Evaluating Urban Heat Island Effects in Rapidly Developing Coastal Cities

In this chapter, we present the analysis of urban heat island (UHI) effects on coastal urban areas using satellite images as a case study in Hangzhou, China. With the sustainable development of coastal areas, land use and land cover have been dramatically changed. Such changes make the phenomenon of urban heat island (UHI) becoming serious, which has brought some negative influences on human activities or public health issues in coastal regions. This study takes Hangzhou as an example of coastal cities and uses the Landsat TM, ETM+ and OLI images to retrieve the urban land surface temperature (LST). We also mapped and compared the intensity of UHI effects in different years of 2003, 2008 and 2013. The result shows that the intensity of UHI effect in 2013 was more serious than previous years, which is increasing year by year. The study also analyzed the relationship between UHI, NDVI, and NDBI and provided some useful suggestions to mitigate the UHI effects on coastal cities such as Hangzhou in China

Effects of Spatial Pattern of GreenSpace on Land Surface Temperature: A case study on Oasis City Aksu, northwest China

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.The urban heat island (UHI) refers to the phenomenon of higher atmospheric and surface temperatures occurring in urban areas than in the surrounding rural areas. Numerous studies have shown that increased percent cover of greenspace (PLAND) can significantly decrease land surface temperatures (LST). Fewer studies, however, have investigated the effects of configuration of greenspace on LST. This thesis aims to fill this gap using oasis city Aksu, northwest China as a case study. PLAND along with two configuration metrics were used to measure the composition and configuration of greenspace. The metrics were calculated by moving window method based on a greenspace map derived from Landsat Thematic Mapper (TM) imagery, and LST data were retrieved from Landsat TM thermal band. Normalized mutual information measure was employed to investigate the relationship between LST and the spatial pattern of greenspace. The results showed that PLAND was the most important predictor of LST. Configuration of greenspace also significantly affected LST. In addition, the variance of LST was largely explained by both composition and configuration of greenspace. Results from this study can expand our understanding of the relationship between LST and vegetation, and provide insights for improving urban greenspace planning and management

Variabilidad de la temperatura de superficies en el NW de la provincia de Neuquén a partir de informción satelital.

La complejidad del terreno y la falta de datos meteorológicos siguiendo el gradiente altitudinal obliga a la exploración de nuevos métodos o esquemas entre los que se encuentra el análisis por medio de modelos o imágenes satelitales. El presente trabajo pretende describir el marco de información con el que se cuenta en el NW neuquino y la introducción de análisis espacial de distribución de la temperatura de superficie a partir de imágenes NOAA- AVHRR con miras a la inclusión futura de nuevos esquemas de estudio.La temperatura del aire presenta gran variabilidad espacial, principalmente en los valores mínimos, una idea de esta distribución puede asociarse a la temperatura de superficie que es obtenida a partir del análisis de imágenes NOAA-AVHRR. Este trabajo presenta el análisis de situaciones particulares de la temperatura de superficie de la zona NW de la Provincia de Neuquén utilizando imágenes de satélites NOAA en alta resolución (AVHRR) e imágenes LANDSAT de la región. La temperatura de superficie obtenida utilizando la información de los canales 4 y 5 del sensor AVHRR presenta la distribución espacial de la temperatura del suelo que pone en evidencia la complejidad del comportamiento, asociado al relieve. Se observa la dependencia de las isotermas con la altura, alcanzando los menores valores de temperatura de superficie en los picos. Esta metodología permitiría incorporar información cuya escala consideraría con mayor detalle que en escala sinóptica de la temperatura de superficie de píxeles de aproximadamente 1 km2. El análisis posterior de una mayor cantidad de situaciones, permitiría realizar mapas estacionales de temperatura de superficie en una escala que no es posible obtener con el instrumental que se encuentra instalado en este momento, pudiendo asociarse posteriormente al comportamiento de la temperatura del aire

A study of temperature's spatial distribution in Neuquen River valley through satellite imaging

