This paper aims to investigate the influences of urban growth and green land cover decrease on land surface radiative properties and metropolitan climate of Bucharest in Romania. Remote sensing data from Landsat TM/ETM/OLI, Sentinel 2 and time series MODIS Terra/Aqua thermal infrared sensors as well as in-situ meteorological data have been used to assess urban land cover– air and land surface temperature interactions over period between 2000 and 2019 years. The air (Ta) and land surface temperature (Ts), key parameters for urban climate research, were analyzed in relation with variables land surface albedo and Normalized Difference Vegetation Index (NDVI) at city level. Based on these parameters, the urban growth, Urban Heat Island (UHI) effect and the relationships of Ts to other biogeophysical parameters have been analyzed. The correlation analyses revealed that, at the pixel-scale, Ta and Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. Was also analyzed UHI phenomenon during extreme heat waves events. Our results suggest that monthly mean UHI intensity is between 1°C and 6°C, and the most intense UHI occurs in day-time in the summer period during heat waves periods. The analysis shows that different urban/periurban zones and landscapes bring diurnally and seasonally different contributions to the local and regional thermal environment. City land cover was the most important contributor to increases in regional Ts. Vegetation had a clear cooling effect as the normalized vegetation difference index (NDVI) increased during summer periods.
This paper investigated the influences of urban growth on thermal environment in relationship with other biophysical variables for Bucharest and Timisoara cities in Romania. Satellite remote sensing provides a cost-effective and time-saving methodology for spatio-temporal analyses of land surface temperature (Ts) distribution and urban thermal environment monitoring. Time series satellite remote sensing data from Landsat TM/ETM+/OLI, MODIS Terra/Aqua and NOAA AVHRR were used to assess urban vegetation land cover– temperature interactions over period between 2000 and 2018 years. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban growth. For this purpose, a set of meteorological and climatic data recorded in synoptic stations were used. The land surface temperature (Ts), a key parameter for urban thermal characteristics analysis, was also analyzed in relation with the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) at city level. Based on these parameters, the urban growth, and urban heat island effect (UHI) and the relationships of Ts to other biophysical parameters have been analyzed. Results show that the city area ratio of impervious surface in both towns Bucharest and Timisoara increased significantly during investigated period, the intensity of urban heat island and heat wave events being most significant. The correlation analyses revealed that, at the pixel-scale, Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively.
This paper investigated urban growth and green land cover decrease impacts on Bucharest metropolitan climate. Time series of Landsat TM/ETM/OLI, MODIS Terra/Aqua and NOAA AVHRR thermal infrared data as well as in-situ meteorological data have been used to assess urban land cover– air and land surface temperature interactions over 2000- 2018 period. The air (Ta) and land surface temperature (Ts), key parameters for urban climate study were analyzed in relation with the Normalized Difference Vegetation Index (NDVI) and surface latent heat flux (SLHF) at city level. Based on these parameters, the urban growth, Urban Heat Island (UHI) effect and the relationships of Ts to other biogeophysical parameters have been investigated. Correlation analysis revealed that, at the pixel-scale, Ta and Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. Was also analyzed UHI phenomenon during extreme heat waves events. Our results suggest that the most intense UHI occurs in day-time in the summer period during heat waves periods. Satellite data in synergy with insitu data revealed a clear land surface temperature contrast between the central, median and peripheral zones of Bucharest metropolitan zone in Romania. The analysis shows that different urban/periurban zones and landscapes bring diurnally and seasonally different contributions to the local and regional thermal environment. Urban land cover was the most important contributor to increases in regional Ts. Vegetation had a clear cooling effect as the normalized vegetation difference index (NDVI) increased during summer periods.
