Touristification and Verticality in the Andes: A Profile of Huaraz, Peru

Mountain cities specializing in tourism increasingly aim at valorizing cultural and natural heritage to compete for global attention. In this context, the postmodern urbanization of mountains plays a decisive role: driven by touristification processes, it alters the sociospatial and economic configuration of mountain cities and their hinterlands, which are becoming vertically arranged “operational landscapes”, and profoundly changes city–mountain interactions. To foster sustainable development in urbanizing mountain destinations, it is crucial to understand these settlements’ embeddedness in both (1) nature and culture and (2) space and time. The Andean city of Huaraz is a case in point: an intermediate center in highland Peru, it is characterized by a strategic location in the Callejón de Huaylas (Santa Valley), influenced by Hispanic and Quechua culture and dominated by the glaciers of the Cordillera Blanca. Combining (1) a theoretical framework that considers planetary urbanization, touristification and vertical complementarity and (2) a case study technique inspired by urban environmental profiles, we trace the development of the city–mountain relation in Huaraz, focusing on the way in which the material and non-material dimensions of the surrounding mountains influence urban development. We conclude with a call for overcoming a set of three persisting dichotomies that continue to impair sustainable development.

Urban growth drives trait composition of urban spontaneous plant communities in a mountainous city in China

Urban ecosystems feature intense anthropogenic activities and environmental stressors that filter species with varying life-history traits. The traits therefore provide an essential aspect to understanding how species respond to urban environments. We conducted this study in Chongqing, a mountainous city in southwestern China, and tested the hypothesis that the velocity of urban growth can alter functional compositions of urban plant communities through selection on species’ taxonomic distributions and functional traits. We found that for most traits, their values spanned a wide range across the 70 spontaneous species in this study, and seed size and leaf element composition played a key role in contributing to the functional differentiation among species. At the same time, urban growth intensity was negatively correlated with leaf N concentration, the N:P ratio, and specific leaf area (SLA), and positively correlated with the leaf C:N ratio. This suggests that species in urban centers are associated with an acquisitive nutrient-use strategy and may gain strong competitive strategies to be favored by greater selective pressure in those long-term urban centers. Lastly, we show that urbanization as a strong filter tends to reduce the chance of species with unique traits for the spontaneous plant communities. Our study offers insights into mechanisms through which spontaneous plant communities are filtered by urbanization with a special focus on the ecological consequences of the velocity of urban growth.

Noise exposure of the residential areas close to urban expressways in a high-rise mountainous city

Urban expressways can generate excessive noise in the surrounding urban areas, and it tends to be more complex in mountainous cities, due to the undulating terrain, dense population and compact urban structures. This article aims to investigate the objective acoustic environment and road traffic noise exposure, including the noisy evaluation, annoyance and effect of roadside apartments in residential areas close to urban expressways in the high-density, high-rise, mountainous city of Chongqing. Three housing estates were selected for a series of field measurements, questionnaire surveys and noise mapping. There was a significant negative correlation between night-time noise levels and the distances to the urban expressway ( p < 0.01). Moreover, the differences between the daytime and night-time noise levels were generally insignificant (0.7 to 3.6 dBA) at the roadside locations. Differences in reaction to noise exposure in a variety of both person-related and housing condition variables were found, especially between roadside and non-roadside locations or residents. In addition, 75.0% of roadside residents identified the traffic noise as ‘very’ or ‘extremely’ annoying, and 66.7% of them regarded the acoustic environment as the priority environmental factor that needs to be improved. Difference in the ‘bedroom-window orientation’ had a significant effect on subjective noise evaluation. Rectangular-shaped apartments along the roadside obtain better noise reduction capacities than tower-blocks through the simulation. The acoustic performance of road cuttings, as an appropriately designed earth embankment, is improved along with deeper vertical alignment, and slope angles of 30° and 75° should be avoided.

Study on Mountain City Landscape Gradient Characteristics and Urban Construction Coupling: Taking the Yangtze River to the Eastern Ridge Line of Nan Mountain in Chongqing as an Example

China has a vast area of mountains that are of great research interest. Chongqing is a typical mountain city in China. In urban construction, a mountain is not only an important limiting condition for urban development, but also an important condition for shaping the urban form. The area from the Yangtze River to the eastern ridge line of Nan Mountain in Nanan District is strongly representative of mountain cities with a complex landform, fragile ecological environment and a long history and culture. In recent years, the construction and optimization of this area are increasingly closely related to the landscape environment. However, due to the special environments of mountain cities, altitude and landform conditions become the key influencing conditions for further development of the cities. Therefore, this paper takes this region as an example, focuses on remote sensing and field measurement data, combines government data with that from scholarly research, and conducts relevant exploration through GIS, ENVI and some chart processing software. At first, from the perspective of the landscape gradient and urban construction, the characteristics of the urban landscape gradient are sorted out, and the developmental status of each urban area is analyzed. Then, the coupling relationships between the landscape features of each gradient and each urban area are analyzed. Finally, based on the analysis results, three major optimization measures are proposed to maintain ecological harmony in the mountainous area, reconstruct the mountain characteristic culture, and create unique mountain aesthetics, all with the hope of providing some guidance for the future development of the study area and similar mountain cities.

