Spelling suggestions: "subject:"land used/land cover""
21 |
Simulações dos efeitos da cobertura vegetal no balanço hídrico da bacia do rio Ji-Paraná, RO / Simulations of the effects of vegetation cover in water balance of Ji-Paraná river basin, Rondônia, BrazilAlailson Venceslau Santiago 12 December 2005 (has links)
Entender como o balanço hídrico de uma bacia hidrográfica é afetado pela conversão de florestas em cultivos agrícolas e pastagens permite avaliar os possíveis impactos da mudança de uso e cobertura do solo na sustentabilidade regional. Com o modelo hidrológico de grande escala VIC (Variable Infiltration Capacity) calibrado para as condições locais simulou-se os possíveis efeitos em três cenários de substituição da cobertura vegetal na bacia do rio Ji-Paraná, Rondônia. Um cenário imagina a substituição total da floresta pela cultura da soja, e nessas condições a vazão do rio aumentou em 28% durante o período chuvoso, e em até 70% na época seca, quando comparados às vazões atuais. Quando a substituição foi por pastagens esse aumento foi um pouco menor, 11% no período chuvoso e 16% no período seco. Esses dois cenários mutuamente exclusivos foram selecionados por representar condições extremas de uso do solo. Um terceiro cenário simulou a possível condição original da bacia coberta totalmente pela floresta. Esse último cenário permite inferir sobre as possíveis conseqüências das mudanças já ocorridas visto que as medidas de vazão são recentes (menos de 30 anos). Nessa condição a vazão sofreu redução de 9% durante o período chuvoso e de 20% no período seco. O modelo indicou ainda redução de 30% na evapotranspiração dessas culturas, durante o período seco, quando comparado ao cenário de floresta. / The understanding of how the water balance of a hydrographic basin is affected by the conversion of forests into crops and pasture allow to evaluate the possible impacts of the land use and land cover changes in the regional sustainability. Using a macro-scale hydrologic VIC (Variable Infiltration Capacity) model calibrated for local conditions we simulated the possible effects on the hydrology under three scenarios of land cover substitution of the Ji-Paraná basin, state of Rondônia (western region of Brazil). One scenario simulated the total replacement of forest by soybeans crops, under this condition the outflow of the river increased in 28% during the rainy period, and up to 70% at the dry period, when comparative to the current outflows. When forest was replaced by pastures, this increase was a little lower, 11% in rainy season and 16% in the dry period. These two exclusive scenarios have been selected by representing extreme conditions of land use. One third scenario simulated the possible original condition of the basin covered by forest. This last scenario allows to infer on the possible consequences of the actual changes since recent measures of outflow (less than 30 years). In this condition the outflow suffered a reduction of 9% during the rainy period and 20% in the dry period. The model indicated a decrease of 30% in evapotranspiration for these crops in dry period compared to the forest scenario.
|
22 |
Linking spatial patterns of land-use to agents of deforestation in the Brazilian AmazonBorrego Lorena, Rodrigo 09 April 2008 (has links)
Changes in land use and land cover are associated with many environmental issues observed on the earth’s surface. In the last decades, these changes were unprece-dented, mainly in tropical forest areas. The Brazilian Amazon, the world’s largest tropical forest, lost around 200.000 km² of primary forest in the last ten years (INPE, 2005). Considering this, and the consequences caused by this deforestation, it is important to know and define correctly the responsible agents, aiming at better pub-lic policies that can help preserve the forest. Searching for indicators that could help to identify the deforestation agents, some studies, such as Mertens and Lambin (1997), suggest that every deforestation process shapes the forest land in a specific way, producing a spatial pattern that can be interpreted as indicative of the agents with specific economic activities. Based on this hypothesis, the objective of this study was to contribute to a better understanding of land change processes in the Amazon forest, investigating the linkages between spatial patterns of deforestation, as visualized in satellite images, and different agents and their specific economic activities. To reach this objective, our methodological approach was based on socio-economic data acquired at a household level combined with data from satellite im-ages. First, different spatial patterns of deforestation were identified on the satellite images, based on the typologies proposed by Husson et al. (1995). Then, some of the identified spatial patterns were isolated and analyzed for specific aspects, such as, the deforestation rate calculated through satellite images. socio-economic character-istics based on household survey data and evolution of land use and land cover based on thematic maps derived from satellite images. In addition, cluster analysis was applied using the socio-economic data (household survey) and land use and land cover data (satellite images) in a search for homogeneous groups related to the spa-tial pattern. In the end, an Analysis of Variance (ANOVA) was applied to confirm the differences between spatial patterns.
