ABSTRACT Heat island characteristics depend on the background climate of the site where the city is located. Therefore, an index was defined for the Isfahan metropolitan area to quantify the surface urban heat island intensity. This new index is based on the representative pixels of urban and non-urban areas. For this purpose, MODIS land cover type product (MCD12Q1) data were used to distinguish between urban and non-urban areas. Also, data from the MODIS/Terra land surface temperature product (MOD11A1) from 2000 to 2018 were utilized for daytime and nighttime to study the surface heat island intensity. Then, the representative pixels of urban and non-urban areas were identified using the spatial correlation method, and the heat island index was calculated for the metropolitan area of Isfahan. The study showed that the frequency distribution of the nighttime heat island index follows a normal distribution and is often 3.5 to 4º K above the temperature of the surrounding areas of the city. The 365-day floating mean of the surface urban heat island reveals that this index has increased in recent years. The research of temporal behavior showed that the intensity of the surface urban heat island reaches its maximum in January and becomes weaker in summer, while the survey of spatial behavior showed that the core of the surface urban heat island extends towards downtown areas, where the oldest part of the city is located.

RESUMEN Las características de la isla de calor dependen del clima del lugar donde se encuentra la ciudad. Por lo tanto, se definió un índice para el área metropolitana de Isfahan con el fin de cuantificar la intensidad de la isla de calor urbana superficial. Este nuevo índice se basa en los píxeles representativos de las áreas urbanas y no urbanas. Con este fin se utilizaron datos del producto MODIS para estudiar el tipo de cobertura terrestre (MCD12Q1) con el fin de distinguir entre áreas urbanas y no urbanas. Además, los datos del producto MODIS/Terra para analizar la temperatura de la superficie terrestre (MOD11A1) de 2000 a 2018 se utilizaron durante el día y la noche para estudiar la intensidad de la isla de calor superficial. Luego, los pixeles representativos de áreas urbanas y no urbanas se identificaron utilizando el método de correlación espacial y se calculó el índice de isla de calor para el área metropolitana de Isfahan. El estudio mostró que la distribución de frecuencias para el índice de isla de calor durante la noche sigue una distribución normal y, a menudo, está entre 3.5 y 4º K por arriba de la temperatura de las áreas circundantes de la ciudad. La media flotante de 365 días de la isla de calor urbana superficial revela que este índice ha aumentado en los últimos años. La investigación del comportamiento temporal mostró que la intensidad de la isla de calor urbana superficial es alcanza su máximo en enero y se debilita en verano. La encuesta de comportamiento espacial mostró que el núcleo de la isla de calor urbana superficial se extiende hacia las áreas del centro de la ciudad, donde se encuentra la parte más antigua de ésta.

Abstract Human activities are altering the existing patterns of Land Use Land Cover (LULC) and Land Surface Temperature (LST) on a global scale. However, long-term trends of LULC and LST are largely unknown in many remote mountain areas such as the Karakorum. . The objective of our study therefore was to evaluate the historical changes in land use and land cover (LULC) in an alpine environment located in Islamabad Capital Territory, Pakistan. We used Landsat satellite pictures (namely Landsat 5 TM and Landsat 8 OLI) from the years 1988, 2002, and 2016 and applied the Maximum Likelihood Classification (MLC) approach to categorize land use classes. Land Surface Temperatures (LST) were calculated using the thermal bands (6, 10, and 11) of Landsat series data. The correlation between the Human Modification Index (HMI) and LULC as well as LST was evaluated by utilizing data from Google Earth Engine (GEE). Over the study period, the urbanized area increased by 9.94%, whilst the agricultural and bare soil areas decreased by 3.81% and 3.94%, respectively. The findings revealed a significant change in the LULC with a decrease of 1.99% in vegetation. The highest LST class exhibited a progressive trend, with an increase from 12.27% to 48.48%. Based on the LST analysis, the built-up area shows the highest temperature, followed by the barren, agricultural, and vegetation categories. Similarly, the HMI for different LST categories indicates that higher LST categories have higher levels of human alteration compared to lower LST categories, with a strong correlation (R-value = 0.61) between HMI and LST. The findings can be utilized to promote sustainable urban management and for biodiversity conservation efforts. The work also has the potential of utilizing it to protect delicate ecosystems from human interference and to formulate strategies and regulations for sustainable urban growth, including aspects of land utilization and zoning, reduction of urban heat stress, and urban infrastructure. (LULC (LST scale However longterm long term Karakorum Territory Pakistan namely OLI 1988 2002 201 MLC (MLC classes 6, 6 (6 10 11 (HMI GEE. GEE (GEE) period 994 9 94 9.94% 381 3 81 3.81 394 3.94% respectively 199 1 99 1.99 trend 1227 12 27 12.27 4848 48 48.48% analysis builtup built up temperature barren Similarly Rvalue R value 0.61 061 0 61 efforts growth zoning stress infrastructure 198 200 20 ( (GEE 9.94 38 3.8 39 3.94 19 1.9 122 2 12.2 484 4 48.48 0.6 06 9.9 3. 3.9 1. 12. 48.4 0. 9. 48.

