Land-cover classification in a moist tropical region of Brazil with Landsat TM imagery.

Science.gov (United States)

Li, Guiying; Lu, Dengsheng; Moran, Emilio; Hetrick, Scott

2011-01-01

This research aims to improve land-cover classification accuracy in a moist tropical region in Brazil by examining the use of different remote sensing-derived variables and classification algorithms. Different scenarios based on Landsat Thematic Mapper (TM) spectral data and derived vegetation indices and textural images, and different classification algorithms - maximum likelihood classification (MLC), artificial neural network (ANN), classification tree analysis (CTA), and object-based classification (OBC), were explored. The results indicated that a combination of vegetation indices as extra bands into Landsat TM multispectral bands did not improve the overall classification performance, but the combination of textural images was valuable for improving vegetation classification accuracy. In particular, the combination of both vegetation indices and textural images into TM multispectral bands improved overall classification accuracy by 5.6% and kappa coefficient by 6.25%. Comparison of the different classification algorithms indicated that CTA and ANN have poor classification performance in this research, but OBC improved primary forest and pasture classification accuracies. This research indicates that use of textural images or use of OBC are especially valuable for improving the vegetation classes such as upland and liana forest classes having complex stand structures and having relatively large patch sizes.

Estimativa da taxa de desmatamento do município de bannach, pará - amazônia legal, utilizando imagens landsat5/tm Estimation of deforestation rate in bannach municipality, pará state - amazon, using images landsat5/tm

Directory of Open Access Journals (Sweden)

Christiano Luna Arraes

2010-12-01

Full Text Available A Amazônia, maior floresta tropical do planeta, apresenta uma superfície de aproximadamente 6,4 milhões de quilômetros quadrados na América do Sul e ocupa 63% do território Brasileiro. Devido ao desmatamento, o monitoramento dessas áreas se faz necessário, principalmente pelo avanço das fronteiras agrícolas. Assim, o presente trabalho tem como objetivo estimar a taxa de desmatamento anual e diária para o Município de Bannach, Pará, Brasil. Foram adquiridas imagens do satélite Landsat 5, sensor TM (Thematic Mapper, para os anos de 1997 a 2009. Utilizou-se a classificação supervisionada por Maximum Likelihood. O índice de exatidão global apresentou resultados superiores a 90% e índices Kappa superiores a 0,83 para todos os anos de estudo. Ao longo da série temporal, observa-se um aumento do desmatamento de forma contínua, acarretado principalmente pela pecuária.The Amazon, the planet’s largest rain forest, has an area of approximately 6.4 million square kilometers in South America and occupies 63% of the Brazilian territory. Due to deforestation, the monitoring of these areas is needed, mainly by the expansion of management of the productive farming process. Thus, this study aims to estimate the annual and daily rate of deforestation for the Municipality of Bannach, Para State, Brazil. The Landsat images, sensor 5 TM (Thematic Mapper from 1997 to 2009 years were used. The supervised classification by Maximum Likelihood was made for analysis the deforestation rate. The index showed an overall accuracy results above 90% and the Kappa index above 0.83 for all years of study. Therefore, throughout the series, there is an increase in deforestation continuously with mainly land use by livestock.

BOREAS RSS-15 SIR-C and Landsat TM Biomass and Landcover Maps of the NSA

Science.gov (United States)

Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Ranson, K. Jon

2000-01-01

As part of BOREAS, the RSS-15 team conducted an investigation using SIR-C, X-SAR, and Landsat TM data for estimating total above-ground dry biomass for the SSA and NSA modeling grids and component biomass for the SSA. Relationships of backscatter to total biomass and total biomass to foliage, branch, and bole biomass were used to estimate biomass density across the landscape. The procedure involved image classification with SAR and Landsat TM data and development of simple mapping techniques using combinations of SAR channels. For the SSA, the SIR-C data used were acquired on 06-Oct-1994, and the Landsat TM data used were acquired on 02-Sep-1995. The maps of the NSA were developed from SIR-C data acquired on 13-Apr-1994. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

An Improved Physics-Based Model for Topographic Correction of Landsat TM Images

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Ainong Li

2015-05-01

Full Text Available Optical remotely sensed images in mountainous areas are subject to radiometric distortions induced by topographic effects, which need to be corrected before quantitative applications. Based on Li model and Sandmeier model, this paper proposed an improved physics-based model for the topographic correction of Landsat Thematic Mapper (TM images. The model employed Normalized Difference Vegetation Index (NDVI thresholds to approximately divide land targets into eleven groups, due to NDVI’s lower sensitivity to topography and its significant role in indicating land cover type. Within each group of terrestrial targets, corresponding MODIS BRDF (Bidirectional Reflectance Distribution Function products were used to account for land surface’s BRDF effect, and topographic effects are corrected without Lambertian assumption. The methodology was tested with two TM scenes of severely rugged mountain areas acquired under different sun elevation angles. Results demonstrated that reflectance of sun-averted slopes was evidently enhanced, and the overall quality of images was improved with topographic effect being effectively suppressed. Correlation coefficients between Near Infra-Red band reflectance and illumination condition reduced almost to zero, and coefficients of variance also showed some reduction. By comparison with the other two physics-based models (Sandmeier model and Li model, the proposed model showed favorable results on two tested Landsat scenes. With the almost half-century accumulation of Landsat data and the successive launch and operation of Landsat 8, the improved model in this paper can be potentially helpful for the topographic correction of Landsat and Landsat-like data.

Landsat 1-5 Multispectral Scanner V1

Data.gov (United States)

National Aeronautics and Space Administration — Abstract: The Landsat Multispectral Scanner (MSS) was a sensor onboard Landsats 1 through 5 and acquired images of the Earth nearly continuously from July 1972 to...

Predicting soil erosion using Rusle and NDVI time series from TM Landsat 5

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Daniel Fonseca de Carvalho

2014-03-01

Full Text Available The objective of this work was to evaluate the seasonal variation of soil cover and rainfall erosivity, and their influences on the revised universal soil loss equation (Rusle, in order to estimate watershed soil losses in a temporal scale. Twenty-two TM Landsat 5 images from 1986 to 2009 were used to estimate soil use and management factor (C factor. A corresponding rainfall erosivity factor (R factor was considered for each image, and the other factors were obtained using the standard Rusle method. Estimated soil losses were grouped into classes and ranged from 0.13 Mg ha-1 on May 24, 2009 (dry season to 62.0 Mg ha-1 on March 11, 2007 (rainy season. In these dates, maximum losses in the watershed were 2.2 and 781.5 Mg ha-1 , respectively. Mean annual soil loss in the watershed was 109.5 Mg ha-1 , but the central area, with a loss of nearly 300.0 Mg ha-1 , was characterized as a site of high water-erosion risk. The use of C factor obtained from remote sensing data, associated to corresponding R factor, was fundamental to evaluate the soil erosion estimated by the Rusle in different seasons, unlike of other studies which keep these factors constant throughout time.

Application of Landsat 5-TM and GIS data to elk habitat studies in northern Idaho

Science.gov (United States)

Hayes, Stephen Gordon

1999-12-01

An extensive geographic information system (GIS) database and a large radiotelemetry sample of elk (n = 153) were used to study habitat use and selection differences between cow and bull elk (Cervus elaphus) in the Coeur d'Alene Mountains of Idaho. Significant sex differences in 40 ha area use, and interactive effects of sex and season on selection of 40 ha areas from home ranges were found. In all seasons, bulls used habitats with more closed canopy forest, more hiding cover, and less shrub and graminoid cover, than cows. Cows selected areas with shrub and graminoid cover in winter and avoided areas with closed canopy forest and hiding cover in winter and summer seasons. Both sexes selected 40 ha areas of unfragmented hiding cover and closed canopy forest during the hunting season. Bulls also avoided areas with high open road densities during the rut and hunting season. These results support present elk management recommendations, but our observations of sexual segregation provide biologists with an opportunity to refine habitat management plans to target bulls and cows specifically. Furthermore, the results demonstrate that hiding cover and canopy closure can be accurately estimated from Landsat 5-TM imagery and GIS soil data at a scale and resolution to which elk respond. As a result, our habitat mapping methods can be applied to large areas of private and public land with consistent, cost-efficient results. Non-Lambertian correction models of Landsat 5-TM imagery were compared to an uncorrected image to determine if topographic normalization increased the accuracy of elk habitat maps of forest structure in northern Idaho. The non-Lambertian models produced elk habitat maps with overall and kappa statistic accuracies as much as 21.3% higher (p < 0.0192) than the uncorrected image. Log-linear models and power analysis were used to study the dependence of commission and omission error rates on topographic normalization, vegetation type, and solar incidence angle

Analysis of land cover/use changes using Landsat 5 TM data and indices.

Science.gov (United States)

Ettehadi Osgouei, Paria; Kaya, Sinasi

2017-04-01

Urban expansion and unprecedented rural to urban transition, along with a huge population growth, are major driving forces altering land cover/use in metropolitan areas. Many of the land cover classes such as farmlands, wetlands, forests, and bare soils have been transformed during the past years into human settlements. Identification of the city growth trends and the impact of it on the vegetation cover of an area is essential for a better understanding of the sustainability of urban development processes, both planned and unplanned. Analyzing the causes and consequences of land use dynamics helps local government, urban planners, and managers for the betterment of future plans and minimizing the negative effects.This study determined temporal changes in vegetation cover and built-up area in Istanbul (Turkey) using the normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), and built-up area index (BUAI). The temporal data were based on Landsat 5 Thematic Mapper (TM) images acquired in June of 1984, 2002, 2007, 2009, and 2011. The NDVI was applied to all the Landsat images, and the resulting NDVI images were overlaid to generate an NDVI layer stack image. The same procedure was repeated using the SAVI and BUAI images. The layer stack images revealed those areas that had changed in terms of the different indices over the years. To determine temporal change trends, the values of 150 randomly selected control points were extracted from the same locations in the NDVI, SAVI, and BUAI layer stack images. The results obtained from these control points showed that vegetation cover decreased considerably because of a remarkable increase in the built-up area.

ESTUDO COMPARATIVO ENTRE OS ÍNDICES NDVI OBTIDOS A PARTIR DOS SENSORES LANDSAT 5 - TM E RESOURCESAT - LISS III

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Cesar Vinícius Mendes Nery

2013-07-01

Full Text Available A importância das imagens de sensoriamento remoto para o monitoramento da cobertura vegetal é algo inegável. Por mais de três décadas a série Landsat tem fornecido imagens da terra, porém a partir de novembro de 2011 o satélite interrompeu a disponibilização de suas imagens para o monitoramento ambiental. Uma das alternativas de imagens ao Landsat têm sido as imagens do sensor LISS III a bordo do satélite indiano Resourcesat 1. O presente trabalho tem como área de estudo o município de Janaúba, por estar em uma área de transição de dois biomas, e o mesmo tem por objetivo comparar os dois sensores, o sensor TM que se encontra a bordo do satélite Landsat 5 e o sensor LISS III a bordo do satélite Resourcesat 1. Para esse estudo comparativo as imagens foram adquiridas do site do Instituto Nacional de Pesquisas Espaciais (INPE e seus valores de níveis digitais (ND foram convertidos em reflectância com correção atmosférica utilizando o método de correção DOS. Amostras de pixels das imagens índice foram coletadas para o estudo de correlação e ajuste de uma equação linear por meio da técnica de regressão. Utilizando a equação ajustada foram gerados dois mapas temáticos de ambos os sensores, sendo os mesmos comparados pelo teste estatístico Kappa. Os resultados mostraram uma forte correlação entre os valores de NDVI (0,81, sendo possível o ajuste de uma equação linear que expresse a forma dessa relação. O sensor TM, superestimou os valores de NDVI em relação ao sensor LISS III (Inclinação de 1,1035. O valor de Kappa para os mapas temáticos obtidos foi de 0,5894 e o índice de acerto foi de 98,81%, o que mostra uma boa similaridade entre eles. O sensor LISS III pode ser perfeitamente utilizado como alternativa ao Landsat 5.

Relações empíricas entre características dendrométricas da Caatinga brasileira e dados TM Landsat 5

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André Quintão de Almeida

2014-04-01

Full Text Available O objetivo deste trabalho foi ajustar modelos para estimar características dendrométricas da Caatinga brasileira a partir de dados do sensor TM do Landsat 5. Medidas de diâmetro e altura das árvores foram obtidas de 60 parcelas de inventário (400 m2, em dois municípios do Estado de Sergipe. A área basal e o volume de madeira foram estimados com uso de equação alométrica e de fator de forma (f = 0,9. As variáveis explicativas foram obtidas do sensor TM, após correção radiométrica e geométrica, tendo-se considerado, na análise, seis bandas espectrais, com resolução espacial de 30 m, além dos índices de razão simples (SR, de vegetação por diferença normalizada (NDVI e de vegetação ajustado ao solo (Savi. Na escolha das melhores variáveis explicativas, foram considerados coeficiente de determinação (R2, raiz do erro quadrático médio (RMSE e critério bayesiano de informação (CBI. A área basal por hectare não apresentou correlação significativa com nenhuma das variáveis explicativas utilizadas. Os melhores modelos foram ajustados à altura média das árvores por parcela (R2 = 0,4; RMSE = 13% e ao volume de madeira por hectare (R2 = 0,6; RMSE = 42%. As métricas derivadas do sensor TM do Landsat 5 têm grande potencial para explicar variações de altura média das árvores e do volume de madeira por hectare, em remanescentes de Caatinga situados no Nordeste brasileiro.

Landsat thematic mapper (TM) soil variability analysis over Webster County, Iowa

Science.gov (United States)

Thompson, D. R.; Henderson, K. E.; Pitts, D. E.

1984-01-01

Thematic mapper simulator (TMS) data acquired June 7, June 23, and July 31, 1982, and Landsat thematic mapper (TM) data acquired August 2, September 3, and October 21, 1982, over Webster County, Iowa, were examined for within-field soil effects on corn and soybean spectral signatures. It was found that patterns displayed on various computer-generated map products were in close agreement with the detailed soil survey of the area. The difference in spectral values appears to be due to a combination of subtle soil properties and crop growth patterns resulting from the different soil properties. Bands 4 (0.76-.90 micron), 5 (1.55-1.75 micron), and 7 (2.08-2.35 micron) were found to be responding to the within-field soil variability even with increasing ground cover. While these results are preliminary, they do indicate that the soil influence on the vegetation is being detected by TM and should provide improved information relating to crop and soil properties.

An integrtated approach to the use of Landsat TM data for gold exploration in west central Nevada

Science.gov (United States)

Mouat, D. A.; Myers, J. S.; Miller, N. L.

1987-01-01

This paper represents an integration of several Landsat TM image processing techniques with other data to discriminate the lithologies and associated areas of hydrothermal alteration in the vicinity of the Paradise Peak gold mine in west central Nevada. A microprocessor-based image processing system and an IDIMS system were used to analyze data from a 512 X 512 window of a Landsat-5 TM scene collected on June 30, 1984. Image processing techniques included simple band composites, band ratio composites, principal components composites, and baseline-based composites. These techniques were chosen based on their ability to discriminate the spectral characteristics of the products of hydrothermal alteration as well as of the associated regional lithologies. The simple band composite, ratio composite, two principal components composites, and the baseline-based composites separately can define the principal areas of alteration. Combined, they provide a very powerful exploration tool.

LANDSAT TM and SAR - ERS1 data for analysis of Vrancea seismic region

International Nuclear Information System (INIS)

Zoran, M.

2002-01-01

This paper is aimed to present the results of the application of LANDSAT TM and SAR- ERS1 satellite data for Vrancea seismic area investigation, in order to emphasize geomorphological features as well as to identify faulting zones responsible of seismic events generation. Remote sensing analysis and field studies of active faults can provide a geologic history that overcomes many of the shortcomings of instrumental and historic records. Vrancea - Focsani is structurally and seismically complex area, bounded by latitudes 45.6 angle N and 46.0 angle N and longitudes 26.5 angle E and 27.5 angle E. The Peceneaga -Camena Fault, a deep crustal fracture with dextral slip, is considered to be North-Eastern boundary of the Moesian Platform. The Eastern unit of the Moesian Sub-Plate is characterized by a series of principal faults with a North-Western orientation and by a secondary system of faults orientated NE-SW. NW trending crustal fractures are also evidenced East of the Peceneaga-Camena Fault, within our test area. A SAR- ERS1 image and a multispectral Landsat TM data set were used and processed with EASI/PACE image processing software package as well as with developed algorithms. In order to a better management all the information available on the study area, data acquired have been integrated in a unique database. This information consists of thematic maps from cartography, land use map from classification of remotely sensed data. This study revealed that satellite data used are excellent for recognizing the continuity and regional relationships of faults. Linear features in TM images appear shorter and denser distributed, whereas ERS1 images are dominated by the principal structures. In certain cases they complete the lineaments and lineament patterns derived from TM data. Higher spatial resolution satellite data and SAR interferometric data are needed for mapping of these features. Remote sensing techniques provide a means for locating, identifying and mapping

Detecting Uniform Areas for Vicarious Calibration using Landsat TM Imagery: A Study using the Arabian and Saharan Deserts

Science.gov (United States)

Hilbert, Kent; Pagnutti, Mary; Ryan, Robert; Zanoni, Vicki

2002-01-01

This paper discusses a method for detecting spatially uniform sites need for radiometric characterization of remote sensing satellites. Such information is critical for scientific research applications of imagery having moderate to high resolutions (African Saharan and Arabian deserts contained extremely uniform sites with respect to spatial characteristics. We developed an algorithm for detecting site uniformity and applied it to orthorectified Landsat Thematic Mapper (TM) imagery over eight uniform regions of interest. The algorithm's results were assessed using both medium-resolution (30-m GSD) Landsat 7 ETM+ and fine-resolution (research shows that Landsat TM products appear highly useful for detecting potential calibration sites for system characterization. In particular, the approach detected spatially uniform regions that frequently occur at multiple scales of observation.

LBA-ECO LC-01 Landsat TM Land Use/Land Cover, Northern Ecuadorian Amazon: 1986-1999

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains Landsat TM imagery for the years 1986, 1989, 1996, and 1999, that have been classified into four land use/land cover (LULC) classes: Forest,...

Electronic spreadsheet to acquire the reflectance from the TM and ETM+ Landsat images

Directory of Open Access Journals (Sweden)

Antonio R. Formaggio

2005-08-01

Full Text Available The reflectance of agricultural cultures and other terrestrial surface "targets" is an intrinsic parameter of these targets, so in many situations, it must be used instead of the values of "gray levels" that is found in the satellite images. In order to get reflectance values, it is necessary to eliminate the atmospheric interference and to make a set of calculations that uses sensor parameters and information regarding the original image. The automation of this procedure has the advantage to speed up the process and to reduce the possibility of errors during calculations. The objective of this paper is to present an electronic spreadsheet that simplifies and automatizes the transformation of the digital numbers of the TM/Landsat-5 and ETM+/Landsat-7 images into reflectance. The method employed for atmospheric correction was the dark object subtraction (DOS. The electronic spreadsheet described here is freely available to users and can be downloaded at the following website: http://www.dsr.inpe.br/Calculo_Reflectancia.xls.

Improved Topographic Normalization for Landsat TM Images by Introducing the MODIS Surface BRDF

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Yanli Zhang

2015-05-01

Full Text Available In rugged terrain, the accuracy of surface reflectance estimations is compromised by atmospheric and topographic effects. We propose a new method to simultaneously eliminate atmospheric and terrain effects in Landsat Thematic Mapper (TM images based on a 30 m digital elevation model (DEM and Moderate Resolution Imaging Spectroradiometer (MODIS atmospheric products. Moreover, we define a normalized factor of a Bidirectional Reflectance Distribution Function (BRDF to convert the sloping pixel reflectance into a flat pixel reflectance by using the Ross Thick-Li Sparse BRDF model (Ambrals algorithm and MODIS BRDF/albedo kernel coefficient products. Sole atmospheric correction and topographic normalization were performed for TM images in the upper stream of the Heihe River Basin. The results show that using MODIS atmospheric products can effectively remove atmospheric effects compared with the Fast Line-of-Sight Atmospheric Analysis of Spectral Hypercubes (FLAASH model and the Landsat Climate Data Record (CDR. Moreover, superior topographic effect removal can be achieved by considering the surface BRDF when compared with the surface Lambertian assumption of topographic normalization.

An Operational Scheme for Deriving Standardised Surface Reflectance from Landsat TM/ETM+ and SPOT HRG Imagery for Eastern Australia

Directory of Open Access Journals (Sweden)

Neil Flood

2013-01-01

Full Text Available Operational monitoring of vegetation and land surface change over large areas can make good use of satellite sensors that measure radiance reflected from the Earth’s surface. Monitoring programs use multiple images for complete spatial coverage over time. Accurate retrievals of vegetation cover and vegetation change estimates can be hampered by variation, in both space and time, in the measured radiance, caused by atmospheric conditions, topography, sensor location, and sun elevation. In order to obtain estimates of cover that are comparable between images, and to retrieve accurate estimates of change, these sources of variation must be removed. In this paper we present a preprocessing scheme for minimising atmospheric, topographic and bi-directional reflectance effects on Landsat-5 TM, Landsat-7 ETM+ and SPOT-5 HRG imagery. The approach involves atmospheric correction to compute surface-leaving radiance, and bi-directional reflectance modelling to remove the effects of topography and angular variation in reflectance. The bi-directional reflectance model has been parameterised for eastern Australia, but the general approach is more widely applicable. The result is surface reflectance standardised to a fixed viewing and illumination geometry. The method can be applied to the entire record for these instruments, without intervention, which is of increasing importance with the increased availability of long term image archives. Validation shows that the corrections improve the estimation of reflectance at any given angular configuration, thus allowing the removal from the reflectance signal of much variation due to factors independent of the land surface. The method has been used to process over 45,000 Landsat-5 TM and Landsat-7 ETM+ scenes and 2,500 SPOT-5 scenes, over eastern Australia, and is now in use in operational monitoring programs.

Cádiz bay walers lurbidily varialions from Landsat TM images analysis

OpenAIRE

Gutiérrez Mas, José Manuel; Luna del Barco, A.; Parrado Román, J. M.; Sánchez, E.; Fernández Palacios, A.; Ojeda, J.

1999-01-01

Landsat TM images has been analysed to obtain extent and direction data about turbidity flumes in several hydrodinamic sinoptic situations in Cadiz bay waters. Results are beside data from water samples. Five turbidity levels has been differentiated: very high turbidity, high, middle, low and very low, and three geographic sectors: a) Inner zone, closed to coast and with shoal waters of high and very high turbidity. This sector is very affected by littoral processes (tidals, surge and contine...

BOREAS TE-18 Landsat TM Maximum Likelihood Classification Image of the NSA

Science.gov (United States)

Hall, Forrest G. (Editor); Knapp, David

2000-01-01

The BOREAS TE-18 team focused its efforts on using remotely sensed data to characterize the successional and disturbance dynamics of the boreal forest for use in carbon modeling. The objective of this classification is to provide the BOREAS investigators with a data product that characterizes the land cover of the NSA. A Landsat-5 TM image from 20-Aug-1988 was used to derive this classification. A standard supervised maximum likelihood classification approach was used to produce this classification. The data are provided in a binary image format file. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

Analysis of the quality of image data acquired by the LANDSAT-4 Thematic Mapper (TM) of the Black Hills area, South Dakota

Science.gov (United States)

Colwell, R. N. (Principal Investigator)

1983-01-01

The structure, format, and quality of the LANDSAT-4 TM and MSS photographic and digital products for one scene covering the Black Hills area of South Dakota were assessed and the extent to which major resource categories can be detected and identified on various photographic products generated from a subset of TM spectral bands and from all bands of the MSS was determined. The overall spectral, spatial, and radiometric quality of the TM data was found to be excellent. Agricultural fields of variable shape, size, and orientation were detected with relative ease. The addition of the short-wave infrared band (TM5) has significantly improved the ability to detect and identify crop types on single date imagery.

