Search Results (216)

This study examines diurnal surface temperature dynamics across major Moroccan cities during the growing season and explores the interaction between urban and vegetated surfaces. We also introduce the Urban Thermal Impact Ratio (UTIR), a novel metric designed to quantify urban thermal comfort as a function of the surface urban heat island (SUHI) intensity. The analysis is based on outputs from a land surface model (LSM) for the year 2010, integrating high-resolution Landsat and MODIS data to characterize land cover and biophysical parameters across twelve land cover types. Our findings reveal moderate urban–vegetation temperature differences in coastal cities like Tangier (1.8 °C) and Rabat (1.0 °C), where winter vegetation remains active. In inland areas, urban morphology plays a more dominant role: Fes, with a 20% impervious surface area (ISA), exhibits a smaller SUHI than Meknes (5% ISA), due to higher urban heating in the latter. The Atlantic desert city of Dakhla shows a distinct pattern, with a nighttime SUHI of 2.1 °C and a daytime urban cooling of −0.7 °C, driven by irrigated parks and lawns enhancing evapotranspiration and shading. At the regional scale, summer UTIR values remain below one in Tangier-Tetouan-Al Hoceima, Rabat-Sale-Kenitra, and Casablanca-Settat, suggesting that urban conditions generally stay within thermal comfort thresholds. In contrast, higher UTIR values in Marrakech-Safi, Beni Mellal-Khénifra, and Guelmim-Oued Noun indicate elevated heat discomfort. At the city scale, the UTIR in Tangier, Rabat, and Casablanca demonstrates a clear diurnal pattern: it emerges around 11:00 a.m., peaks at 1:00 p.m., and fades by 3:00 p.m. This study highlights the critical role of vegetation in regulating urban surface temperatures and modulating urban–rural thermal contrasts. The UTIR provides a practical, scalable indicator of urban heat stress, particularly valuable in data-scarce settings. These findings carry significant implications for climate-resilient urban planning, optimized energy use, and the design of public health early warning systems in the context of climate change. Full article

With increasing global challenges related to water scarcity and phosphorus depletion, the recovery and reuse of wastewater-derived nutrients offer a sustainable path forward. This study evaluates the dual role of lanthanides (Ce³⁺ and La³⁺) in recovering phosphorus from municipal wastewater and supporting corn (Zea mays) cultivation through lanthanide phosphate (Ln-P) and lanthanide-reclaimed wastewater (LRWW, wastewater spiked with lanthanide). High-purity precipitates of CePO₄ (98%) and LaPO₄ (92%) were successfully obtained without pH adjustment, as confirmed by X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectroscopy (EDS). Germination assays revealed that lanthanides, even at concentrations up to 2000 mg/L, did not significantly alter germination rates compared to traditional coagulants, though root and shoot development declined above this threshold—likely due to reduced hydrogen peroxide (H₂O₂) production and elevated total dissolved solids (TDSs), which induced physiological drought. Greenhouse experiments using desert-like soil amended with Ln-P and irrigated with LRWW showed no statistically significant differences in corn growth parameters—including plant height, stem diameter, leaf number, leaf area, and biomass—when compared to control treatments. Photosynthetic performance, including stomatal conductance, quantum efficiency, and chlorophyll content, remained unaffected by lanthanide application. Metal uptake analysis indicated that lanthanides did not inhibit phosphorus absorption and even enhanced the uptake of calcium and magnesium. Minimal lanthanide accumulation was detected in plant tissues, with most retained in the root zone, highlighting their limited mobility. These findings suggest that lanthanides can be safely and effectively used for phosphorus recovery and agricultural reuse, contributing to sustainable nutrient cycling and aligning with the United Nations’ Sustainable Development Goals of zero hunger and sustainable cities. Full article

Ningxia has emerged as a strategic hub for China’s photovoltaic (PV) industry by leveraging abundant solar energy resources and geoclimatic advantages. This study analyzed the spatiotemporal expansion trends and microclimatic impacts of PV installations (2015–2024) using Gaofen-1 (GF-1) and Landsat8 satellite imagery with deep learning algorithms and multidimensional environmental metrics. Among semantic segmentation models, DeepLabV3+ had the best performance in PV extraction, and the Mean Intersection over Union, precision, and F1-score were 91.97%, 89.02%, 89.2%, and 89.11%, respectively, with accuracies close to 100% after manual correction. Subsequent land surface temperature inversion and spatial buffer analysis quantified the thermal environmental effects of PV installation. Localized cooling patterns may be influenced by albedo and vegetation dynamics, though further validation is needed. The total PV site area in Ningxia expanded from 59.62 km² to 410.06 km² between 2015 and 2024. Yinchuan and Wuzhong cities were primary growth hubs; Yinchuan alone added 99.98 km² (2022–2023) through localized policy incentives. PV installations induced significant daytime cooling effects within 0–100 m buffers, reducing ambient temperatures by 0.19–1.35 °C on average. The most pronounced cooling occurred in western desert regions during winter (maximum temperature differential = 1.97 °C). Agricultural zones in central Ningxia exhibited weaker thermal modulation due to coupled vegetation–PV interactions. Policy-driven land use optimization was the dominant catalyst for PV proliferation. This study validates “remote sensing + deep learning” framework efficacy in renewable energy monitoring and provides empirical insights into eco-environmental impacts under “PV + ecological restoration” paradigms, offering critical data support for energy–ecology synergy planning in arid regions. Full article