En el presente trabajo se estudia la distribución espacial de la temperatura de brillo y superficie, con la utilización de imágenes satelitales lAndSAt7 EtM+ y noAA-AVHRR en el valle cultivado del río neuquén. El estudio de la distribución espacial de la temperatura en una zona con un terreno algo complejo implica la utilización de una gran densidad de mediciones meteorológicas. Muchas veces no es posible concretar la densidad adecuada de la red agrometeorológica debido a los altos costos de instalación y mantenimiento. Los sensores remotos proporcionan un gran caudal de información en una variedad de resoluciones, con costos considerablemente menores. la determinación de zonas cálidas y frías en el valle permitiría hacer más eficientes los métodos de riego y de lucha contra heladas y proporcionaría herramientas para la mejor planificación productiva de la zona.This paper looks into the spatial distribution of brightness and surface temperature through the use of lAndSAt7 EtM+ and noAA-AVHRR satellite imagery in the cultivated valley of the Neuquén river. Studying the spatial distribution of temperatures in an area with a somewhat complex terrain requires the use of a great density of meteorological measurements. It is often impossible to obtain the right density of the argometeorological network due to the high installation and maintenance costs. Remote sensors provide a large flow of information in various resolutions, at considerably lower costs. determining the valley's warm and cold zones would allow for more efficient irrigation and frost-protection methods, and it would provide tools to improve the area's productive planning.Departamento de Geografí

Remote sensing of energy and water fluxes over Volta Savannah catchments in West Africa

The deterioration of the West African savannah in the last three decades is believed to be closely linked with about 0.5 C rise in temperature leading to evaporation losses and declining levels of the Volta Lake in Ghana. Although hydrological models can be used to predict climate change impacts on the regional hydrology, spatially-observed ground data needed for this purpose are largely unavailable. This thesis seeks to address this problem by developing improved methods for estimating energy and water fluxes (e.g. latent heat [ET]) from remotely sensed data and to demonstrate how these may be used to parameterize hydrological models. The first part of the thesis examines the potential of the Penman-Monteith method to estimate local-scale ET using groundbased hydrometeorological observations, vegetation coefficients and environmental data. The model results were compared with pan observations, scintillometer (eddy correlation) measurements and the Thomthwaite empirical method. The Penman- Monteith model produced better evaporation estimates (~3.90 mm day(^-1) for the Tamale district) than its counterpart methods. The Thomthwaite, for example, overestimated predictions by 5.0-11.0 mm day(^-1). Up-scaling on a monthly time scale and parameterization of the Grindley soil moisture balance model with the Thomthwaite and Penman-Monteith data, however, produced similar estimates of actual evaporation and soil moisture, which correlated strongly (R(^2) = 0.95) with water balance estimates. To improve ET estimation at the regional-scale, the second part of the thesis develops spatial models through energy balance modelling and data up-scaling methods, driven by radiometric measurements from recent satellite sensors such as the Landsat ETM+, MODIS and ENVISAT-AATSR. The results were validated using estimates from the Penman-Monteith method, field observations, detailed satellite measurements and published data. It was realised that the MODIS sensor is a more useful source of energy and water balance parameters than AA TSR. For example, stronger correlations were found between MODIS estimates of ET and other energy balance variables such as NDVI, surface temperature and net radiation (R(^2) = 0.67-0.73) compared with AATSR estimates (R(^2) = 0.31-0.40). There was also a good spatial correlation between MODIS and Landsat ETM+ results (R(^2) = 0.71), but poor correlations were found between AATSR and Landsat data (R(^2) = 0.0-0.13), which may be explained by differences in instrument calibration. The results further showed that ET may be underestimated with deviations of ~2.0 mm day 1 when MODIS/AATSR measurements are validated against point observations because of spatial mismatch. The final part of the thesis demonstrates the application of the ET model for predicting runoff (Q) using a simplified version of the regional water balance equation. This is followed byanalysis of flow sensitivity to declining scenarios of biomass volume. The results showed the absence of Q for >90% of the study area during the dry season due largely to crude model approximation and lack of rainfall data, which makes model testing during the wet season important. Runoff prediction may be improved if spatial estimates of rainfall, ET and geographical data (e.g. land-use/cover maps, soil & geology maps and DEM) could be routinely derived from satellite imagery

