10 research outputs found
Assessing Spatial Correlations Between Land Cover Types and Land Surface Temperature Trends Using Vegetation Index Techniques in Google Earth Engine: A Case Study of Thessaloniki, Greece
No full textThe Urban Heat Island (UHI) phenomenon, combined with reduced vegetation and heat generated by human activities, presents a major environmental challenge for many European urban areas. The UHI effect is especially concerning in hot and temperate climates, like the Mediterranean region, during the summer months as it intensifies the discomfort and raises the risk of heat-related health issues. As a result, assessing urban heat dynamics and steering sustainable land management practices is becoming increasingly crucial. Analyzing the relationship between land cover and Land Surface Temperature (LST) can significantly contribute to achieving this objective. This study evaluates the spatial correlations between various land cover types and LST trends in Thessaloniki, Greece, using data from the Coordination of Information on the Environment (CORINE) program and advanced vegetation index techniques within Google Earth Engine (GEE). Our analysis revealed that there has been a gradual increase in average surface temperature over the past five years, with a more pronounced increase observed in the last two years (2022 and 2023) with mean annual LST values reaching 26.07 °C and 27.09 °C, respectively. By employing indices such as the Normalized Difference Vegetation Index (NDVI) and performing correlation analysis, we further analyzed the influence of diverse urban landscapes on LST distribution across different land use categories over the study area, contributing to a deeper understanding of UHI effects
Mapping Drought Incidents in the Mediterranean Region with Remote Sensing: A Step Toward Climate Adaptation
No full textThe Mediterranean region, identified by scientists as a ‘climate hot spot’, is experiencing warmer and drier conditions, along with an increase in the intensity and frequency of extreme weather events. One such extreme phenomena is droughts. The recent wildfires in this region are a concerning consequence of this phenomenon, causing severe environmental damage and transforming natural landscapes. However, droughts involve a two-way interaction: On the one hand, climate change and various human activities, such as urbanization and deforestation, influence the development and severity of droughts. On the other hand, droughts have a significant impact on various sectors, including ecology, agriculture, and the local economy. This study investigates drought dynamics in four Mediterranean countries, Greece, France, Italy, and Spain, each of which has experienced severe wildfire events in recent years. Using satellite-based Earth observation data, we monitored drought conditions across these regions over a five-year period that includes the dates of major wildfires. To support this analysis, we derived and assessed key indices: the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), and Normalized Difference Drought Index (NDDI). High-resolution satellite imagery processed within the Google Earth Engine (GEE) platform enabled the spatial and temporal analysis of these indicators. Our findings reveal that, in all four study areas, peak drought conditions, as reflected in elevated NDDI values, were observed in the months leading up to wildfire outbreaks. This pattern underscores the potential of satellite-derived indices for identifying regional drought patterns and providing early signals of heightened fire risk. The application of GEE offered significant advantages, as it allows efficient handling of long-term and large-scale datasets and facilitates comprehensive spatial analysis. Our methodological framework contributes to a deeper understanding of regional drought variability and its links to extreme events; thus, it could be a valuable tool for supporting the development of adaptive management strategies. Ultimately, such approaches are vital for enhancing resilience, guiding water resource planning, and implementing early warning systems in fire-prone Mediterranean landscapes
Satellite Imagery for Comprehensive Urban Morphology and Surface Roughness Analysis: Leveraging GIS Tools and Google Earth Engine for Sustainable Urban Planning
No full textHigh-resolution remotely sensed data, which are characterised by their advanced spectral and spatial capabilities, provide unprecedented opportunities to monitor and analyse the dynamic structures of urban environments. Platforms like Google Earth Engine (GEE) enhance these capabilities, as they provide access to vast datasets and tools for analysing key urban parameters, including land use, vegetation cover, and surface roughness–all critical components in urban sustainability studies. This study presents a knowledge-based framework for processing high-resolution satellite imagery tailored to address the demands of sustainable urban planning in the Municipality of Kalamaria in Thessaloniki, Greece. The framework emphasises the extraction of essential urban parameters, such as the spatial distribution of built-up and green spaces, alongside the analysis of surface roughness