Fusion of Terra-MODIS and Landsat TM data for geothermal sites investigation in Jiangsu Province, China

Science.gov (United States)

Chen, Shengbo

2006-01-01

Geothermal resources are generally confined to areas of the Earth's crust where heat flow higher than in surrounding areas heats the water contained in permeable rocks (reservoirs) at depth. It is becoming one of attractive solutions for clean and sustainable energy future for the world. The geothermal fields commonly occurs at the boundaries of plates, and only occasionally in the middle of a plate. The study area, Jiangsu Province, as an example, located in the east of China, is a potential area of geothermal energy. In this study, Landsat thematic Mapper (TM) data were georeferenced to position spatially the geothermal energy in the study area. Multi-spectral infrared data of Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra platform were georeferenced to Landsat TM images. Based on the Wien Displacement Law, these infrared data indicate the surface emitted radiance under the same atmospheric condition, and stand for surface bright temperature respectively. Thus, different surface bright temperature data from Terra-MODIS band 20 or band 31 (R), together with Landsat TM band 4 (G) and band 3 (B) separately, were made up false color composite images (RGB) to generate the distribution maps of surface bright temperatures. Combing with geologic environment and geophysical anomalies, the potential area of geothermal energy with different geo-temperature were mapped respectively. Specially, one geothermal spot in Qinhu Lake Scenery Area in Taizhou city was validated by drilling, and its groundwater temperature is up to some 51°.

Predictive models of turbidity and water depth in the Doñana marshes using Landsat TM and ETM+ images.

Science.gov (United States)

Bustamante, Javier; Pacios, Fernando; Díaz-Delgado, Ricardo; Aragonés, David

2009-05-01

We have used Landsat-5 TM and Landsat-7 ETM+ images together with simultaneous ground-truth data at sample points in the Doñana marshes to predict water turbidity and depth from band reflectance using Generalized Additive Models. We have point samples for 12 different dates simultaneous with 7 Landsat-5 and 5 Landsat-7 overpasses. The best model for water turbidity in the marsh explained 38% of variance in ground-truth data and included as predictors band 3 (630-690 nm), band 5 (1550-1750 nm) and the ratio between bands 1 (450-520 nm) and 4 (760-900 nm). Water turbidity is easier to predict for water bodies like the Guadalquivir River and artificial ponds that are deep and not affected by bottom soil reflectance and aquatic vegetation. For the latter, a simple model using band 3 reflectance explains 78.6% of the variance. Water depth is easier to predict than turbidity. The best model for water depth in the marsh explains 78% of the variance and includes as predictors band 1, band 5, the ratio between band 2 (520-600 nm) and band 4, and bottom soil reflectance in band 4 in September, when the marsh is dry. The water turbidity and water depth models have been developed in order to reconstruct historical changes in Doñana wetlands during the last 30 years using the Landsat satellite images time series.

Combining lake and watershed characteristics with Landsat TM data for remote estimation of regional lake clarity

Science.gov (United States)

McCullough, Ian M.; Loftin, Cyndy; Sader, Steven A.

2012-01-01

Water clarity is a reliable indicator of lake productivity and an ideal metric of regional water quality. Clarity is an indicator of other water quality variables including chlorophyll-a, total phosphorus and trophic status; however, unlike these metrics, clarity can be accurately and efficiently estimated remotely on a regional scale. Remote sensing is useful in regions containing a large number of lakes that are cost prohibitive to monitor regularly using traditional field methods. Field-assessed lakes generally are easily accessible and may represent a spatially irregular, non-random sample of a region. We developed a remote monitoring program for Maine lakes >8 ha (1511 lakes) to supplement existing field monitoring programs. We combined Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) brightness values for TM bands 1 (blue) and 3 (red) to estimate water clarity (secchi disk depth) during 1990–2010. Although similar procedures have been applied to Minnesota and Wisconsin lakes, neither state incorporates physical lake variables or watershed characteristics that potentially affect clarity into their models. Average lake depth consistently improved model fitness, and the proportion of wetland area in lake watersheds also explained variability in clarity in some cases. Nine regression models predicted water clarity (R2 = 0.69–0.90) during 1990–2010, with separate models for eastern (TM path 11; four models) and western Maine (TM path 12; five models that captured differences in topography and landscape disturbance. Average absolute difference between model-estimated and observed secchi depth ranged 0.65–1.03 m. Eutrophic and mesotrophic lakes consistently were estimated more accurately than oligotrophic lakes. Our results show that TM bands 1 and 3 can be used to estimate regional lake water clarity outside the Great Lakes Region and that the accuracy of estimates is improved with additional model variables that reflect

Radiometric characterization of Landsat Collection 1 products

Science.gov (United States)

Micijevic, Esad; Haque, Md. Obaidul; Mishra, Nischal

2017-09-01

Landsat data in the U.S. Geological Survey (USGS) archive are being reprocessed to generate a tiered collection of consistently geolocated and radiometrically calibrated products that are suitable for time series analyses. With the implementation of the collection management, no major updates will be made to calibration of the Landsat sensors within a collection. Only calibration parameters needed to maintain the established calibration trends without an effect on derived environmental records will be regularly updated, while all other changes will be deferred to a new collection. This first collection, Collection 1, incorporates various radiometric calibration updates to all Landsat sensors including absolute and relative gains for Landsat 8 Operational Land Imager (OLI), stray light correction for Landsat 8 Thermal Infrared Sensor (TIRS), absolute gains for Landsat 4 and 5 Thematic Mappers (TM), recalibration of Landsat 1-5 Multispectral Scanners (MSS) to ensure radiometric consistency among different formats of archived MSS data, and a transfer of Landsat 8 OLI reflectance based calibration to all previous Landsat sensors. While all OLI/TIRS, ETM+ and majority of TM data have already been reprocessed to Collection 1, a completion of MSS and remaining TM data reprocessing is expected by the end of this year. It is important to note that, although still available for download from the USGS web pages, the products generated using the Pre-Collection processing do not benefit from the latest radiometric calibration updates. In this paper, we are assessing radiometry of solar reflective bands in Landsat Collection 1 products through analysis of trends in on-board calibrator and pseudo invariant site (PICS) responses.

Monitoring the turbidity and surface temperature changes and effects of the 17 August 1999 earthquake in the Izmit Gulf, Turkey by the Landsat TM/ETM data.

Science.gov (United States)

Tüfekçi, Kenan; Akman, A Unal

2005-09-01

The temporal turbidity and surface temperature changes and effects of the 17 August 1999 earthquake in the Izmit Gulf, Turkey have been investigated using Landsat TM/ETM data. The gulf is in the Mediterranean-Black Sea transition climatic zone and is partially surrounded by green vegetation cover and degraded and densely urbanized-industrialized areas. Landsat TM/ETM data acquired in 1990-1999 confirms increase in turbidity. Turbidity is always low in the southern part and high in the northern part of the gulf, because the more urbanized and industrialized areas are located in the northern part. The Landsat-7 ETM data acquired in the same year (1999) shows seasonal changes in turbidity. Moreover, the two high turbidity and surface temperature anomalies, one of which is parallel to the 17 August 1999 earthquake surface rupture (east-west) and the other which is in the northwest-southeast direction were mapped from Landsat-5 TM data acquired the day (18.08.1999) following the earthquake in the east end of the gulf. On the basis of turbidity implying the sea bottom movement, it is possible to state that a second rupture in the northwest and southeast direction could have occurred at the sea bottom during the earthquake. The distribution of the seismicity centers and the orientation of the lineaments in the area support this finding.

Intercomparison of 30+ years of AVHRR and Landsat-5 TM Surface Reflectance using Multiple Pseudo-Invariant Calibration Sites

Science.gov (United States)

Santamaría-Artigas, A. E.; Franch, B.; Vermote, E.; Roger, J. C.; Justice, C. O.

2017-12-01

The 30+ years daily surface reflectance long term data record (LTDR) from the Advanced Very High Resolution Radiometer (AVHRR) is a valuable source of information for long-term studies of the Earth surface. This LTDR was generated by combining observations from multiple AVHRR sensors aboard different NOAA satellites starting from the early 1980s, and due to the lack of on-board calibration its quality should be evaluated. Previous studies have used observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) over pseudo-invariant calibration sites (PICS) as a calibrated reference to assess the performance of AVHRR products. However, this limits the evaluation to the period after MODIS launch. In this work, the AVHRR surface reflectance LTDR was evaluated against Landsat-5 Thematic Mapper (TM) data using observations from 4 well known pseudo-invariant calibration sites (i.e. Sonoran, Saharan, Sudan1, and Libya4) over an extended time period (1984-2011). For the intercomparison, AVHRR and TM observations of each site were extracted and averaged over a 20 km x 20 km area and aggregated to monthly mean values. In order to account for the spectral differences between sensors, Hyperion hyperspectral data from the Sonoran and Libya4 sites were convolved with sensor-specific relative spectral responses, and used to compute spectral band adjustment factors (SBAFs). Results of the intercomparison are reported in terms of the root mean square difference (RMSD) and determination coefficient (r2). In general, there is good agreement between the surface reflectance products from both sensors. The overall RMSD and r2 for all the sites and AVHRR/TM combinations were 0.03 and 0.85 for the red band, and 0.04 and 0.81 for the near-infrared band. These results show the strong performance of the AVHRR surface reflectance LTDR through all of the considered period. Thus, remarking its usefulness and value for long term Earth studies. Figure 1 shows the red (filled markers

BOREAS Level-3a Landsat TM Imagery: Scaled At-sensor Radiance in BSQ Format

Science.gov (United States)

Nickerson, Jaime; Hall, Forrest G. (Editor); Knapp, David; Newcomer, Jeffrey A.; Cihlar, Josef

2000-01-01

For BOREAS, the level-3a Landsat TM data, along with the other remotely sensed images, were collected in order to provide spatially extensive information over the primary study areas. This information includes radiant energy, detailed land cover, and biophysical parameter maps such as FPAR and LAI. Although very similar in content to the level-3s Landsat TM products, the level-3a images were created to provide users with a more usable BSQ format and to provide information that permitted direct determination of per-pixel latitude and longitude coordinates. Geographically, the level-3a images cover the BOREAS NSA and SSA. Temporally, the images cover the period of 22-Jun-1984 to 30-Jul-1996. The images are available in binary, image-format files. With permission from CCRS and RSI, several of the full-resolution images are included on the BOREAS CD-ROM series. Due to copyright issues, the images not included on the CD-ROM may not be publicly available. See Sections 15 and 16 for information about how to acquire the data. Information about the images not on the CD-ROMs is provided in an inventory listing on the CD-ROMs.

Uso de imagens TM/Landsat-5 e termometria na identificação e mapeamento de solos afetados por sais na região de Sousa, PB TM/Landsat-5 images and thermometry in the identification and mapping of salt affected soils in the region of Sousa, Brazil

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Cícero O. Lima

2001-05-01

Full Text Available A região de São Gonçalo/Baixada de Sousa é um dos principais centros agrícolas do Estado da Paraíba. O manejo inadequado das terras e da irrigação tem sido responsável pela redução do rendimento das culturas e pela degradação dos solos, por salinização. Na mitigação das vulnerabilidades agrícolas, o geoprocessamento está consolidado como ferramenta poderosa no estudo e monitoramento do meio ambiente, visando ao desenvolvimento sustentável, com diminuição dos riscos a desastres. O objetivo deste trabalho foi o uso de imagens TM/Landsat-5 (análise visual e processamento digital, de medidas superficiais de temperatura e de um SIG na identificação e mapeamento de solos afetados por sais. Os resultados mostraram que, ao longo dos últimos anos, houve incremento da área de solos degradados pela salinização e, hoje, aproximadamente 39,48% da área estudada apresentam ocorrência de solos afetados por sais.The São Gonçalo/Baixada de Sousa region is one of the main agricultural centers of the State of Paraíba. The inadequate management of the lands and irrigation has been responsible for the reduction of the agriculture income and for the soil degradation by salt. In the mitigation of the agricultural vulnerabilities, geoprocessing is consolidated as a powerful tool in the study and monitoring of the environment, aiming at sustainable development with risk reduction of disasters. The objective of this work was the use of TM/Landsat-5 images (visual analysis and digital processing, superficial measures of temperatures and a GIS in the identification and mapping of salt affected soils. The results showed that along the last years the area of soil degradation by salt had increased and today approximately 39.48% of the studied area presents salt affected soils.

BOREAS TE-18 Landsat TM Physical Classification Image of the NSA

Science.gov (United States)

Hall, Forrest G. (Editor); Knapp, David

2000-01-01

The BOREAS TE-18 team focused its efforts on using remotely sensed data to characterize the successional and disturbance dynamics of the boreal forest for use in carbon modeling. The objective of this classification is to provide the BOREAS investigators with a data product that characterizes the land cover of the NSA. A Landsat-5 TM image from 21-Jun-1995 was used to derive the classification. A technique was implemented that uses reflectances of various land cover types along with a geometric optical canopy model to produce spectral trajectories. These trajectories are used in a way that is similar to training data to classify the image into the different land cover classes. The data are provided in a binary, image file format. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Global change effects on early holocene sedimentation of the Brazilian continental shelf determined from TM-LANDSAT 5 data of the seafloor

International Nuclear Information System (INIS)

Cabral, A.P.; Vianna, M.L.; Gherardi, D.F.M.

1992-01-01

A study of the shaping of the seafloor morphology on the Brazilian northeast continental shelf caused by climatic changes in the beginning of the Holocene is being made with the support of TM-Landsat 5 data. Special emphasis is given on analysis of data from ancient shorelines between 20-45m depth, to be correlated with abrupt global climate change between 10,000-8,000 BP. The transport of a quartz sand deposit by the ocean currents through time, effected by active sandwave fields at the 20 m isobath is also described. Two images were used corresponding to two dates: 1984 and 1989. Geometric correction, filter application and contrast enhancement were performed. A comparison between 84' and 89' images was carried out, to detect changing patterns of the sand waves, along a 5 year period, caused by the seasonal wintertime wind-forced ocean currents. Based on this registration, estimates of displacement rates for the sand deposit could be made

Seasonal differences assist in mapping granite outcrops using Landsat TM imagery across the Southwest Australian Floristic Region

NARCIS (Netherlands)

Alibegovic, G.; Schut, A.G.T.; Wardell-Johnson, G.W.; Robinson, T.P.

2015-01-01

Knowledge of the location and extent of granite outcrops (GOs) in the Southwest Australian Floristic Region is important to understand their role as refugia. We present a methodology to map GOs using biannual Landsat TM imagery. An adaptive vegetation cover mask capitalising on seasonal differences,

Summary of Current Radiometric Calibration Coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI Sensors

Science.gov (United States)

Chander, Gyanesh; Markham, Brian L.; Helder, Dennis L.

2009-01-01

This paper provides a summary of the current equations and rescaling factors for converting calibrated Digital Numbers (DNs) to absolute units of at-sensor spectral radiance, Top-Of- Atmosphere (TOA) reflectance, and at-sensor brightness temperature. It tabulates the necessary constants for the Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Advanced Land Imager (ALI) sensors. These conversions provide a basis for standardized comparison of data in a single scene or between images acquired on different dates or by different sensors. This paper forms a needed guide for Landsat data users who now have access to the entire Landsat archive at no cost.

Albedo à superfície a partir de imagens Landsat 5 em áreas de cana-de-açúcar e cerrado Surface albedo from Landsat 5 images in areas of sugar cane and cerrado

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Pedro R. Giongo

2010-03-01

Full Text Available Propôs-se, neste trabalho, estimar dados de albedo à superfície terrestre usando-se o sensor Thematic Mapper (TM do satélite LANDSAT 5 e compará-lo com dados de duas estações agrometeorológicas localizadas em região de Cerrado e a outra em cultivo da cana-de-açúcar. A região de estudo está localizada no município de Santa Rita do Passa Quatro, SP, Brasil. Para a realização do estudo obtiveram-se seis imagens orbitais do satélite Landsat 5 sensores TM, na órbita 220 e ponto 75, nas datas de 22/02, 11/04, 29/05, 01/08, 17/08 e 21/11, todas do ano de 2005, a que correspondem os dias juliano de 53, 101, 149, 213, 229 e 325, respectivamente. As correções geométricas para as imagens foram realizadas e geradas as cartas de albedo. O algoritmo SEBAL estimou satisfatoriamente os valores de albedo de superfícies sobre áreas de cerrado e de cana-de-açúcar, na região de Santa Rita do Passa Quatro, SP, consistentes com observações realizadas do albedo à superfície.This study aimed to estimate albedo data from the land surface sensor using the images of Thematic Mapper (TM satellite LANDSAT 5 and to compare it with data from two agrometeorological stations located in the region of Cerrado, and another in sugar cane cultivation. The study area is located in the municipality of Santa Rita do Passa Quatro - SP, Brazil. To carry out the study six orbital images were obtained from the satellite Landsat 5 TM sensors in the orbit 220 and in the section 75, for the dates of 22/02, 11/04, 29/05, 01/08, 17/08 and 21/11 (all in the year of 2005 which correspond to the days 53, 101, 149, 213, 229 and 325, respectively. The geometric correction for images was performed and the letters of albedo were generated. The algorithm SEBAL estimated, satisfactorily, the values of albedo on the surface areas of Cerrado and sugar cane in the region of Santa Rita do Passa Quatro - SP, consistent with observations made of the surface albedo.

Results of agriclimatological studies using multiple satellite sensors like NOAA AVHRR; GMS IR and LANDSAT MSS and TM

International Nuclear Information System (INIS)

Choudhury, A.M.

1990-08-01

Bangladesh Space Research and Remote Sensing Organization (SPARRSO) routinely receives NOAA and GMS imagery and uses them in agrometeorological monitoring, it also uses LANDSAT MSS and TM data for this purpose. Analysis of multiple satellite sensor data shows advantages for high resolution sensors. However, in the ease of crop monitoring, a good correlation has been obtained between results obtained with NOAA AVHRR and LANDSAT MSS for vegetation index. Crop estimation has been made using all kinds of sensors and it has been found that higher resolution data always give more accurate results. (author). 3 refs

LandSAT TM 1994

Data.gov (United States)

Kansas Data Access and Support Center — Before the Landsat commercialization contract was signed between the Department of Commerce and the Earth Observation Satellite Company (EOSAT) on September 27,...

APLICAÇÃO DE IMAGENS IKONOS II E TM/LANDSAT-5 NA ELABORAÇÃO DE UMA BASE CARTOGRÁFICA PARA A RESERVA DE DESENVOLVIMENTO SUSTENTÁVEL MAMIRAUÁ – AMAZONAS / APPLICATION OF IKONOS II AND TM/LANDSAT-5 SATELLITES DATA FOR DIGITAL BASE MAPPING THE SUSTAINABLE DEVELOPMENT RESERVE MAMIRAUÁ, AMAZON, BRAZIL

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Josimara Martins Dias

2009-12-01

Full Text Available This paper has as purpose present the methodology developed to produce an updated digital map base support for participatory management Mamirauá Reserve of Sustainable Development in the state of Amazonas, Braszil. Because this protected área is situated within an area of flooded forest, both the physical landscape and social organization often change, and the dynamic demand the systematic update of cartographic databases. This work has images of orbital sensors IKONOS II and LANDSAT 5 TM, interviews with users and collecting spatial data in the Mamirauá Reserve. This work obtained a cartographic base at 1:100.000 scale and a geodatabase compatible with the local references, with which is possible to generate thematic maps updated to support dialogue in the sustainable management programs of the Mamirauá Reserve and minimize conflicts with communities.

Tropical forest biomass and successional age class relationships to a vegetation index derived from Landsat TM data

Science.gov (United States)

Sader, Steven A.; Waide, Robert B.; Lawrence, William T.; Joyce, Armond T.

1989-01-01

Forest stand structure and biomass data were collected using conventional forest inventory techniques in tropical, subtropical, and warm temperate forest biomes. The feasibility of detecting tropical forest successional age class and total biomass differences using Landsat-Thematic mapper (TM) data, was evaluated. The Normalized Difference Vegetation Index (NDVI) calculated from Landsat-TM data were not significantly correlated with forest regeneration age classes in the mountain terrain of the Luquillo Experimental Forest, Puerto Rico. The low sun angle and shadows cast on steep north and west facing slopes reduced spectral reflectance values recorded by TM orbital altitude. The NDVI, calculated from low altitude aircraft scanner data, was significatly correlated with forest age classes. However, analysis of variance suggested that NDVI differences were not detectable for successional forests older than approximately 15-20 years. Also, biomass differences in young successional tropical forest were not detectable using the NDVI. The vegetation index does not appear to be a good predictor of stand structure variables (e.g., height, diameter of main stem) or total biomass in uneven age, mixed broadleaf forest. Good correlation between the vegetation index and low biomass in even age pine plantations were achieved for a warm temperate study site. The implications of the study for the use of NDVI for forest structure and biomass estimation are discussed.

Evaluation of Different Topographic Corrections for Landsat TM Data by Prediction of Foliage Projective Cover (FPC in Topographically Complex Landscapes

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Sisira Ediriweera

2013-12-01

Full Text Available The reflected radiance in topographically complex areas is severely affected by variations in topography; thus, topographic correction is considered a necessary pre-processing step when retrieving biophysical variables from these images. We assessed the performance of five topographic corrections: (i C correction (C, (ii Minnaert, (iii Sun Canopy Sensor (SCS, (iv SCS + C and (v the Processing Scheme for Standardised Surface Reflectance (PSSSR on the Landsat-5 Thematic Mapper (TM reflectance in the context of prediction of Foliage Projective Cover (FPC in hilly landscapes in north-eastern Australia. The performance of topographic corrections on the TM reflectance was assessed by (i visual comparison and (ii statistically comparing TM predicted FPC with ground measured FPC and LiDAR (Light Detection and Ranging-derived FPC estimates. In the majority of cases, the PSSSR method performed best in terms of eliminating topographic effects, providing the best relationship and lowest residual error when comparing ground measured FPC and LiDAR FPC with TM predicted FPC. The Minnaert, C and SCS + C showed the poorest performance. Finally, the use of TM surface reflectance, which includes atmospheric correction and broad Bidirectional Reflectance Distribution Function (BRDF effects, seemed to account for most topographic variation when predicting biophysical variables, such as FPC.

An assessment of areal evapotranspiration using Landsat TM data

Energy Technology Data Exchange (ETDEWEB)

Chae, Hyo-Sok; Park, Jae-Young [Water Resources Research Institute, Taejeon(Korea); Song, Young-Soo [Chonbuk National Univ., Chonju(Korea)

2000-08-31

Surface energy balance components were evaluated by Landsat TM data and GIS with meteorological data. Calibration and validation for the applicability of this methodology were made through the estimating of the large-scale evapotranspiration (ET). In addition, sensitivity and error analysis was conducted to see the effects of the surface energy balance components on ET and the accuracy of each components. Bochong-chon located on the upper part of Guem River basin was selected as the case study area. Spatial distribution map of ET were produced for five dates: Jan. 1, Apr. 3, May. 10, and Nov. 27, 1995. The study results showed that ET was greatly varied with the aspect and the land use type on the surface. In the case of having northeast and southeast in the aspect, ET was linearly increased depending on growing net radiation. While surface temperature has a high value, NDVI(Normalized Difference Vegetation Index) has a low value in the vegetated area. Therefore, ground heat flux was increased but ET was relatively decreased. The results of sensitivity and error analysis showed that net radiation is most sensitive and effective, ranging from 12.5% to 23.6% of sensitivity. Furthermore, the surface temperature, air temperature, and wind speed have the significant effects on ET estimation using remotely sensed data. (author). 26 refs., 4 tabs., 8 figs.

Landsat TM data processing for lithological discrimination in the Caraculo area (Namibe Province, SW Angola)

Science.gov (United States)

Alberti, A.; Alessandro, V.; Pieruccini, U.; Pranzini, E.

1993-10-01

Landsat TM data were used for lithological discrimination and mapping in the little-known, semiarid 900 km 2 area around Caraculo station and the middle course of the Rio Giraul (Namibe Province, SW Angola) following two main procedures. The first of these was based on visual evaluation of three-band composites, band-ratio composites and Principal Component Analysis. The second method relied on the extraction of spectral signatures, and their use to obtain automatic classifications. Satisfactory results were reached with the first procedure, thus allowing - with limited support of ground information — the draft of a lithological map, while the second method was not systematically efficient, even for confirmation of data acquired with the first procedure. Image interpretation suggests that an extensive but hithertoun differentiated metasedimentary complex consisting of a heterogeneous supracrustal sequence should be subdivided into at least two units. Field observations proved that one of these is marked by a notable frequency of marbles and the other is characterized by a widespread occurrence of amphibolitic bodies. Moreover, a belt of undetermined (thermally metamorphosed ?) metamorphic rocks is interposed between them. The distinction of so far unidentified units, though restricted to interpretation of processed Landsat TM data, has significant geological implications also in the regional context and will be helpful in guiding future work with conventional geological methods.