Resumo As atividades humanas estão alterando os padrões existentes de uso e cobertura do solo (LULC) e temperatura da superfície terrestre (TST) em escala global. No entanto, as tendências a longo prazo de LULC e LST são, em grande parte, desconhecidas em muitas áreas montanhosas remotas, como em Karakorum. O objetivo do nosso estudo foi, portanto, avaliar as mudanças históricas no uso e cobertura da terra (LULC) em um ambiente alpino localizado no Território da Capital Islamabad, Paquistão. Utilizamos imagens de satélite Landsat (nomeadamente Landsat 5 TM e Landsat 8 OLI) dos anos de 1988, 2002 e 2016 e aplicamos a abordagem de Classificação de Máxima Verossimilhança (MLC) para categorizar as classes de uso da terra. As temperaturas da superfície terrestre (TST) foram calculadas usando as bandas térmicas (6, 10 e 11) dos dados da série Landsat. A correlação entre o Índice de Modificação Humana (HMI) e o LULC, bem como o LST, foi avaliada utilizando dados do Google Earth Engine (GEE). Durante o período de estudo, a área urbanizada aumentou 9,94%, enquanto as áreas agrícolas e de solo descoberto diminuíram 3,81% e 3,94%, respectivamente. Os resultados revelaram uma mudança significativa no LULC, com uma diminuição de 1,99% na vegetação. A classe LST mais alta apresentou tendência progressiva, com aumento de 12,27% para 48,48%. Com base na análise do LST, a área construída apresentou a temperatura mais elevada, seguida pelas categorias árida, agrícola e vegetação. Da mesma forma, o HMI para diferentes categorias de LST indicou que as categorias mais altas de LST apresentaram níveis mais elevados de alteração humana em comparação com as categorias mais baixas de LST, com uma forte correlação (valor R = 0,61) entre HMI e LST. As conclusões podem ser tomadas como base para promover a gestão urbana sustentável e para esforços de conservação da biodiversidade. O trabalho também tem o potencial de ser utilizado para proteger ecossistemas delicados da interferência humana e para formular estratégias e regulamentos para o crescimento urbano sustentável, incluindo aspectos de utilização e zoneamento da terra, redução do estresse térmico urbano e infraestrutura urbana. (LULC TST (TST global entanto são parte remotas Karakorum portanto Islamabad Paquistão nomeadamente OLI 1988 200 201 MLC (MLC 6, 6 (6 1 11 (HMI GEE. GEE . (GEE) 994 9 94 9,94% 381 3 81 3,81 394 3,94% respectivamente 199 99 1,99 vegetação progressiva 1227 12 27 12,27 4848 48 48,48% elevada árida forma valor 0,61 061 0 61 biodiversidade 198 20 ( (GEE 9,94 38 3,8 39 3,94 19 1,9 122 2 12,2 484 4 48,48 0,6 06 9,9 3, 3,9 1, 12, 48,4 0, 9, 48,

Resumen Muchas ciudades se ven afectadas por el efecto de las islas de calor. En este contexto, el objetivo de este estudio fue analizar la distribución espacial y temporal de las islas de calor urbanas y la influencia de las áreas verdes en la formación de los microclimas urbanos en el municipio de Río de Janeiro, Brasil. Como resultados, se observó que Río de Janeiro está influenciada por las islas de calor, siendo las áreas más antiguas y urbanizadas las más afectadas por altas temperaturas. Se pudo constatar el papel de la vegetación en la formación de los microclimas urbanos mediante el coeficiente de correlación negativo entre la temperatura de la superficie (Ts) y los índices de vegetación (NDVI) y (EVI), así como un coeficiente de correlación positivo entre la temperatura de la superficie (Ts) y el Índice de Áreas Construidas por Diferencia Normalizada (NDBI), lo que demuestra la influencia de la urbanización en el aumento de la temperatura. contexto Brasil resultados temperaturas Ts (Ts NDVI (NDVI EVI, EVI , (EVI) NDBI, NDBI (NDBI) (EVI (NDBI

Abstract Many cities are impacted by the effect of heat islands. In this context, the aim of this study was to analyze the spatial and temporal distribution of urban heat islands and the influence of green areas on the formation of urban microclimates in the city of Rio de Janeiro. As a result, it was observed that Rio de Janeiro city is under heat islands influence, in which the oldest and most urbanized areas of the city are the most affected by high temperatures. It was possible to verify the role of vegetation in the formation of urban microclimates through the negative correlation coefficient between surface temperature (Ts) and vegetation indexes (NDVI and EVI), along with the positive correlation coefficient between surface temperature (Ts) and the Index of Areas Built by Normalized Difference (NDBI), what demonstrates the influence of urbanization on the increase of temperature. context result temperatures Ts (Ts NDVI EVI, EVI , EVI) NDBI, NDBI (NDBI) (NDBI

Resumo Muitas cidades são impactadas pelo efeito das ilhas de calor. Neste contexto, objetivou-se com esse analisar a distribuição espacial e temporal das ilhas de calor urbanas e a influência das áreas verdes na formação dos microclimas urbanos no município do Rio de Janeiro. Como resultados, observou-se que Rio de Janeiro encontra-se sob influência das ilhas de calor, as áreas mais antigas da cidade e sobretudo mais urbanizadas são as mais acometidas pelas altas temperaturas. Foi possível constatar o papel da vegetação na formação dos microclimas urbanos por meio do coordenador de psicologia negativa entre a temperatura da superfície (Ts) e os índices de vegetação (NDVI) e (EVI), e ainda um coeficiente de transferência positiva entre Temperatura da Superfície (Ts) e Índice de Áreas Construídas por Diferença Normalizada (NDBI), demonstrando a influência da urbanização no aumento da temperatura. contexto objetivouse objetivou se resultados observouse observou encontrase encontra temperaturas Ts (Ts NDVI (NDVI EVI, EVI , (EVI) NDBI, NDBI (NDBI) (EVI (NDBI