attributes, including displacement height and roughness length. Unlike conventional methods, our framework enables a detailed intra-urban analysis as these surface roughness attributes are calculated within 200 m × 200 m sub-units. Surface roughness indicators offer essential insights into aerodynamic drag and turbulent air mixing, both of which are directly influenced by the structural characteristics of the urban landscape. Using this approach, ‘wake interference flow’ type was identified as the dominant airflow pattern in the study area. This type was observed in 105 out of 150 sub-units, suggesting that these areas likely suffer from poor air circulation and are prone to higher concentrations of air pollutants. The integration of Google Earth Engine offered a scalable and replicable solution for large-scale urban analysis making it easily adaptable to other urban areas, especially where detailed morphological datasets are unavailable. By providing a robust, scalable, and data-driven tool for assessing urban form and airflow characteristics, our study offers a significant advancement in sustainable urban planning and climate resilience strategies, with clear potential for adaptation in other cities facing similar data limitations
Monitoring the Impact of Urban Development on Archaeological Heritage Using UAV Mapping: A Framework for Preservation and Urban Growth Management
No full textUrbanization poses growing threats to archaeological heritage sites embedded within cities, necessitating innovative monitoring and documentation strategies. This study investigates the use of Unmanned Aerial Vehicle (UAV) photogrammetry for mapping and 3D modelling of urban archaeological landscapes, focusing on the Byzantine-era Didymoteicho Fortress in northern Greece. High-resolution aerial imagery was captured and processed into an orthophoto mosaic and a detailed 3D model of the site’s monuments and their urban surroundings. The UAV-based survey provided comprehensive, up-to-date spatial data that traditional ground methods could not easily achieve in dense urban settings. The results illustrate how UAV mapping can document complex heritage structures, detect risks (such as structural deterioration or encroachment by development), and inform preservation efforts. The discussion situates these findings within global heritage management practices, highlighting UAV technology as a cost-effective, accurate, and non-invasive tool for safeguarding cultural heritage in urban areas. The suggested methodology enhances heritage documentation and risk assessment, demonstrating strong potential for policy integration and proactive conservation planning in historic cities
Redefining Archaeological Research: Digital Tools, Challenges, and Integration in Advancing Methods
No full textThis paper explores the diverse array of digital tools utilized for data acquisition in archaeology. This abstract outlines the various categories of digital tools commonly employed, including geographic information systems (GISs), global positioning systems (GPSs), remote sensing technologies, 3D scanning and photogrammetry, drones and aerial photography, as well as mobile applications and digital recording systems. Each category is elucidated with examples of their application in archaeological research, emphasizing their roles in site mapping, spatial data collection, artefact documentation, and landscape analysis. Furthermore, it discusses the advancements, challenges, and best practices associated with the integration of digital tools into archaeological fieldwork. It also highlights the potential for future developments in digital technologies to enhance data acquisition capabilities further, ultimately contributing to a deeper understanding of human history and cultural heritage
Numerical simulations of comminution slurries over complex topographies: Putting together CFD and pipeline integrity
No full textArtículo de publicación ISIThe use of computational fluid dynamics gives new and interesting insights for risk analysis of crosscountry
ore hydraulic transport operations. In particular, they offer the possibility to predict, with reasonable
accuracy, the progression and final condition of spills driven by pipeline leaks at selected locations,
at a relatively modest computational cost. In this work, a depth-averaged, two-dimensional numerical
model is used to simulate an ore concentrate pipeline rupture and subsequent spill, reproduced as a constant
flow condition at the leak point. Although the model is well suited to solve the governing flow equations
on arbitrary topographies by means of digital elevation models, two specific locations featuring
relatively mild and steep slopes, are analysed with regard to their implications on the potential requirements
for emergency team response. Results, obtained using different slurry rheologies, are compared
with those obtained using a simpler, common flow resistance model derived for water flowing over rough
surfaces.The authors gratefully acknowledge support from the
Department of Civil Engineering of University of Chile and the
Chilean National Commission for Scientific and Technological
Research, CONICYT, through Fondecyt Project No. 11110201 and