Multi-band remote sensing based retrieval model and 3D analysis of water depth in Hulun Lake, China

Hulun Lake, a large lake located on the cold and arid Hulunbeir grassland in the Inner Mongolia Autonomous Region, is the fifth largest in China and the largest in the north of the country. However, the information on the lake’s characteristics (e.g., water depth versus surface area) is scarce in literature. Based on the lake’s physiographic features, this study developed and used a model that merges the sunlight reflection band with the thermal infrared radiation band to simulate the lake’s characteristics. The model verification and error analysis indicated an optimal model structure of logarithm. Thus, this logarithmic model was selected to analyze the spectral data. The results indicated that the model did a good job in reproducing observed water depths and accurately predicted the depths on 24 September 2007. This showed that this model can be reliably applied to the cold and arid region. Subsequently, the results were used to generate a triangular irregular network (TIN) model, which in turn was used to compute the functional relations between water level, surface area, and volume. The correlation between water level and volume is superior to that between water level and area. The regression equation developed in this study can be used to estimate the volume when water elevation is knowninfo:eu-repo/semantics/publishedVersio

Temperatura de superficie en el Valle del Río Neuquén Utilizando Imágenes LANDSAT

AbstractStudies of surface and air temperature from LANDSAT need a great density of meteorological stations following the altitudinal variation and complexity of terrain.Alternative methods for the study of the spatial distribution are useful. In this paper, the seasonal variation of surface temperature is analyzed by LANDSAT7 ETM + thermal channel information considering an area of the productive valley of the Neuquén River. Landsat 7 ETM + images offer information with 60 m of spatial resolution; its behavior showed agreement with topography. The calculation of surface temperature using LANDSAT imagery should include surface meteorological data: atmospheric water vapor content and mean air temperature near to the surface, simultaneously to the passage of the satellite.The data were corrected using Atmospheric Correction Parameter Calculator, available online. Areas near Neuquén river show lower surface temperature in summer, while the southeastern areas presented surface temperature between 4oC and 5°C smaller, and the zones of greater slope in the northern area on the plateau presented surface temperature approximately 4°C. In summer, the cultivated areacan be more clearly differentiated, that would be indicative of phenological changes of fruit trees and the greater contrasts of temperature due to the differential warming from various surfaces. Temperature differences were smaller in winter. In winter, the temperature of surface of the humid areas, zones with water and zone of the plateau is relatively greater to the surrounding areasEstudios de la temperatura del aire y del suelo, suelen ser escasos debido a la necesidad de contar con redes de información micro o meso meteorológicas que incorporen una importante densidad espacial de observaciones siguiendo el gradiente altitudinal y la complejidad del terreno. Por ello se hace necesario incorporar métodos alternativos para el estudio de la distribución espacial de variables meteorológicas.En este trabajo se presenta el análisis de la variabilidad estacional de la temperatura de superficie a partir de imágenes LANDSAT 7 ETM+ usando de información del canal térmico en el valle productivo del río Neuquén.Las imágenes Landsat 7 ETM+ brindan información con 60 m de resolución,su comportamiento muestra concordancia con la variabilidad espacial de la topografía. Para el cálculo de la temperatura de superficie con imágenes LANDSAT debe contarse con datos meteorológicos de superficie, como el contenido de vapor de agua atmosférico y la temperatura media del aire cercano a la superficie, en tiempos simultáneos al pasaje del satélite. Para la obtención de dichos datos se utilizó la herramienta Atmospheric Correction Parameter Calculator, disponible online.Los patrones de temperatura efectiva en el valle del río Neuquén a partir del análisis de imágenes LANDSAT presentan un área ribereña que puede ser delimitada como un área con menor temperatura en verano. Mientras que las áreas en la región ubicada al sudeste presentan valores de temperatura entre 4oC y 5°C menores, y las zonas de mayor pendiente ubicadas hacia el norte y el área sobre la meseta presentan temperatura de superficie aproximadamente 4°C mayor que las ubicadas al este.En verano se puede diferenciar más claramente la zona cultivada, lo que sería indicativo de los cambios fenológicos de los cultivos y de los mayores contrastes de temperatura debidos al calentamiento diferencial de las superficies a partir de la mayor disponibilidad energética por unidad de área en verano, en invierno los contrastes fueron menores.En invierno la temperatura de superficie de las áreas húmedas, zonas con agua y zona de meseta es relativamente mayor a las áreas circundantes.AbstractStudies of surface and air temperature from LANDSAT need a great density of meteorological stations following the altitudinal variation and complexity of terrain.Alternative methods for the study of the spatial distribution are useful. In this paper, the seasonal variation of surface temperature is analyzed by LANDSAT7 ETM + thermal channel information considering an area of the productive valley of the Neuquén River. Landsat 7 ETM + images offer information with 60 m of spatial resolution; its behavior showed agreement with topography. The calculation of surface temperature using LANDSAT imagery should include surface meteorological data: atmospheric water vapor content and mean air temperature near to the surface, simultaneously to the passage of the satellite.The data were corrected using Atmospheric Correction Parameter Calculator,available online. Areas near Neuquén river show lower surface temperature in summer, while the southeastern areas presented surface temperature between 4oC and 5°C smaller, and the zones of greater slope in the northern area on the plateau presented surface temperature approximately 4°C. In summer, the cultivated area can be more clearly differentiated, that would be indicative of phenological changes of fruit trees and the greater contrasts of temperature due to the differential warming from various surfaces. Temperature differences were smaller in winter. In winter, the temperature of surface of the humid areas, zones