A lack of access to healthy food has been a problem for low-income residents in many developed urban areas. Due to travel time and additional transportation costs, these residents often opt for unhealthy food rather than nutritious alternatives. This study examines the spatial distribution of food deserts in Mississauga—one of Canada’s most populous cities and a city with one of the highest diabetes rates in the Province of Ontario. Network analysis was employed to map the geographic inaccessibility to essential nutritious food, defined as residential areas that are beyond a 15-min walking distance from grocery stores. Socioeconomic indicators were integrated to identify and compare the regions that are socioeconomically disadvantaged and, therefore, most affected by food inaccessibility. The results reveal the presence of several food deserts spatially dispersed in Mississauga. The implications of these findings are discussed, with a focus on the relationship between food desert locations and the socioeconomic conditions of the affected residents. This study provides a practical, replicable approach for identifying food deserts that can be easily applied in other regions. The model developed offers valuable tools for policymakers and urban planners to address food desert issues, improving access to healthy food and positively impacting the health and well-being of affected populations. Full article

Surface urban heat island (SUHI) effects are intensifying in arid desert cities due to rapid urban expansion, limited vegetation, and increasing impervious and barren land surfaces. This leads to serious ecological and socio-environmental challenges in cities. This study investigates the relationship between landscape composition and land surface temperature (LST) in Phoenix and Tucson, two rapidly growing cities located in the Sonoran Desert of the southwestern United States. Landsat-9 OLI-2/TIRS-2 satellite imagery was used to derive the LST value and calculate spectral indices. A multi-resolution grid-based approach was applied to assess spatial correlations between land cover and mean LST across varying spatial scales. The strongest positive correlations were observed with barren land, followed by impervious surfaces, while green space showed a negative correlation. Furthermore, the Urban Thermal Field Variation Index (UTFVI) and the Ecological Evaluation Index (EEI) assessments indicated that over one-third of both cities are exposed to strong SUHI effects and poor ecological quality. The findings highlight the critical need for ecologically sensitive urban planning, emphasizing the importance of the morphological structure of cities, the necessity of planning holistic blue–green infrastructure systems, and the importance of reducing impervious surfaces to decrease LST, mitigate SUHI and SUHI impacts, and increase urban resilience in desert environments. These results provide evidence-based guidance for landscape planning and climate adaptation in hyper-arid urban environments. Full article

Background: Polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matter (PM) are high in Saudi cities due to industry and traffic, often exceeding safety limits. This study assesses PM_2.5 and PM₁₀ and health risks in Riyadh’s desert environment. Method: High-purity chemicals and PAH standards were used. Air samples were collected at King Saud University, extracted, cleaned, and analyzed by GC-MS. QA/QC ensured accuracy, with RSDs of 4.6–7.9%. Results: Seasonal temperature shifts in Riyadh influence PM and PAH levels. Higher summer temperatures raise PM/PAH, posing health risks, especially via inhalation. Winter favors PAH accumulation on particles. Conclusions: Seasonal temperature shifts significantly affect PM_2.5, PM₁₀, and PAH levels in Riyadh, with summer posing the highest health risks. Inhalation is the main exposure route, especially for PM_2.5. Full article

In desert plants, outcrossing is frequently limited by pollinator scarcity, leading to a certain percentage of self-fertilization. However, research on the ecological adaptations of self-fertilized seeds remains limited. Gymnocarpos przewalskii Maxim, a Tertiary relict plant in the arid deserts of Northwest China, exhibits pronounced self-pollination. In this study, the population of G. przewalskii from the fifth regiment of Alar City was selected to explore its self-pollination types, self-pollination percentages, and ecological adaptations. We found that artificially cross-pollinated G. przewalskii produced heavier seeds, faster germination, seedlings with greater biomass, and stronger environmental adaptability than self-pollination. However, the frequency of insect visits per flower was less than one. The fruit setting rate of natural pollination was 6.90%, while that of self-pollination was 4.43%, accounting for 64.20% of the natural fruit setting rate. Additionally, G. pzewalskii’s filaments elongated rapidly to make the anthers and stigma at the same height before flowering. These characteristics suggest that G. przewalskii is capable of autonomous self-pollination and is prior selfing. Gymnocarpos przewalskii likely produces a high proportion of the selfing merely to ensure population survival. These findings offer valuable insights into the adaptation of desert plants to the scarcity of pollinators. Full article