The results suggested that the different spatial patterns of deforestation found in the study area can be related to specific economic activities. Nevertheless, the re-sults have indicated that the spatial configuration is not a consequence of its main economic activity. They suggest that the spatial configuration is linked to the settle-ment project, and the main economic activity in the spatial patterns is a consequence of a set of factors such as: size of property, location and disposition of the property, presence or absence of infrastructure (road, market, transportation, economic and technical).
|
23 |
The Long-term Impact of Land Use Land Cover Change on Urban Climate: Evidence from the Phoenix Metropolitan Area, ArizonaJanuary 2018 (has links)
abstract: This dissertation research studies long-term spatio-temporal patterns of surface urban heat island (SUHI) intensity, urban evapotranspiration (ET), and urban outdoor water use (OWU) using Phoenix metropolitan area (PMA), Arizona as the case study. This dissertation is composed of three chapters. The first chapter evaluates the SUHI intensity for PMA using Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) product and a time-series trend analysis to discover areas that experienced significant changes of SUHI intensity between 2000 and 2017. The heating and cooling effects of different urban land use land cover (LULC) types was also examined using classified Landsat satellite images. The second chapter is focused on urban ET and the impacts of urban LULC change on ET. An empirical model of urban ET for PMA was built using flux tower data and MODIS land products using multivariate regression analysis. A time-series trend analysis was then performed to discover areas in PMA that experienced significant changes of ET between 2001 and 2015. The impact of urban LULC change on ET was examined using classified LULC maps. The third chapter models urban OWU in PMA using a surface energy balance model named METRIC (Mapping Evapotranspiration at high spatial Resolution with Internalized Calibration) and time-series Landsat Thematic Mapper 5 imagery for 2010. The relationship between urban LULC types and OWU was examined with the use of very high-resolution land cover classification data generated from the National Agriculture Imagery Program (NAIP) imagery and regression analysis. Socio-demographic variables were selected from census data at the census track level and analyzed against OWU to study their relationship using correlation analysis. This dissertation makes significant contributions and expands the knowledge of long-term urban climate dynamics for PMA and the influence of urban expansion and LULC change on regional climate. Research findings and results can be used to provide constructive suggestions to urban planners, decision-makers, and city managers to formulate new policies and regulations when planning new constructions for the purpose of sustainable development for a desert city. / Dissertation/Thesis / Doctoral Dissertation Geography 2018
|
24 |
Krajina česko-rakouského pohraničí: vývoj a dědictví / The Landscape of the Czech-Austrian Borderland: Development and HeritageRašín, Robin January 2010 (has links)
Charles University in Prague Faculty of Science Department of Social Geography and Regional Development Robin Rašín The Landscape of the Czech-Austrian Borderland: Development and Heritage Summary Roztoky u Křivoklátu 2010 1 Landscape is a key geographical concept and geographical research on land change and land use has a tradition that can be dated back for almost a hundred years. The development of the subject orientation of land change science can be divided into two phases. (i) During the first phase (50's/60's of the 20th century) the description of landscape and its morphology (structure) were at the centre of research interest along with the research of the potential for agro-production. This particular type of study was motivated by the need to find a solution to the problem of the increasing inability to supply a growing (European) population with agricultural products. (ii) In the second phase (circa from 70's of the 20th century), the attention of scientists towards the accelerated rate of land change on a global scale that can be associated with: the increase of human population, changes in agricultural techniques, mining, environmental exploitation et cetera. There is an obvious need to solve the negative impacts of the human activities on the landscape at different scales (from local to...