Abstract One century after the first drive tour to detect the effects of urbanization on the local climate (Vienna, Austria, 1927; Karlsruhe, Germany, 1929), the method is still valid, as evidenced by recent research mentioned throughout this article. This method was applied in two data recording campaigns in eastern Mexico: June to September 2012 in a coastal city (Coatzacoalcos, 320 thousand inhabitants) and August to November 2018 in a mountainous site (Emiliano Zapata, 20 thousand inhabitants). In both campaigns, the urban heat island (ICU, for its acronym in Spanish) was detected within the urban canopy, whose intensity depended on the type of surface and the dominant atmospheric circulation systems at the time of data recording. The peak ICU intensity at the coastal site is 8.7 °C in the daytime and 3 °C at night, while it is up to 1.9 °C at the mountainous site. The tours included the urban area and its periphery, with temperature recorded at points representative of the different surfaces or land uses. Gasoline motor vehicles were used. The data recording equipment was calibrated before the campaigns and installed as far away from the engine as possible to avoid data biased by the heat emitted by the engine. Sensors were set to record data at 1-minute intervals. At each recording point, a 10-minute waiting time was allowed to stabilize sensors; then, the temperature corresponding to minute 10 was recorded. We used a HOBO U10-003 data logger in Coatzacoalcos and a Kestrel 4500 portable meteorological station in Emiliano Zapata. Data were recorded outside of the hours when minimum and maximum temperatures occur because around them it is impossible to identify a clear trend to nighttime or evening cooling or morning warming - a trend necessary to know to reproduce simultaneous thermal measurements. In both sites, the temperatures recorded were corrected according to the thermal trend during tours and altitudinal differences between recording points. Eighteen and ten tours were driven for coastal and mountainous sites, respectively. Various weather conditions were considered, for example, clear or partly cloudy skies prior to a cold front or a tropical wave. From the results, it is inferred that the type of surface, the meteorological events during data recording, and the size of the urban area are key factors determining ICU intensity. At the coastal site, an anticyclone seems to promote the development of the ICU, except for significant meteorological disturbances that induce a weak ICU (thermal differences less than 2 °C). Although the mountainous site, Emiliano Zapata, has an area and population 1:10 relative to the coastal site, it does have an ICU, with a higher temperature in the central urban area, compared to its surroundings where vegetated areas predominate. The average ICU intensity is weak, 1.5 ºC. It is worth mentioning that the analysis of atmospheric temperature alone is limited because multiple additional factors, such as wind, atmospheric humidity, and anthropogenic heat emissions, influence the ICU genesis and evolution. Based on the results and experience gathered in this study, we recommend continuing data recording efforts to extend the ICU study period and include other seasons of the year to have a more detailed characterization. While driving tours have proven to be a suitable method for ICU recording in urban areas, setting a relatively dense network of fixed rooftop stations may improve the analysis and yield at least two ICU detection levels (within the urban canopy through drive tours and above it by fixed stations). Infrared satellite images could supplement the analysis to represent the phenomenon at three levels: ground, canopy, and above-canopy.

Resumen A casi un siglo del primer recorrido en vehículo para detectar efectos de la urbanización en el clima local (Viena, Austria, 1927; Karlsruhe, Alemania, 1929) el método sigue vigente como lo evidencian investigaciones recientes. El presente trabajo recupera datos de temperatura atmosférica de dos campañas de mediciones mediante trayectos vehiculares en el oriente de México: de junio a septiembre de 2012 en una ciudad costera (Coatzacoalcos, 320 000 habitantes) y de agosto a noviembre de 2018 en un asentamiento montañoso (Emiliano Zapata, 20 000 habitantes). En ambas campañas se detectó la presencia de la isla de calor urbana, cuya intensidad resultó dependiente del tipo de superficie y de los sistemas de circulación atmosférica predominantes al momento de las mediciones. La intensidad máxima de la isla de calor urbana diurna en el sitio costero es de 8.7 °C y de 3 °C en el periodo nocturno, mientras que en el sitio montañoso fue de hasta 1.9 °C. También se mostró que la intensidad de ambas islas de calor urbana excede a lo estimado estadísticamente para ciudades de Latinoamérica en función de la población.

Resumen Este trabajo analizó el comportamiento mostrado por la isla de calor en la Ciudad de México durante el periodo comprendido de 1950 a 2010. Se trabajó con datos climatológicos de temperatura media por década; la selección de las estaciones consideró el periodo de funcionamiento y datos disponibles. Se estudió la tendencia de la temperatura media de tres estaciones que cumplieron con características específicas; encontrarse dentro del área urbana desde el inicio de operación; haber sido absorbida por la mancha urbana en algún punto de su periodo de funcionamiento; encontrarse en un área rural. Se constató el incremento de la temperatura al interior del área urbana a través del periodo tiempo en contraste con la zona periurbana que se mantuvo relativamente estable, así mismo, las isotermas mostraron un comportamiento de constante expansión conforme la mancha urbana aumentó en superficie.