This research addresses the critical issue of urban heat islands (UHI), in which urban areas experience significantly higher temperatures than their surroundings, adversely affecting human comfort and well-being. Focusing on Inglewood, a city neighboring Los Angeles, California, and Phoenix, Arizona, this study uses a comprehensive methodology involving microclimate analysis-based Universal Thermal Climate Index (UTCI) calculations to assess the impact of horizontal green surfaces and different levels of tree canopies on outdoor thermal stress mitigation. Phoenix was selected due to its hyper-arid desert climate, providing a contrasting context to assess the effectiveness of green infrastructure under extreme heat conditions. The results demonstrate that these interventions effectively reduce strong and moderate heat stress levels (32 °C < UTCI < 38 °C and 26 °C < UTCI < 32 °C); the model with maximum tree canopy achieved an 18.48% reduction in strong heat stress in Inglewood, while combined interventions led to a maximum reduction of 18.92%. However, the findings also reveal that under extreme heat conditions, particularly in hyper-arid environments such as Phoenix, the interventions may have a limited effect, with localized increases in extreme heat stress attributed to microclimate dynamics, reduced vegetation cooling efficiency, and modeling limitations. Despite these challenges, the overall reduction in average UTCI values underscores the potential of integrated green infrastructure strategies for mitigating urban heat stress. This study provides urban planning strategies for integrating these interventions to create more sustainable and resilient urban environments, supporting policymakers and urban planners in their efforts to reduce the effects of UHI. Full article

Aerosol optical depth (AOD) data from 2020 to 2022 during the COVID-19 pandemic in a typical desert industrial city, Wuhai, was analyzed to investigate aerosol optical properties, origins of different types of aerosols, and the impacts of the COVID-19 lockdown on desert pollution. Results show that annual AOD (500 nm) and Ångström exponent α were 0.36 ± 0.12 and 0.75 ± 0.22 in 2020, 0.30 ± 0.12 and 0.75 ± 0.14 in 2021, and 0.28 ± 0.09 and 0.74 ± 0.19 in 2022, respectively, representing a slightly polluted environment characterized by a mixture of coarse-mode dust aerosols and fine-mode anthropogenic aerosols. Seasonal analysis reveals that the highest AOD primarily occurred in spring due to frequent dust events, while the lowest AOD was observed in winter. Potential Source Contribution Function (PSCF) identified the Alxa Desert as a major potential source during the entire year, and anthropogenic industrial and mining activities in northern Ningxia and southern Inner Mongolia were also important contributors, particularly outside of the winter season. The prevailing wind direction in Wuhai was from the northwest (NW-quadrant), originating from the depopulated desert or Gobi area, accounting for 85.11% in spring, 61.45% in summer, 68.09% in autumn, and 100% in winter. The remaining air masses came from southeastern (SE-quadrant) densely populated areas. Despite the dominance of NW air flows, SE anthropogenic air masses resulted in the highest AOD of 0.47 ± 0.24 in spring, 0.38 ± 0.23 in summer, and 0.32 ± 0.17 in autumn, with corresponding finest particle sizes of 0.83 ± 0.31, 0.91 ± 0.30, and 1.02 ± 0.22 in α. This suggests that anthropogenic influence remains significant even under strict control measures during the COVID-19 lockdown. In winter, the northwest air masses contributed to the highest pollution of 0.49 ± 0.39 (AOD) and finest particle size of 0.90 ± 0.32 (α), likely associated with the coal/straw burning for winter heating. In addition, the particles leading to moderate pollution primarily ranged around 0.2–0.25 µm, and fine particle pollution persists throughout the year. Full article