Evaluation of Radiometric and Atmospheric Correction Algorithms for Aboveground Forest Biomass Estimation Using Landsat 5 TM Data

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Pablito M. López-Serrano

2016-04-01

Full Text Available Solar radiation is affected by absorption and emission phenomena during its downward trajectory from the Sun to the Earth’s surface and during the upward trajectory detected by satellite sensors. This leads to distortion of the ground radiometric properties (reflectance recorded by satellite images, used in this study to estimate aboveground forest biomass (AGB. Atmospherically-corrected remote sensing data can be used to estimate AGB on a global scale and with moderate effort. The objective of this study was to evaluate four atmospheric correction algorithms (for surface reflectance, ATCOR2 (Atmospheric Correction for Flat Terrain, COST (Cosine of the Sun Zenith Angle, FLAASH (Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes and 6S (Second Simulation of Satellite Signal in the Solar, and one radiometric correction algorithm (for reflectance at the sensor ToA (Apparent Reflectance at the Top of Atmosphere to estimate AGB in temperate forest in the northeast of the state of Durango, Mexico. The AGB was estimated from Landsat 5 TM imagery and ancillary information from a digital elevation model (DEM using the non-parametric multivariate adaptive regression splines (MARS technique. Field reference data for the model training were collected by systematic sampling of 99 permanent forest growth and soil research sites (SPIFyS established during the winter of 2011. The following predictor variables were identified in the MARS model: Band 7, Band 5, slope (β, Wetness Index (WI, NDVI and MSAVI2. After cross-validation, 6S was found to be the optimal model for estimating AGB (R2 = 0.71 and RMSE = 33.5 Mg·ha−1; 37.61% of the average stand biomass. We conclude that atmospheric and radiometric correction of satellite images can be used along with non-parametric techniques to estimate AGB with acceptable accuracy.

An investigation of several aspects of LANDSAT-5 data quality. [Palmer County, Shelby, mt; White sands, NM; Great Salt Lake, UT; San Matted Bridge and Sacramento, California

Science.gov (United States)

Wrigley, R. C. (Principal Investigator)

1984-01-01

Band-to-band registration, geodetic registration, interdector noise, and the modulation transfer function (MTE) are discussed for the Palmer County; TX scene. Band combinations for several LANDSAT 4 and LANDSAT 5 scenes; the geodetic registration test for the Sacramento, CA area; periodic noise components in TM band 5; and grey level measurements by detector for Great Salt Lake (UT) dark water forescans and backscans are considered. Results of MTF analyses of the San Mateo Bridge and of TM high resolution and aerial Daedalus scanner imagery are consistent and appear to be repeatable. An oil-on-sand target was constructed on the White Sands Missile Range in New Mexico. The two-image analysis procedure used is summarized.

Regional analysis of tertiary volcanic Calderas (western U.S.) using Landsat Thematic Mapper imagery

Science.gov (United States)

Spatz, David M.; Taranik, James V.

1989-01-01

The Landsat Thematic Mapper (TM) imagery of the Basin and Range province of southern Nevada was analyzed to identify and map volcanic rock assemblages at three Tertiary calderas. It was found that the longer-wavelength visible and the NIR TM Bands 3, 5, and 7 provide more effective lithologic discrimination than the shorter-wavelength bands, due partly to deeper penetration of the longer-wavelength bands, resulting in more lithologically driven radiances. Shorter-wavelength TM Bands 1 and 2 are affected more by surficial weathering products including desert varnish which may or may not provide an indirect link to lithologic identity. Guidelines for lithologic analysis of volcanic terrains using Landsat TM imagery are outlined.

Improved outgassing models for the Landsat-5 thematic mapper

Science.gov (United States)

Micijevic, E.; Chander, G.; Hayes, R.W.

2008-01-01

The Landsat-5 (L5) Thematic Mapper (TM) detectors of the short wave infrared (SWIR) bands 5 and 7 are maintained on cryogenic temperatures to minimize thermal noise and allow adequate detection of scene energy. Over the instrument's lifetime, gain oscillations are observed in these bands that are caused by an ice-like contaminant that gradually builds up on the window of a dewar that houses these bands' detectors. This process of icing, an effect of material outgassing in space, is detected and characterized through observations of Internal Calibrator (IC) data. Analyses of IC data indicated three to five percent uncertainty in absolute gain estimates due to this icing phenomenon. The thin-film interference lifetime models implemented in the image product generation systems at the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) successfully remove up to 80 percent of the icing effects for the image acquisition period from the satellite's launch in 1984 until 2001; however, their correction ability was found to be much lower for the time thereafter. This study concentrates on improving the estimates of the contaminant film growth rate and the associated change in the period of gain oscillations. The goal is to provide model parameters with the potential to correct 70 to 80 percent of gain uncertainties caused by outgassing effects in L5 TM bands 5 and 7 over the instrument's entire lifetime. ?? 2007 IEEE.

Land cover mapping with emphasis to burnt area delineation using co-orbital ALI and Landsat TM imagery

Science.gov (United States)

Petropoulos, George P.; Kontoes, Charalambos C.; Keramitsoglou, Iphigenia

2012-08-01

In this study, the potential of EO-1 Advanced Land Imager (ALI) radiometer for land cover and especially burnt area mapping from a single image analysis is investigated. Co-orbital imagery from the Landsat Thematic Mapper (TM) was also utilised for comparison purposes. Both images were acquired shortly after the suppression of a fire occurred during the summer of 2009 North-East of Athens, the capital of Greece. The Maximum Likelihood (ML), Artificial Neural Networks (ANNs) and Support Vector Machines (SVMs) classifiers were parameterised and subsequently applied to the acquired satellite datasets. Evaluation of the land use/cover mapping accuracy was based on the error matrix statistics. Also, the McNemar test was used to evaluate the statistical significance of the differences between the approaches tested. Derived burnt area estimates were validated against the operationally deployed Services and Applications For Emergency Response (SAFER) Burnt Scar Mapping service. All classifiers applied to either ALI or TM imagery proved flexible enough to map land cover and also to extract the burnt area from other land surface types. The highest total classification accuracy and burnt area detection capability was returned from the application of SVMs to ALI data. This was due to the SVMs ability to identify an optimal separating hyperplane for best classes' separation that was able to better utilise ALI's advanced technological characteristics in comparison to those of TM sensor. This study is to our knowledge the first of its kind, effectively demonstrating the benefits of the combined application of SVMs to ALI data further implying that ALI technology may prove highly valuable in mapping burnt areas and land use/cover if it is incorporated into the development of Landsat 8 mission, planned to be launched in the coming years.

Examination of Abiotic Drivers and Their Influence on Spartina alterniflora Biomass over a Twenty-Eight Year Period Using Landsat 5 TM Satellite Imagery of the Central Georgia Coast

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John P. R. O’Donnell

2016-06-01

Full Text Available We examined the influence of abiotic drivers on inter-annual and phenological patterns of aboveground biomass for Marsh Cordgrass, Spartina alterniflora, on the Central Georgia Coast. The linkages between drivers and plant response via soil edaphic factors are captured in our graphical conceptual model. We used geospatial techniques to scale up in situ measurements of aboveground S. alterniflora biomass to landscape level estimates using 294 Landsat 5 TM scenes acquired between 1984 and 2011. For each scene we extracted data from the same 63 sampling polygons, containing 1222 pixels covering about 1.1 million m2. Using univariate and multiple regression tests, we compared Landsat derived biomass estimates for three S. alterniflora size classes against a suite of abiotic drivers. River discharge, total precipitation, minimum temperature, and mean sea level had positive relationships with and best explained biomass for all dates. Additional results, using seasonally binned data, indicated biomass was responsive to changing combinations of variables across the seasons. Our 28-year analysis revealed aboveground biomass declines of 33%, 35%, and 39% for S. alterniflora tall, medium, and short size classes, respectively. This decline correlated with drought frequency and severity trends and coincided with marsh die-backs events and increased snail herbivory in the second half of the study period.

Mapping of sugarcane crop area in the Paraná State using Landsat/TM/OLI and IRS/LISS-3 images

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Clóvis Cechim Junior

Full Text Available ABSTRACT The knowledge on reliable estimates of areas under sugarcane cultivation is essential for the Brazilian agribusiness, since it helps in the development of public policies, in determining prices by sugar mills to producers and allows establishing the logistics of production disposal. The objective of this work was to develop a methodology for mapping the sugarcane crop area in the state of Paraná, Brazil, using images from the Landsat/TM/OLI and IRS/LISS-3 satellites, for the crop years from 2010/2011 to 2013/2014. The mappings were conducted through the supervised Maximum likelihood classification (Maxver achieving, on average, an overall accuracy of 94.13% and kappa index of 0.82. The correlation with the official data of the IBGE ranged from moderate to strong (0.64 ≤ rs ≤ 0.80 with average agreement (dr of 0.81. There was an increase of 2.73% (18,630 ha in the area with sugarcane in Paraná between 2010/2011 and 2013/2014.

Actual evapotranspiration estimation in a Mediterranean mountain region by means of Landsat-5 TM and TERRA/AQUA MODIS imagery and Sap Flow measurements in Pinus sylvestris forest stands.

Science.gov (United States)

Cristóbal, J.; Poyatos, R.; Ninyerola, M.; Pons, X.; Llorens, P.

2009-04-01

Evapotranspiration monitoring has important implications on global and regional climate modelling, as well as in the knowledge of the hydrological cycle and in the assessment of environmental stress that affects forest and agricultural ecosystems. An increase of evapotranspiration while precipitation remains constant, or is reduced, could decrease water availability for natural and agricultural systems and human needs. Consequently, water balance methods, as the evapotranspiration modelling, have been widely used to estimate crop and forest water needs, as well as the global change effects. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute evapotranspiration at regional scales in a feasible way. Currently, the 38% of Catalonia (NE of the Iberian Peninsula) is covered by forests, and one of the most important forest species is Scots Pine (Pinus sylvestris) which represents the 18.4% of the area occupied by forests. The aim of this work is to model actual evapotranspiration in Pinus sylvestris forest stands, in a Mediterranean mountain region, using remote sensing data, and compare it with stand-scale sap flow measurements measured in the Vallcebre research area (42° 12' N, 1° 49' E), in the Eastern Pyrenees. To perform this study a set of 30 cloud-free TERRA-MODIS images and 10 Landsat-5 TM images of path 198 and rows 31 and 32 from June 2003 to January 2005 have been selected to perform evapotranspiration modelling in Pinus sylvestris forest stands. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected two different types of products which contain the remote sensing data we have used to model daily evapotranspiration, daily LST product and daily calibrated reflectances product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital

Analyzing Landsat time-series data across adjacent path/rows and across multiple cycles of FIA: Lessons learned in southern Missouri

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Mark Nelson; Sean Healey; W. Keith Moser; Mark Hansen; Warren Cohen; Mark Hatfield; Nancy Thomas; Jeff Masek

2009-01-01

The North American Forest Dynamics (NAFD) Program is assessing disturbance and regrowth in the forests of the continent. These forest dynamics are interpreted from per-pixel estimates of forest biomass, which are produced for a time series of Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced TM Plus images. Image data are combined with sample plot data from the...

A Comparison of Spectral Angle Mapper and Artificial Neural Network Classifiers Combined with Landsat TM Imagery Analysis for Obtaining Burnt Area Mapping

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Marko Scholze

2010-03-01

Full Text Available Satellite remote sensing, with its unique synoptic coverage capabilities, can provide accurate and immediately valuable information on fire analysis and post-fire assessment, including estimation of burnt areas. In this study the potential for burnt area mapping of the combined use of Artificial Neural Network (ANN and Spectral Angle Mapper (SAM classifiers with Landsat TM satellite imagery was evaluated in a Mediterranean setting. As a case study one of the most catastrophic forest fires, which occurred near the capital of Greece during the summer of 2007, was used. The accuracy of the two algorithms in delineating the burnt area from the Landsat TM imagery, acquired shortly after the fire suppression, was determined by the classification accuracy results of the produced thematic maps. In addition, the derived burnt area estimates from the two classifiers were compared with independent estimates available for the study region, obtained from the analysis of higher spatial resolution satellite data. In terms of the overall classification accuracy, ANN outperformed (overall accuracy 90.29%, Kappa coefficient 0.878 the SAM classifier (overall accuracy 83.82%, Kappa coefficient 0.795. Total burnt area estimates from the two classifiers were found also to be in close agreement with the other available estimates for the study region, with a mean absolute percentage difference of ~1% for ANN and ~6.5% for SAM. The study demonstrates the potential of the examined here algorithms in detecting burnt areas in a typical Mediterranean setting.

Examining the Capability of Supervised Machine Learning Classifiers in Extracting Flooded Areas from Landsat TM Imagery: A Case Study from a Mediterranean Flood

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Gareth Ireland

2015-03-01

Full Text Available This study explored the capability of Support Vector Machines (SVMs and regularised kernel Fisher’s discriminant analysis (rkFDA machine learning supervised classifiers in extracting flooded area from optical Landsat TM imagery. The ability of both techniques was evaluated using a case study of a riverine flood event in 2010 in a heterogeneous Mediterranean region, for which TM imagery acquired shortly after the flood event was available. For the two classifiers, both linear and non-linear (kernel versions were utilised in their implementation. The ability of the different classifiers to map the flooded area extent was assessed on the basis of classification accuracy assessment metrics. Results showed that rkFDA outperformed SVMs in terms of accurate flooded pixels detection, also producing fewer missed detections of the flooded area. Yet, SVMs showed less false flooded area detections. Overall, the non-linear rkFDA classification method was the more accurate of the two techniques (OA = 96.23%, K = 0.877. Both methods outperformed the standard Normalized Difference Water Index (NDWI thresholding (OA = 94.63, K = 0.818 by roughly 0.06 K points. Although overall accuracy results for the rkFDA and SVMs classifications only showed a somewhat minor improvement on the overall accuracy exhibited by the NDWI thresholding, notably both classifiers considerably outperformed the thresholding algorithm in other specific accuracy measures (e.g. producer accuracy for the “not flooded” class was ~10.5% less accurate for the NDWI thresholding algorithm in comparison to the classifiers, and average per-class accuracy was ~5% less accurate than the machine learning models. This study provides evidence of the successful application of supervised machine learning for classifying flooded areas in Landsat imagery, where few studies so far exist in this direction. Considering that Landsat data is open access and has global coverage, the results of this study

MONITORING MANGROVE AREA IN BENOA BAY USING LANDSAT TM AND ETM + DATA

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Ni Luh Made Ari Sugianthi

2012-11-01

Full Text Available Mangrove ecosystems are crucial for the management of some coastal resources in Indonesia. Thisresearch used Landsat TM 1994, Landsat ETM+ 2002 with the purpose to know mangrove area change foreight years, mangrove density and accuracy of image as source of data to mangrove area in Benoa Bay. Fromimage analysis that using maximum likelihood method, the mangrove is classified into 3 classes i.e.:mangroves with high density, medium density and low density. For the ground check, used single plotmethod by using 6 trees.The extent of mangrove area in Benoa Bay were 447.69 ha in 1994 and 622.08 ha in 2002. Thechange of the extent of mangrove area during 8 years (1994 – 2002 increased by 174.41 ha. The area ofdensities in 1994, high density was 225.15 ha, medium density was 122.48 ha and low density was 130.05ha. In 2002, high density was 262.8 ha, medium density was 265.95 ha, and low density was 133.30 ha.Based on the regression analysis between mangrove density and the value of interpretation, the density ofmangrove in Benoa Bay which the criteria of high density is 364.723 – 466.311 tree/ha, medium density is237.738 - 364.723 tree/ha and low density is 186.944 – 237.738 tree/ha. The determination coefficient (r2was 0.6312. Based on the regression analysis in 2002 used in interpretation of mangrove density in 1994,which the criteria of high density is 357.10 tree/ha –316.47 tree/ha, medium density is 273.29 tree/ha –316.47 tree/ha and low density is 252.98 tree/ha –273.29 tree/ha.The accuracy of the Landsat ETM+ 2002 for mangrove area classification in Benoa Bay was 90%.These values were above the acceptable limit of accuracy stated of 80 %, so that this classification accuracywas acceptable.

Assessment of land cover changes in Lampedusa Island (Italy) using Landsat TM and OLI data

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Mei, Alessandro; Manzo, Ciro; Fontinovo, Giuliano; Bassani, Cristiana; Allegrini, Alessia; Petracchini, Francesco

2016-10-01

The Lampedusa Island displays important socio-economic criticalities related to an intensive touristic activity, which implies an increase in electricity consumption and waste production. An adequate island conversion to a more environmental, sustainable community needs to be faced by the local Management Plans establishment. For this purpose, several thematic datasets have to be produced and evaluated. Socio-economic and bio-ecological components as well as land cover/use assessment are some of the main topics to be managed within the Decision Support Systems. Considering the lack of Land Cover (LC) and vegetation change detection maps in Lampedusa Island (Italy), this paper focuses on the retrieval of these topics by remote sensing techniques. The analysis was carried out by Landsat 5 TM and Landsat 8 OLI multispectral images from 1984 to 2014 in order to obtain spatial and temporal information of changes occurred in the island. Firstly, imagery was co-registered and atmospherically corrected; secondly, it was then classified for land cover and vegetation distribution analysis with the use of QGIS and Saga GIS open source softwares. The Maximum Likelihood Classifier (MLC) was used for LC maps production, while the Normalized Difference Vegetation Index (NDVI) was used for vegetation examination and distribution. Topographic maps, historical aerial photos, ortophotos and field data are merged in the GIS for accuracy assessment. Finally, change detection of MLC and NDVI are provided respectively by Post-Classification Comparison (PCC) and Image Differencing (ID). The provided information, combined with local socio-economic parameters, is essential for the improvement of environmental sustainability of anthropogenic activities in Lampedusa.

Use of ERS-2 Sar and Landsat TM Images for Geological Mapping and Mineral Exploration Of Sol Hamid Area, South Eastern Desert, Egypt

International Nuclear Information System (INIS)

Ramadan, T.M.

2003-01-01

Sol hamid area is chiefy occupied by neo proterozoic rocks, partly covered by miocene sediments and recent sand sheets and dunes. The neo proterozoic rocks include ophiolitic ultramafic to mafic rocks, meta volcano-sedimentary rocks, meta volcanics, gabbros-diorite rocks, granodiorites, biotite granites and alkali granites. Magnesite, chromite, iron ores, manganese and barite ore deposits are hosted in different at the study area. ERS-2 SAR data enabled to obtain an image that reveals some buried fluvial features beneath the surface cover of desert sand. These features are not observable in Landsat TM image of similar resolution. In this work, Principal Component Analysis (PCA) technique was used for merging ERS-2 SAR and Landsat TM images to make use of the potential of data fusion technique of image processing in the interpretation of geological features. This procedure has resulted in enhancing subsurface structure such as faults that control distribution of several deposits in the study area. This study represents an example to demonstrate the utility of merging various remote sensing data for exploring mineral deposits in arid region

Monitoring wetlands changes using Tiangong-1 hyperspectral data and landsat TM imagery%基于天宫一号高光谱数据与Landsat TM数据的湿地利用变化监测

Institute of Scientific and Technical Information of China (English)

胡勇; 刘良云

2014-01-01

本文利用2013年4月18日获取的天宫一号高光谱成像仪数据和1985年5月1日获取的Landsat TM数据,对黄河入海口地区湿地的土地利用状况进行了监测研究.通过对比分类结果发现,该地区近30年来人类活动对湿地的影响强烈,滩涂开垦、水产养殖业占用自然水面现象严重.同时由于天宫一号高光谱成像仪数据具有更高的光谱和空间分辨率,其分类精度优于Landsat TM,更适合于湿地的监测.

TOTAL WOOD VOLUME ESTIMATION OF EUCALYPTUS SPECIES BY IMAGES OF LANDSAT SATELLITE

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Elias Fernando Berra

2012-12-01

Full Text Available http://dx.doi.org/10.5902/198050987566Models relating spectral answers with biophysical parameters aim estimate variables, like wood volume, without the necessity of frequent field measurements. The objective was to develop models to estimate wood volume by Landsat 5 TM images, supported by regional forest inventory data. The image was geo-referenced and converted to spectral reflectance. After, the images-index NDVI (Normalized Difference Vegetation Index and SR (Simple Ratio was generated. The reflectance values of the bands (TM1, TM2, TM3 e TM4 and of the indices (NDVI and SR was related with the wood volume. The biggest correlation with volume was with the NDVI and SR indices. The variables selection was made by Stepwise method, which returned three regression models as significant to explain the variation in volume. Finally, the best fitted model was selected (volume = -830,95 + 46,05 (SR + 107,47 (TM2, which was applied on the Landsat image where the pixels had started to represent the estimated volume in m³/ha on the Eucalyptus sp. production units. This model, significant at 95% confidence level, explains 68% of the wood volume variation.

Proposal for a remote sensing trophic state index based upon Thematic Mapper/Landsat images

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Evlyn Márcia Leão de Moraes Novo

2013-12-01

Full Text Available This work proposes a trophic state index based on the remote sensing retrieval of chlorophyll-α concentration. For that, in situ Bidirectional Reflectance Factor (BRF data acquired in the Ibitinga reservoir were resampled to match Landsat/TM spectral simulated bands (TM_sim bands and used to run linear correlation with concurrent measurements of chlorophyll-α concentration. Monte Carlo simulation was then applied to select the most suitable model relating chlorophyll-α concentration and simulated TM/Landsat reflectance. TM4_sim/TM3_sim ratio provided the best model with a R2 value of 0.78. The model was then inverted to create a look-up-table (LUT relating TM4_sim/TM3_sim ratio intervals to chlorophyll-α concentration trophic state classes covering the entire range measured in the reservoir. Atmospheric corrected Landsat TM images converted to surface reflectance were then used to generate a TM4/TM3 ratio image. The ratio image frequency distribution encompassed the range of TM4_sim/TM3_sim ratio indicating agreement between in situ and satellite data and supporting the use of satellite data to map chlorophyll- concentration trophic state distribution in the reservoir. Based on that, the LUT was applied to a Landsat/TM ratio image to map the spatial distribution of chlorophyll- trophic state classes in Ibitinga reservoir. Despite the stochastic selection of TM4_sim/TM3_sim ratio as the best input variable for modeling the chlorophyll-α concentration, it has a physical basis: high concentration of phytoplankton increases the reflectance in the near-infrared (TM4 and decreases the reflectance in the red (TM3. The band ratio, therefore, enhances the relationship between chlorophyll- concentration and remotely sensed reflectance.

Cross-comparison of the IRS-P6 AWiFS sensor with the L5 TM, L7 ETM+, & Terra MODIS sensors

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Chander, G.; Xiong, X.; Angal, A.; Choi, T.; Malla, R.

2009-01-01

As scientists and decision makers increasingly rely on multiple Earth-observing satellites to address urgent global issues, it is imperative that they can rely on the accuracy of Earth-observing data products. This paper focuses on the crosscomparison of the Indian Remote Sensing (IRS-P6) Advanced Wide Field Sensor (AWiFS) with the Landsat 5 (L5) Thematic Mapper (TM), Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+), and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. The cross-comparison was performed using image statistics based on large common areas observed by the sensors within 30 minutes. Because of the limited availability of simultaneous observations between the AWiFS and the Landsat and MODIS sensors, only a few images were analyzed. These initial results are presented. Regression curves and coefficients of determination for the top-of-atmosphere (TOA) trends from these sensors were generated to quantify the uncertainty in these relationships and to provide an assessment of the calibration differences between these sensors. ?? 2009 SPIE.

Application and Comparison of the MODIS-Derived Enhanced Vegetation Index to VIIRS, Landsat 5 TM and Landsat 8 OLI Platforms: A Case Study in the Arid Colorado River Delta, Mexico

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Jarchow, Christopher J.; Didan, Kamel; Barreto-Muñoz, Armando; Glenn, Edward P.