Impacts of eco-environmental quality, spatial configuration, and landscape connectivity of urban vegetation patterns on seasonal land surface temperature in Harare metropolitan city, Zimbabwe

The study examined the impact of eco-environmental quality conditions, spatial configurations and landscape connectivity of urban vegetation on seasonal land surface temperature (LST) in Harare, Zimbabwe between May and October 2018. The results showed that densely built-up areas with sparse vegetation experienced extremely poor eco-environmental conditions. Clustered and highly connected were more beneficial in decreasing LST. These findings have important urban and landscape planning implications regarding how the spatial configuration and land-scape connectivity patterns of urban vegetation can be optimized to mitigate Urban Heat Island (UHI) effects and to improve the thermal comfort conditions in rapidly urbanizing cities

Analysis of urban heat island climates along the I-85/I-40 corridor in central North Carolina

Land surface temperature is a significant parameter for identifying micro-climatic changes and their spatial distributions relative to the urban environment. This paper examined and identified the urban heat islands and their spatial and temporal variability along the I-85/I-40 corridor in central North Carolina between 1990 and 2002. More specifically, the study focused on: (1) understanding the behavior of the spectral and thermal signatures of various land cover and land use types and their relationships with UHI development, and (2) applying digital remote sensing techniques to observe and measure the temporal and spatial variability of these surface heat islands. An assemblage of remotely sensed imagery (Landsat data), land surface temperature data, land cover and land use classifications, vegetation indices, and archived weather data was used to create maps, charts and statistical models to indicate and display the magnitude and spatial extent of these thermal climates. The data revealed that urbanization in the I-85/I-40 corridor region increased significantly between 1990 and 2002. Quantitative results from the satellite imagery also indicated that differences in land cover/ land use types, anthropogenic heat sources, and land surface temperature variability likely contributed to a temperature rise in the corridor study area thus thermal climate development

Pansharpened landsat 8 thermal-infrared data for improved land surface temperature characterization in a heterogeneous urban landscape

Challenges associated with adolescents are prevalent in South African societies. During the adolescence stage, children may become involved in deviant behaviour. Although a significant number of studies have focused on the factors that contribute to adolescents’ deviant behaviour, including parental factors, there is paucity of research specifically in rural communities. This study explores the contribution of parental factors to adolescents’ deviant behaviour in rural communities in South Africa. Guided by the qualitative approach, the present study makes use of semi-structured interviews to collect data and thematic analysis to analyse data