Due to continuing worldwide urban expansion, research into how urban environments affect local flora/fauna has grown significantly. Studies on the impacts of urbanization on birds have explored a wide variety of behaviors (e.g., foraging, breeding, migratory), but there is little research on the impacts of cities on avian coloniality. Various urban-environmental factors may impact colonial birds. The predominance of impervious surfaces in cities, for example, has been associated with the decline of several bird species due to negative effects on availability and quality of habitat. The urban heat island effect and shifts in resource availability (e.g., food, water) may also affect colonial birds. Here, we used five years of community-science data available in eBird to investigate urban impacts on group size in Cliff Swallows (Petrochelidon pyrrhonota), an abundant colonial bird species that now breeds readily under bridges and other built structures over or near water in Phoenix, Arizona, USA. We hypothesized that, based on the colonial breeding habits of these neotropical migratory birds in this desert environment, swallows in Phoenix would form larger groups in areas with more food and water sources and with more built structures. In fact, we found that proximity to water sources and cropland, but not impervious surface density, was positively and significantly related to group size. These results suggest that, in this desert ecosystem, an abundance of food/water resources provided by humans permits Cliff Swallows to form larger social groups during breeding. Although many studies show harmful impacts of cities on local wildlife, our findings highlight how urban and/or agricultural ‘oases’ may relieve some native species from natural resource limitations and permit them to thrive and increase in group size in human-impacted environments. Full article

Urban heat islands (UHIs) constitute one of the most conspicuous anthropogenic impacts on local climates, characterized by elevated land surface temperatures in urban areas compared to surrounding rural regions. This study represents a novel and comprehensive effort to characterize the spectral signature of SUHI through the lens of the two-dimensional (2D) turbulence theory, with a particular focus on identifying energy cascade regimes and their climatic modulation. The theory of two-dimensional (2D) turbulence, first described by Kraichnan and Batchelor, predicts two distinct energy cascade regimes: an inverse energy cascade at larger scales (low wavenumbers) and a direct enstrophy cascade at smaller scales (high wavenumbers). These cascades can be detected and characterized through spatial power spectra analysis, offering a scale-dependent understanding of the SUHI phenomenon. Despite the theoretical appeal, empirical validation of the 2D turbulence hypothesis in urban thermal landscapes remains scarce. This study aims to fill this gap by analyzing the spatial power spectra of land surface temperatures across 14 cities representing diverse climatic zones, capturing varied urban morphologies, structures, and materials. We analyzed multi-decadal LST datasets to compute spatial power spectra across summer and winter seasons, identifying spectral breakpoints that separate large-scale energy retention from small-scale dissipative processes. The findings reveal systematic deviations from classical turbulence scaling laws, with spectral slopes before the breakpoint ranging from ~K^−1.6 to ~K^−2.7 in winter and ~K^−1.5 to ~K^−2.4 in summer, while post-breakpoint slopes steepened significantly to ~K^−3.5 to ~K^−4.6 in winter and ~K^−3.3 to ~K^−4.3 in summer. These deviations suggest that urban heat turbulence is modulated by anisotropic surface heterogeneities, mesoscale instabilities, and seasonally dependent energy dissipation mechanisms. Notably, desert and Mediterranean climates exhibited the most pronounced small-scale dissipation, whereas oceanic and humid subtropical cities showed more gradual spectral transitions, likely due to differences in moisture availability and convective mixing. These results underscore the necessity of incorporating turbulence theory into urban climate models to better capture the scale-dependent nature of urban heat exchange. The observed spectral breakpoints offer a diagnostic tool for identifying critical scales at which urban heat mitigation strategies—such as green infrastructure, optimized urban ventilation, and reflective materials—can be most effective. Furthermore, our findings highlight the importance of regional climatic context in shaping urban spectral energy distributions, necessitating climate-specific urban design interventions. By advancing our understanding of urban thermal turbulence, this research contributes to the broader discourse on sustainable urban development and resilience in a warming world. Full article

Direct access to good-quality drinking water in Uzbekistan is becoming a major issue. This challenge is exacerbated by growing demands, driven by population growth, industrial development, and desert land cultivation. In this regard, there is a significant need for a thorough analysis of the existing water resources. This study aims to identify the chemical composition of springs’ water in the Kashkadarya region of Uzbekistan and to assess their suitability as drinking water sources. To analyze the water quality, three springs were selected, Hazrat Bashir, Boshmanbulak, and Chillabulak, which are the most used springs by the population of this region, and the artesian waters of the city of Shakhrisabz were also included in the study. The quality of the spring water was evaluated based on the primary water quality indicators, including salt composition, heavy metals, and some essential trace elements such as iron (Fe), chromium (Cr), and selenium (Se) in the selected samples. According to the results, the spring water in Chillabulak was found to be relatively harder than the other samples, with magnesium and calcium concentrations of 28 and 390 mg/L, respectively. However, the study also revealed that the water from the other three examined samples meets sanitary norms and water quality standards, confirming their suitability for human consumption. The results can be used to develop water quality management strategies and environmental protection, as well as to inform the population about the ecological safety of regional aquatic reserves. Full article