2018-01-01

The Enhanced Vegetation Index (EVI) is a key Earth science parameter used to assess vegetation, originally developed and calibrated for the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites. With the impending decommissioning of the MODIS sensors by the year 2020/2022, alternative platforms will need to be used to estimate EVI. We compared Landsat 5 (2000–2011), 8 (2013–2016) and the Visible Infrared Imaging Radiometer Suite (VIIRS; 2013–2016) to MODIS EVI (2000–2016) over a 420,083-ha area of the arid lower Colorado River Delta in Mexico. Over large areas with mixed land cover or agricultural fields, we found high correspondence between Landsat and MODIS EVI (R2 = 0.93 for the entire area studied and 0.97 for agricultural fields), but the relationship was weak over bare soil (R2 = 0.27) and riparian vegetation (R2 = 0.48). The correlation between MODIS and Landsat EVI was higher over large, homogeneous areas and was generally lower in narrow riparian areas. VIIRS and MODIS EVI were highly similar (R2 = 0.99 for the entire area studied) and did not show the same decrease in performance in smaller, narrower regions as Landsat. Landsat and VIIRS provide EVI estimates of similar quality and characteristics to MODIS, but scale, seasonality and land cover type(s) should be considered before implementing Landsat EVI in a particular area. PMID:29757265

Investigating Land Surface Temperature Changes Using Landsat Data in Konya, Turkey

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O. Orhan

2016-06-01

Full Text Available The main purpose of this paper is to investigate multi-temporal land surface temperature (LST and Normalized Difference Vegetation Index (NDVI changes of Konya in Turkey using remotely sensed data. Konya is located in the semi-arid central Anatolian region of Turkey and hosts many important wetland sites including Salt Lake. Six images taken by Landsat-5 TM and Landsat 8- OLI satellites were used as the basic data source. These raw images were taken in 1984, 2011 and 2014 intended as long-term and short-term. Firstly, those raw images was corrected radiometric and geometrically within the scope of project. Three mosaic images were obtained by using the full-frame images of Landsat-5 TM / 8- OLI which had been already transformed comparison each other. Then, Land Surface Temperature (LST, Normalized Difference Vegetation Index (NDVI maps have been produced to determine the dimension of the drought. The obtained results showed that surface temperature rates in the basin increased about 5°C between 1984 and 2014 as long periods, increased about 2-3°C between 2011and 2014 as short periods. Meteorological data supports the increase in temperature.

Using Google Earth Engine To Apply Spectral Mixture Analysis Over Landsat 5TM Imagery To Map Fire Scars In The Alto Teles Pires River Basin, Mato Grosso State, Brazil.

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Antunes Daldegan, G.; Ribeiro, F.; Roberts, D. A.

2016-12-01

The two most extensive biomes in Brazil, the Amazon Forest and the Cerrado (the Brazilian savanna), are subject to many fire events every dry season. Both biomes are well-known for their ecological and environmental importance but, due to the intensive human occupation over the last decades, they have been experiencing high deforestation rates with much of their natural landscape being converted to agriculture and pasture uses. The Cerrado, as a savanna, has naturally evolved adapted to fire. According to some researchers, this biome has been exposed to fire for the last 25 million years, forging the diversification of many C4 grass species, for example. The Amazon forest does not have similar characteristics and studies have shown that forest areas that have been already burned become more prone to recurrent burns. Forest patches that are close to open areas have their edges exposed to higher insolation and greater turbulence, drying the understory vegetation and litter, turning those areas more susceptible to fire events. In cases where grass species become established in the understory they can be a renewable source of fuel for recurrent burns. This study aimed to identify and map fire scars present in the region of Alto Teles Pires river basin, State of Mato Grosso - Brazil, during 10 years (2002-2011). This region is located in the transition zone between the two biomes and is known for its high deforestation rates. By taking advantage of the Landsat 5TM imagery collection present in Google Earth Engine platform as well as applying Spectral Mixture Analysis (SMA) techniques over them it was possible to estimate fractions of Green Vegetation (GV), Non-Photosynthetic Vegetation (NPV), and Soil targets, which are the surfaces that compose the vast majority of the landscape in the study region. Iteratively running SMA analysis over the imagery using burned vegetation endmembers allowed us to further identify fire scars present in the region, returning excellent

Analysis of conifer forest regeneration using Landsat Thematic Mapper data

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Fiorella, Maria; Ripple, William J.

1995-01-01

Landsat Thematic Mapper (TM) data were used to evaluate young conifer stands in the western Cascade Mountains of Oregon. Regression and correlation analyses were used to describe the relationships between TM band values and age of young Douglas-fir stands (2 to 35 years old). Spectral data from well regenerated Douglas-fir stands were compared to those of poorly regenerated conifer stands. TM bands 1, 2, 3, 5, 6, and 7 were inversely correlated with the age (r greater than or equal to -0.80) of well regenerated Douglas-fir stands. Overall, the 'structural index' (TM 4/5 ratio) had the highest correlation to age of Douglas-fir stands (r = 0.96). Poorly regenerated stands were spectrally distinct from well regenerated Douglas-fir stands after the stands reached an age of approximately 15 years.

Estimativa do balanço de energia utilizando imagens TM - Landsat 5 e o algoritmo SEBAL no litoral sul de Pernambuco

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Célia Cristina Machado

2014-03-01

Full Text Available As trocas de energia na interface solo-planta-atmosfera, por meio das componentes do balanço de radiação (Rn e dos fluxos de calor no solo (G, sensível (H e latente (LE, são essenciais para a modelagem climática e hidrológica que, por sua vez, afetam toda a biosfera. Dessa forma, esta pesquisa teve por objetivos: (1 estimar e comparar o comportamento dos componentes do balanço de energia, usando o algoritmo SEBAL - Surface Energy Balance Algorithm for Land, em diferentes tipos de uso e cobertura do solo e (2 validar o algoritmo. Para isso, foram usadas três imagens TM - Landsat 5 de órbita e ponto 214/066, com datas de passagem em 26 de agosto de 2006, 6 de setembro de 2010 e 28 de janeiro de 2011, todas recortadas para enquadrar o litoral sul de Pernambuco. Os resultados mostraram a capacidade do SEBAL de estimar a variabilidade espacial dos diferentes componentes do balanço de energia, com capacidade de distinguir diferentes ocupações do solo. O cômputo do balanço de energia possibilita observar as formas diferenciadas do uso da energia pelos diferentes tipos de cobertura do solo e verificar aqueles que propiciam melhor conforto térmico. As estimativas da evapotranspiração obtidas pelo algoritmo SEBAL apresentaram uma boa concordância com os resultados obtidos pelo método da FAO-Penman-Monteith demonstrando, dessa forma, a potencialidade da abordagem metodológica escolhida.

Continuous Calibration Improvement in Solar Reflective Bands: Landsat 5 Through Landsat 8

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Mishra, Nischal; Helder, Dennis; Barsi, Julia; Markham, Brian

2016-01-01

Launched in February 2013, the Operational Land Imager (OLI) on-board Landsat 8 continues to perform exceedingly well and provides high science quality data globally. Several design enhancements have been made in the OLI instrument relative to prior Landsat instruments: pushbroom imaging which provides substantially improved Signal-to-Noise Ratio (SNR), spectral bandpasses refinement to avoid atmospheric absorption features, 12 bit data resolution to provide a larger dynamic range that limits the saturation level, a set of well-designed onboard calibrators to monitor the stability of the sensor. Some of these changes such as refinements in spectral bandpasses compared to earlier Landsats and well-designed on-board calibrator have a direct impact on the improved radiometric calibration performance of the instrument from both the stability of the response and the ability to track the changes. The on-board calibrator lamps and diffusers indicate that the instrument drift is generally less than 0.1% per year across the bands. The refined bandpasses of the OLI indicate that temporal uncertainty of better than 0.5% is possible when the instrument is trended over vicarious targets such as Pseudo Invariant Calibration Sites (PICS), a level of precision that was never achieved with the earlier Landsat instruments. The stability measurements indicated by on-board calibrators and PICS agree much better compared to the earlier Landsats, which is very encouraging and bodes well for the future Landsat missions too.

Identification of areas of recharge and discharge using Landsat-TM satellite imagery and aerial photography mapping techniques

Science.gov (United States)

Salama, R. B.; Tapley, I.; Ishii, T.; Hawkes, G.

1994-10-01

Aerial photographs (AP) and Landsat (TM) colour composites were used to map the geomorphology, geology and structures of the Salt River System of Western Australia. Geomorphic features identified are sand plains, dissected etchplain, colluvium, lateritic duricrust and rock outcrops. The hydrogeomorphic units include streams, lakes and playas, palaeochannels and palaeodeltas. The structural features are linear and curvilinear lineaments, ring structures and dolerite dykes. Suture lines control the course of the main river channel. Permeable areas around the circular granitic plutons were found to be the main areas of recharge in the uplands. Recharge was also found to occur in the highly permeable areas of the sandplains. Discharge was shown to be primarily along the main drainage lines, on the edge of the circular sandplains, in depressions and in lakes. The groundwater occurrence and hydrogeological classification of the recharge potential of the different units were used to classify the mapped areas into recharge and discharge zones. The results also show that TM colour composites provide a viable source of data comparable with AP for mapping and delineating areas of recharge and discharge on a regional scale.

A Comparative Study of Landsat TM and SPOT HRG Images for Vegetation Classification in the Brazilian Amazon

Science.gov (United States)

Lu, Dengsheng; Batistella, Mateus; de Miranda, Evaristo E.; Moran, Emilio

2009-01-01

Complex forest structure and abundant tree species in the moist tropical regions often cause difficulties in classifying vegetation classes with remotely sensed data. This paper explores improvement in vegetation classification accuracies through a comparative study of different image combinations based on the integration of Landsat Thematic Mapper (TM) and SPOT High Resolution Geometric (HRG) instrument data, as well as the combination of spectral signatures and textures. A maximum likelihood classifier was used to classify the different image combinations into thematic maps. This research indicated that data fusion based on HRG multispectral and panchromatic data slightly improved vegetation classification accuracies: a 3.1 to 4.6 percent increase in the kappa coefficient compared with the classification results based on original HRG or TM multispectral images. A combination of HRG spectral signatures and two textural images improved the kappa coefficient by 6.3 percent compared with pure HRG multispectral images. The textural images based on entropy or second-moment texture measures with a window size of 9 pixels × 9 pixels played an important role in improving vegetation classification accuracy. Overall, optical remote-sensing data are still insufficient for accurate vegetation classifications in the Amazon basin. PMID:19789716

A Comparative Study of Landsat TM and SPOT HRG Images for Vegetation Classification in the Brazilian Amazon.

Science.gov (United States)

Lu, Dengsheng; Batistella, Mateus; de Miranda, Evaristo E; Moran, Emilio

2008-01-01

Complex forest structure and abundant tree species in the moist tropical regions often cause difficulties in classifying vegetation classes with remotely sensed data. This paper explores improvement in vegetation classification accuracies through a comparative study of different image combinations based on the integration of Landsat Thematic Mapper (TM) and SPOT High Resolution Geometric (HRG) instrument data, as well as the combination of spectral signatures and textures. A maximum likelihood classifier was used to classify the different image combinations into thematic maps. This research indicated that data fusion based on HRG multispectral and panchromatic data slightly improved vegetation classification accuracies: a 3.1 to 4.6 percent increase in the kappa coefficient compared with the classification results based on original HRG or TM multispectral images. A combination of HRG spectral signatures and two textural images improved the kappa coefficient by 6.3 percent compared with pure HRG multispectral images. The textural images based on entropy or second-moment texture measures with a window size of 9 pixels × 9 pixels played an important role in improving vegetation classification accuracy. Overall, optical remote-sensing data are still insufficient for accurate vegetation classifications in the Amazon basin.

Identification and application of the valid wavelength bands for burnt area detection and fire severity classification using Landsat/TM data

International Nuclear Information System (INIS)

Maki, M.; Tamura, M.

2003-01-01

Firstly, by using Landsat Thematic Mapper (TM) imagery before and after forest fire, the valid wavelength bands for detecting burnt areas were examined and compared to NDVI. Secondly, by using the valid wavelength bands, mapping of burnt area and classification of fire severity were examined. The results show that (a) channel 4 and 7 were more sensitive than other channels for detecting burnt area, (b) BAI (Burnt Area Index) [(ch. 4-ch. 7)/(ch. 4+ch. 7)] was more useful than NDVI for detecting burnt areas, and (c) BAI imagery was more useful for classification of burn severity than NDVI imagery

Radiometric analysis of the longwave infrared channel of the Thematic Mapper on LANDSAT 4 and 5

Science.gov (United States)

Schott, John R.; Volchok, William J.; Biegel, Joseph D.

1986-01-01

The first objective was to evaluate the postlaunch radiometric calibration of the LANDSAT Thematic Mapper (TM) band 6 data. The second objective was to determine to what extent surface temperatures could be computed from the TM and 6 data using atmospheric propagation models. To accomplish this, ground truth data were compared to a single TM-4 band 6 data set. This comparison indicated satisfactory agreement over a narrow temperature range. The atmospheric propagation model (modified LOWTRAN 5A) was used to predict surface temperature values based on the radiance at the spacecraft. The aircraft data were calibrated using a multi-altitude profile calibration technique which had been extensively tested in previous studies. This aircraft calibration permitted measurement of surface temperatures based on the radiance reaching the aircraft. When these temperature values are evaluated, an error in the satellite's ability to predict surface temperatures can be estimated. This study indicated that by carefully accounting for various sensor calibration and atmospheric propagation effects, and expected error (1 standard deviation) in surface temperature would be 0.9 K. This assumes no error in surface emissivity and no sampling error due to target location. These results indicate that the satellite calibration is within nominal limits to within this study's ability to measure error.

Principal Component Analysis and Morphostructural Characterization of a Portion of The Eastern Continental Shelf of Ceará, Brazil, Using Landsat 5-Tm Images

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Cynthia Romariz Duarte

2016-09-01

Full Text Available This study used Landsat 5 Thematic Mapper (5-TM images in the morphostructural characterization of the shallow continental shelf of the eastern coast of Ceará (CE, in the Jaguaribe river mouth. The dam built near the river mouth to transpose the water towards Fortaleza, CE, ensures good water transparency since little of the river-carried sediment reaches the sea. The used image was captured on date and time to ensure low tide. Data using Secchi disc indicated good water transparency in the turbidity zone and seaside, coastal and marine areas. Bathymetry studies and underwater photos confirm the existence of many of the features described in this study. Digital image processing techniques have been applied in the study: colored compositions (RGB 124, 90° directional filter (band 1, and a colored composition employing the filtered band 1 and band 2 and 4. The filtered image of band 1 allowed recognizing different features when interpreted in detail scale. The principal component analysis (PCA was used here, calculating eigenvalues and eigenvectors. When applied to bands 1 to 5 and 7, PCA generated good results in PC2, whose correlation with the blue band was 0.85 (explained cumulative variance of more than 96%. Applied to the visible bands, PCA produced very similar results in PC1, and the correlation between the blue band and PC1 was 0.86 (explained cumulative variance of 94%. These results show that band 1 is the main contributor in studies of submerged morphological features. Each process resulted in a new image, from which it was possible to produce the map of the area representing morphostructural characteristics. The use of digitally processed satellite images in the visible region greatly improves the characterization and mapping of submerged features in places with shallow and good transparency waters.

Quantifying BRDF Effects in Comparing Landsat-7 and AVIRIS Near-Simultaneous Acquisitions for Studies of High Plains Vegetation Cover

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Goetz, A. F. H.; Heidebrecht, K. B.; Gutmann, E. D.; Warner, A. S.; Johnson, E. L.; Lestak, L. R.

1999-01-01

Approximately 100,000 sq. km of the High Plains of the central United States are covered by sand dunes and sand sheets deposited during the Holocene. Soil-dating evidence shows that there were at least four periods of dune reactivation during major droughts in the last 10,000 years. The dunes in this region are anchored by vegetation. We have undertaken a study of land-use change in the High Plains from 1985 to the present using Landsat 5 TM and Landsat 7 ETM+ images to map variation in vegetation cover during wet and dry years. Mapping vegetation cover of less than 20% is important in modeling potential surface reactivation since at this level the vegetation no longer sufficiently shields sandy surfaces from movement by wind. Landsat TM data have both the spatial resolution and temporal coverage to facilitate vegetation cover analysis for model development and verification. However, there is still the question of how accurate TM data are for the measurement of both growing and senescent vegetation in and and semi-arid regions. AVIRIS provides both high spectral resolution as well as high signal-to-noise ratio and can be used to test the accuracy of Landsat TM and ETM+ data. We have analyzed data from AVIRIS flown nearly concurrently with a Landsat 7 overpass. The comparison between an AVIRIS image swath of 11 km width subtending a 30 deg. angle and the same area covered by a 0.8 deg. angle from Landsat required accounting for the BRDF. A normalization technique using the ratio of the reflectances from registered AVIRIS and Landsat data proved superior to the techniques of column averaging on AVIRIS data alone published previously by Kennedy et al. This technique can be applied to aircraft data covering a wider swath angle than AVIRIS to develop BRDF responses for a wide variety of surfaces more efficiently than from ground measurements.

Introduction program of M5TM cladding in Japan

International Nuclear Information System (INIS)

Mardon, Jean Paul; Kaneko, Nori

2008-01-01

Experience from irradiation in PWR has confirmed that M5 TM possesses all the properties required for upgraded operation including new fuel management approaches and high duty reactor operation. Specifically, the alloy M5 TM has demonstrated impressive improvements over Zircaloy-4 for fuel rod cladding and fuel assembly structural components. Moreover, several irradiation campaigns have been worldwide performed in order to confirm the excellent M5 TM in-pile behavior in very demanding PWR irradiation conditions (high void fraction, heat flux, temperature, lithium content and Zinc injection). Regarding licensing, the authorization for loading M5 TM alloy has been granted by US, UK, South Korean, German, Chinese, South-African, Swedish and Belgian Safety Authorities. Also the French Nuclear Safety Authority has given individually its authorization to load all-M5 TM fuel assembly batches in 1300MWe plants and a generic license to load all-M5 TM fuel in EDF N4 reactors and M5 TM fuel clad in 900MWe reactors for MOX parity fuel management. Licensing is also now underway in Switzerland, Finland, Brazil and Spain. The M5 TM alloy has demonstrated its superiority at burn-ups beyond current licensing limits, through operations in PWR at fuel rod burn-ups exceeding 71GWd/tU in the United States and 78GWd/tU in Europe. The Japanese nuclear industry has planned a stepwise approach to increase the burn-up of the fuel. Step-I fuel (48GWd/tU Fuel Assembly maximum burn-up) which was introduced in the late 80s. In the 90s started the licensing of the Step-II fuel (55GWd/tU Fuel Assembly maximum burn-up). Because the extension of the burn-up is important to reduce discharge fuel and cycle cost, the Japanese industry has plans to further extend the burn-up. In such burn-up region, fuel cladding with even better corrosion properties and very low hydrogen pick-up shall be necessary. M5 TM alloy, with high anticorrosion/hydriding properties, is suitable for not only the Step-II fuel

Downscaling of Aircraft, Landsat, and MODIS-bases Land Surface Temperature Images with Support Vector Machines

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High spatial resolution Land Surface Temperature (LST) images are required to estimate evapotranspiration (ET) at a field scale for irrigation scheduling purposes. Satellite sensors such as Landsat 5 Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) can offer images at s...

ESTIMATIVA DO VOLUME TOTAL DE MADEIRA EM ESPÉCIES DE EUCALIPTO A PARTIR DE IMAGENS DE SATÉLITE LANDSAT

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Elias Fernando Berra

2012-01-01

Full Text Available Models relating spectral answers with biophysical parameters aim estimate variables, such as wood volume, without the necessity of frequent field measurements. The objective was to develop models to estimatewood volume by Landsat 5 TM images, supported by regional forest inventory data. The image was georeferenced and converted to spectral reflectance. After, the images-index NDVI (Normalized Difference Vegetation Index and SR (Simple Ratio was generated. The reflectance values of both spectral bands (TM1, TM2, TM3 e TM4 and indices (NDVI and SR was related with the wood volume. The biggest correlation with volume was with the NDVI and SR indices. The variables selection was made by Stepwise method, which returned three regression models as significant to explain the variation in volume. Finally,the best fitted model was selected (volume = -830,95 + 46,05 × (SR + 107,47 × (TM2, which was applied on the Landsat image where the pixels had started to represent the estimated volume in m³/ha on the Eucalyptus sp. production units. This model, significant at 95 % confidence level, explains 68 % of the wood volume variation.

Application of Landsat Thematic Mapper data for coastal thermal plume analysis at Diablo Canyon

Science.gov (United States)

Gibbons, D. E.; Wukelic, G. E.; Leighton, J. P.; Doyle, M. J.

1989-01-01

The possibility of using Landsat Thematic Mapper (TM) thermal data to derive absolute temperature distributions in coastal waters that receive cooling effluent from a power plant is demonstrated. Landsat TM band 6 (thermal) data acquired on June 18, 1986, for the Diablo Canyon power plant in California were compared to ground truth temperatures measured at the same time. Higher-resolution band 5 (reflectance) data were used to locate power plant discharge and intake positions and identify locations of thermal pixels containing only water, no land. Local radiosonde measurements, used in LOWTRAN 6 adjustments for atmospheric effects, produced corrected ocean surface radiances that, when converted to temperatures, gave values within approximately 0.6 C of ground truth. A contour plot was produced that compared power plant plume temperatures with those of the ocean and coastal environment. It is concluded that Landsat can provide good estimates of absolute temperatures of the coastal power plant thermal plume. Moreover, quantitative information on ambient ocean surface temperature conditions (e.g., upwelling) may enhance interpretation of numerical model prediction.

Drought monitoring of Tumen river basin wetlands between 1991 and 2016 using Landsat TM/ETM+

Science.gov (United States)

Yu, H.; Zhu, W.; Lee, W. K.; Heo, S.

2017-12-01

Wetlands area described as "the kidney of earth" owing to the importance of functions for stabilizing environment, long-term protection of water sources, as well as effectively minimize sediment loss, purify surface water from industrial and agricultural pollutants, and enhancing aquifer recharge. Drought monitoring in wetlands is vital due to the condition of water supply directly affecting the growth of wetland plants and local biodiversity. In this study, Vegetation Temperature Condition Index derived from Normalized Difference Vegetation Index and Land Surface Temperature is used to observe drought status from 1991 to 2016. For doing this, Landsat TM/ETM+ data for six periods are used to analytical processing. On the other hand, soil moisture maps which are acquired from CMA Land Data Assimilation System Version 1.0 for validating reliability of drought monitoring. As a result, the study shows most of area at normal moist level (decreased 25.8%) became slightly drought (increased 29.7%) in Tumen river basin cross-border (China and North Korea) wetland. The correlation between vegetation temperature condition index and soil moisture are 0.69, 0.32 and 0.2 for the layers of 0 5cm, 0 10cm, and 10 20cm, respectively. Although climate change probably contributes to the process of drought by decreasing precipitation and increasing temperature, human activities are shown as main factor that led to the process in this wetland.

Glacial lake monitoring in the Karakoram Range using historical Landsat Thematic Mapper archive (1982 - 2014)

Science.gov (United States)

Chan, J. Y. H.; Kelly, R. E. J.; Evans, S. G.