|
25 |
Geospatial Modeling of Land Cover Change in the Chocó-Darien Global Ecoregion of South America: Assessing Proximate Causes and Underlying Drivers of Deforestation and ReforestationFagua, José Camilo 01 December 2018 (has links)
The Chocó-Darien Global Ecoregion (CGE) in South America is one of 25 global biodiversity hotspots prioritized for conservation. I performed the first land-use and land-cover (LULC) change analysis for the entire CGE in this dissertation. There were three main objectives: 1) Select the best available imagery to build annual land-use and land-cover maps from 2001 to 2015 across the CGE. 2) Model LULC across the CGE to assess forest change trends from 2002 to 2015 and identify the effect of proximate causes of deforestation and reforestation. 3) Estimate the effects of underlying drivers on deforestation and reforestation across the CGE between 2002 and 2015. I developed annual LULC maps across the CGE from 2002 to 2015 using MODIS (Moderate Resolution Imaging Spectro radiometer) vegetation index products and random forest classification. The LULC maps resulted in high accuracies (Kappa = 0.87; SD = 0.008). We detected a gradual replacement of forested areas with agriculture and secondary vegetation (agriculture reverting to early regeneration of natural vegetation) across the CGE. Forest loss was higher between 2010-2015 when compared to 2002-2010. LULC change trends, proximate causes, and reforestation transitions varied according to administrative authority (countries: PanamanianCGE, Colombian CGE, and Ecuadorian CGE). Population growth and road density were underlying drivers of deforestation. Armed conflicts, Gross Domestic Product, and average annual rain were proximate causes and underlying drivers related reforestation.
|
26 |
Mapping Wetlands Using GIS and Remote Sensing Techniques, A Case Study of Wetlands in Greater Accra, GhanaAmoah, Michael Kofi Mborah 19 December 2022 (has links)
No description available.
|
27 |
Geospatial Analysis of the Impact of Land-Use and Land Cover Change on Maize Yield in Central NigeriaWegbebu, Reynolds 05 June 2023 (has links)
No description available.
|
28 |
Using Landscape Variables to Assess Stream Health in Ohio's Western Allegheny PlateauKing, Lisa A. 25 April 2008 (has links)
No description available.
|
29 |
Hydrologic Response of Upper Ganga Basin to Changing Land Use and ClimateChawla, Ila January 2013 (has links) (PDF)
Numerous studies indicate that the hydrology of a river basin is influenced by Land Use Land Cover (LULC) and climate. LULC affects the quality and quantity of water resources through its influence on Evapotranspiration (ET) and initiation of surface runoff while climate affects the intensity and spatial distribution of rainfall and temperature which are major drivers of the hydrologic cycle. Literature reports several works on either the effect of changing LULC or climate on the hydrology. However, changes in LULC and climate occur simultaneously in reality. Thus, there is a need to perform an integrated impact assessment of such changes on the hydrological regime at a basin scale. In order to carry out the impact assessment, physically-based hydrologic models are often employed. The present study focuses on assessment of the effect of changing LULC and climate on the hydrology of the Upper Ganga basin (UGB), India, using the Variable Infiltration Capacity (VIC) hydrologic model.
In order to obtain the changes that have occurred in the LULC of the basin over a time period, initially LULC analysis is carried out. For this purpose, high resolution multispectral satellite imageries from Landsat are procured for the years 1973, 1980, 2000 and 2011. The images are pre-processed to project them to a common projection system and are then co-registered. The processed images are used for classification into different land cover classes. This step requires training sites which are collected during the field visit as part of this work. The classified images, thus obtained are used to analyse temporal changes in LULC of the region. The results indicate an increase in crop land and urban area of the region by 47% and 122% respectively from 1973 to 2011. After initial decline in dense forest for the first three decades, an increase in the dense forest is observed between 2000- 2011 (from 11.44% to 14.8%). Scrub forest area and barren land are observed to decline in the study region by 62% and 96% respectively since 1973.