With the development of international cultural heritage, the positive shift from historic environments to historic urban landscapes has been explored in China. At the same time, China is also trying to extend its heritage corridors to historic urban landscape corridors; thus, the spatial organization characteristics and themes of historic landscapes are being explored. This study took the Dunhuang Oasis area as an example and, based on regional, cultural, and natural heritage sites and man-made environmental characteristics, identified and evaluated historic urban landscape corridors. The least cumulative resistance model was applied to identify historic landscape corridors, and the multicenter evaluation model was used to classify the historic landscape corridors. From the perspective of corridor identification, the military defense and historic landscapes of the city ruins together reflect the human need for “city administration–border defense–ancient trade and commerce”. Grottoes and scenic landscapes are more dependent on the Gobi Desert, mountains, and other areas intertwined with the oasis. The drainage system and water conservancy landscape consists of four stable landscape corridors containing east, west, north, and south canals, which are the basic driving force for the growth of the town. From the corridor hierarchy, we studied layer formation from the Dunhuang urban area, the western and northern local oasis dry canal, Mingsha Mountain–Crecent Spring, etc., as interconnected trunk corridors. The periphery of the Dunhuang urban area encompasses the southern trunk canal, southeastern Mogao Grottoes–Sanwei Mountain road, and other branch corridors. This study determined the composition and level of importance of historic landscape corridors, while at the same time enhancing the visual representation and skyline organization, which can be used for territorial spatial planning and research in functional urban areas. Full article

Energy-efficient building envelope design is essential for minimizing cooling loads and reducing energy consumption, particularly in hot desert climates. This study presents a model that optimizes insulation thickness by taking into account climate-specific conditions and economic factors. The model employs a life-cycle cost analysis framework, incorporating energy savings, insulation costs, and payback periods across various climatic zones. A typical wall is considered with three commonly applied insulation materials. The optimization is validated by energy modeling. A key contribution of this study is the introduction of a correction factor based on average humidity for each city, which adjusts the conduction-based model to account for latent heat effects from moisture-dependent insulation degradation. Unlike existing building codes, which prescribe fixed insulation requirements regardless of regional climate conditions, our approach dynamically adapts insulation thickness based on Cooling Degree Days (CDDs) and economic feasibility. The results reveal significant variations in optimal insulation thickness across different cities, demonstrating the necessity of climate-responsive insulation strategies. The analysis indicates that locations with higher CDD, such as Jeddah and Dhahran, require thicker insulation to reduce cooling loads effectively, whereas cities with lower cooling demand, such as Khamis Mushait, necessitate thinner insulation for economic viability. The results show that polystyrene (K = 0.034 W/m.K) has the least cost, whereas polyurethane (K = 0.24 W/m.K) records the least thickness in Saudi Arabia. This study presents a model that optimizes insulation thickness by taking into account climate-specific conditions and economic factors. Full article

Improving microclimate conditions is a pivotal aspect of urban design, particularly in hot, arid climates, where it directly influences outdoor comfort, mitigates the urban heat island (UHI) effect, and reduces the indoor cooling energy demand. The objective of this study is to quantitatively assess the impacts of neighborhoods’ urban size when combined with compact streets’ geometry regarding the outdoor thermal comfort generated in a typical vernacular settlement of the Saharan region of Algeria. The Ksar of Al-Atteuf in the city of Ghardaïa is taken as a case study. The related interior thermal conditions of buildings assumed to be potentially affected by the urban morphology are also examined. To study the effectiveness of the two urban morphology parameters (i.e., urban size and compactness) on outdoor and indoor thermal conditions, a mixed methods approach was adopted, integrating in situ climatic measurements and dynamic simulations. Indoor temperatures were examined in a traditional house located in the core of the Ksar. Year-round operative temperature (OT) simulations were achieved using the Ladybug tool within Grasshopper, and they were complemented by the Universal Thermal Climate Index (UTCI) values calculated during peak hot and cold weeks. Furthermore, a parametric analysis was conducted, focusing on the thermal performance of the compact urban fabric by varying progressively the neighborhood sizes from 20 m, 40 m, and 60 m. The results indicate stable indoor thermal conditions across the monitored residential building, which suggests that the architectural envelope is closely affected by its immediate surroundings. On the other hand, the UTCI analysis revealed significant differences in outdoor thermal comfort since the larger urban area provides better mitigation of heat stress in summer and cold stress in winter, the improved outdoor thermal conditions generated at the neighborhood level, being proportional to the size of the urban area. The findings underscore the value of compact urban fabrics in creating climate-responsive built environments and provide further insights into sustainable urban planning and energy-efficient design practices in hot, arid regions. Full article