2014-12-01

Glacierized regions are one of the most dynamic land surface environments on the planet (Evans and Delaney, In Press). They are susceptible to various types of natural hazards such as landslides, glacier avalanches, and glacial lake outburst floods (GLOF). GLOF events are increasingly common and present catastrophic flood hazards, the causes of which are sensitive to climate change in complex high mountain topography (IPCC, 2013). Inundation and debris flows from GLOF events have repeatedly caused significant infrastructure damages and loss of human lives in the high mountain regions of the world (Huggel et al, 2002). The research is designed to develop methods for the consistent detection of glacier lakes formation during the Landsat Thematic Mapper (TM) era (1982 - present), to quantify the frequency of glacier lake development and estimate lake volume using Landsat imagery and digital elevation model (DEM) data. Landsat TM scenes are used to identify glacier lakes in the Shimshal and Shaksgam valley, particularly the development of Lake Virjeab in year 2000 and Kyagar Lake in 1998. A simple thresholding technique using Landsat TM infrared bands, along with object-based segmentation approaches are used to isolate lake extent. Lake volume is extracted by intersecting the lake extent with the DEM surface. Based on previous studies and DEM characterization in the region, Shuttle Radar Topography Mission (SRTM) DEM is preferred over Advanced Spaceborne Thermal Emission and Reflection (ASTER) GDEM due to higher accuracy. Calculated errors in SRTM height estimates are 5.81 m compared with 8.34 m for ASTER. SRTM data are preferred because the DEM measurements were made over short duration making the DEM internally consistent. Lake volume derived from the Landsat TM imagery and DEM are incorporated into a simple GLOF model identified by Clague and Matthews (1973) to estimate the potential peak discharge (Qmax) of a GLOF event. We compare the simple Qmax estimates with

Preparing Landsat Image Time Series (LITS for Monitoring Changes in Vegetation Phenology in Queensland, Australia

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Santosh Bhandari

2012-06-01

Full Text Available Time series of images are required to extract and separate information on vegetation change due to phenological cycles, inter-annual climatic variability, and long-term trends. While images from the Landsat Thematic Mapper (TM sensor have the spatial and spectral characteristics suited for mapping a range of vegetation structural and compositional properties, its 16-day revisit period combined with cloud cover problems and seasonally limited latitudinal range, limit the availability of images at intervals and durations suitable for time series analysis of vegetation in many parts of the world. Landsat Image Time Series (LITS is defined here as a sequence of Landsat TM images with observations from every 16 days for a five-year period, commencing on July 2003, for a Eucalyptus woodland area in Queensland, Australia. Synthetic Landsat TM images were created using the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM algorithm for all dates when images were either unavailable or too cloudy. This was done using cloud-free scenes and a MODIS Nadir BRDF Adjusted Reflectance (NBAR product. The ability of the LITS to measure attributes of vegetation phenology was examined by: (1 assessing the accuracy of predicted image-derived Foliage Projective Cover (FPC estimates using ground-measured values; and (2 comparing the LITS-generated normalized difference vegetation index (NDVI and MODIS NDVI (MOD13Q1 time series. The predicted image-derived FPC products (value ranges from 0 to 100% had an RMSE of 5.6. Comparison between vegetation phenology parameters estimated from LITS-generated NDVI and MODIS NDVI showed no significant difference in trend and less than 16 days (equal to the composite period of the MODIS data used difference in key seasonal parameters, including start and end of season in most of the cases. In comparison to similar published work, this paper tested the STARFM algorithm in a new (broadleaf forest environment and also

Geological interpretation of Landsat TM imagery and aeromagnetic survey data, northern Precordillera region, Argentina

Science.gov (United States)

Chernicoff, C. J.; Nash, C. R.

2002-03-01

This case study demonstrates a methodology for obtaining maximum geoscientific value from reconnaissance (1000 m line spacing) aeromagnetic data through integration with high-resolution satellite imagery. In this study, lithostratigraphic interpretation of optimally processed Landsat TM data at reconnaissance mapping scale (1:100,000) has been carried out as a precursor to geophysical interpretation, providing the basic 'framework' in which to view the imaged geophysical data. The Landsat-derived framework shows the correct positions and vergences of major structures, which characterize this part of the Andean foreland thrust-and-fold belt. Within the structural framework derived from satellite imagery, the locations of major shallow-source aeromagnetic anomalies related to intermediate/mafic extrusive and subvolcanic rocks and the controlling structures of these economically important magmatic events can be correctly interpreted. Results of the study indicate a significant, coherent, and previously unrecognized post-Permian, pre-Miocene volcanic/subvolcanic center, which is probably associated with regional sinistral strike-slip along a reactivated N-S accretionary suture and a pre-existing Precambrian/Paleozoic basement structure. Subsequent west-vergent thick-skinned thrusting associated with uplift of Sierra Valle Fertil Precambrian block has developed a set of distinctive NW-oriented strike-slip faults at the site of the volcanic center. The NW structures cut and rotate late Miocene thin-skinned structures associated with the Precordillera fold-and-thrust belt. Intrusive rocks associated with the inferred Oligocene volcanic center form easily recognizable, partially remanent dipole anomalies, are associated with alteration and Au mineralization (Cerro Guachi, El Pescado, Gnrl. Belgrano mines), and are located along NW-oriented sinistral splay faults. The strike-slip related tectonic/magmatic event is currently regarded as Oligocene in age and may correlate

TRAJECTORY ANALYSIS OF FOREST CHANGES IN NORTHERN AREA OF CHANGBAI MOUNTAINS, CHINA FROM LANDSAT TM IMAGE

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F. Huang

2012-07-01

Full Text Available Based on the information from integrated Landsat TM/ETM images and geographic information systems (GIS, using dynamic model, landscape indices and temporal trajectory analysis, spatio-temporal changes in forest in the northern area of Changbai Mountains were investigated in the past 20 years. The results showed that the forests decreased by 141461 ha at the annual decrease rate of 0.19% from 1986 to 2006. The numbers of forest patch increased, while the patch size of forest land declined. Forestland experienced the process of substantial fragmentation. Close forest showed a net reduction of 13.3×104ha. The typical trajectories of forest changes included forestland-forestland-cropland, forestland-cropland-cropland, forestland-forestland-grassland and forestland-cropland-built-up land. The total area of human-induced change is 1.7 times than that of natural change in the study area. Population, cropland area and gross domestic product increased significantly as forests decreased.

Bulk processing of the Landsat MSS/TM/ETM+ archive of the European Space Agency: an insight into the level 1 MSS processing

Science.gov (United States)

Saunier, Sébastien; Northrop, Amy; Lavender, Samantha; Galli, Luca; Ferrara, Riccardo; Mica, Stefano; Biasutti, Roberto; Goryl, Philippe; Gascon, Ferran; Meloni, Marco

2017-10-01

Whilst recent years have witnessed the development and exploitation of operational Earth Observation (EO) satellite constellation data, the valorisation of historical archives has been a challenge. The European Space Agency (ESA) Landsat Multi Spectral Scanner (MSS) products cover Greenland, Iceland, Continental Europe and North Africa represent an archive of over 600,000 processed Level 1 (L1) scenes that will accompany around 1 million ESA Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) products already available. ESA began acquiring MSS data in 1975 and it is well known that this dataset can be degraded due to missing data and a loss in accuracy. For these reasons, the content of the product format has been reviewed and the ESA Landsat processing baseline significantly updated to ensure products are fit for user purposes. This paper presents the new MSS product format including the updated metadata parameters for error traceability, and the specification of the Quality Assurance Band (BQA) engineered to allow the best pixel selection and also the application of image restoration techniques. This paper also discusses major improvements applied to the radiometric and geometric processing. For the benefits of the community, ESA is now able to maximize the number of L1 MSS products that can potentially be generated from the raw Level 0 (L0) data and ensure the highest possible data quality is reached. Also, by improving product format, processing and adding a pixel based quality band, the MSS archive becomes interoperable with recently reprocessed Landsat data and that from live missions by way of assuring product quality on a pixel basis.

Operational calibration and validation of landsat data continuity mission (LDCM) sensors using the image assessment system (IAS)

Science.gov (United States)

Micijevic, Esad; Morfitt, Ron

2010-01-01

Systematic characterization and calibration of the Landsat sensors and the assessment of image data quality are performed using the Image Assessment System (IAS). The IAS was first introduced as an element of the Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) ground segment and recently extended to Landsat 4 (L4) and 5 (L5) Thematic Mappers (TM) and Multispectral Sensors (MSS) on-board the Landsat 1-5 satellites. In preparation for the Landsat Data Continuity Mission (LDCM), the IAS was developed for the Earth Observer 1 (EO-1) Advanced Land Imager (ALI) with a capability to assess pushbroom sensors. This paper describes the LDCM version of the IAS and how it relates to unique calibration and validation attributes of its on-board imaging sensors. The LDCM IAS system will have to handle a significantly larger number of detectors and the associated database than the previous IAS versions. An additional challenge is that the LDCM IAS must handle data from two sensors, as the LDCM products will combine the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) spectral bands.

Determinação da evapotranspiração real diária em áreas irrigadas do projeto Jaíba (Minas Gerais, Brasil, mediante imagens Landsat 5 - TM

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Gabriel Alves Veloso

2017-06-01

Full Text Available O presente trabalho teve como objetivo a estimativa da evapotranspiração em áreas irrigadas do projeto Jaíba (MG e áreas circunvizinhas por meio de dados satelitários. Foram utilizadas cinco imagens do satélite Landsat 5 –TM, órbita 219 ponto 70, do ano de 2011. A estimativa da evapotranspiração real diária foi obtida através do algoritmo SEBAL (Surface Energy Balance Algorithm for Land. O SEBAL é constituído de várias etapas, que consiste na estimativa do balanço de radiação e balanço de energia e evapotranspiração. Para a obtenção desses parâmetros, utilizou-se dados da estação meteorológica localizada na cena Landsat. Foram obtidos valores médios para a evapotranspiração no período de 24 horas de 6,85 mm.dia-1, 4,0 mm.dia-1, 2,6 mm.dia-1, 2,2 mm.dia-1 e 3,4 mm.dia-1 para os dias juliano DJ 31, DJ 111, DJ 175, DJ 191 e DJ 255, respectivamente. Observou-se que a evapotranspiração apresentou variação no período analisado devido à quantidade de radiação disponível para cada dia, indicando um comportamento decíduo nas áreas de floresta estacional. A técnica utilizada demonstrou-se eficiente nas análises dos componentes estudados, sendo o SEBAL uma ferramenta importante para a gestão ambiental dos recursos hídricos.

Comparative study of Tm-doped and Tm-Sc co-doped Lu3Al5O12 scintillator

International Nuclear Information System (INIS)

Sugiyama, Makoto; Yanagida, Takayuki; Fujimoto, Yutaka

2014-01-01

The crystals of Tm doped and Tm-Sc co-doped Lu 3 Al 5 O 12 (LuAG) grown by the floating zone (FZ) method were examined for their optical and scintillation properties. In transmittance spectra, strong absorption lines due to Tm 3+ 4f–4f transitions were observed. X-ray excited radioluminescence spectra were measured and broad and sharp emission peaks were detected. The former one was attributed to Sc 3+ and the latter one was due to Tm 3+ 4f–4f transitions. Scintillation yield enhancement due to Sc co-doping was observed by means of 137 Cs pulse height spectra. Scintillation decay times were several tens of μs under pulse X-ray excitation. - Highlights: • LuAG:Tm and LuAG:Tm, Sc single crystals have been grown by the FZ method. • Tm 3+ 4f–4f absorption has been observed in transmittance spectra. • Scintillation yield of Tm-doped LuAG has been enhanced by Sc co-doping

An Initial Analysis of LANDSAT-4 Thematic Mapper Data for the Discrimination of Agricultural, Forested Wetland, and Urban Land Covers

Science.gov (United States)

Quattrochi, D. A.

1984-01-01

An initial analysis of LANDSAT 4 Thematic Mapper (TM) data for the discrimination of agricultural, forested wetland, and urban land covers is conducted using a scene of data collected over Arkansas and Tennessee. A classification of agricultural lands derived from multitemporal LANDSAT Multispectral Scanner (MSS) data is compared with a classification of TM data for the same area. Results from this comparative analysis show that the multitemporal MSS classification produced an overall accuracy of 80.91% while the TM classification yields an overall classification accuracy of 97.06% correct.

Landsat TM inventory and assessment of waterbird habitat in the southern altiplano of South America

Science.gov (United States)

Boyle, T.P.; Caziani, S.M.; Waltermire, R.G.

2004-01-01

The diverse set of wetlands in southern altiplano of South America supports a number of endemic and migratory waterbirds. These species include endangered endemic flamingos and shorebirds that nest in North America and winter in the altiplano. This research developed maps from nine Landsat Thematic Mapper (TM) images (254,300 km2) to provide an inventory of aquatic waterbird habitats. Image processing software was used to produce a map with a classification of wetlands according to the habitat requirements of different types of waterbirds. A hierarchical procedure was used to, first, isolate the bodies of water within the TM image; second, execute an unsupervised classification on the subsetted image to produce 300 signatures of cover types, which were further subdivided as necessary. Third, each of the classifications was examined in the light of field data and personal experience for relevance to the determination of the various habitat types. Finally, the signatures were applied to the entire image and other adjacent images to yield a map depicting the location of the various waterbird habitats in the southern altiplano. The data sets referenced with a global positioning system receiver were used to test the classification system. Multivariate analysis of the bird communities censused at each lake by individual habitats indicated a salinity gradient, and then the depth of the water separated the birds. Multivariate analysis of the chemical and physical data from the lakes showed that the variation in lakes were significantly associated with difference in depth, transparency, latitude, elevation, and pH. The presence of gravel bottoms was also one of the qualities distinguishing a group of lakes. This information will be directly useful to the Flamingo Census Project and serve as an element for risk assessment for future development.

LANDSAT-4 MSS and Thematic Mapper data quality and information content analysis

Science.gov (United States)

Anuta, P.; Bartolucci, L.; Dean, E.; Lozano, F.; Malaret, E.; Mcgillem, C. D.; Valdes, J.; Valenzuela, C.

1984-01-01

LANDSAT-4 thematic mapper (TM) and multispectral scanner (MSS) data were analyzed to obtain information on data quality and information content. Geometric evaluations were performed to test band-to-band registration accuracy. Thematic mapper overall system resolution was evaluated using scene objects which demonstrated sharp high contrast edge responses. Radiometric evaluation included detector relative calibration, effects of resampling, and coherent noise effects. Information content evaluation was carried out using clustering, principal components, transformed divergence separability measure, and supervised classifiers on test data. A detailed spectral class analysis (multispectral classification) was carried out to compare the information content of the MSS and TM for a large number of scene classes. A temperature-mapping experiment was carried out for a cooling pond to test the quality of thermal-band calibration. Overall TM data quality is very good. The MSS data are noisier than previous LANDSAT results.

Reconstructing turbidity in a glacially influenced lake using the Landsat TM and ETM+ surface reflectance climate data record archive, Lake Clark, Alaska

Science.gov (United States)

Baughman, Carson; Jones, Benjamin M.; Bartz, Krista K.; Young, Daniel B.; Zimmerman, Christian E.

2015-01-01

Lake Clark is an important nursery lake for sockeye salmon (Oncorhynchus nerka) in the headwaters of Bristol Bay, Alaska, the most productive wild salmon fishery in the world. Reductions in water clarity within Alaska lake systems as a result of increased glacial runoff have been shown to reduce salmon production via reduced abundance of zooplankton and macroinvertebrates. In this study, we reconstruct long-term, lake-wide water clarity for Lake Clark using the Landsat TM and ETM+ surface reflectance products (1985–2014) and in situwater clarity data collected between 2009 and 2013. Analysis of a Landsat scene acquired in 2009, coincident with in situ measurements in the lake, and uncertainty analysis with four scenes acquired within two weeks of field data collection showed that Band 3 surface reflectance was the best indicator of turbidity (r2 = 0.55,RMSE turbidity for Lake Clark between 1991 and 2014. We did, however, detect interannual variation that exhibited a non-significant (r2 = 0.20) but positive correlation (r = 0.20) with regional mean summer air temperature and found the month of May exhibited a significant positive trend (r2 = 0.68, p = 0.02) in turbidity between 2000 and 2014. This study demonstrates the utility of hindcasting turbidity in a glacially influenced lake using the Landsat surface reflectance products. It may also help land and resource managers reconstruct turbidity records for lakes that lack in situ monitoring, and may be useful in predicting future water clarity conditions based on projected climate scenarios.

Comparison of hyperspectral transformation accuracies of multispectral Landsat TM, ETM+, OLI and EO-1 ALI images for detecting minerals in a geothermal prospect area

Science.gov (United States)

Hoang, Nguyen Tien; Koike, Katsuaki

2018-03-01

Hyperspectral remote sensing generally provides more detailed spectral information and greater accuracy than multispectral remote sensing for identification of surface materials. However, there have been no hyperspectral imagers that cover the entire Earth surface. This lack points to a need for producing pseudo-hyperspectral imagery by hyperspectral transformation from multispectral images. We have recently developed such a method, a Pseudo-Hyperspectral Image Transformation Algorithm (PHITA), which transforms Landsat 7 ETM+ images into pseudo-EO-1 Hyperion images using multiple linear regression models of ETM+ and Hyperion band reflectance data. This study extends the PHITA to transform TM, OLI, and EO-1 ALI sensor images into pseudo-Hyperion images. By choosing a part of the Fish Lake Valley geothermal prospect area in the western United States for study, the pseudo-Hyperion images produced from the TM, ETM+, OLI, and ALI images by PHITA were confirmed to be applicable to mineral mapping. Using a reference map as the truth, three main minerals (muscovite and chlorite mixture, opal, and calcite) were identified with high overall accuracies from the pseudo-images (> 95% and > 42% for excluding and including unclassified pixels, respectively). The highest accuracy was obtained from the ALI image, followed by ETM+, TM, and OLI images in descending order. The TM, OLI, and ALI images can be alternatives to ETM+ imagery for the hyperspectral transformation that aids the production of pseudo-Hyperion images for areas without high-quality ETM+ images because of scan line corrector failure, and for long-term global monitoring of land surfaces.

Análise de índices biofísicos a partir de imagens TM Landsat 5 em paisagem heterogênea no Sudoeste da Amazônia

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Rodrigo Tartari

2015-11-01

Full Text Available O sudoeste da Amazônia Brasileira é composto por um mosaico de paisagem com transição de campos naturais e floresta ombrófila densa. A bacia do rio Puruzinho, localizada no “Arco do Desmatamento” no interflúvio Purus-Madeira, tem passado por mudança no uso e cobertura da terra. Assim, o objetivo deste estudo foi avaliar a variação espacial de índices biofísicos de uma paisagem heterogênea na bacia hidrográfica do rio Puruzinho. O índice de vegetação da diferença normalizada (NDVI, índice de área foliar (IAF, temperatura da superfície, albedo e saldo de radiação da superfície (Rn foram estimados pelo SEBAL (Surface Energy Balance Algorithm for Land a partir de imagens TM Landsat 5, e analisados sobre floresta densa, campos naturais, área desmatada e área urbana de Humaitá-AM. Todos os índices biofísicos foram significativamente diferentes, considerando o uso e cobertura da terra. Os índices biofísicos apresentaram padrão inverso entre a área urbana e a floresta densa, com menor NDVI, IAF e saldo de radiação e maior temperatura e albedo da superfície na área urbana. Portanto, as variáveis estimadas pelo SEBAL foram adequadas para avaliar o efeito das mudanças no uso do solo sobre as variáveis estimadas e distinguir áreas antropizadas de áreas naturais.

Comparison of sampling designs for estimating deforestation from landsat TM and MODIS imagery: a case study in Mato Grosso, Brazil.

Science.gov (United States)

Zhu, Shanyou; Zhang, Hailong; Liu, Ronggao; Cao, Yun; Zhang, Guixin

2014-01-01

Sampling designs are commonly used to estimate deforestation over large areas, but comparisons between different sampling strategies are required. Using PRODES deforestation data as a reference, deforestation in the state of Mato Grosso in Brazil from 2005 to 2006 is evaluated using Landsat imagery and a nearly synchronous MODIS dataset. The MODIS-derived deforestation is used to assist in sampling and extrapolation. Three sampling designs are compared according to the estimated deforestation of the entire study area based on simple extrapolation and linear regression models. The results show that stratified sampling for strata construction and sample allocation using the MODIS-derived deforestation hotspots provided more precise estimations than simple random and systematic sampling. Moreover, the relationship between the MODIS-derived and TM-derived deforestation provides a precise estimate of the total deforestation area as well as the distribution of deforestation in each block.

Utilizing a Multi-Source Forest Inventory Technique, MODIS Data and Landsat TM Images in the Production of Forest Cover and Volume Maps for the Terai Physiographic Zone in Nepal

Directory of Open Access Journals (Sweden)

Kalle Eerikäinen

2012-12-01

Full Text Available An approach based on the nearest neighbors techniques is presented for producing thematic maps of forest cover (forest/non-forest and total stand volume for the Terai region in southern Nepal. To create the forest cover map, we used a combination of Landsat TM satellite data and visual interpretation data, i.e., a sample grid of visual interpretation plots for which we obtained the land use classification according to the FAO standard. These visual interpretation plots together with the field plots for volume mapping originate from an operative forest inventory project, i.e., the Forest Resource Assessment of Nepal (FRA Nepal project. The field plots were also used in checking the classification accuracy. MODIS satellite data were used as a reference in a local correction approach conducted for the relative calibration of Landsat TM images. This study applied a non-parametric k-nearest neighbor technique (k-NN to the forest cover and volume mapping. A tree height prediction approach based on a nonlinear, mixed-effects (NLME modeling procedure is presented in the Appendix. The MODIS image data performed well as reference data for the calibration approach applied to make the Landsat image mosaic. The agreement between the forest cover map and the field observed values of forest cover was substantial in Western Terai (KHAT 0.745 and strong in Eastern Terai (KHAT 0.825. The forest cover and volume maps that were estimated using the k-NN method and the inventory data from the FRA Nepal project are already appropriate and valuable data for research purposes and for the planning of forthcoming forest inventories. Adaptation of the methods and techniques was carried out using Open Source software tools.

Feature level fusion for enhanced geological mapping of ophiolile complex using ASTER and Landsat TM data

International Nuclear Information System (INIS)

Pournamdari, M; Hashim, M

2014-01-01

Chromite ore deposit occurrence is related to ophiolite complexes as a part of the oceanic crust and provides a good opportunity for lithological mapping using remote sensing data. The main contribution of this paper is a novel approaches to discriminate different rock units associated with ophiolite complex using the Feature Level Fusion technique on ASTER and Landsat TM satellite data at regional scale. In addition this study has applied spectral transform approaches, consisting of Spectral Angle Mapper (SAM) to distinguish the concentration of high-potential areas of chromite and also for determining the boundary between different rock units. Results indicated both approaches show superior outputs compared to other methods and can produce a geological map for ophiolite complex rock units in the arid and the semi-arid region. The novel technique including feature level fusion and Spectral Angle Mapper (SAM) discriminated ophiolitic rock units and produced detailed geological maps of the study area. As a case study, Sikhoran ophiolite complex located in SE, Iran has been selected for image processing techniques. In conclusion, a suitable approach for lithological mapping of ophiolite complexes is demonstrated, this technique contributes meaningfully towards economic geology in terms of identifying new prospects

Measurements of the 169Tm(n,2n)168Tm cross section between 9.0 and 17.5 MeV

Science.gov (United States)

Soter, J.; Bhike, Megha; Krishichayan, Fnu; Finch, S. W.; Tornow, W.

2016-09-01

Measurements of the 169Tm(n,2n)168Tm cross section have been performed in 0.5 MeV intervals for neutron energies ranging from 9.0 MeV to 17.5 MeV in order to resolve discrepancies in the current literature data. The neutron activation technique was used with 90Zr and 197Au as monitor foils. After irradiation, de-excitation gamma rays were recorded off-line with High-Purity Germanium (HPGE) detectors in TUNL's Low-Background Counting Facility. In addition, data for the 169Tm(n,3n)167Tm reaction have also been obtained from 15.5 MeV to 17.5 MeV. The results of these measurements provide the basis for investigating properties of the interial confinement fusion plasma in deuterium-tritium (DT) capsules at the National Ignition Facility located at Lawrence Livermore National Laboratory.

An initial analysis of LANDSAT 4 Thematic Mapper data for the classification of agricultural, forested wetland, and urban land covers

Science.gov (United States)

Quattrochi, D. A.; Anderson, J. E.; Brannon, D. P.; Hill, C. L.

1982-01-01

An initial analysis of LANDSAT 4 thematic mapper (TM) data for the delineation and classification of agricultural, forested wetland, and urban land covers was conducted. A study area in Poinsett County, Arkansas was used to evaluate a classification of agricultural lands derived from multitemporal LANDSAT multispectral scanner (MSS) data in comparison with a classification of TM data for the same area. Data over Reelfoot Lake in northwestern Tennessee were utilized to evaluate the TM for delineating forested wetland species. A classification of the study area was assessed for accuracy in discriminating five forested wetland categories. Finally, the TM data were used to identify urban features within a small city. A computer generated classification of Union City, Tennessee was analyzed for accuracy in delineating urban land covers. An evaluation of digitally enhanced TM data using principal components analysis to facilitate photointerpretation of urban features was also performed.

Detection of soil erosion within pinyon-juniper woodlands using Thematic Mapper (TM) satellite data

Science.gov (United States)

Price, Kevin P.; Ridd, Merrill K.

1991-01-01

The sensitivity of Landsat TM data for detecting soil erosion within pinyon-juniper woodlands, and the potential of the spectral data for assigning the universal soil loss equation (USLE) crop managemnent (C) factor to varying cover types within the woodlands are assessed. Results show greatly accelerated rates of soil erosion on pinyon-juniper sites. Percent cover by pinyon-juniper, total soil-loss, and total nonliving ground cover accounted for nearly 70 percent of the variability in TM channels 2, 3, 4, and 5. TM spectral data were consistently better predictors of soil erosion than the biotic and abiotic field variables. Satellite data were more sensitive to vegetation variation than the USLE C factor, and USLE was found to be a poor predictor of soil loss on pinyon-juniper sites. A new string-to-ground soil erosion prediction technique is introduced.