Due to anthropogenic and climatic changes, Carpathian Mountains forests in Romania experience environmental degradation. As a result of global climate change, there is growing evidence that some of the most severe weather events could become more frequent in Romania over the next 50 to 100 years. In the case of Carpathian mountain forests, winter storms and heat waves are considered key climate risks, particularly in prealpine and alpine areas. Effects of climate extremes on forests can have both short-term and long-term implications for standing biomass, tree health and species composition. The preservation and enhancement of mountain forest vegetation cover in natural, semi-natural forestry ecosystems is an essential factor in sustaining environmental health and averting natural hazards. This paper aims to: (i) describe observed trends and scenarios for summer heat waves, windstorms and heavy precipitation, based on results from satellite time series NOAA AVHRR, MODIS Terra/Aqua and Landsat TM/ETM+/OLI NDVI and LAI data recorded during 2000-2016 period correlated with meteorological parameters, regional climate models, and other downscaling procedures, and (ii) discuss potential impacts of climate changes and extreme events on Carpathian mountain forest system in Romania. The response of forest land cover vegetation in Carpathian Mountains, Romania to climatic factors varies in different seasons of the years, the diverse vegetation feedbacks to climate changes being related to different vegetation characteristics and meteorological conditions. Based on integrated analysis of satellite and field data was concluded that forest ecosystem functions are responsible of the relationships between mountain specific vegetation and climate.
Understanding spatio-temporal changes of urban environments is essential for regional and local planning and environmental management. With the rapid changes of Bucharest city in Romania during past decades, green spaces have been fragmented and dispersed causing impairment and dysfunction of these urban elements. The main goal of this study is to address these tasks in synergy with in-situ data and new analytical methods. Spatio- temporal monitoring of urban vegetation land cover changes is important for policy decisions, regulatory actions and subsequent land use activities. This study explored the use of time-series MODIS Terra/Aqua Normalized Difference Vegetation Index (NDVI), Leaf Area Index (LAI), Land Surface Temperature (LST) and evapotranspiration (ET) data to provide vegetation change detection information for metropolitan area of Bucharest. Training and validation are based on a reference dataset collected from IKONOS high resolution remote sensing data. The mean detection accuracy for period 2002- 2014 was assessed to be of 87%, with a reasonable balance between change commission errors (20.24%), change omission errors (25.65%), and Kappa coefficient of 0.72. Annual change detection rates across the urban/periurban areas over the study period (2002–2014) were estimated at 0.79% per annum in the range of 0.46% (2002) to 0.77% (2014).Vegetation dynamics in urban areas at seasonal and longer timescales reflect large-scale interactions between the terrestrial biosphere and the climate system. Extracted green space areas were further analyzed quantitatively in relation with air quality data and extreme climate events. The results have been analyzed in terms of environmental impacts and future climate trends.
In this paper we present several numerical simulations of the surface plasmon resonance for Kretschmann type configuration in a metal-chalcogenide waveguide. We assume that the chalcogenide (GaLaS) waveguide layer have finite thickness, whereas the gold film layer and the air cover layer are semi-infinite layers (from an optical point of view). We determined the thickness of the chalcogenide film for which plasmonic resonant coupling of the incident radiation to the waveguide occurs. We calculated the propagation constant for the TE- and TM- modes (both for visible and IR domain), the attenuation coefficient and the electromagnetic field distribution within the waveguide. The obtained results provide the conditions for design an optical memory device 2D based on light-light interaction in plasmonic configuration.
Cities are exposed more and more to climate change from greenhouse gas induced radiative forcing, and localized effects from urbanization such as the urban heat island. Urban land covers as the biophysical state of the earth’s surface and immediate subsurface are sources and sinks for most of the material and energy movements and interactions between the geosphere and biosphere. Climate change is considered to be the biggest environmental threat in the future in the South- Eastern part of Europe. The aim of this paper is to investigate the influences of urban growth on urban thermal environment as well as the relationships of thermal characteristics to other biophysical parameters in Bucharest metropolitan area of Romania based on time series MODIS Terra/Aqua and IKONOS data acquired during 2000-2014 periods. Land Surface Temperature (LST) is a key variable for studying urban land surface processes and surface atmosphere interactions, being a crucial component in the study of the surface energy and water budgets. Urbanization created an evolved inverse relationship between impervious and vegetation coverage, and brought about new LST patterns because of LST’s correlations with both impervious and vegetation coverage. City thermal environment risk management strategies for mitigating and adapting to climate change must propose efficient plans to reduce greenhouse gas (GHG) emissions and cool the city through changes in the built environment, land use, and transportation.
