Insights into heat islands at the regional scale using a data-driven approach

Urban heat island (UHI) phenomenon is crucial in the context of climate change. However, while substantial attention has been given to studying UHIs within cities, our understanding at the regional level still needs to be improved. This study delves into the intricate dynamics of the regional heat island (RHI) by examining its relationship with land use/land cover (LULC), vegetation, and elevation. The objective is to enhance our knowledge of RHI to inform effective mitigation strategies. The research employs a data-driven approach, leveraging satellite data and spatial modeling, examining surface and canopy-layer regional heat islands, and considering daytime and nighttime variations. To assess the impact of LULC, the study evaluates three main categories: anthropized (urbanized), agricultural, and wooded/semi-natural environments. Furthermore, it delves into the influence of vegetation on RHI and incorporates elevation data to understand its role in RHI intensity. The findings reveal meaningful variations in heat islands across different LULCs, providing essential insights. Although urbanized areas exhibit the highest RHI intensity, agricultural regions contribute notably to RHI due to land use changes and reduced vegetation cover. This emphasizes the significant impact of human activities. In contrast, wooded and semi-natural environments demonstrate potential for mitigating RHI, owing to their dense vegetation and shading effects. Elevation, while generally associated with reduced heat island, shows variations based on local conditions. Ultimately, this research underscores the complexity of the RHI phenomenon and the importance of considering factors such as different temperatures and their daily variation, landscape heterogeneity, and elevation. Additionally, the study emphasizes the significance of sustainable spatial planning and land management. Targeted efforts to increase vegetation in high daytime land surface temperature areas can reduce heat storage and mitigate RHI. Similarly, planning for agroforestry and green infrastructure in agricultural areas can significantly increase resilience to climate

Towards an operational model for estimating day and night instantaneous near-surface air temperature for urban heat island studies: outline and assessment

Near-surface air temperature (NSAT) is key for assessing urban heat islands, human health, and well-being. However, a widely recognized and cost- and time-effective replicable approach for estimating hourly NSAT is still urgent. In this study, we outline and validate an easy-to-replicate, yet effective, operational model, for automating the estimation of high-resolution day and night instantaneous NSAT. The model is tested on a heat wave event and for a large geographical area. The model combines remotely sensed land surface temperature and digital elevation model, with air temperature from local fixed weather station networks. Achieved NSAT has daily and hourly frequency consistent with MODIS revisiting time. A geographically weighted regression method is employed, with exponential weighting found to be highly accurate for our purpose. A robust assessment of different methods, at different time slots, both day- and night-time, and during a heatwave event, is provided based on a cross-validation protocol. Four-time periods are modelled and tested, for two consecutive days, i.e. 31st of July 2020 at 10:40 and 21:50, and 1st of August 2020 at 02:00 and 13:10 local time. High R2 was found for all time slots, ranging from 0.82 to 0.88, with a bias close to 0, RMSE ranging from 1.45 °C to 1.77 °C, and MAE from 1.15 °C to 1.36 °C. Normalized RMSE and MAE are roughly 0.05 to 0.08. Overall, if compared to other recognized regression models, higher effectiveness is allowed also in terms of spatial autocorrelation of residuals, as well as in terms of model sensitivity

Utilizing the eutrophication in bioresources recovery and biogas production - a case study in Egypt

In this work, the nutrients and eutrophication problem are integrated into a nature-based solution by incorporating microalgae-based nutrient removal from wastewater and collecting the residue in an anaerobic digestion plant to produce biogas that is directly exported to an existing gas-fired power plant and closes the bioresource loop. El Burullus lake in Egypt was selected as a case study because it is rich in nutrients and suitable for the integrated system. The theoretical results were promising as for one-hectare, nutrient pollution could be reduced with a total nitrogen removal rate of 4 kg d-1, a total phosphorus removal rate of 1.1 kg d-1, and a total COD removal rate of 9.3 kg d-1. The digester volume corresponding to the biomass produced was 120 m3 per hectare of algae pond and the methane yield (Y) from anaerobic digestion was 73 m^3 d^(-1)

Milano Citt\ue0 Metropolitana Resiliente : un percorso operativo a supporto della redazione del futuro Piano Territoriale Metropolitano