The land cover information along with meteorological data and soil data are used to drive the VIC model to investigate the impact of LULC changes on streamflow and evapotranspiration (ET) components of hydrology in the UGB. For the simulation purpose, the entire basin is divided into three regions (1) upstream (with Bhimgodha as the outlet), (2) midstream (with Ankinghat as the outlet) and (3) downstream (with Allahabad as the outlet). The VIC model is calibrated and validated for all the three regions independently at monthly scale. Model performance is assessed based on the criterion of normalized root mean square error (NRMSE), coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE). It is observed that the model performed well with reasonable accuracy for upstream and midstream regions. In case of the downstream region, due to lack of observed discharge data, model performance could not be assessed. Hence, the simulations for the downstream region are performed using the calibrated model of the midstream region. The model outputs from the three regions are aggregated appropriately to generate the total hydrologic response of the UGB. Using the calibrated models for different region of the UGB, sensitivity analysis is performed by generating hydrologic scenarios corresponding to different land use (LU) and climate conditions.
In order to investigate the impact of changing LU on hydrological variables, a scenario is generated in which climate is kept constant and LU is varied. Under this scenario, only the land cover related variables are altered in the model keeping the meteorological variables constant. Thus, the effect of LU change is segregated from the effect of climate. The results obtained from these simulations indicated that the change in LU significantly affects peak streamflow depth which is observed to be 77.58% more in August 2011 in comparison with the peak streamflow of August, 1973. Furthermore, ET is found to increase by 46.44% since 1973 across the entire basin.
In order to assess the impact of changing climate on hydrological variables, a scenario is generated in which LU is kept constant and climate is varied from 1971-2005. Under this scenario, land cover related variables are kept constant in the model and meteorological variables are varied for different time periods. The results indicate decline in the simulated discharge for the years 1971, 1980, 1990, 2000 and 2005, which is supported by decline in observed annual rainfall for the respective years. Amongst 1971 and 2005, year 2005 received 26% less rainfall resulting in 35% less discharge. Furthermore, ET is observed to be negligibly affected.
To understand the integrated impact of changing LU and climate on hydrological variables, a scenario is generated in which both climate and LU are altered. Based on the data available, three years (1973, 1980 and 2000) are considered for the simulations. Under this scenario, both land cover and meteorological variables are varied in the model. The results obtained showed that the discharge hydrograph for the year 1980 has significantly higher peak compared to the hydrographs of years 1973 and 2000. This could be due to the fact that the year 1980 received maximum rainfall amongst the three years considered for simulations. Although the basin received higher rainfall in the year 1980 compared to that in 2000, ET from the basin in the year 1980 is found to be 21% less than that of the year 2000. This could be attributed to the change in LU that occurred between the years 1980 and 2000. Amongst the years 1973 and 2000, there is not much difference in the observed rainfall but ET for the year 2000 is observed to be significantly higher than that of year 1973.
It is concluded from the present study that in the UGB, changing LULC contributes significantly to the changes in peak discharge and ET while rainfall pattern considerably influences the runoff pattern of the region. Future work proposed includes assessment of hydrologic response of basin under future LULC and climate scenarios. Also the model efficiency can be assessed by performing hydrologic simulations at different grid sizes.