Abstract This work analyzed the behavior shown by the heat island in Mexico City from 1950 to 2010. We worked with climatological data of average temperature per decade; the selection of the stations considered the period of operation and available data. The average temperature trend of three stations that met specific characteristics was studied. These characteristics were: being within the urban area from the start of the operation, having been absorbed by the urban area at some point in its period of operation, being in a rural area. The increase in temperature inside the urban area was verified over the period in contrast to the periurban area, which remained relatively stable; likewise, the isotherms showed a behavior of constant expansion as the urban area surface increased.

Resumen La isla de calor urbano superficial es una de las principales causas de la disminución del confort bioclimático en áreas donde los patrones de superficie son heterogéneos, en especial en el verano. El municipio de Oporto tiene características de uso del suelo y materiales de cubierta cuyas propiedades térmicas y radiativas son profundamente diferentes. En este sentido, el presente estudio busca examinar la influencia de la cobertura terrestre en la temperatura superficial utilizando imágenes de satélite. Las temperaturas superficiales se extrajeron de la imagen Landsat 8-OLI y se han derivado varios índices espectrales para identificar el potencial de enfriamiento por evaporación. Los principales resultados muestran que las "islas de calor urbano superficiales" se ubican mayoritariamente en el núcleo central de Oporto y las principales vías de comunicación, donde los efectos de la densificación urbana y las propiedades de recubrimiento del material utilizado impiden la evapotranspiración. Ideas destacadas: Artículo de investigación sobre la influencia de la isla de calor urbana en el municipio de Oporto, en Portugal, basado en análisis de teledetección (imagen Landsat 8-OLI).

Abstract The surface urban heat island is one of the main causes for the decrease in bioclimatic comfort in areas with heterogeneous surface patterns, especially in the summer. The municipality of Porto has characteristics of land use and roofing materials provide thermal and radiative properties that are widely disseminated. The present study seeks to influence the coverage of land cover over land surface temperature using satellite images. As land surface temperature were extracted from the Landsat 8-OLI image, several spectral indices have been derived to identify the potential for evaporative cooling. Main results show that the "superficial urban heat island" are located mainly in the central core of the city of Porto and the main communication routes, where the effects of urban densification and the material covering properties used prevent evapotranspiration, favor the increase radiation absorption and, consecutively, a significant increase in land surface temperature. Highlights: Research article on the influence of the urban heat island in the municipality of Porto, in Portugal, based on remote sensing analysis (Landsat 8 image-OLI).

Resumo A ilha de calor urbano superficial é uma das principais causas para a diminuição do conforto bioclimático em áreas onde os padrões superficiais são heterogéneos, sobretudo no verão. O município do Porto apresenta caraterísticas de uso do solo e materiais de cobertura cujas propriedades térmicas e radiativas são profundamente dissemelhantes. Neste sentido, o presente estudo procura examinar a influência da cobertura do solo sobre a temperatura de superfície, recorrendo às imagens de satélite. As temperaturas de superfície foram extraídas da imagem Landsat 8-oLI, e vários índices espectrais foram derivados para identificar o potencial de arrefecimento evaporativo. Os principais resultados mostram que as "ilhas de calor urbano superficial" se localizam maioritariamente no núcleo central da cidade do Porto e das principais vias de comunicação, onde os efeitos da densificação urbana e das propriedades materiais de cobertura utilizados impedem a evapotranspiração, favorecem o aumento da absorção radiativa e, consecutivamente, o aumento significativo de temperatura de superfície. Ideias destacadas: Artigo de investigação sobre a influência da ilha de calor urbano no município do Porto, em Portugal, a partir da análise por detecção remota (imagem Landsat 8-OLI).

Resumen A partir del procesamiento de imágenes satelitales de alta y baja resolución (Landsat y Modis), el desarrollo de correlaciones bivariadas entre Temperaturas de Superficie Terrestre diurnas, nocturnas y 27 métricas asociadas a la estructura urbana y localización, este trabajo ha analizado la intensidad del fenómeno de la Isla de Calor Urbano en La Ciudad de México en uno de los meses más cálidos del año 2018. Esto ha permitido identificar las zonas más vulnerables ante dicho fenómeno y su asociación con las características de estructura urbana de la misma. En este sentido, se identificó que las temperaturas nocturnas más altas se encuentran a una menor distancia del centro de la Ciudad, es decir, en la zona más consolidada de la misma. La población de 65 o más años, que es la más vulnerable a sufrir problemas de salud asociados a las altas temperaturas por un problema de termorregulación corporal, se localizan en zonas de la ciudad donde se concentran las temperaturas nocturnas más altas. Asimismo, aunque en menor medida, se tiene una correlación directa con las altas temperaturas y las zonas de mayor densidad de vivienda, mayor superficie de calles pavimentadas y mayor concentración de unidades económicas por hectárea. Por el contrario, las zonas con las temperaturas nocturnas más bajas identificadas dentro de la Ciudad se localizaron en las zonas con mayores alturas sobre el nivel del mar, sobre pendientes más pronunciadas y con mayor superficie de áreas libres. Asimismo, la población de 0 a 14 años identificada también dentro del rango de vulnerabilidad a las altas temperaturas se localiza principalmente en las zonas con temperaturas moderadas y/o bajas en las zonas periurbanas principalmente. Por otro lado, para identificar las variaciones térmicas diurnas y nocturnas, tanto en suelo artificial como en suelo con cobertura natural, se generaron perfiles térmicos con mediciones a cada 1000 m, identificando también el uso de suelo. Este perfil térmico ha permitido observar oscilaciones térmicas más pronunciadas durante el día, localizando las temperaturas más altas en las áreas de cultivo, suelo habitacional y de uso mixto. Por el contrario, las temperaturas nocturnas se estabilizan y manifiestan el fenómeno de la Isla de Calor Urbano en el cual se muestra que las temperaturas más altas se concentran en la zona más densa de la ciudad (Alcaldía Cuauhtémoc y Alcaldía Benito Juárez), que han almacenado una mayor cantidad de calor debido a las características de los materiales y composición del entorno urbano, y las zonas con cobertura natural bajan debido a la facilidad para disipar el calor.