Il contributo si pone l\u2019obiettivo di presentare il percorso di ricerca svolto per supportare la redazione di un piano clima per la Citt\ue0 Metropolitana di Milano. Il lavoro svolto ha avuto l\u2019obiettivo di allineare il contesto locale della CMM al dibattito internazionale e ai nuovi temi della pianificazione climatica integrata alla pianificazione territoriale e spaziale e perseguire i target di riduzione delle emissioni di gas serra e di risposta all\u2019adattamento gi\ue0 stabiliti a livello internazionale. Nello specifico, a partire dall\u2019esperienza pianificatoria della CMM, dal capitale tecnico gi\ue0 attivo sui temi proposti, e a seguito di una ricognizione approfondita dello stato dell\u2019arte in tema di pianificazione per l\u2019energia e il clima a livello locale, lo studio si \ue8 occupato di: (1) portare conoscenza e trasferire i temi del cambiamento climatico all'interno delle pratiche pianificatorie locali, rileggendo strumenti e piani nell\u2019ottica della resilienza territoriale; (2) comunicare e disseminare le sfide dei cambiamenti climatici alle popolazioni locali, comprese le attivit\ue0 formative rivolte ai tecnici dell\u2019amministrazione pubblica; (3) affrontare le sfide spaziali e climatiche in maniera integrata con obiettivi di efficacia. Il lavoro pone in particolare l\u2019accento sull\u2019importanza della dimensione spaziale e morfologica dei diversi contesti urbanizzati nell\u2019affrontare strategie e soluzioni di adattamento, aspetto spesso trascurato dalla pianificazione climatica. La costruzione di mappe di vulnerabilit\ue0 alla micro-scala locale consente, infatti, di proporre soluzioni meta-progettuali specifiche e azioni su misura per i diversi contesti, aumentando quindi l\u2019efficacia degli interventi

Semi-automatic land cover classification and urban modelling based on morphological features : remote sensing, geographical information systems, and urban morphology : defining models of land occupation along the Mediterranean side of Spain

From a global point of view, as argued by Levy (1999), the modern city has undergone radical changes in its physical form, either in terms of territorial expansion as well as in terms of interna! physical transformations. Today, approximately 75% of the European population lives in urban areas ,which makes the urban fulure of the conlinent a major cause of concern (Brazil, Cavalcanti, & Longo, 2014). lndeed, the demand for urban land, both within and around the cities, is becoming increasingly acule (European Environmenl Agency, 2006). Ouring the last decades, also Spain has been undergoing an important process of urban growth, which has implied the consumption of a large amounl of land, al hough the overall population growth rale, mostly along certain specific geographic areas, has remained at least unchanged or even, in sorne cases, il has also decreased. Such a phenomenon has been quite remarkable along the Mediterranean side. As argued by Gaja (2008), the urban development in Spain has been strongly linked to the model of economic development , which relies, since its launch in the 50's, onlhree main factors , i.e.:emigration, building, and mass tourism. Nowadays , in Spain, and mostly along the Medilerranean side, several urban areas are facing important phenomena of urban sprawl, also feared by he European Union. An accurate information about the pattern of land use/land cover, over time, is a fundamental requirement for a better understanding of the urban models. Currently, even though plenty of approaches to the image classification, through Remote Sensing (RS) techniques, have been advanced, Land Cover/Land Use classification is still an exciting challenge (Weng, 2010). Actually, the increasing development of RS and GIS technologies, during the last decades, has provided further capabiliies for measuring, analysing, understanding, modelling the "physical expressions" of urban growth phenomena, either in terms of pattern and process (Bhatta, 2012), and based on land use/land cover mapping and change delection over time. Based on such a technological approach, here we first aim to set up a suitable methodology for detecting generalized land cover classes based on an assisted automatic (or semi-aulomatic) pixel-based approach, calibrated upon Landsat Thematic Mapper (TM) mullispectral imagery, at 30 meters of spatial resolution. Beside, through the use of Geographical lnformation Syslem (GIS) we provide a spatial analysis and modelling of different urban models, from a morphological standpoint, in order to define the main pattern of land occupation al municipal scale, and along the Mediterranean side of Spain, al the year 2011. We focus on two main issues. On one hand, RS techniques have been used to set up a proper semi-automatic classification methodology, based on the use of Landsat imagery, capable of handling huge geographical areas quickly and efficiently. This process is basically aimed to detect the urban areas, at the year 2011, along the Mediterranean side of Spain, depending on the administrative division of Autonomous Communities. On the other hand, the spatial patterns of urban settlements have been analysed by using a GIS platform for quantifying a set of spatial metrics about the urban form. Hence, once get the quantification of different morphological features, including the analysis aboul either the urban profile, the urban texture, and the street network pattern, an automatic classification of different urban morphological models has been proposed, based on a stalistical approaches, namely factor and cluster analysisDesde un punto de vista global,como sostiene Levy (1999), la ciudad moderna ha experimentado cambios radicales en su forma física, ya sea en términos de expansión territorial, así como en términos de transformaci ones internas. Hoy en día, aproximadamente el 75% de la población europea vive en zonas urbanas, lo que hace del futuro urbano delcontinente, una causa importante de preocupación (Brasil, Cavalcanti, y Longo, 2014). De hecho, la demanda de suelo urbano, dentro y alrededor de las ciudades , es cada vez más aguda (Agencia Europea de Medio Ambiente,2006). Durante las últimas décadas, también España ha experimentado un importante proceso de crecimiento urbano que ha implicado el consumo de una gran cantidad de tierra, aunque la tasa de crecimiento de la población en general, sobre todo a lo largo de ciertas áreas geográficas específicas , se ha mantenido al menos sin cambios o incluso, en algunos casos, también ha disminuido. Este fenómeno ha sido muy evidente a lo largo de la vertiente mediterránea. Como sostiene Gaja (2008), el desarrollo urbano en España se ha visto fuertemente vinculado con el modelo de desarrollo económico, que se basa, desde su lanzamiento en la década de los 50,en tres factores principales, a saber: la emigración, la construcción y el turismo de masas. Hoy en día, en España, y sobre todo a lo largo de la vertiente mediterránea, varias zonas urbanas se enfrentan a fenómenos importantes de expansión urbana, también temidos por la Unión Europea. Al respecto,un requisito fundamental para mejorar la comprensión y el estudio de los modelos urbanos es obtener en eltiempo una información precisa sobre los patrones de cubiertas y uso de suelo. Actualmente, a pesar de la existencia de numerosos métodos para la clasificación de imágenes digitales a través de técnicas de teledetección, para ext raer información sobre cobertura/uso de suelo, este enfoque sigue siendo un reto apasionante (Weng, 2010). El creciente desarrollo de las tecnologías de RS y GIS, durante las últimas décadas, ha proporcionado nuevas capacidades para medir, analizar, comprender, y modelar las "expresiones físicas" de los fenómenos de crecimiento urbano, en términos de patrones y procesos (Bhatta, 2012), y con base en el mapeo y análisis de cambios de cobertura/uso de suelo a través el tiempo. Basándose en un enfoque tecnológico, el primero objetivo es establecer una metodología adecuada para la detección de clases de cobertura de la tierra generalizadas que encuentra su fundamento en una asistido automático (o semiautomático), enfoque basado en píxeles, calibradas en Landsat Thematic Mapper (TM) imágenes multiespectrales, a 30 metros de resolución espacial. Al lado, a través del uso del Sistema de Información Geográfica (SIG), es posible proveer un análisis espacial y la modelización de diferentes modelos urbanos, desde un punto de vista morfológico, con el fin de definir el patrón principal de la ocupación del suelo a escala municipal a lo largo de la vertiente mediterránea de España, en el año 2011. En particular no enfocamos en dos cuestiones principales. Por un lado, las técnicas de RS se han utilizado para establecer una metodología de clasificación semi-automático adecuada, basada en el uso de imágenes Landsat, capaz de manejar grandes zonas geográficas de forma rápida y eficiente. Este proceso, básicamente, va dirigido a detectar las áreas urbanas, en el año 2011, a lo largo de la vertiente mediterránea de España, según la división administrativa de las Comunidades Autónomas. Por otro lado, los patrones espaciales de asentamientos urbanos han sido analizados mediante el uso de una plataforma GIS para cuantificar un conjunto de métricas espaciales sobre la forma urbana. Finalmente, una vez obtenida la cuantificación de diferentes características morfológicas, se ha proporcionado una clasificación automática de los diferentes modelos morfológicos urbanos, basada en un enfoque estadístico, es decir, análisis factorial y clúster.Postprint (published version