Combining Landsat TM multispectral satellite imagery and different modelling approaches for mapping post-fire erosion changes in a Mediterranean site

Science.gov (United States)

Petropoulos, George P.; Kairis, Orestis; Karamesouti, Mina; Papanikolaou, Ioannis D.; Kosmas, Constantinos

2013-04-01

South European countries are naturally vulnerable to wildfires. Their natural resources such as soil, vegetation and water may be severely affected by wildfires, causing an imminent environmental deterioration due to the complex interdependence among biophysical components. Soil surface water erosion is a natural process essential for soil formation that is affected by such interdependences. Accelerated erosion due to wildfires, constitutes a major restrictive factor for ecosystem sustainability. In 2007, South European countries were severely affected by wildfires, with more than 500,000 hectares of land burnt in that year alone, well above the average of the last 30 years. The present work examines the changes in spatial variability of soil erosion rates as a result of a wildfire event that took place in Greece in 2007, one of the most devastating years in terms of wildfire hazards. Regional estimates of soil erosion rates before and after the fire outbreak were derived from the Revised Universal Soil Loss Equation (RUSLE, Renard et al. 1991) and the Pan-European Soil Erosion Risk Assessment model (PESERA, Kirkby, 1999; Kirkby et al., 2000). Inputs for both models included climatic, land-use, soil type, topography and land use management data. Where appropriate, both models were also fed with input data derived from the analysis of LANDSAT TM satellite imagery available in our study area, acquired before and shortly after the fire suppression. Our study was compiled and performed in a GIS environment. In overall, the loss of vegetation from the fire outbreak caused a substantial increase of soil erosion rates in the affected area, particularly towards the steep slopes. Both tested models were compared to each other and noticeable differences were observed in the soil erosion predictions before and after the fire event. These are attributed to the different parameterization requirements of the 2 models. This quantification of sediment supply through the river

Comparison of MODIS and Landsat TM5 images for mapping tempo-spatial dynamics of Secchi disk depths in Poyang Lake national nature reserve, China

NARCIS (Netherlands)

Wu, G.; Leeuw, de J.; Skidmore, A.K.; Prins, H.H.T.; Liu, Y.

2008-01-01

Landsat has successfully been applied to map Secchi disk depth of inland water bodies. Operational use for monitoring a dynamic variable like Secchi disk depth is however limited by the 16-day overpass cycle of the Landsat system and cloud cover. Low spatial resolution Moderate Resolution Imaging

Exploring TM image texture and its relationships with biomass estimation in Rondônia, Brazilian Amazon Explorando texturas de imagens TM e suas relações com estimativas de biomassa em Rondônia

Directory of Open Access Journals (Sweden)

Dengsheng Lu

2005-06-01

Full Text Available Many texture measures have been developed and used for improving land-cover classification accuracy, but rarely has research examined the role of textures in improving the performance of aboveground biomass estimations. The relationship between texture and biomass is poorly understood. This paper used Landsat Thematic Mapper (TM data to explore relationships between TM image textures and aboveground biomass in Rondônia, Brazilian Amazon. Eight grey level co-occurrence matrix (GLCM based texture measures (i.e., mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment, and correlation, associated with seven different window sizes (5x5, 7x7, 9x9, 11x11, 15x15, 19x19, and 25x25, and five TM bands (TM 2, 3, 4, 5, and 7 were analyzed. Pearson's correlation coefficient was used to analyze texture and biomass relationships. This research indicates that most textures are weakly correlated with successional vegetation biomass, but some textures are significantly correlated with mature forest biomass. In contrast, TM spectral signatures are significantly correlated with successional vegetation biomass, but weakly correlated with mature forest biomass. Our findings imply that textures may be critical in improving mature forest biomass estimation, but relatively less important for successional vegetation biomass estimation.Muitas medidas de textura têm sido desenvolvidas e utilizadas para melhorar a acurácia de classificações de cobertura das terras, mas raramente têm-se avaliado a importância dessas medidas em estimativas de biomassa. Este trabalho utilizou dados Landsat TM para explorar as relações entre texturas de imagens TM e biomassa em Rondônia, Amazônia. Foram analisadas oito medidas de textura baseadas em matrizes de co-ocorrência de tons de cinza (i.e., média, variância, homogeneidade, contraste, dissimilaridade, entropia, segundo momento e correlação, associadas com sete diferentes tamanhos de janela (5x5, 7x7

Comparison of Sampling Designs for Estimating Deforestation from Landsat TM and MODIS Imagery: A Case Study in Mato Grosso, Brazil

Directory of Open Access Journals (Sweden)

Shanyou Zhu

2014-01-01

Full Text Available Sampling designs are commonly used to estimate deforestation over large areas, but comparisons between different sampling strategies are required. Using PRODES deforestation data as a reference, deforestation in the state of Mato Grosso in Brazil from 2005 to 2006 is evaluated using Landsat imagery and a nearly synchronous MODIS dataset. The MODIS-derived deforestation is used to assist in sampling and extrapolation. Three sampling designs are compared according to the estimated deforestation of the entire study area based on simple extrapolation and linear regression models. The results show that stratified sampling for strata construction and sample allocation using the MODIS-derived deforestation hotspots provided more precise estimations than simple random and systematic sampling. Moreover, the relationship between the MODIS-derived and TM-derived deforestation provides a precise estimate of the total deforestation area as well as the distribution of deforestation in each block.

Mapping Deciduous Rubber Plantation Areas and Stand Ages with PALSAR and Landsat Images

Directory of Open Access Journals (Sweden)

Weili Kou

2015-01-01

Full Text Available Accurate and updated finer resolution maps of rubber plantations and stand ages are needed to understand and assess the impacts of rubber plantations on regional ecosystem processes. This study presented a simple method for mapping rubber plantation areas and their stand ages by integration of PALSAR 50-m mosaic images and multi-temporal Landsat TM/ETM+ images. The L-band PALSAR 50-m mosaic images were used to map forests (including both natural forests and rubber trees and non-forests. For those PALSAR-based forest pixels, we analyzed the multi-temporal Landsat TM/ETM+ images from 2000 to 2009. We first studied phenological signatures of deciduous rubber plantations (defoliation and foliation and natural forests through analysis of surface reflectance, Normal Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, and Land Surface Water Index (LSWI and generated a map of rubber plantations in 2009. We then analyzed phenological signatures of rubber plantations with different stand ages and generated a map, in 2009, of rubber plantation stand ages (≤5, 6–10, >10 years-old based on multi-temporal Landsat images. The resultant maps clearly illustrated how rubber plantations have expanded into the mountains in the study area over the years. The results in this study demonstrate the potential of integrating microwave (e.g., PALSAR and optical remote sensing in the characterization of rubber plantations and their expansion over time.

Concentration effect of Tm3+ on cathodoluminescence properties of SiO2: Tm3+ and SiO2:Ho3+, Tm3+ systems

CSIR Research Space (South Africa)

Dhlamini, MS

2012-05-01

Full Text Available .physb.2011.09.091 Concentration effect of Tm3+ on cathodoluminescence properties of SiO2: Tm 3+ and SiO2:Ho 3+, Tm3+ systems M.S. Dhlamini, G.H. Mhlongo, H.C. Swart, O.M. Ntwaeaborwa, K.T. Hillie ABSTRACT: Cathodoluminescence (CL) properties of Si...O2 powders activated with thulium (Tm3+) and holmium (Ho3+) ions prepared by a sol–gel process were investigated. Different molar concentrations of Tm3+ co-doped with Ho3+ were studied. The 460 nm peak was monitored and the influence of the beam...

Cytoskeletal Tropomyosin Tm5NM1 Is Required for Normal Excitation–Contraction Coupling in Skeletal Muscle

Science.gov (United States)

Vlahovich, Nicole; Kee, Anthony J.; Van der Poel, Chris; Kettle, Emma; Hernandez-Deviez, Delia; Lucas, Christine; Lynch, Gordon S.; Parton, Robert G.; Gunning, Peter W.

2009-01-01

The functional diversity of the actin microfilaments relies in part on the actin binding protein tropomyosin (Tm). The muscle-specific Tms regulate actin-myosin interactions and hence contraction. However, there is less known about the roles of the numerous cytoskeletal isoforms. We have shown previously that a cytoskeletal Tm, Tm5NM1, defines a Z-line adjacent cytoskeleton in skeletal muscle. Recently, we identified a second cytoskeletal Tm in this region, Tm4. Here we show that Tm4 and Tm5NM1 define separate actin filaments; the former associated with the terminal sarcoplasmic reticulum (SR) and other tubulovesicular structures. In skeletal muscles of Tm5NM1 knockout (KO) mice, Tm4 localization was unchanged, demonstrating the specificity of the membrane association. Tm5NM1 KO muscles exhibit potentiation of T-system depolarization and decreased force rundown with repeated T-tubule depolarizations consistent with altered T-tubule function. These results indicate that a Tm5NM1-defined actin cytoskeleton is required for the normal excitation–contraction coupling in skeletal muscle. PMID:19005216

Cytoskeletal tropomyosin Tm5NM1 is required for normal excitation-contraction coupling in skeletal muscle.

Science.gov (United States)

Vlahovich, Nicole; Kee, Anthony J; Van der Poel, Chris; Kettle, Emma; Hernandez-Deviez, Delia; Lucas, Christine; Lynch, Gordon S; Parton, Robert G; Gunning, Peter W; Hardeman, Edna C

2009-01-01

The functional diversity of the actin microfilaments relies in part on the actin binding protein tropomyosin (Tm). The muscle-specific Tms regulate actin-myosin interactions and hence contraction. However, there is less known about the roles of the numerous cytoskeletal isoforms. We have shown previously that a cytoskeletal Tm, Tm5NM1, defines a Z-line adjacent cytoskeleton in skeletal muscle. Recently, we identified a second cytoskeletal Tm in this region, Tm4. Here we show that Tm4 and Tm5NM1 define separate actin filaments; the former associated with the terminal sarcoplasmic reticulum (SR) and other tubulovesicular structures. In skeletal muscles of Tm5NM1 knockout (KO) mice, Tm4 localization was unchanged, demonstrating the specificity of the membrane association. Tm5NM1 KO muscles exhibit potentiation of T-system depolarization and decreased force rundown with repeated T-tubule depolarizations consistent with altered T-tubule function. These results indicate that a Tm5NM1-defined actin cytoskeleton is required for the normal excitation-contraction coupling in skeletal muscle.

Radar, geologic, airborne gamma ray and Landsat TM digital data integration for geological mapping of the Estrela granite complex (Para State)

International Nuclear Information System (INIS)

Cunha, Edson Ricardo Soares Pereira da

2002-01-01

This work is focused on the geotectonic context of the Carajas Mineral Province, Amazon Craton, which represents the most important Brazilian Mineral Province and hosts iron, cooper, gold, manganese and nickel deposits. At the end of Archean age, during the techno-metamorphic evolution, moderated alkaline granitoids were generated, such as, Estrela Granite Complex (EGC). This work has used digital integration products with the purpose of study the granite suite, its host rock, and the surrounded area. The digital integrated data were gamma-ray and geological data with satellite images (SAR-SAREX e TM-Landsat). The geophysics data, originally in 32 bits and grid format, were interpolated and converted to 8 bits images. The geological data (facies map) was digitalized and converted to a raster format. The remote sensing images were geometrically corrected to guarantee an accuracy on the geological mapping. On the data processing phase, SAR images were digital integrated with gamma-ray data, TM-Landsat image and the raster facies map. The IHS transformation was used as the technique to integrate the multi-source data. On the photogeological interpretation, SAR data were extremely important to permit the extraction of the main tectonic lineaments which occur on the following directions: +/- N45W, +/- N70W, +/- NS, +/- N20E, +/- N45E e +/- N75E. This procedure was done both in analogic and automatic form, being the automatic process more useful to complement information in the extracting process. Among the digital products generated, SAR/GAMA products (uranium, thorium and total count) were the ones that give the most important contribution. The interpretation of the SAR/GAMA's products added to the field campaign have allowed to map the limits of units that occur in the region and four facies of the Estrela Granite Complex were detected. The origin of the granite suite might be related to a magmatic differentiation or to distinct intrusion pulses. The use of the

Obtaining land cover changes information from multitemporal analysis of Landsat-TM images: results from a case study in West African dryland

Science.gov (United States)

Nutini, F.; Boschetti, M.; Brivio, P. A.; Antoninetti, M.

2012-04-01

The Sahelian belt of West Africa is a semiarid region characterized by wide climate variations, which can in turn affect the livelihood of local populations particularly in rangeland areas, as happens during the dramatic food crisis in the 70-80s caused by rainfall scarcity. The monitoring of natural resources and rainfed agricultural activities, with the aim to provide information to support Sahelian food security action, needs the production of detailed thematic maps as emphasized by several scientific papers. In this framework, a study was conducted to develop a method to exploit time series of remote sensed satellite data to 1) provide reliable land cover (LC) map at local scale in a dry region and 2) obtain a LC change (LCC) map that contribute to identify the plausible causes of local environmental instability. Satellite images used for this work consist in a time series of Landsat Thematic Mapper (TM) (path row 195-50) acquired in the 2000 (6 scenes) and 2007 (9 scenes) from February (Dry season) to September (end of wet season). The study investigates the different contribution provided by spectra information of a single Landsat TM image and by time series of derived NDVI. Different tests have been conducted with different combination of data set (spectral and temporal)in order to identify the best approach to obtain a LC map in five classes of interest: Shrubland, Cultivated Land, Water body, Herbaceous vegetation and Bare soil. The best classification approach is exposed and applied on two years in the last decade. The comparison between this two LC results in land cover change map, that displays the changes of vegetation patterns that have been characterized the area. The discussed results show a largely stable dryland region, but locally characterized by hot-spot of decreasing in natural vegetation inside the rangelands and an increasing of cultivations along fossil valleys where human activities are slightly intense. The discussion shows that this hot

The Potential of Time Series Merged from Landsat-5 TM and HJ-1 CCD for Crop Classification: A Case Study for Bole and Manas Counties in Xinjiang, China

Directory of Open Access Journals (Sweden)

Pengyu Hao

2014-08-01

Full Text Available Time series data capture crop growth dynamics and are some of the most effective data sources for crop mapping. However, a drawback of precise crop classification at medium resolution (30 m using multi-temporal data is that some images at crucial time periods are absent from a single sensor. In this research, a medium-resolution, 15-day time series was obtained by merging Landsat-5 TM and HJ-1 CCD data (with similar radiometric performances in multi-spectral bands. Subsequently, optimal temporal windows for accurate crop mapping were evaluated using an extension of the Jeffries–Matusita (JM distance from the merged time series. A support vector machine (SVM was then used to compare the classification accuracy of the optimal temporal windows and the entire time series. In addition, different training sample sizes (10% to 90% of the entire training sample in 10% increments; five repetitions for each sample size were used to investigate the stability of optimal temporal windows. The results showed that time series in optimal temporal windows can achieve high classification accuracies. The optimal temporal windows were robust when the training sample size was sufficiently large. However, they were not stable when the sample size was too small (i.e., less than 300 and may shift in different agro-ecosystems, because of different classes. In addition, merged time series had higher temporal resolution and were more likely to comprise the optimal temporal periods than time series from single-sensor data. Therefore, the use of merged time series increased the possibility of precise crop classification.

Landsat Thematic Mapper monitoring of turbid inland water quality

Science.gov (United States)

Lathrop, Richard G., Jr.

1992-01-01

This study reports on an investigation of water quality calibration algorithms under turbid inland water conditions using Landsat Thematic Mapper (TM) multispectral digital data. TM data and water quality observations (total suspended solids and Secchi disk depth) were obtained near-simultaneously and related using linear regression techniques. The relationships between reflectance and water quality for Green Bay and Lake Michigan were compared with results for Yellowstone and Jackson Lakes, Wyoming. Results show similarities in the water quality-reflectance relationships, however, the algorithms derived for Green Bay - Lake Michigan cannot be extrapolated to Yellowstone and Jackson Lake conditions.

Identification of central Kenyan Rift Valley Fever virus vector habitats with Landsat TM and evaluation of their flooding status with airborne imaging radar

Science.gov (United States)

Pope, K. O.; Sheffner, E. J.; Linthicum, K. J.; Bailey, C. L.; Logan, T. M.; Kasischke, E. S.; Birney, K.; Njogu, A. R.; Roberts, C. R.

1992-01-01

Rift Valley Fever (RVF) is a mosquito-borne virus that affects livestock and humans in Africa. Landsat TM data are shown to be effective in identifying dambos, intermittently flooded areas that are potential mosquite breeding sites, in an area north of Nairobi, Kenya. Positive results were obtained from a limited test of flood detection in dambos with airborne high resolution L, C, and X band multipolarization SAR imagery. L and C bands were effective in detecting flooded dambos, but LHH was by far the best channel for discrimination between flooded and nonflooded sites in both sedge and short-grass environments. This study demonstrates the feasibility of a combined passive and active remote sensing program for monitoring the location and condition of RVF vector habitats, thus making future control of the disease more promising.

Landsat's international partners

Science.gov (United States)

Byrnes, Raymond A.

2012-01-01

Since the launch of the first Landsat satellite 40 years ago, International Cooperators (ICs) have formed a key strategic alliance with the U.S. Geological Survey (USGS) to not only engage in Landsat data downlink services but also to enable a foundation for scientific and technical collaboration. The map below shows the locations of all ground stations operated by the United States and IC ground station network for the direct downlink and distribution of Landsat 5 (L5) and Landsat 7 (L7) image data. The circles show the approximate area over which each station has the capability for direct reception of Landsat data. The red circles show the components of the L5 ground station network, the green circles show components of the L7 station network, and the dashed circles show stations with dual (L5 and L7) status. The yellow circles show L5 short-term ("campaign") stations that contribute to the USGS Landsat archive. Ground stations in South Dakota and Australia currently serve as the primary data capture facilities for the USGS Landsat Ground Network (LGN). The Landsat Ground Station (LGS) is located at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The Alice Springs (ASN) ground station is located at the Geoscience Australia facility in Alice Springs, Australia. These sites receive the image data, via X-band Radio Frequency (RF) link, and the spacecraft housekeeping data, via S-band RF link. LGS also provides tracking services and a command link to the spacecrafts.

Efficiency and precision for estimating timber and non-timber attributes using Landsat-based stratification methods in two-phase sampling in northwest California

Science.gov (United States)

Antti T. Kaartinen; Jeremy S. Fried; Paul A. Dunham

2002-01-01

Three Landsat TM-based GIS layers were evaluated as alternatives to conventional, photointerpretation-based stratification of FIA field plots. Estimates for timberland area, timber volume, and volume of down wood were calculated for California's North Coast Survey Unit of 2.5 million hectares. The estimates were compared on the basis of standard errors,...

Radar, geologic, airborne gamma ray and Landsat TM digital data integration for geological mapping of the Estrela granite complex (Para State); Integracao digital de imagens de radar e Landsat-TM com dados geologicos e aerogamaespectrometricos no auxilio ao mapeamento geologico da regiao do complexo granitico Estrela-Para (PA)

Energy Technology Data Exchange (ETDEWEB)

Cunha, Edson Ricardo Soares Pereira da

2002-07-01

This work is focused on the geotectonic context of the Carajas Mineral Province, Amazon Craton, which represents the most important Brazilian Mineral Province and hosts iron, cooper, gold, manganese and nickel deposits. At the end of Archean age, during the techno-metamorphic evolution, moderated alkaline granitoids were generated, such as, Estrela Granite Complex (EGC). This work has used digital integration products with the purpose of study the granite suite, its host rock, and the surrounded area. The digital integrated data were gamma-ray and geological data with satellite images (SAR-SAREX e TM-Landsat). The geophysics data, originally in 32 bits and grid format, were interpolated and converted to 8 bits images. The geological data (facies map) was digitalized and converted to a raster format. The remote sensing images were geometrically corrected to guarantee an accuracy on the geological mapping. On the data processing phase, SAR images were digital integrated with gamma-ray data, TM-Landsat image and the raster facies map. The IHS transformation was used as the technique to integrate the multi-source data. On the photogeological interpretation, SAR data were extremely important to permit the extraction of the main tectonic lineaments which occur on the following directions: +/- N45W, +/- N70W, +/- NS, +/- N20E, +/- N45E e +/- N75E. This procedure was done both in analogic and automatic form, being the automatic process more useful to complement information in the extracting process. Among the digital products generated, SAR/GAMA products (uranium, thorium and total count) were the ones that give the most important contribution. The interpretation of the SAR/GAMA's products added to the field campaign have allowed to map the limits of units that occur in the region and four facies of the Estrela Granite Complex were detected. The origin of the granite suite might be related to a magmatic differentiation or to distinct intrusion pulses. The use of the

Low cost monitoring from space using Landsat TM time series and open source technologies: the case study of Iguazu park

Science.gov (United States)

Nole, Gabriele; Lasaponara, Rosa

2015-04-01

Up to nowadays, satellite data have become increasingly available, thus offering a low cost or even free of charge unique tool, with a great potential for operational monitoring of vegetation cover, quantitative assessment of urban expansion and urban sprawl, as well as for monitoring of land use changes and soil consumption. This growing observational capacity has also highlighted the need for research efforts aimed at exploring the potential offered by data processing methods and algorithms, in order to exploit as much as possible this invaluable space-based data source. The work herein presented concerns an application study on the monitoring of vegetation cover and urban sprawl conducted with the use of satellite Landsat TM data. The selected test site is the Iguazu park highly significant, being it one of the most threatened global conservation priorities (http://whc.unesco.org/en/list/303/). In order to produce synthetic maps of the investigated areas to monitor the status of vegetation and ongoing subtle changes, satellite Landsat TM data images were classified using two automatic classifiers, Maximum Likelihood (MLC) and Support Vector Machines (SVMs) applied by changing setting parameters, with the aim to compare their respective performances in terms of robustness, speed and accuracy. All process steps have been developed integrating Geographical Information System and Remote Sensing, and adopting free and open source software. Results pointed out that the SVM classifier with RBF kernel was generally the best choice (with accuracy higher than 90%) among all the configurations compared, and the use of multiple bands globally improves classification. One of the critical elements found in the case of monitoring of urban area expansion is given by the presence of urban garden mixed with urban fabric. The use of different configurations for the SVMs, i.e. different kernels and values of the setting parameters, allowed us to calibrate the classifier also to

Cytoskeletal Tropomyosin Tm5NM1 Is Required for Normal Excitation–Contraction Coupling in Skeletal Muscle

OpenAIRE

Vlahovich, Nicole; Kee, Anthony J.; Van der Poel, Chris; Kettle, Emma; Hernandez-Deviez, Delia; Lucas, Christine; Lynch, Gordon S.; Parton, Robert G.; Gunning, Peter W.; Hardeman, Edna C.

2009-01-01

The functional diversity of the actin microfilaments relies in part on the actin binding protein tropomyosin (Tm). The muscle-specific Tms regulate actin-myosin interactions and hence contraction. However, there is less known about the roles of the numerous cytoskeletal isoforms. We have shown previously that a cytoskeletal Tm, Tm5NM1, defines a Z-line adjacent cytoskeleton in skeletal muscle. Recently, we identified a second cytoskeletal Tm in this region, Tm4. Here we show that Tm4 and Tm5N...