Abstract From the processing of high- and low-resolution satellite images (Landsat and Modis), the development of bivariate correlations between daytime and nighttime land surface temperatures, and 27 metrics associated with urban structure and location, this work has analyzed the intensity of the phenomenon of Urban Heat Island manifested in Mexico City in one of the warmest months of the year 2018 to identify the most vulnerable areas to this phenomenon and their urban structure characteristics. Thus, the highest temperatures are found at a shorter distance from the inner city, as the most consolidated area. The population aged 65 or over, which is the most vulnerable to health problems associated with high temperatures and body thermoregulation, is located in areas of the city where the highest night temperatures are concentrated. Likewise, to a lesser extent, there is a direct correlation between high temperatures and areas with higher housing density, a greater surface area of paved streets, and a greater concentration of economic units per hectare. On the contrary, the zones with the lowest temperatures identified within the city were located in areas with the greatest heights above sea level, on steeper slopes, and with a greater surface of open areas. Likewise, the population aged 0 to 14 years, also identified within the range of vulnerability to high temperatures, is located mainly in areas with moderate and/or low temperatures. On the other hand, to identify the diurnal and nocturnal thermal variations, both in artificial and natural cover soil and their land use, thermal profiles were generated with measurements at every 1000 meters. This has allowed it to observe more pronounced thermal oscillations during the day, with the highest temperatures in the cultivation areas, residential land, and mixed-use. On the contrary, night temperatures stabilize and manifest the phenomenon of the Urban Heat Island in which it is shown that the highest temperatures are concentrated in the densest area of the city (Alcaldía Cuauhtémoc and Alcaldía Benito Juárez), which have stored a greater amount of heat due to the characteristics of the materials and composition of the urban environment, and the areas with a natural cover go down due to the ease of dissipating heat.

Global population growth and rapid urbanisation have resulted in the rapid transformation of natural topographies that are now dominated by engineering materials and structures. It is widely recognised that economic development is largely attributable to infrastructure development. However, this development has come about with adverse consequences. In this paper, the effects of surface characteristics, climatic parameters and material properties on the thermal environment and near-surface heat islands in urban areas were investigated. An experiment was conducted in which simple concrete structures with varying surface characteristics were constructed and instrumented. The effect of solar absorptivity was clearly visible, with structures surfaced with low absorptivity materials exhibiting lower surface and effective temperatures. Following the experimental programme, numerical simulations of the simple concrete structures were performed using finite element modelling. The analyses showed that the thermal environment of concrete structures is sensitive to changes in solar absorptivity, climatic parameters, cross-sectional dimensions, and material properties. It was found that the use of low absorptivity or highly reflective surfacing and the selection of appropriate dimensions can be used to significantly reduce the temperatures of concrete infrastructure, including buildings and pavements, thereby providing an evidential basis for the use of low absorptivity surfacing materials to mitigate climate change in Southern Africa.

Abstract The Guadalajara Metropolitan Area (GMA), in western Mexico, has experienced a rapid demographic and urban growth in recent decades. As a result of land use changes, an Urban Heat Island (UHI) has developed and intensified, which reflects not only in air surface temperature increases, but also in higher atmospheric moisture content and more intense precipitation events. Storms have become more frequent since the beginning of 1980s, which makes them one of the major meteorological hazards for the city. Such an increase in strong storms appears to be related to the urbanization process which in turn, has increased the vulnerability of the GMA to intense rains. The urban expansion towards the higher parts of the region has led to more water runoff and flash flood events in the low-level parts of the metropolitan area. An analysis by means of observed meteorological data and a rainfall - runoff model shows that the combined effect of increased precipitation and vulnerability results in a higher risk of urban flash floods. The loss of natural vegetation, the main roads that act as water channels that converge into the central part of the city, an insufficient drainage system and the lack of prevention actions have resulted in more frequent urban flash floods. All these vulnerability factors are associated with an inadequate urban expansion process. The model of flood risk may be used to define adaptation measures to face a changing climate.