In frame of global warming, the field of urbanization and urban thermal environment are important issues among
scientists all over the world. This paper investigated the influences of urbanization on urban thermal environment as well
as the relationships of thermal characteristics to other biophysical variables in Bucharest metropolitan area of Romania
based on satellite remote sensing imagery Landsat TM/ETM+, time series MODIS Terra/Aqua data and IKONOS
acquired during 1990 - 2012 period. Vegetation abundances and percent impervious surfaces were derived by means of
linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to
accurately examine the urban growth. The land surface temperature (Ts), a key parameter for urban thermal
characteristics analysis, was also retrieved from thermal infrared band of Landsat TM/ETM+, from MODIS Terra/Aqua
datasets. Based on these parameters, the urban growth, urban heat island effect (UHI) and the relationships of Ts to other
biophysical parameters have been analyzed. Results indicated that the metropolitan area ratio of impervious surface in
Bucharest increased significantly during two decades investigated period, the intensity of urban heat island and heat
wave events being most significant. The correlation analyses revealed that, at the pixel-scale, Ts possessed a strong
positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. This analysis provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.
To preserve urban vegetation land cover quality and mitigate its degradation is an important task for urban planning and
environmental management of Bucharest metropolitan area in Romania. Since vegetation land cover dynamics directly
affect the urban landscape characteristics and air quality, remote sensing represents an effective tool for vegetation land
cover quality assessment at regional scale. In particular, the use of satellite-based vegetation indices, like the NDVI
(Normalized Difference Vegetation Index), can provide important information when evaluating Urban Vegetation Cover
Quality (UVCQ) patterns in urban areas, which represents one of the most sensitive landscape components to urban
environmental degradation. This paper proposes an approach for the regional-scale assessment of UVCQ by means of an
NDVI-based (functional) indicator using freely available time series MODIS Terra/Aqua (Moderate Resolution Imaging
Spectroradiometer) satellite data. As a case study, Bucharest metropolitan area landscape experiencing climate and
anthropogenic changes, increasing human pressure and high vulnerability to degradation was chosen. As UVCQ
indicator, the NDVI-based vegetation cover classification was produced by means of unsupervised multivariate statistical
techniques and compared with spatio-temporal changes during 2002-2012 period, statistical indicators, and field data
related to land cover management observed in the study area. Results demonstrate that the obtained remotely sensed
vegetation land cover characterization can be effectively considered as a proxy of the UVCQ status of the examined area.
Due to the large availability over time and low cost of satellite images, the proposed approach can be applied to wider
urban/periurban regions, to monitor vegetation quality and indirectly control vegetation land degradation.
Climate variability and change are risk factors for climate sensitive activities such as forestry. Managing these risks requires “climate knowledge”, i.e. a sound understanding of causes and consequences of climate variability and knowledge of potential management options that are suitable in light of the climatic risks posed. Thresholding based on biophysical variables derived from time series satellite data is a new approach to classifying forest land cover via remote sensing through use of Normalized Difference Vegetation Index –NDVI and Enhanced vegetation Index- EVI. This paper aims to assess spatio-temporal forest changes through applied time-series Landsat TM, ETM, MODIS Terra/Aqua and IKONOS satellite remote sensing data of Cernica forest area near Bucharest, Romania, during 1990-2011 period. Additional forest biophysical parameter Land Surface Temperature/Emissivity - LST was considered in this paper. This information is complemented by in-situ monitoring data (field measurements, data collection) together with modeling tools (theoretical developments, mathematical and bio-geophysical parameterization, statistics of the main urban structures in their interdependency) and spatial analysis methods.
Spectral patterns of different forest land cover can identify certain pollution compounds, and water stress conditions
based on the interaction of photons with the molecular structure of the forest target structure. Based on such methods, the objective of this research was to evaluate and characterize selected forest test area Baneasa- Tunari located in the Northern part of Bucharest metropolitan region, Romania, where the climate and anthropogenic stressors endanger natural and economical values of environment. Based on time-series Landsat TM, ETM, MODIS Terra/Aqua and IKONOS satellite data have been investigated urban forest land cover and forest biophysical parameters (Normalized Difference Vegetation Index- NDVI and Leaf Area Index- LAI) changes over 1990- 2011 period of time. Accuracy of image processing results (spectral classification) was confirmed through in-situ spectroradiometrical analysis of reflectance spectra with portable GER 2600 spectroradiometer.