Modelli di urbanizzazione costiera: morfologia e complessità strutturale, a scala urbana e territoriale, nella Regione Metropolitana di Barcellona

El trabajo se presenta como reflexión sobre la “forma” de diferentes tipologías de ciudades y acerca de las relaciones que las vinculan a un ámbito territorial, en una visión de desarrollo contemporáneo; con particular atención a la influencia que ejercita la cercanía al mar sobre los sistemas urbanos. El objetivo es delinear, gráficamente, esquemas de modelos a través de una operación de abstracción hecha sobre polígonos definidos por el proyecto CORINE Land Cover 2000; asignar, a cada esquema, valores numéricos a diferentes escalas, después de clasificar grupos distintos de asentamientos urbanos por medio de análisis estadísticos; reflexionar, finalmente, sobre los perímetros efectivos de interacción territorial entre los modelos definidos, puesto que, a lo largo de la costa mediterránea, los límites municipales se van difuminando a causa de las nuevas dinámicas urbanizadoras. Además se pretende estudiar conceptos como difusión y fragmentación urbana, “dibujando” dichos patrones de modelos de urbanización reconocibles sobre el territorio y estableciendo criterios de lectura lógico-conceptual de los fenómenos de desarrollo urbano.The work is presented as a reflection on the form of different cities typologies and proximity the relationships that bind a territorial basis, in a contemporary vision of development, with particular attention to the influence of urban systems close to the sea. The objective is to delineate, graphically models through an operation of abstraction made on sites identified by Land Cover dataset of CORINE project for year 2000; allocate to each scheme, different scales of numerical values, after classifying different urban settlements groups by means of statistical analyses; showing, finally, on the effective perimeters the interaction between defined spatial models, because, along the Mediterranean coast, the municipal boundaries are blurring by the effect of the new dynamics developers. In addition seeks discussing concepts such as dissemination and urban fragmentation, drawing various patterns of recognizable urbanization models over the territory and establishing criteria for reading logical conceptual of the urban development phenomena