|
30 |
Metodologia de classificação de imagens multiespectrais aplicada ao mapeamento do uso da terra e cobertura vegetal na Amazônia: exemplo de caso na região de São Félix do Xingu, sul do Pará. / Methodology for multispectral image classification applied to the mapping of land use and land cover in Amazonia: a case example in the region of Sao Felix do Xingu, south of Para.Kawakubo, Fernando Shinji 05 August 2010 (has links)
Este trabalho apresenta uma metodologia de classificação de imagens multiespectrais aplicada a análise e mapeamento da evolução do uso da terra/cobertura vegetal em São Félix do Xingu, Sul do Pará. Imagens frações representando as proporções de sombra, vegetação e solo foram estimadas a partir das bandas 1 a 5 e 7 do Landsat-5 TM e relacionadas com as estruturas das classes de uso da terra/cobertura vegetal. As imagens frações geradas do modelo linear de mistura espectral foram importantes para reduzir a massa de dados e ao mesmo tempo realçar alvos de interesse na imagem. A banda do infravermelho próximo (TM-4) foi importante para realçar áreas de queimadas. A classificação adotada foi divida em etapas combinando técnica de segmentação por crescimento de regiões e uso de máscaras. Por meio da máscara foi possível restringir o processo de segmentação em regiões pré-estabelecidas com o intuito de adquirir um melhor particionamento da imagem. Adotando este procedimento, ao invés de realizar uma única segmentação para mapear todas as classes em uma única vez, foram realizadas várias segmentações ao longo das etapas. As regiões segmentadas foram agrupadas com um classificador não-supervionado batizado de ISOSEG. Os resultados mostram que a metodologia é bastante eficiente. A matriz de erro gerada para a classificação de 2008 apontou que as confusões mais freqüentes ocorreram entre as classes que apresentaram em certas localidades proporções de misturas parecidas: Capoeira e Campo/Pastagem-2; Campo/Pastagem-1 e Campo/Pastagem-2; Queimada-1 e Queimada-2; Solo Exposto e Campo/Pastagem-1. Considerando nove classes, o índice Kappa atingiu 0,58, o que representa um valor de concordância classificada como moderada. Quando o numero de classes foi reduzido para 6, agrupando as classes que apresentaram as maiores confusões, o índice Kappa subiu para 0,80, atingindo um valor de concordância quase perfeita. A comparação dos resultados das classificações de 1987, 1992, 2000 e 2008 juntamente com a analise de dados auxiliares permitiu traçar um modelo de evolução do desmatamento e do uso da terra para São Félix do Xingu. O intenso desmatamento observado principalmente a partir de 2000 foi relacionado com o incremento da atividade pecuária, sendo São Félix do Xingu o município que detém atualmente o segundo maior rebanho bovino do País. / In this work we present a methodological procedure for multi-spectral images classification to evaluate and map land-use and land-cover changes in São Félix do Xingu, Southern Pará (Brazilian Amazon). Fraction images representing shade, vegetation and soil abundance at the pixel scale were estimated using all six reflective bands of Thematic Mapper sensor (TM-1 to TM-5 and TM-7) and related to different types of land-use and land-cover classes. The linear spectral mixing analysis method was an alternative approach adopted to reduce the data-dimensionality while at the same time enhancing targets of interest. Also, the near-infrared band (TM-4) was employed to separate areas affected by burns (Queimadas in Portuguese). The classification routines were performed in stages by combining region-growing segmentation and use of masking techniques. For each stage, the segmentation process was directed to preselected areas by masking techniques in order to obtain a better image partitioning. This procedure resulted in more than one segmentation thereby reducing confusing errors during the classification routine. An unsupervised classifier by region named ISOSEG was employed to classify the segmented images. The analysis of classification results was mainly qualitative and visual except for the 2008 classification which was assessed through an error matrix. According to the error matrix analysis, misclassifications arose more frequently when a set of classes with similar mixture proportions were involved, such as: Capoeira and Campo/Pastagem-2; Campo/Pastagem-1 and Campo/Pastagem- 2; Queimada-1 and Queimada-2, and finally Bare Soil and Campo/Pastagem-1. As a robust measure of concordance for dichotomous data, the kappa statistic reached a value of 0.62 by considering nine land types of classes and it rose to 0.80 when the mapping classes were diminished to six. Theses kappa values represent moderate and strong agreements between the remotely sensed classification and the reference data, respectively. Making use of the classification results from 1987, 1992, 2000 and 2008 and auxiliary data, we tried to design a simple land evolution model to São Félix do Xingu. The deforestation process notably intensified since 2000 has been driven mainly by a continuous increase in cattle breeding, for wich São Félix do Xingu has the second-largest cattle herd of all Brazilian municipalities.
|
Page generated in 0.0851 seconds