The main environmental issues affecting the broad acceptability of NPP (Nuclear Power Plant) are the emission of
radioactive materials, the generation of radioactive and heat waste, and the potential for nuclear accidents. Satellite
remote sensing is an important tool for spatio-temporal analysis and surveillance of environment, thermal heat waste of waters being a major concern in many coastal ecosystems involving nuclear power plants, as sharp changes in water
temperature can significantly affect the distribution and physiology of aquatic biota and contribute to global warming. The thermal plume signature in the NPP hydrological system in TIR (Thermal Infrared) spectral bands of Landsat TM and ETM TIR band 6, ASTER, and MODIS TIR bands time series satellite have been used for WST (Water Surface Temperature) detection, mapping and monitoring. As a test case the methodology was applied for NPP Cernavoda, Romania during period of 1990-2011 years. Thermal discharge from two nuclear reactors cooling is dissipated as waste heat in Danube-Black -Sea Channel and Danube River. If during the winter thermal plume is localized to an area of a few km of NPP, the temperature difference between the plume and non-plume areas being about 1.5 oC, during summer and fall, is a larger thermal plume up to 5- 6 km far along Danube Black Sea Channel, the temperature change being of about 1.0 oC.
As climatic variability and anthropogenic stressors are growing up continuously, must be defined the proper criteria for
forest vegetation assessment. In order to characterize current and future state of forest vegetation satellite imagery is a
very useful tool. Vegetation can be distinguished using remote sensing data from most other (mainly inorganic) materials
by virtue of its notable absorption in the red and blue segments of the visible spectrum, its higher green reflectance and,
especially, its very strong reflectance in the near-IR. Vegetation reflectance has variations with sun zenith angle, view
zenith angle, and terrain slope angle. To provide corrections of these effects, for visible and near-infrared light, was used
a developed a simple physical model of vegetation reflectance, by assuming homogeneous and closed vegetation canopy
with randomly oriented leaves. A simple physical model of forest vegetation reflectance was applied and validated for
Cernica forested area, near Bucharest town through two ASTER satellite data , acquired within minutes from one
another ,a nadir and off-nadir for band 3 lying in the near infra red, most radiance differences between the two scenes can
be attributed to the BRDF effect. Other satellite data MODIS, Landsat TM and ETM as well as, IKONOS have been
used for different NDVI and classification analysis.
Due to significant anthropogenic changes that have occurred in the last several decades in Bucharest city's landscape,
urbanization has become an important factor affecting urban surface parameters, hence in the surface-atmosphere
interaction processes, with a great potential to alter the local climate. Land use and land cover (LULC) influence a
variety of processes important in characterizing urban /periurban biophysical parameters' quality, including aerosol
deposition rates, biogenic emissions, albedo, surface temperatures, climatic parameters and other.
Analysis of surface biophysical parameters changes in urban/periurban areas of Bucharest town based on multi-spectral
and multi-temporal satellite imagery (Landsat TM, ETM and IKONOS) for 1989 - 2009 period provides the most
reliable technique of environmental monitoring regarding the net radiation and heat fluxes associated with urbanization
at the regional scale. Investigation of radiation properties, energy balance and heat fluxes is based on information derived
from various satellite sensors and in-situ monitoring data, linked to numerical models and quantitative biophysical
information extracted from spatially distributed NDVI-data and net radiation. This study attempts to provide
environmental awareness to urban planners suggesting that future changes in urban land cover could substantially affect
climate by altering biophysical land-atmosphere interactions.
Light transport is currently used clinically both as a therapeutic tool and as a diagnostic tool. A concern in all these cases
is the difficulty of knowing which regions of the tissues are sufficiently illuminated for therapeutic results, or from which
regions the collected fluorescence was emitted. Development of optical models that explain the observed scattering
properties of soft biological tissues is of considerable interest. Such modeling can give how the scattering properties are
influenced by the numbers, sizes and arrangements of the tissue structure. In this article we give a brief overview of the
laser light transport in tissue and also discuss some representative applications of tissue optics for biomedical
applications.
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