Flooding Risk Assessment and Analysis Based on GIS and the TFN-AHP Method: A Case Study of Chongqing, China

Flood risk assessment and mapping is required for management and mitigation of flood in mountain cities. However, the specific characteristics of population, society, economy, environment, transportation and other disaster-bearing bodies in various regions of mountain cities are significantly different, which increases the uncertainty of risk assessment index weight and risk assessment accuracy. To overcome these problems, the triangular fuzzy number-based analytical hierarchy process (TFN-AHP) was employed to determine the weights of eleven indexes influencing flooding. Further, the geographic information system (GIS) spatial statistics technique was introduced to investigate global regional risk pattern, as well as to identify local risk hot spots. Experiments were conducted using open data of Chongqing, China. From the results, it was observed that the TFN-AHP has a higher efficiency in flood risk assessment on mountain cities than the AHP method. The dynamically changing risk pattern and risk hot spots were explored, and the results are generally consistent with seasonal characteristics of precipitation. Lastly, sensitivity analysis of assessment factors’ weights was conducted. The comparative consequences indicate that TFN-AHP can better assess the flooding risk and can be successfully applied to urban development policy.

Mass Concentration, Chemical Composition, and Source Characteristics of PM2.5 in a Plateau Slope City in Southwest China

In order to investigate the seasonal variations in the chemical characteristics of PM2.5 at the plateau slope of a mountain city in southwest China, 178 PM2.5 filters (89 quartz and 89 Teflon samples for PM2.5) were collected to sample the urban air of Wenshan in spring and autumn 2016 at three sites. The mass concentrations, water-soluble inorganic ions, organic and inorganic carbon concentrations, and inorganic elements constituting PM2.5 were determined, principal component analysis was used to identify potential sources of PM2.5, and the backward trajectory model was used to calculate the contribution of the long-distance transmission of air particles to the Wenshan area. The average concentration of PM2.5 in spring and autumn was 44.85 ± 10.99 μg/m3. Secondary inorganic aerosols contributed 21.82% and 16.50% of the total PM2.5 in spring and autumn, respectively. The daily mean value of OC/EC indicated that the measured SOC content was generated by the photochemical processes active during the sampling days. However, elements from anthropogenic sources (Ti, Si, Ca, Fe, Al, K, Mg, Na, Sb, Zn, P, Pb, Mn, As and Cu) accounted for 99.38% and 99.24% of the total inorganic elements in spring and autumn, respectively. Finally, source apportionment showed that SIA, dust, industry, biomass burning, motor vehicle emissions and copper smelting emissions constituted the major components in Wenshan. This study is the first to investigate the chemical characterizations and sources of PM2.5 in Wenshan, and it provides effective support for local governments formulating air pollution control policies.

Analysis on the change of Yubei District construction land in Chongqing

With the development of economy, countries all over the world are experiencing urbanization at different speeds. As the largest developing country in the world, China is experiencing long-term and sustained rapid economic growth and large-scale urbanization. Chongqing, China is a municipality directly under the Central Government of the People’s Republic of China. It is also a world-famous mountainous city and a comprehensive industrial city. As the main urban area of Chongqing, the population and land use scale are rapidly expanding, and the urban infrastructure construction is further promoted. This paper analyzes the land use change of Yubei District in recent 20 years, which is of great significance to guide the urban planning scientifically and rationally, control the scale of urban land use, and protect the limited arable land resources and ecological environment..

Hotspot Detection and Spatiotemporal Evolution of Catering Service Grade in Mountainous Cities from the Perspective of Geo-Information Tupu

Catering services are an essential part of urban life. The spatial structure and evolution of catering services can reflect the characteristics of an urban structure to a certain extent. In this study, we selected the main urban area of Chongqing, a typical mountainous city, as the research area. According to data sources for 200,000 catering POI data points in 2015 and 2020, we extracted the hotspots according to catering service grade based on kernel density. We quantitatively analyzed the spatiotemporal structure of catering services in the mountainous city. In addition, we used digital field hierarchical structure Tupu and generalized symmetric structure Tupu to identify the spatial morphology and evolution characteristics to enhance the understanding of geoscience trends. The results showed that (1) the distribution of catering services was statically consistent with the “multi-center group” distribution of the mountainous city and dynamically similar to the “sprawling leap” development of the mountainous city where it developed from independent points to cross mountains and rivers. Moreover, we found that there was a tendency of adhering development between groups. (2) From the perspective of symmetrical distribution, the symmetrical distribution of the catering industry reflected a certain generalized symmetrical structure with mountains and rivers in the mountainous city. Furthermore, the city tended to develop symmetrically along the topography, thus forming the symmetry of economic geography.

Analysis on Landscape Planning of Mountain City

Analysis on Landscape Planning of Mountain City