Mapping and analysis of geological fractures extracted by remote sensing on Landsat TM images, example of the Imilchil-Tounfite area (Central High Atlas, Morocco)

Energy Technology Data Exchange (ETDEWEB)

Alaoui, H. El; Moujahid, El; Ibouh, H.; Bachnou, A.; Babram, M. Ait; Harti, A. EI

2016-07-01

The use of remote sensing, in this research, can be summarized in mapping and statistical studies of lineaments on the satellites images of the Jurassic outcrops in the Imilchil-Tounfite area, Central High Atlas of Morocco. This is to apply various manual techniques for extracting lineaments from Landsat TM image. Analytical techniques used in this work are: the principal component analysis (PCA) applied to selective bands of the visible and infrared, which allows creating new images with better visual interpretation. Directional filters N0°, N45°, N90°, and N135° with a 5×5 matrix were used to enhance lineaments in the corresponding perpendicular directions, and therefore to obtain a good discrimination of those structures. Preliminary results highlight a dominant geological fracturing trending ENE/WSW with 52% of the total lineaments, a second fracture trending is WNW/ESE at 23%, a third fracture series trending NE/SW with 20% and finally, a minor series of fractures trending NW/SE with 5% of the total lineaments. Distribution and statistical relationship, between fractures and the affected surface on the one hand and the fracture length on the other hand, shows a network of well-structured fractures. The final lineament map constitutes a contribution to complete the geology and assisting the mining and hydrogeological prospection, in the Imilchil-Tounfite area. (Author)

Feasibility of Invasive Grass Detection in a Desertscrub Community Using Hyperspectral Field Measurements and Landsat TM Imagery

Directory of Open Access Journals (Sweden)

Stuart E. Marsh

2011-10-01

Full Text Available Invasive species’ phenologies often contrast with those of native species, representing opportunities for detection of invasive species with multi-temporal remote sensing. Detection is especially critical for ecosystem-transforming species that facilitate changes in disturbance regimes. The African C4 grass, Pennisetum ciliare, is transforming ecosystems on three continents and a number of neotropical islands by introducing a grass-fire cycle. However, previous attempts at discriminating P. ciliare in North America using multi-spectral imagery have been unsuccessful. In this paper, we integrate field measurements of hyperspectral plant species signatures and canopy cover with multi-temporal spectral analysis to identify opportunities for detection using moderate-resolution multi-spectral imagery. By applying these results to Landsat TM imagery, we show that multi-spectral discrimination of P. ciliare in heterogeneous mixed desert scrub is feasible, but only at high abundance levels that may have limited value to land managers seeking to control invasion. Much higher discriminability is possible with hyperspectral shortwave infrared imagery because of differences in non-photosynthetic vegetation in uninvaded and invaded landscapes during dormant seasons but these spectra are unavailable in multispectral sensors. Therefore, we recommend hyperspectral imagery for distinguishing invasive grass-dominated landscapes from uninvaded desert scrub.

The Use of Landsat and Aerial Photography for the Assessment of ...

African Journals Online (AJOL)

Coastal erosion is a worldwide hazard, the consequences of which can only be mitigated via thorough and efficient monitoring of erosion. This study aimed to employ remote sensing techniques on aerial photographs and Landsat TM/ETM+ imagery for the detection and monitoring of coastal erosion in False Bay, South ...

Identifying Spatial Units of Human Occupation in the Brazilian Amazon Using Landsat and CBERS Multi-Resolution Imagery

OpenAIRE

Dal’Asta, Ana Paula; Brigatti, Newton; Amaral, Silvana; Escada, Maria Isabel Sobral; Monteiro, Antonio Miguel Vieira

2012-01-01

Every spatial unit of human occupation is part of a network structuring an extensive process of urbanization in the Amazon territory. Multi-resolution remote sensing data were used to identify and map human presence and activities in the Sustainable Forest District of Cuiabá-Santarém highway (BR-163), west of Pará, Brazil. The limits of spatial units of human occupation were mapped based on digital classification of Landsat-TM5 (Thematic Mapper 5) image (30m spatial resolution). High-spatial-...

Modeling of multi-strata forest fire severity using Landsat TM data

Science.gov (United States)

Q. Meng; R.K. Meentemeyer

2011-01-01

Most of fire severity studies use field measures of composite burn index (CBI) to represent forest fire severity and fit the relationships between CBI and Landsat imagery derived differenced normalized burn ratio (dNBR) to predict and map fire severity at unsampled locations. However, less attention has been paid on the multi-strata forest fire severity, which...

Land cover mapping, fire regeneration, and scaling studies in the Canadian boreal forest with 1 km AVHRR and Landsat TM data

Science.gov (United States)

Steyaert, L.T.; Hall, F.G.; Loveland, Thomas R.

1997-01-01

A multitemporal 1 km advanced very high resolution radiometer (AVHRR) land cover analysis approach was used as the basis for regional land cover mapping, fire disturbance-regeneration, and multiresolution land cover scaling studies in the boreal forest ecosystem of central Canada. The land cover classification was developed by using regional field observations from ground and low-level aircraft transits to analyze spectral-temporal clusters that were derived from an unsupervised cluster analysis of monthly normalized difference vegetation index (NDVI) image composites (April-September 1992). Quantitative areal proportions of the major boreal forest components were determined for a 821 km ?? 619 km region, ranging from the southern grasslands-boreal forest ecotone to the northern boreal transitional forest. The boreal wetlands (mostly lowland black spruce, tamarack, mosses, fens, and bogs) occupied approximately 33% of the region, while lakes accounted for another 13%. Upland mixed coniferous-deciduous forests represented 23% of the ecosystem. A SW-NE productivity gradient across the region is manifested by three levels of tree stand density for both the boreal wetland conifer and the mixed forest classes, which are generally aligned with isopleths of regional growing degree days. Approximately 30% of the region was directly affected by fire disturbance within the preceding 30-35 years, especially in the Canadian Shield Zone where large fire-regeneration patterns contribute to the heterogeneous boreal landscape. Intercomparisons with land cover classifications derived from 30-m Landsat Thematic Mapper (TM) data provided important insights into the relative accuracy of the 1 km AVHRR land cover classification. Primarily due to the multitemporal NDVI image compositing process, the 1 km AVHRR land cover classes have an effective spatial resolution in the 3-4 km range; therefore fens, bogs, small water bodies, and small patches of dry jack pine cannot be resolved within

Spatiotemporal Change Detection Using Landsat Imagery: the Case Study of Karacabey Flooded Forest, Bursa, Turkey

Science.gov (United States)

Akay, A. E.; Gencal, B.; Taş, İ.

2017-11-01

This short paper aims to detect spatiotemporal detection of land use/land cover change within Karacabey Flooded Forest region. Change detection analysis applied to Landsat 5 TM images representing July 2000 and a Landsat 8 OLI representing June 2017. Various image processing tools were implemented using ERDAS 9.2, ArcGIS 10.4.1, and ENVI programs to conduct spatiotemporal change detection over these two images such as band selection, corrections, subset, classification, recoding, accuracy assessment, and change detection analysis. Image classification revealed that there are five significant land use/land cover types, including forest, flooded forest, swamp, water, and other lands (i.e. agriculture, sand, roads, settlement, and open areas). The results indicated that there was increase in flooded forest, water, and other lands, while the cover of forest and swamp decreased.

Magnetic order and crystal fields in the Pnma phases of Tm2BaTO5(T=Co and Ni)

International Nuclear Information System (INIS)

Harker, S.J.; Stewart, G.A.

2000-01-01

The magnetic ordering and crystal field interactions of the Pnma phases of both Tm 2 BaCoO 5 and Tm 2 BaNiO 5 are investigated by 169 Tm Moessbauer spectroscopy and the temperature-dependent hyperfine interactions are compared with those obtained elsewhere for Tm 2 BaCuO 5 . The Pnma phases are shown to order magnetically at temperatures of 3.5(2) K (Tm 2 BaCoO 5 ) and 4.85(5) K (Tm 2 BaNiO 5 ), the order being induced by the transition metal. For Tm 2 BaNiO 5 an additional first-order transition observed at T≤1.4 K is identified with the independent magnetic order of the thulium sub-lattice. (orig.)

Preliminary Geologic/spectral Analysis of LANDSAT-4 Thematic Mapper Data, Wind River/bighorn Basin Area, Wyoming

Science.gov (United States)

Lang, H. R.; Conel, J. E.; Paylor, E. D.

1984-01-01

A LIDQA evaluation for geologic applications of a LANDSAT TM scene covering the Wind River/Bighorn Basin area, Wyoming, is examined. This involves a quantitative assessment of data quality including spatial and spectral characteristics. Analysis is concentrated on the 6 visible, near infrared, and short wavelength infrared bands. Preliminary analysis demonstrates that: (1) principal component images derived from the correlation matrix provide the most useful geologic information. To extract surface spectral reflectance, the TM radiance data must be calibrated. Scatterplots demonstrate that TM data can be calibrated and sensor response is essentially linear. Low instrumental offset and gain settings result in spectral data that do not utilize the full dynamic range of the TM system.

Analysis of Eocene depositional environments - Preliminary TM and TIMS results, Wind River Basin, Wyoming

Science.gov (United States)

Stucky, Richard K.; Krishtalka, Leonard; Redline, Andrew D.; Lang, Harold R.

1987-01-01

Both Landsat TM and aircraft Thermal IR Multispectral Scanner (TIMS) data have been used to map the lithofacies of the Wind River Basin's Eocene physical and biological environments. Preliminary analyses of these data have furnished maps of a fault contact boundary and a complex network of fluvial ribbon channel sandstones. The synoptic view thereby emerging for Eocene fluvial facies clarifies the relationships of ribbon channel sandstones to fossil-bearing overbank/floodplain facies and certain peleosols. The utility of TM and TIMS data is thereby demonstrated.

Aboveground Forest Biomass Estimation with Landsat and LiDAR Data and Uncertainty Analysis of the Estimates

OpenAIRE

Dengsheng Lu; Qi Chen; Guangxing Wang; Emilio Moran; Mateus Batistella; Maozhen Zhang; Gaia Vaglio Laurin; David Saah

2012-01-01

Landsat Thematic mapper (TM) image has long been the dominate data source, and recently LiDAR has offered an important new structural data stream for forest biomass estimations. On the other hand, forest biomass uncertainty analysis research has only recently obtained sufficient attention due to the difficulty in collecting reference data. This paper provides a brief overview of current forest biomass estimation methods using both TM and LiDAR data. A case study is then presented that demonst...

Gating function of isoleucine-116 in TM-3 (position III:16/3.40) for the activity state of the CC-chemokine receptor 5 (CCR5)

DEFF Research Database (Denmark)

Steen, A; Sparre-Ulrich, A H; Thiele, Stefanie

2014-01-01

TM receptors - it is a leucine indicating an altered function. Here, we describe the significance of this position and its possible interaction with TM-3 for CCR5 activity. EXPERIMENTAL APPROACH: The effects of [L203F]-CCR5 in TM-5 (position V:13/5.47), [I116A]-CCR5 in TM-3 (III:16/3.40) and [L203F...... ) with a threefold increase in agonist potency. In silico, [I116A]-CCR5 switched χ1-angle in [L203F]-CCR5. Furthermore, [I116A]-CCR5 was constitutively active to a similar degree as [L203F]-CCR5. Tyr(244) in TM-6 (VI:09/6.44) moved towards TM-5 in silico, consistent with its previously shown function for CCR5...... in the active state, a mechanism proposed previously for the β2 -adrenoceptor. The results provide an understanding of chemokine receptor function and thereby information for the development of biased and non-biased antagonists and inverse agonists....

An Improved Method for Producing High Spatial-Resolution NDVI Time Series Datasets with Multi-Temporal MODIS NDVI Data and Landsat TM/ETM+ Images

Directory of Open Access Journals (Sweden)

Yuhan Rao

2015-06-01

Full Text Available Due to technical limitations, it is impossible to have high resolution in both spatial and temporal dimensions for current NDVI datasets. Therefore, several methods are developed to produce high resolution (spatial and temporal NDVI time-series datasets, which face some limitations including high computation loads and unreasonable assumptions. In this study, an unmixing-based method, NDVI Linear Mixing Growth Model (NDVI-LMGM, is proposed to achieve the goal of accurately and efficiently blending MODIS NDVI time-series data and multi-temporal Landsat TM/ETM+ images. This method firstly unmixes the NDVI temporal changes in MODIS time-series to different land cover types and then uses unmixed NDVI temporal changes to predict Landsat-like NDVI dataset. The test over a forest site shows high accuracy (average difference: −0.0070; average absolute difference: 0.0228; and average absolute relative difference: 4.02% and computation efficiency of NDVI-LMGM (31 seconds using a personal computer. Experiments over more complex landscape and long-term time-series demonstrated that NDVI-LMGM performs well in each stage of vegetation growing season and is robust in regions with contrasting spatial and spatial variations. Comparisons between NDVI-LMGM and current methods (i.e., Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM, Enhanced STARFM (ESTARFM and Weighted Linear Model (WLM show that NDVI-LMGM is more accurate and efficient than current methods. The proposed method will benefit land surface process research, which requires a dense NDVI time-series dataset with high spatial resolution.

The electronic structure and ferromagnetism of TM (TM=V, Cr, and Mn)-doped BN(5, 5) nanotube: A first-principles study

International Nuclear Information System (INIS)

He, K.H.; Zheng, G.; Chen, G.; Wan, M.; Ji, G.F.

2008-01-01

We study the electronic structure and ferromagnetism of V-, Cr-, and Mn-doped single-wall BN(5, 5) nanotube by using polarized spin calculations within first principles. The optimized structures show that the transition-metal atoms move outwards and the calculated electronic properties demonstrate that the isolated V-, Cr-, and Mn-doped BN(5, 5) nanotubes show half-metallicity. The total ferromagnetic moments are 2μ B , 3.02μ B , and 3.98μ B for V-, Cr-, and Mn-doped BN(5, 5), respectively. The study suggests that such transition-metal (TM)-doped nanotubes may be useful in spintronics and nanomagnets

Using Landsat satellite imagery to detect small-size forest stands of Pinus nigra Arn. and Pinus sylvestris L. affected by Scolytidae; Uso de imagenes satelite Landsat para la deteccion de rodales de Pinus nigra Arn. y Pinus sylvestris L. afectados por escolitidos

Energy Technology Data Exchange (ETDEWEB)

Blanco, E.; Bonet, J. A.; Eizaguirre, M.

2009-07-01

Medium resolution images from multispectral sensors like Landsat TM have been extensively used for decades in order to identify decline and defoliation generated by insects and other forest pests. The present work analyses the usefulness of these kinds of images to detect small-size stands of Pinus nigra Arn. and Pinus sylvestris L. affected by Scolytidae attacks. The study area was located in the Solsones region (Eastern Pyrenees), selecting 34 training zones (17 damaged small-size stands and 17 healthy small-size stands). The exploratory analysis of the images was conducted with the ERDAS IMAGINE 8.x. program.The results of the study showed significant differences between the affected and non-affected stands in 5 of the 7 spectral bands analysed. TM5 and TM7 bands were identified as those having the highest power to detect damaged stands. The digital levels obtained and the spaces of characteristics created, both showed trends to group small-size affected stands versus healthy, achieving improvements in the methodological procedure employed. (Author) 31 refs.

Multitemporal Snow Cover Mapping in Mountainous Terrain for Landsat Climate Data Record Development

Science.gov (United States)

Crawford, Christopher J.; Manson, Steven M.; Bauer, Marvin E.; Hall, Dorothy K.

2013-01-01

A multitemporal method to map snow cover in mountainous terrain is proposed to guide Landsat climate data record (CDR) development. The Landsat image archive including MSS, TM, and ETM+ imagery was used to construct a prototype Landsat snow cover CDR for the interior northwestern United States. Landsat snow cover CDRs are designed to capture snow-covered area (SCA) variability at discrete bi-monthly intervals that correspond to ground-based snow telemetry (SNOTEL) snow-water-equivalent (SWE) measurements. The June 1 bi-monthly interval was selected for initial CDR development, and was based on peak snowmelt timing for this mountainous region. Fifty-four Landsat images from 1975 to 2011 were preprocessed that included image registration, top-of-the-atmosphere (TOA) reflectance conversion, cloud and shadow masking, and topographic normalization. Snow covered pixels were retrieved using the normalized difference snow index (NDSI) and unsupervised classification, and pixels having greater (less) than 50% snow cover were classified presence (absence). A normalized SCA equation was derived to independently estimate SCA given missing image coverage and cloud-shadow contamination. Relative frequency maps of missing pixels were assembled to assess whether systematic biases were embedded within this Landsat CDR. Our results suggest that it is possible to confidently estimate historical bi-monthly SCA from partially cloudy Landsat images. This multitemporal method is intended to guide Landsat CDR development for freshwaterscarce regions of the western US to monitor climate-driven changes in mountain snowpack extent.

An evaluation of simulated Thematic Mapper data and Landsat MSS data for discriminating suburban and regional land use and land cover

Science.gov (United States)

Toll, D. L.

1984-01-01

An airborne multispectral scanner, operating in the same spectral channels as the Landsat Thematic Mapper (TM), was used in a region east of Denver, CO, for a simulation test performed in the framework of using TM to discriminate the level I and level II classes. It is noted that at the 30-m spatial resolution of the Thematic Mapper Simulator (TMS) the overall discrimination for such classes as commercial/industrial land, rangeland, irrigated sod, irrigated alfalfa, and irrigated pasture was superior to that of the Landsat Multispectral Scanner, primarily due to four added spectral bands. For residential and other spectrally heterogeneous classes, however, the higher resolution of TMS resulted in increased variability within the class and a larger spectral overlap.

An analysis of Landsat Thematic Mapper P-Product internal geometry and conformity to earth surface geometry

Science.gov (United States)

Bryant, N. A.; Zobrist, A. L.; Walker, R. E.; Gokhman, B.

1985-01-01

Performance requirements regarding geometric accuracy have been defined in terms of end product goals, but until recently no precise details have been given concerning the conditions under which that accuracy is to be achieved. In order to achieve higher spatial and spectral resolutions, the Thematic Mapper (TM) sensor was designed to image in both forward and reverse mirror sweeps in two separate focal planes. Both hardware and software have been augmented and changed during the course of the Landsat TM developments to achieve improved geometric accuracy. An investigation has been conducted to determine if the TM meets the National Map Accuracy Standards for geometric accuracy at larger scales. It was found that TM imagery, in terms of geometry, has come close to, and in some cases exceeded, its stringent specifications.

Local search for optimal global map generation using mid-decadal landsat images

Science.gov (United States)

Khatib, L.; Gasch, J.; Morris, Robert; Covington, S.

2007-01-01

NASA and the US Geological Survey (USGS) are seeking to generate a map of the entire globe using Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) sensor data from the "mid-decadal" period of 2004 through 2006. The global map is comprised of thousands of scene locations and, for each location, tens of different images of varying quality to chose from. Furthermore, it is desirable for images of adjacent scenes be close together in time of acquisition, to avoid obvious discontinuities due to seasonal changes. These characteristics make it desirable to formulate an automated solution to the problem of generating the complete map. This paper formulates a Global Map Generator problem as a Constraint Optimization Problem (GMG-COP) and describes an approach to solving it using local search. Preliminary results of running the algorithm on image data sets are summarized. The results suggest a significant improvement in map quality using constraint-based solutions. Copyright ?? 2007, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved.

Correlations between transmembrane 4 L6 family member 5 (TM4SF5, CD151, and CD63 in liver fibrotic phenotypes and hepatic migration and invasive capacities.

Directory of Open Access Journals (Sweden)

Minkyung Kang

Full Text Available Transmembrane 4 L6 family member 5 (TM4SF5 is overexpressed during CCl4-mediated murine liver fibrosis and in human hepatocellular carcinomas. The tetraspanins form tetraspanin-enriched microdomains (TEMs consisting of large membrane protein complexes on the cell surface. Thus, TM4SF5 may be involved in the signal coordination that controls liver malignancy. We investigated the relationship between TM4SF5-positive TEMs with liver fibrosis and tumorigenesis, using normal Chang hepatocytes that lack TM4SF5 expression and chronically TGFβ1-treated Chang cells that express TM4SF5. TM4SF5 expression is positively correlated with tumorigenic CD151 expression, but is negatively correlated with tumor-suppressive CD63 expression in mouse fibrotic and human hepatic carcinoma tissues, indicating cooperative roles of the tetraspanins in liver malignancies. Although CD151 did not control the expression of TM4SF5, TM4SF5 appeared to control the expression levels of CD151 and CD63. TM4SF5 interacted with CD151, and caused the internalization of CD63 from the cell surface into late lysosomal membranes, presumably leading to terminating the tumor-suppressive functions of CD63. TM4SF5 could overcome the tumorigenic effects of CD151, especially cell migration and extracellular matrix (ECM-degradation. Taken together, TM4SF5 appears to play a role in liver malignancy by controlling the levels of tetraspanins on the cell surface, and could provide a promising therapeutic target for the treatment of liver malignancies.

tmRDB (tmRNA database)

DEFF Research Database (Denmark)

Zwieb, Christian; Gorodkin, Jan; Knudsen, Bjarne

2003-01-01

Maintained at the University of Texas Health Science Center at Tyler, Texas, the tmRNA database (tmRDB) is accessible at the URL http://psyche.uthct.edu/dbs/tmRDB/tmRDB.html with mirror sites located at Auburn University, Auburn, Alabama (http://www.ag.auburn.edu/mirror/tmRDB/) and the Bioinforma......Maintained at the University of Texas Health Science Center at Tyler, Texas, the tmRNA database (tmRDB) is accessible at the URL http://psyche.uthct.edu/dbs/tmRDB/tmRDB.html with mirror sites located at Auburn University, Auburn, Alabama (http......://www.ag.auburn.edu/mirror/tmRDB/) and the Bioinformatics Research Center, Aarhus, Denmark (http://www.bioinf.au.dk/tmRDB/). The tmRDB collects and distributes information relevant to the study of tmRNA. In trans-translation, this molecule combines properties of tRNA and mRNA and binds several proteins to form the tmRNP. Related RNPs are likely...

Determining the rate of forest conversion in Mato Grosso, Brazil, using Landsat MSS and AVHRR data

Science.gov (United States)

Nelson, Ross; Horning, Ned; Stone, Thomas A.

1987-01-01

AVHRR-LAC thermal data and Landsat MSS and TM spectral data were used to estimate the rate of forest clearing in Mato Grosso, Brazil, between 1981 and 1984. The Brazilian state was stratified into forest and nonforest. A list sampling procedure was used in the forest stratum to select Landsat MSS scenes for processing based on estimates of fire activity in the scenes. Fire activity in 1984 was estimated using AVHRR-LAC thermal data. State-wide estimates of forest conversion indicate that between 1981 and 1984, 353,966 ha + or - 77,000 ha (0.4 percent of the state area) were converted per year. No evidence of reforestation was found in this digital sample. The relationship between forest clearing rate (based on MSS-TM analysis) and fire activity (estimated using AVHRR data) was noisy (R-squared = 0.41). The results suggest that AVHRR data may be put to better use as a stratification tool than as a subsidiary variable in list sampling.

Landsat Thematic Mapper digital information content for agricultural environments

Science.gov (United States)

Haack, Barry; Bryant, Nevin; Adams, Steven

1986-01-01

Landsat Thematic Mapper (TM) data collected for Imperial Valley, California in December, 1982 were digitally examined to assess their utility to distinguish among agricultural and other land-covers. Statistics for thirty-seven training sites representing a variety of crops plus urban, water and desert land-covers were obtained and analyzed using transformed divergence (TD) calculations. TD values were employed to assess intraclass variability and the best bands for classification. Four subscenes were selected for clustering or unsupervised signature extraction. These areas were agriculture, urban, desert and water land-covers. The number of clusters for these subscenes were examined and the best TM bands for interclass separability were identified. The results of the clustering and training site analyses for interclass separability were compared. The TM data were useful for the digital delimitation of most crops and other cover types in this analysis. Four bands of data are adequate for classification with the best results obtained by the selection of one band from each of the available portions of the electromagnetic spectrum. Different band combinations are best for various land-cover intraclass separability.

Changes in the NDVI of Boreal Forests over the period 1984 to 2003 measured using time series of Landsat TM/ETM+ surface reflectance and the GIMMS AVHRR NDVI record.

Science.gov (United States)

McMillan, A. M.; Rocha, A. V.; Goulden, M. L.

2006-12-01

There is a prevailing opinion that the boreal landscape is undergoing change as a result of warming temperatures leading to earlier springs, greater forest fire frequency and possibly CO2 fertilization. One widely- used line of evidence is the GIMMS AVHRR NDVI record. Several studies suggest increasing rates of photosynthesis in boreal forests from 1982 to 1991 (based on NDVI increases) while others suggest declining photosynthesis from 1996 to 2003. We suspect that a portion of these changes are due to the successional stage of the forests. We compiled a time-series of atmospherically-corrected Landsat TM/ETM+ images spanning the period 1984 to 2003 over the BOREAS Northern Study Area and compared spatial and temporal patterns of NDVI between the two records. The Landsat time series is higher resolution and, together with the Canadian Fire Service Large Fire Database, provides stand-age information. We then (1) analyzed the agreement between the Landsat and GIMMS AVHRR time series; (2) determined how the stage of forest succession affected NDVI; (3) assessed how the calculation method of annual averages of NDVI affects decadal-scale trends. The agreement between the Landsat and the AVHRR was reasonable although the depression of NDVI associated with the aerosols from the Pinatubo volcano was greater in the GIMMS time series. Pixels containing high proportions of stands burned within a decade of the observation period showed very high gains in NDVI while the more mature stands were constant. While NDVI appears to exhibit a large sensitivity to the presence of snow, the choice of a May to September averaging period for NDVI over a June to August averaging period did not affect the interannual patterns in NDVI at this location because the snow pack was seldom present in either of these periods. Knowledge of the spatial and temporal patterns of wild fire will prove useful in interpreting trends of remotely-sensed proxies of photosynthesis.