Resumen La Zona Metropolitana de Guadalajara (ZMG), en el occidente de México, ha experimentado un rápido crecimiento demográfico y urbano durante las últimas décadas. Como resultado de los cambios en el uso del suelo, se ha desarrollado e intensificado una isla de calor urbano (UHI), que se refleja no solo en aumentos de la temperatura de la superficie del aire, sino también en un mayor contenido de humedad atmosférica y eventos de precipitación más intensos. Las tormentas se han vuelto más frecuentes desde principios de la década de 1980, lo que las convierte en uno de los principales peligros meteorológicos para la ciudad. Este aumento de tormentas fuertes parece estar relacionado con el proceso de urbanización que, a su vez, ha aumentado la vulnerabilidad de la ZMG a las lluvias intensas. Esta expansión hacia las partes más altas de la región ha provocado más escorrentías y eventos de inundaciones repentinas en las partes bajas del área metropolitana. Un análisis por medio de datos meteorológicos observados y un modelo de lluvia-escorrentía muestra que el efecto combinado de mayor precipitación y vulnerabilidad resulta en un mayor riesgo de inundaciones urbanas repentinas. La pérdida de vegetación natural, las vías principales que actúan como canales de agua, que confluyen en la parte central de la ciudad, un sistema de drenaje insuficiente y la falta de acciones de prevención han dado como resultado inundaciones urbanas súbitas más frecuentes. Todos estos factores de vulnerabilidad están asociados a un inadecuado proceso de expansión urbana. El modelo de riesgo de inundaciones puede utilizarse para definir medidas de adaptación para hacer frente a un clima cambiante.

Resumen La combinación de condiciones naturales (latitudes tropicales) y antropogénicas (Cambio Climático, Isla de Calor Urbana) inducen el incremento extremo de la temperatura; aunque los mecanismos no son claros. El cambio de uso de suelo es una de las principales causas de la Isla de Calor Urbana (ICU), aunque su intensidad depende de las condiciones locales. La investigación del medio ambiente en entornos urbanos es de relevancia, considerando que para el año 2030 el 60% de la población mundial se concentrará en ciudades y desde ahí enfrentará condiciones climáticas cada vez más extremas. Este estudio se centra en la relación del cambio de uso de suelo y la temperatura de superficie (TS) para conocer su influencia en la ICU de la ciudad de Tuxtla Gutiérrez. A fin de conocer el patrón espacial de las temperaturas extremas en la ciudad de Tuxtla Gutiérrez, Chiapas se analizó el comportamiento histórico de la temperatura del aire (TA) y de superficie (TS). Respecto a la TA, a partir de 1980 la frecuencia de las temperaturas superiores a 40 °C aumentó en un 18% y de las temperaturas nocturnas por arriba de los 28 °C en un 14%. El análisis histórico de temperaturas ambientales ayudó a determinar las tres fechas para la obtención de imágenes Landsat 5 (5 de abril de 2001) y Landsat 8 (1 de abril de 2011 y 2017). Para el análisis termal se emplea el Método de Clasificación de Emisividad el cual estima las TS con base en la emisividad reportada para cada uso y cobertura de suelo; en este estudio se emplean nueve clases: agua, árbol, camino de asfalto, césped, suelo desnudo, suelo agrícola desnudo, techo de concreto, techo de metal y techo de teja. En 2017, la máxima TS (>40 °C) se registró en los techos de metal de centros comerciales con estacionamientos a cielo abierto. Este uso de suelo cubre menos del 3% de la ciudad. El suelo desnudo agrícola cubre la periferia de la ciudad y representa el 11% de la ciudad, se reporta con una TS promedio de 35 °C, seguida de los caminos de asfalto con 34 °C y techos de concreto con 32 °C. La resolución espacial de las imágenes limita la apreciación del efecto amortiguador de temperaturas de un árbol y únicamente es sensible al efecto de agrupaciones, por ello la mínima TS (< 28 °C) se registra en zonas arboladas mayores a 3 ha. La variación de TS cuando se elimina la cobertura arbórea (1.3 a 3.1 °C) es mayor que cuando se reforesta (0.1 a 1.2 °C). Se recomienda realizar el análisis con imágenes termales de mayor resolución espacial para apreciar el efecto refrescante de árboles individuales. Comparando los resultados entre las tres fechas de análisis, la cobertura que más ha disminuido en superficie es árbol convirtiéndose en suelo agrícola desnudo, techo de concreto y teja. Estos cambios de cobertura se asocian al aumento en la temperatura promedio de la ciudad, que en el año 2001 se encontraba en el rango de temperatura poco agradable (29° a 31°C), para 2011 era extremadamente desagradable (31° a 33 °C) y en 2017 llego al rango de temperatura de condiciones de estrés (33° a 35 °C). El reemplazo de árboles por superficies impermeables es la principal causa del aumento de la TS en Tuxtla Gutiérrez. La metodología empleada permite el registro de temperatura de superficie de las diferentes coberturas dentro de la ciudad, evitando la homogenización del terreno como se haría con una metodología basada en NDVI. Sin embargo, un área de oportunidad para mejorar los resultados obtenidos con esta metodología es la medición directa de la emisividad de superficie, así como el registro termal durante la noche.

Abstract A combination of natural (tropical latitudes) and human induced (Climate Change, Urban heat island) conditions give rise and exacerbate extreme hot temperatures, but mechanisms are unclear. Land use and land cover change (LULC) is considered one of the main causes of Urban Heat Island (UHI) but its contribution varies depending on local conditions. This study focuses on determining the influence of land use change on the UHI effect in Tuxtla Gutiérrez City by investigating the relationship between LULC and land surface temperature (LST). Through Landsat 5 and Landsat 8 imagery, this study analyzes historical LST. In 2017, the highest LST (>40 °C) occurred in the metal ceiling land class, which is made up of malls with open-air parking zones. This coverage occupied less than 3% of the total city area. Bare agriculture soil (BAS) class, located mainly on the periphery of the city, represented 11% of the city, and reported a mean LST of 35 °C, followed by asphalt roads with 34 °C and concrete ceiling with 32 °C. The lowest LST (< 28 °C), occurred in contiguous areas of trees greater than 3 ha. The LST variation when land use changed from trees to another coverage (1.3 to 3.1 °C) is higher than in the opposite direction (0.1 to 1.2 °C). The elimination or replacement of tress with impervious surfaces are the main causes for LST increase in Tuxtla Gutiérrez.