Investigating the Impact of Heat Stress and Green Space Accessibility for At-Risk Communities

This work addresses the urban heat island issue and its impact on vulnerable populations in cities. Urban heat islands refer to the phenomenon where temperatures in builtup areas exceed those of surrounding rural regions due to the absorption and retention of heat by built-up surfaces and the lack of vegetation. The study focuses on Milan and uses data from Daytime Near-Surface Air Temperature estimates and the Normalized Difference Vegetation Index to assess accessibility to green spaces during an extreme heat event. The goal is to establish a practical approach for assessing urban areas that are particularly vulnerable to extreme heat and have low accessibility to possible ‘urban cool islands’ to inform climate-proof urban planning, design, and policies and promote equitable access to green spaces. The methodology involves constructing a 3x3 table containing nine classes based on matrix logic, representing different degrees of thermal perception-based accessibility to green. The results of this study could be used to prioritize interventions to increase thermal comfort and achieve a more sustainable urban environment

Testing a combind multispectral-multitemporal approach for getting cloudless imaginery for Sentinel-2

Earth observation and land cover monitoring are among major applications for satellite data. However, the use of primary satellite information is often limited by clouds, cloud shadows, and haze, which generally contaminate optical imagery. For purposes of hazard assessment, for instance, such as flooding, drought, or seismic events, the availability of uncontaminated optical data is required. Different approaches exist for masking and replacing cloud/haze related contamination. However, most common algorithms take advantage by employing thermal data. Hence, we tested an algorithm suitable for optical imagery only. The approach combines a multispectral-multitemporal strategy to retrieve daytime cloudless and shadow-free imagery. While the approach has been explored for Landsat information, namely Landsat 5 TM and Landsat 8 OLI, here we aim at testing the suitability of the method for Sentinel-2 Multi-Spectral Instrument. A multitemporal stack, for the same image scene, is employed to retrieve a composite uncontaminated image over a temporal period of few months. Besides, in order to emphasize the effectiveness of optical imagery for monitoring post-disaster events, two temporal stages have been processed, before and after a critical seismic event occurred in Lombok Island, Indonesia, in summer 2018. The approach relies on a clouds and cloud shadows masking algorithm, based on spectral features, and a data reconstruction phase based on automatic selection of the most suitable pixels from a multitemporal stack. Results have been tested with uncontaminated image samples for the same scene. High accuracy is achieved.Peer ReviewedPostprint (published version

Reagire a piogge estreme e ondate di calore a Ferrara. Una proposta metodologica per un centro storico resiliente

reserved4noDalla difficoltà di reperire esperienze operative volte all’adattamento dei tessuti insediativi storici ai cambiamenti climatici, nasce l’idea di proporre per Ferrara lo sviluppo di una metodologia di analisi finalizzata a definire interventi urbanistici volti a reagire all’aumentare dei pericoli, quali piogge estreme e ondate di calore. La ricerca per un centro storico resiliente prende spunto dall’interesse dimostrato dall’Amministrazione comunale nel 2018 aderendo al progetto europeo PROTECHT2SAVE.The proposal to develop an analysis methodology aimed at defining urban interventions to react to heavy rains and heatwaves in Ferrara comes from the difficulty of finding practical experiences aimed at climate change adaptation in the historic centres. The research for a resilient historic centre is inspired by the interest shown by the Public Administration in 2018 by joining the European project PROTECHT2SAVE.mixedM. Fior, P. Rota, N. Colaninno, E. MorelloFior, M.; Rota, P.; Colaninno, N.; Morello, E

An integrated, agile approach for estimating solar radiation on building facades in complex urban environments

Urban solar radiation is a primary factor affecting indoor and outdoor thermal and lighting comfort. However, although 3D solar radiation models are achieving remarkable advances in urban climate planning support and decision making, they are time-consuming and cost-intensive. We aim at compensating for such limitations by providing an agile approach to estimate shadows and solar radiation on building facades, using elevation models (2.5D) and image processing techniques. This is achieved by making the best use of the new visibility toolset for raster processing, provided in ArcGIS, and GRASS GIS solar radiation 2D model. Results give a clear and detailed picture of the radiation condition in the study area, which offers promising opportunities for urban solar planning and assessment in complex urban areas