1130910. The first author would also like to thank the scholarship
for Master Program CONICYT-PFCHA/Magíster Nacional/2013 folio
221320183
Developing citizen science ecosystem:critical factors for quadruple helix stakeholders engagement
No full textPurpose: The purpose of this paper is to provide answers regarding the factors that motivate or discourage the quadruple helix (QH) stakeholders and the wider public in citizen science (CS) activities. The research reveals a current overview of the perceptions, attitudes, concerns and motivation with regard to development of CS ecosystem in four countries: Greece, Lithuania, the Netherlands and Spain. Design/methodology/approach: The researchers deploy a mixed methodology, entailing an in-depth literature review and a large-scale quantitative survey (approximately 2,000 citizens) targeting QH stakeholders and general public from the local national ecosystems. The results contain both descriptive statistics and statistical analysis per country. After the comprehensive overview of drivers and barriers regarding the participation in CS activities in general, the focus is narrowed down on the engagement motivation of different QH stakeholders and the differences in enabling/hindering factors at the local ecosystems. Findings: Depending on the country and the pre-existing level of CS maturity, the results provide a complicated network of factors that unlock or block participation in CS activities. These factors include, to name a few, political maturity, civic engagement, technological infrastructures, economic growth, culture of stakeholder collaboration, psychological stimulus and surplus of resources. The implications of the findings necessitate the alignment of the envisioned CS ecosystem with the local dynamics in each country. Research limitations/implications: The quantitative nature of the survey method, limited sample size and only four countries context are noted as limitations of the study and offer future research potential for longitudinal settings and mixed-methods studies. Originality/value: The results contribute to the wider literature on CS that focuses on perspectives, possibilities and differences in local contexts with respect to the public engagement by developing CS ecosystem. At the same time, its added value lies in the overall practical proposition, and how the latter can effectively and efficiently attract and retain different stakeholder groups and citizens, under a collaborative approach.</p
UAV Mapping and 3D Modeling as a Tool for Promotion and Management of the Urban Space
No full textIn the past few decades, the management of urban spaces with appropriate tools has been in constant discussion due to the plethora of new technologies that have emerged for participatory planning, drone mapping, photogrammetry and 3D modeling. In a multitude of situations, considerable progress has been made regarding the strategic impact of the successful use of technology for the development of urban spaces. The current era provides us with important digital tools and the opportunity to test new perspectives in the sustainable development of cities. This paper aims to explore the contribution of UAVs to the spatial mapping process of urban space, with the goal of collecting quantifiable and qualitative information to use for 3D modeling that can enable a more comprehensive understanding of the urban environment, thus facilitating urban regeneration processes. Three-dimensional models of high accuracy are not mandatory for this research. The location of the selected research area is particularly interesting due to its boundaries, urban voids and public space that can evolve through public participation. The results can be used for crowdsourcing in participatory decision-making processes and for exploring the consequences that these have on the built environment, and they can be used as a new means of involvement of citizens in local decision-making processes
A large-scale dataset for analysing remote working in urban and rural areas across Europe
No full textThis Data Descriptor presents the collected data on remote work among urban and rural workers, emphasizing differences in perceived flexibility, adaptability, preferences, career impacts, well-being, and productivity. The survey, conducted via Prolific between July and August 2024, captured data from 20,013 participants globally with European nationality, offering insights into the benefits and challenges faced by remote workers. Beyond its initial scope, the dataset can be reused to support a wide range of future studies and policy development initiatives. For instance, researchers can utilize this dataset to explore trends in work-life balance, productivity, and urban policy and planning related to remote work. Additionally, urban planners and policymakers can leverage the data to inform strategies for urban and regional development, infrastructure forecasting, planning, and community support in diverse geographic areas. The dataset’s granularity on socio-economic factors makes it an invaluable resource for developing targeted policies that address urban-rural disparities and foster sustainable remote working arrangements across Europe