ABSTRACT The city of Eskişehir is located in the Central Anatolia Region of Turkey, where harsh continental climatic characteristics are prevalent (i.e., cold winters and hot summers). In recent years, quality and quantity of studies on bioclimatic comfort have increased both all over the world and in Turkey. Outdoor bioclimatic comfort conditions are counted amongst the indicators of human quality of life in urban environments, together with other physical, social and economic features such as air quality, GDP, and possibilities of social activities. The calculated values representing bioclimatic comfort conditions have been used instead of individual mean values of some climatic elements, in order to provide an insight of the liveability of a city. The aim of the present research study is to determine: (1) hourly bioclimatic comfort conditions in the Eskişehir city center during sultry summer days, considering bioclimatic comfort values calculated according to 12-year data from urban, sub-urban and rural areas using the physiological equivalent temperature (PET) index and RayMan software for the calculation of solar radiation fluxes on individuals in the hottest five months of the year; (2) the spatial distribution of these comfort values in decades (10-day intervals) using Geographic Information Systems and raster maps, taking into consideration elevation and land use; and (3) which urban design and planning principles could be adopted to deal with adverse thermal comfort conditions triggered by the urban heat island (UHI) effect. The results of the study indicate that the poorest comfort conditions are provided in urban areas, while rural areas are more advantageous in terms of comfort conditions. New bioclimatic-sensitive urban design principles are taken into consideration to create more comfortable areas from the bioclimatic perspective (i.e., windier and less humid sites open to the prevalent wind direction and out of heat stress).

RESUMEN La ciudad de Eskişehir está ubicada en la región de Anatolia central, Turquía, donde prevalecen rigurosas condiciones climáticas continentales (i.e., inviernos fríos y veranos calientes). En años recientes, la calidad y cantidad de los estudios relativos a confort bioclimático han aumentado, tanto globalmente como en Turquía. Las condiciones externas de confort bioclimático se encuentran entre los indicadores de calidad de vida en ambientes urbanos, junto con otras características físicas, sociales y económicas como la calidad del aire, el PIB y la posibilidad de realizar actividades sociales. Los valores que representan condiciones de confort bioclimático se han utilizado en lugar de los valores medios individuales de algunos elementos climáticos para establecer el grado de habitabilidad de una ciudad. El objetivo del presente estudio es determinar: 1) condiciones horarias de confort bioclimático en el centro de la ciudad de Eskişehir en días de calor sofocante, tomando en cuenta valores de confort bioclimático, calculados a partir de una base de datos de 12 años de zonas rurales, urbanas y suburbanas, con un índice de temperatura fisiológica equivalente y el software RayMan para determinar los flujos de radiación solar en individuos durante los cinco meses más calurosos del año; 2) la distribución espacial de estos valores en intervalos de 10 días utilizando sistemas de información geográfica y mapas de bits, tomando en cuenta la elevación y los usos del suelo; y 3) qué diseño urbano y principios de planificación pueden adoptarse para enfrentar condiciones de confort climático adversas desencadenadas por el efecto de la isla urbana de calor. Los resultados del estudio indican que las peores condiciones de confort corresponden a áreas urbanas y las mejores a zonas rurales. Se toman en cuenta nuevos principios de diseño urbano sensibles a aspectos bioclimáticos para crear áreas más confortables desde la perspectiva bioclimática (es decir, sitios con más viento y menos humedad, en los que se aproveche la dirección prevalente del viento y se evite el estrés por exceso de calor).

Abstract Carbonaceous aerosols can affect climate, especially particles containing black carbon (BC). BC originated from the incomplete combustion of fossil fuel and biomass, which can heat the atmosphere and increase ice melting, but little is known about BC sources to Antarctica. We quantified the contribution of distant origin (biomass burning) and local emissions (fossil fuel) to atmospheric BC concentration in the King George Island (Antarctic Peninsula) and the Southern Ocean. We examine the BC concentrations using a multi-wavelength Aethalometer AE-33 and AE-42 aboard the Brazilian Oceanographic Research Ship Almirante Maximiano. The results indicate that the region is influenced by local sources and air masses coming from surrounding continents. Fossil fuel combustion was the major source of carbonaceous aerosols in the region, whereas the total average concentration was 41.8 ± 22.8 ng m-3. The findings indicate a contribution of biomass burning coming from low and mid-latitudes of South America over the Antarctic Peninsula and the Southern Ocean around 62ºS latitude. We demonstrated that fossil fuel is the main contributor to atmospheric BC concentration for the Austral summer and autumn. Scientific stations, local tourism, and traffic are possible local BC sources. Our work invokes the urgency of questionable sustainability issues about Antarctica exploration.

Abstract Heat transfer process in the soil active layer is important for the knowledge of its thermal properties linked with climate issues. The objective of this work was to analyze the energy flux in different soil profiles by estimating the apparent soil thermal diffusivity ($ATD$). The study was carried out in Keller Peninsula, located at King George Island in four different sites differing by soil characteristics, as well as vegetation coverage and landscape setting. The $ATD$ was estimated in function of the long-term hourly temperature records at different soil depths. In addition, we estimated the seasonal mean of the $ATD$ and the freezing $N$-factor. Results showed that $ATD$ values were smaller at shallow depths and increased with depth. The diffusivity values presented lower variability in colder conditions, especially at deeper soil layers. Water content was the main factor affecting soil thermal diffusivity at sites $1$ and $3$ (more than $70$ and $63\%$ of probability). At sites $3$ and $4$ lower $N$-factors were observed, suggesting higher snow pack and permafrost closer to the soil surface. Hence, positive $ATD$ appears in the summer due to thawing increases soil moisture, while negative $ATD$ appears during the freeze of the snow pack and precipitation.

Resumo O tipo e uso cobertura do solo desempenham papel decisivo para a temperatura da superfície continental (LST). Como as cidades são compostas por coberturas variadas, incluindo vegetação, áreas construídas, prédios, estradas e áreas desprovidas de vegetação, compreender os padrões da LST no complexo espaço urbano se faz cada vez mais importante. O presente estudo investigou a relação da LST com o albedo, NDVI, NDWI, NDBI e NDBaI no período de 1994 e 2017. Foram utilizadas imagens dos sensores Thematic Mapper (TM) e Thermal Infrared Sensor (TIRS) a bordo dos satélites Landsat 5 e 8, respectivamente. As imagens foram processadas, reamostradas (resolução espacial de 120 m) no ambiente do software QGIS 3.0 e, por fim, foram extraídos centroides com um total de 1252 pontos. O modelo de regressão clássica (RC) foi aplicado às variáveis seguidas por modelos espaciais autoregressivos e de erro espacial (MEAR e MEE) e os resultados foram comparados a partir de índices de acurácia. Os resultados mostram que o maior coeficiente de correlação existe foi verificado entre albedo e NDBaI (r = 0,88). A relação entre o albedo e a LST, com r = 0,7, também é positiva e significativa ao nível de (р < 0,05). A partir do índice I de Moran Global verificou-se a dependência espacial e não estacionariedade da LST (I = 0,44). O modelo MEE apresentou as melhores métricas de acurácia (AIC = 3307,15 e R2 = 0,65) explicando consideravelmente mais variações na relação dos fatores explicativos e da LST para a região metropolitana de Belém, quando comparados aos modelos convencionais de RC.

Abstract The type of land use and land cover plays a decisive role in land surface temperature (LST). As cities are composed of varied covers, including vegetation, built-up areas, buildings, roads and areas without vegetation, understanding LST patterns in complex urban spaces is becoming increasingly important. The present study investigated the relationship between LST and albedo, NDVI, NDWI, NDBI and NDBaI in the period between 1994 and 2017. Images from Thematic Mapper (TM) and Thermal Infrared Sensor (TIRS) onboard the Landsat 5 and 8 satellites, respectively, were used in the study. The images were processed, resampled (spatial resolution of 120 m) in the environment of the QGIS 3.0 software and, finally, centroids were extracted resulting in a total of 1252 points. A classical regression (CR) model was applied to the variables, followed by spatial autoregressive (SARM) and spatial error (SEM) models, and the results were compared using accuracy indices. The results showed that the highest correlation coefficient was found between albedo and NDBaI (r = 0.88). The relationship between albedo and LST (r = 0.7) was also positive and significant at р < 0.05. The global Moran's I index showed spatial dependence and non-stationarity of the LST (I = 0.44). The SEM presented the best accuracy metrics (AIC = 3307.15 and R2 = 0.65) for the metropolitan region of Belém, explaining considerably more variations in the relationship between explanatory factors and LST when compared to conventional CR models.

Resumen En la ciudad de Presidente Prudente, situada en el oeste del estado de San Pablo (Brasil), se han realizado en las últimas décadas estudios pioneros para constatar la existencia de la isla de calor en una urbe de tamaño poblacional medio, lo que tradicionalmente se investigaba en aglomerados urbanos. Estos trabajos, que abordan la isla de calor urbana como un hecho mensurable, pueden complementarse con un aporte alternativo para profundizar en su conocimiento. Por eso, el presente trabajo observa este fenómeno climático desde la Teoría de los Sistemas Complejos, que permite analizar su constitución desde sus principales componentes y sus relaciones espacio-temporales, lo cual permite conocer la formación y funcionamiento de la isla de calor prudentina como sistema. Esta visión corrobora la presencia del fenómeno, pero en su evolución surgen desfasajes en algunos aspectos, que lleva a formular interrogantes y recurrir a los estudios realizados para abrir nuevos caminos de investigación.

Abstract In the city of Presidente Prudente, located in the western state of São Paulo (Brazil), pioneering studies have been carried out in recent decades to verify the existence of the heat island in a city of medium population size, what was traditionally researched in urban agglomerates. These works, which consider urban heat island as a measurable fact, can be complemented with an alternative contribution to deepen their knowledge. Therefore, the present work observes this climatic phenomenon from the Theory of Complex Systems, which allows analyzing its constitution from the main components and its spatial-temporal relations, which allows to know the formation and operation of the prudentine heat island as a system. This vision corroborates the presence of the phenomenon, but in this evolution, there are gaps in some aspects, which leads to the formulation of questions and the use of studies carried out to open new ways of research.