Aerofotos convencionais e imagens orbitais TM/LANDSAT no mapeamento morfopedológico em Santa Bárbara D'Oeste (SP Mapping and fisiographic characterization of soils using conventional aerial photographs and orbital images TM/LANDSAT-5 in Santa Bárbara D'Oeste (SP

Directory of Open Access Journals (Sweden)

J.A.M. Demattê

1993-12-01

Full Text Available Foram estudados, com o auxílio de fotografias aéreas, aspectos qualitativos e quantitativos do relevo e da rede de drenagem de solos de uma área de Santa Bárbara D'Oeste, SP. Esta região compreende 14.625 ha, onde foram selecionadas bacias hidrográficas de 3ª ordem de ramificação e amostras circulares de 5km². As unidades de mapeamento simples ou associações de solos são: Latossolo Vermelho Escuro, Podzólico, Litossolo + Podzólico, Terra Roxa Estruturada + Latossolo Roxo distrófico. Após a caracterização das feições fisiográficas, da área de ocorrência desses solos, foram realizados dois mapas morfopedológicos. No primeiro utilizou-se fotografias aéreas verticais pancromáticas na escala 1: 35.000 (data de 25/6/78 e no segundo imagens orbitais do sensor "Thematic Mapper" do LANDSAT-5, nas bandas 3, 4 e 5 e composição colorida 3/4/5 na escala 1: 100.000 (data de 12/9/91. As análises qualitativas e quantitativas do relevo (índice de declividade média e rede de drenagem (densidade de drenagem, freqüência de rios, razão de textura mostraram-se eficientes na diferenciação das unidades de solo estudadas, tanto em bacias hidrográficas como em amostras circulares. A utilização de fotografias aéreas, permitiu maior riqueza de detalhes na precisão dos limites das unidades de mapeamento e no maior número de unidades de mapeamento discriminadas em relação as imagens orbitais. A composição colorida 3/4/5 permitiu diferenciar os Latossolos argilosos dos Latossolos de textura média, assim como o Latossolo Húmico.Using aerial photographs quantitative and qualitative parameters of drainage patterns and landscape were studied in an area located in Santa Barbara D'Oeste,SP. This area has 14,625 ha, represented by the following simple map units or associations: Dark Red Latosols; Red Yellow Podzoh'c associated with some Lithosols; Dusky Latosol associated with "Terra Roxa Estruturada" (a Rodudal. Sampling areas were

Diode-pumped laser performance of Tm:Sc2SiO5 crystal at 1971 nm

International Nuclear Information System (INIS)

Liu Bin; Wang Qing-Guo; Tang Hui-Li; Wu Feng; Luo Ping; Zhao Heng-Yu; Shi Jiao-Jiao; He Nuo-Tian; Li Na; Li Qiu; Guo Chao; Wang Zhan-Shan; Xu Jun; Zheng Li-He; Su Liang-Bi; Liu Jun-Fang; Liu Jie; Fan Xiu-Wei; Xu Xiao-Dong

2017-01-01

The 4-at.% Tm:Sc 2 SiO 5 (Tm:SSO) crystal is successfully obtained by the Czochralski method. The optical properties and thermal conductivity of the crystal are investigated. The broad continuous wave (CW) laser output of (100)-cut Tm:SSO with the dimensions of 3 mm× 3 mm× 3 mm under laser diode (LD)-pumping is realized. The full width at half maximum (FWHM) of the laser emitting reaches up to 21 nm. The laser threshold of Tm:SSO is measured to be 0.43 W. Efficient diode-pumped CW laser performance of Tm:SSO is demonstrated with a slope efficiency of 25.9% and maximum output power of 934 mW. (paper)

Combustion synthesis and characterization of MV0.5P0.5O4: Sm3+, Tm3+ (M = Gd, La, Y)

Science.gov (United States)

Motloung, Selepe J.; Lephoto, Mantwa A.; Tshabalala, Kamohelo G.; Ntwaeaborwa, Odireleng M.

2018-04-01

In this paper, GdV0.5P0.5O4: Sm3+, Tm3+, LaV0.5P0.5O4: Sm3+, Tm3+ and YV0.5P0.5O4: Sm3+, Tm3+ phosphor powders were prepared by solution combustion method using urea as a fuel. The phase purity, surface morphology, optical and photoluminescence properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy and photoluminescence spectroscopy. The XRD results indicated that the prepared powders are of a single phase and crystallized in tetragonal structure for Gd and Y systems while monoclinic phase was observed for La system. SEM showed that the samples consisted of mixed structures. The estimated band gaps were 2.2, 2.4 and 2.3 eV for Y, Gd and La systems respectively. The photoluminescence results showed four emission peaks. One peak is assigned to 1G4 - 3H6 transition of Tm3+, and three other emission peaks are attributed to 6G5/2 - 6H5/2, 6G5/2 - 6H7/2 and 6G5/2 - 6H9/2 transitions of Sm3+. The photoluminescent intensity was the highest in the gadolinium system.

Mapping contact metamorphic aureoles in Extremadura, Spain, using Landsat thematic mapper images

Science.gov (United States)

Rowan, L.C.; Anton-Pacheco, C.; Brickey, D.W.; Kingston, M.J.; Payas, A.

1987-01-01

In the Extremadura region of western Spain, Ag, Pb, Zn, and Sn deposits occur in the pieces of late Hercynian granitic plutons and near the pluton contacts in late Proterozoic slate and metagraywacke that have been regionally metamorphosed to the green schist facies. The plutons generally are well exposed and have distinctive geomorphological expression and vegetation; poor exposures of the metasedimentary host rocks and extensive cultivation, however, make delineation of the contact aureoles difficult. Landsat Thematic Mapper (TM) images have been used to distinguish soil developed on the contact metamorphic rocks from soil formed on the stratigraphically equivalent slate-metagraywacke sequence. The mineral constituents of these soils are similar, except that muscovite is more common in the contact metamorphic soil; carbonaceous material is common in both soils. Contact metamorphic soil have lower reflectance, especially in the 1.6-micrometers wavelength region (TM 5), and weaker Al-OH, Mg-OH, and Fe3+ absorption features than do spectra of the slate-metagraywacke soil. The low-reflectance and subdued absorption features exhibited by the contact metamorphic soil spectra are attributed to the high absorption coefficient f the carbonaceous material caused by heating during emplacement of the granitic plutons. These spectral differences are evident in a TM 4/3, 4/5, 3/1 color-composite image. Initially, this image was used to outline the contact aureoles, but digital classification of the TM data was necessary for generating internally consistent maps of the distribution of the exposed contact metamorphic soil. In an August 1984, TM scene of the Caceras area, the plowed, vegetation-free fields were identified by their low TM 4/3 values. Then, ranges of TM 4/5 and 3/1 values were determine for selected plower fields within and outside the contact aureoles; TM 5 produced results similar to TM 4/5. Field evaluation, supported by X-ray diffraction and petrographic

Aboveground Forest Biomass Estimation with Landsat and LiDAR Data and Uncertainty Analysis of the Estimates

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Dengsheng Lu

2012-01-01

Full Text Available Landsat Thematic mapper (TM image has long been the dominate data source, and recently LiDAR has offered an important new structural data stream for forest biomass estimations. On the other hand, forest biomass uncertainty analysis research has only recently obtained sufficient attention due to the difficulty in collecting reference data. This paper provides a brief overview of current forest biomass estimation methods using both TM and LiDAR data. A case study is then presented that demonstrates the forest biomass estimation methods and uncertainty analysis. Results indicate that Landsat TM data can provide adequate biomass estimates for secondary succession but are not suitable for mature forest biomass estimates due to data saturation problems. LiDAR can overcome TM’s shortcoming providing better biomass estimation performance but has not been extensively applied in practice due to data availability constraints. The uncertainty analysis indicates that various sources affect the performance of forest biomass/carbon estimation. With that said, the clear dominate sources of uncertainty are the variation of input sample plot data and data saturation problem related to optical sensors. A possible solution to increasing the confidence in forest biomass estimates is to integrate the strengths of multisensor data.

Analysis of data acquired by Shuttle Imaging Radar SIR-A and Landsat Thematic Mapper over Baldwin County, Alabama

Science.gov (United States)

Wu, S.-T.

1985-01-01

Seasonally compatible data collected by SIR-A and by Landsat 4 TM over the lower coastal plain in Alabama were coregistered, forming a SIR-A/TM multichannel data set with 30 m x 30 m pixel size. Spectral signature plots and histogram analysis of the data were used to observe data characteristics. Radar returns from pine forest classes correlated highly with the tree ages, suggesting the potential utility of microwave remote sensing for forest biomass estimation. As compared with the TM-only data set, the use of SIR-A/TM data set improved classification accuracy of the seven land cover types studied. In addition, the SIR-A/TM classified data support previous finding by Engheta and Elachi (1982) that microwave data appear to be correlated with differing bottomland hardwood forest vegetation as associated with varying water regimens (i.e., wet versus dry).

LEDAPS Landsat Calibration, Reflectance, Atmospheric Correction Preprocessing Code

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) is a NASA project to map disturbance, regrowth, and permanent forest conversion...

An Improved Single-Channel Method to Retrieve Land Surface Temperature from the Landsat-8 Thermal Band

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Jordi Cristóbal

2018-03-01

Full Text Available Land surface temperature (LST is one of the sources of input data for modeling land surface processes. The Landsat satellite series is the only operational mission with more than 30 years of archived thermal infrared imagery from which we can retrieve LST. Unfortunately, stray light artifacts were observed in Landsat-8 TIRS data, mostly affecting Band 11, currently making the split-window technique impractical for retrieving surface temperature without requiring atmospheric data. In this study, a single-channel methodology to retrieve surface temperature from Landsat TM and ETM+ was improved to retrieve LST from Landsat-8 TIRS Band 10 using near-surface air temperature (Ta and integrated atmospheric column water vapor (w as input data. This improved methodology was parameterized and successfully evaluated with simulated data from a global and robust radiosonde database and validated with in situ data from four flux tower sites under different types of vegetation and snow cover in 44 Landsat-8 scenes. Evaluation results using simulated data showed that the inclusion of Ta together with w within a single-channel scheme improves LST retrieval, yielding lower errors and less bias than models based only on w. The new proposed LST retrieval model, developed with both w and Ta, yielded overall errors on the order of 1 K and a bias of −0.5 K validated against in situ data, providing a better performance than other models parameterized using w and Ta or only w models that yielded higher error and bias.

Thermal Infrared Radiometric Calibration of the Entire Landsat 4, 5, and 7 Archive (1982-2010)

Science.gov (United States)

Schott, John R.; Hook, Simon J.; Barsi, Julia A.; Markham, Brian L.; Miller, Jonathan; Padula, Francis P.; Raqueno, Nina G.

2012-01-01

Landsat's continuing record of the thermal state of the earth's surface represents the only long term (1982 to the present) global record with spatial scales appropriate for human scale studies (i.e., tens of meters). Temperature drives many of the physical and biological processes that impact the global and local environment. As our knowledge of, and interest in, the role of temperature on these processes have grown, the value of Landsat data to monitor trends and process has also grown. The value of the Landsat thermal data archive will continue to grow as we develop more effective ways to study the long term processes and trends affecting the planet. However, in order to take proper advantage of the thermal data, we need to be able to convert the data to surface temperatures. A critical step in this process is to have the entire archive completely and consistently calibrated into absolute radiance so that it can be atmospherically compensated to surface leaving radiance and then to surface radiometric temperature. This paper addresses the methods and procedures that have been used to perform the radiometric calibration of the earliest sizable thermal data set in the archive (Landsat 4 data). The completion of this effort along with the updated calibration of the earlier (1985 1999) Landsat 5 data, also reported here, concludes a comprehensive calibration of the Landsat thermal archive of data from 1982 to the present

Quantifying the Physical Composition of Urban Morphology throughout Wales Based on the Time Series (1989–2011 Analysis of Landsat TM/ETM+ Images and Supporting GIS Data

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Douglas Scott

2014-11-01

Full Text Available Knowledge of impervious surface areas (ISA and on their changes in magnitude, location, geometry and morphology over time is significant for a range of practical applications and research alike from local to global scales. Despite this, use of Earth Observation (EO technology in mapping ISAs within some European Union (EU countries, such as the United Kingdom (UK, is to some extent scarce. In the present study, a combination of methods is proposed for mapping ISA based on freely distributed EO imagery from Landsat TM/ETM+ sensors. The proposed technique combines a traditional classifier and a linear spectral mixture analysis (LSMA with a series of Landsat TM/ETM+ images to extract ISA. Selected sites located in Wales, UK, are used for demonstrating the capability of the proposed method. The Welsh study areas provided a unique setting in detecting largely dispersed urban morphology within an urban-rural frontier context. In addition, an innovative method for detecting clouds and cloud shadow layers for the full area estimation of ISA is also presented herein. The removal and replacement of clouds and cloud shadows, with underlying materials is further explained. Aerial photography with a spatial resolution of 0.4 m, acquired over the summer period in 2005 was used for validation purposes. Validation of the derived products indicated an overall ISA detection accuracy in the order of ~97%. The latter was considered as very satisfactory and at least comparative, if not somehow better, to existing ISA products provided on a national level. The hybrid method for ISA extraction proposed here is important on a local scale in terms of moving forward into a biennial program for the Welsh Government. It offers a much less subjectively static and more objectively dynamic estimation of ISA cover in comparison to existing operational products already available, improving the current estimations of international urbanization and soil sealing. Findings of our

Three-dimensional displays for natural hazards analysis, using classified Landsat Thematic Mapper digital data and large-scale digital elevation models

Science.gov (United States)

Butler, David R.; Walsh, Stephen J.; Brown, Daniel G.

1991-01-01

Methods are described for using Landsat Thematic Mapper digital data and digital elevation models for the display of natural hazard sites in a mountainous region of northwestern Montana, USA. Hazard zones can be easily identified on the three-dimensional images. Proximity of facilities such as highways and building locations to hazard sites can also be easily displayed. A temporal sequence of Landsat TM (or similar) satellite data sets could also be used to display landscape changes associated with dynamic natural hazard processes.

Structural, mechanical and electronic properties of OsTM and TMOs{sub 2} (TM = Ti, Zr and Hf): First-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Liu, Qi-Jun, E-mail: qijunliu@home.swjtu.edu.cn [Bond and Band Engineering Group, Institute of High Temperature and High Pressure Physics, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, Ning-Chao; Liu, Fu-Sheng [Bond and Band Engineering Group, Institute of High Temperature and High Pressure Physics, School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Liu, Zheng-Tang [State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

2014-03-15

Highlights: • OsTM and TMOs{sub 2} compounds have no superhard character. • These compounds are mechanically stable and behave in ductile manner. • OsTM has a mixture of covalent-ionic and metallic character. -- Abstract: The first-principles calculations have been performed to study the structural, elastic, mechanical and electronic properties of cubic OsTM (TM = Ti, Zr, and Hf) and hexagonal TMOs{sub 2} compounds. The calculated structural parameters are in good agreement with the available experimental data. To the best of our knowledge, the elastic constants of OsTM and TMOs{sub 2} compounds have been obtained for the first time. The calculated elastic and mechanical properties show that these compounds have no superhard character. These compounds are mechanically stable and behave in ductile manner. The electronic band structures and densities of states of OsTM and TMOs{sub 2} compounds have been analysed. OsTM has a mixture of covalent-ionic and metallic character, and TMOs{sub 2} has strong metallic nature.

Aplicación de imágenes de satélite en la cartografía de uso de suelo y vegetación en una región del Oriente del Valle de México

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E. Buendía Rodríguez

2002-01-01

Full Text Available En México la aplicación de sensores remotos se encuentra en la fase de experimentación, por lo cual se están generando metodologías propias para el estudio del territorio mexicano. Para la clasificación de uso de suelo y vegetación, se realizó un estudio en la cuenca oriental del Valle de México, utilizando imágenes Landsat TM y Spot XS; procesadas mediante el Sistema Personal Interactivo de Percepción Remota versión 2.0 (SPIPR II, para diez unidades de clasificación que fueron: agricultura de riego (AR, agricultura de temporal (AT, pastizal halófilo (PH, bosque de pino (BP, pastizal inducido (PI, zona urbana (ZU, cuerpos de agua (CA, bosque de pino-pastizal (BP-PI, bosque de encino-matorral (BE-MI y bosque de abies (BA. Para el cumplimiento de los objetivos de dicho trabajo se establecieron cuatro tratamientos (componentes principales, análisis de texturas, convolución y filtrado sobre tres combinaciones de bandas (Landsat TM3-TM4-TM5, TM2-TM5-TM7 y Spot XS1-XS2-XS3. La mejor precisión fue para las imágenes clasificadas Landsat TM2-TM5-TM7 sin tratamiento con un 75 %, para Landsat TM3-TM4-TM5 sin tratamiento, fue de 69.07 % y las imágenes clasificadas Spot XS1-XS2-XS3 con el tratamiento de componentes principales tuvieron un 69.07 %.

Geological analysis of parts of the southern Arabian Shield based on Landsat imagery

Science.gov (United States)

Qari, Mohammed Yousef Hedaytullah T.

This thesis examines the capability and applicability of Landsat multispectral remote sensing data for geological analysis in the arid southern Arabian Shield, which is the eastern segment of the Nubian-Arabian Shield surrounding the Red Sea. The major lithologies in the study area are Proterozoic metavolcanics, metasediments, gneisses and granites. Three test-sites within the study area, located within two tectonic assemblages, the Asir Terrane and the Nabitah Mobile Belt, were selected for detailed comparison of remote sensing methods and ground geological studies. Selected digital image processing techniques were applied to full-resolution Landsat TM imagery and the results are interpreted and discussed. Methods included: image contrast improvement, edge enhancement for detecting lineaments and spectral enhancement for geological mapping. The last method was based on two principles, statistical analysis of the data and the use of arithmetical operators. New and detailed lithological and structural maps were constructed and compared with previous maps of these sites. Examples of geological relations identified using TM imagery include: recognition and mapping of migmatites for the first time in the Arabian Shield; location of the contact between the Asir Terrane and the Nabitah Mobile Belt; and mapping of lithologies, some of which were not identified on previous geological maps. These and other geological features were confirmed by field checking. Methods of lineament enhancement implemented in this study revealed structural lineaments, mostly mapped for the first time, which can be related to regional tectonics. Structural analysis showed that the southern Arabian Shield has been affected by at least three successive phases of deformation. The third phase is the most dominant and widespread. A crustal evolutionary model in the vicinity of the study area is presented showing four stages, these are: arc stage, accretion stage, collision stage and post

Continuity of Landsat observations: Short term considerations

Science.gov (United States)

Wulder, Michael A.; White, Joanne C.; Masek, Jeffery G.; Dwyer, John L.; Roy, David P.

2011-01-01

As of writing in mid-2010, both Landsat-5 and -7 continue to function, with sufficient fuel to enable data collection until the launch of the Landsat Data Continuity Mission (LDCM) scheduled for December of 2012. Failure of one or both of Landsat-5 or -7 may result in a lack of Landsat data for a period of time until the 2012 launch. Although the potential risk of a component failure increases the longer the sensor's design life is exceeded, the possible gap in Landsat data acquisition is reduced with each passing day and the risk of Landsat imagery being unavailable diminishes for all except a handful of applications that are particularly data demanding. Advances in Landsat data compositing and fusion are providing opportunities to address issues associated with Landsat-7 SLC-off imagery and to mitigate a potential acquisition gap through the integration of imagery from different sensors. The latter will likely also provide short-term, regional solutions to application-specific needs for the continuity of Landsat-like observations. Our goal in this communication is not to minimize the community's concerns regarding a gap in Landsat observations, but rather to clarify how the current situation has evolved and provide an up-to-date understanding of the circumstances, implications, and mitigation options related to a potential gap in the Landsat data record.

Land Use and Land Cover Change in Guangzhou, China, from 1998 to 2003, Based on Landsat TM /ETM+ Imagery

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Yunpeng Wang

2007-07-01

Full Text Available Land use and land cover change is a major issue in global environment change,and is especially significant in rapidly developing regions in the world. With its economicdevelopment, population growth, and urbanization, Guangzhou, a major metropolitan inSouth China, have experienced a dramatic land use and land cover (LULC change over thepast 30 years. Fast LULC change have resulted in degradation of its ecosystems andaffected adversely the environment. It is urgently needed to monitor its LULC changes andto analyses the consequences of these changes in order to provide information for policy-makers to support sustainable development. This study employed two Landsat TM/ETM images in the dry season to detect LULC patterns in 1998 and 2003, and to examine LULCchanges during the period from 1998 to 2003. The type, rate, and pattern of the changesamong five counties of Guangzhou Municipality were analyzed in details by post-classification method. LULC conversion matrix was produced for each county in order toexplore and explain the urban expansion and cropland loss, the most significant types ofLULC change. Land use conversion matrixes of five counties were discussed respectivelyin order to explore and explain the inherence of land use change. The results showed thaturban expansion in these five counties kept an even rate of increase, while substantialamount of cropland vanished during the period. It is also noted that the conversion between cropland and orchard land was intensive. Forest land became the main source of new croplands.

Detection of soil erosion within pinyon-juniper woodlands using Thematic Mapper (TM) data

Science.gov (United States)

Price, Kevin P.

1993-01-01

Multispectral measurements collected by Landsat Thematic Mapper (TM) were correlated with field measurements, direct soil loss estimates, and Universal Soil Loss Equation (USLE) estimates to determine the sensitivity of TM data to varying degrees of soil erosion in pinyon-juniper woodland in central Utah. TM data were also evaluated as a predictor of the USLE Crop Management C factor for pinyon-juniper woodlands. TM spectral data were consistently better predictors of soil erosion factors than any combination of field factors. TM data were more sensitive to vegetation variations than the USLE C factor. USLE estimates showed low annual rates of erosion which varied little among the study sites. Direct measurements of rate of soil loss using the SEDIMENT (Soil Erosion DIrect measureMENT) technique, indicated high and varying rates of soil loss among the sites since tree establishment. Erosion estimates from the USLE and SEDIMENT methods suggest that erosion rates have been severe in the past, but because significant amounts of soil have already been eroded, and the surface is now armored by rock debris, present erosion rates are lower. Indicators of accelerated erosion were still present on all sites, however, suggesting that the USLE underestimated erosion within the study area.

Cross-Section Measurement of the 169Tm(n,3n)167Tm Reaction and Constraining the Branching Ratio of 167Tm

Science.gov (United States)

Champine, Brian; Gooden, Matthew; Thomas, Keenan; Krishichayan, F.; Norman, Eric; Scielzo, Nick; Tonchev, Anton; Tornow, Werner

2015-10-01

The cross section of the 169Tm(n,3n)167Tm reaction has been measured from 17.5 to 21.5 MeV using activation technique. This energy region was chosen to resolve the two different trends of the previous (n,3n) cross section measurements on 169Tm. In addition, the branching ratio of the 207.8 keV γ-ray line stemming from electron capture of 167Tm was measured to be 0.419(16). The result of these measurements provide more accurate diagnostic estimation of the so called reaction-in-flight neutrons produced via the internal confinement fusion plasma in deuterium-tritium capsules at the National Ignition Facility.

Analysis of the Relationship between Land Surface Temperature and Wildfire Severity in a Series of Landsat Images

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Lidia Vlassova

2014-06-01

Full Text Available The paper assesses spatio-temporal patterns of land surface temperature (LST and fire severity in the Las Hurdes wildfire of Pinus pinaster forest, which occurred in July 2009, in Extremadura (Spain, from a time series of fifteen Landsat 5 TM images corresponding to 27 post-fire months. The differenced Normalized Burn Ratio (dNBR was used to evaluate burn severity. The mono-window algorithm was applied to estimate LST from the Landsat thermal band. The burned zones underwent a significant increase in LST after fire. Statistically significant differences have been detected between the LST within regions of burn severity categories. More substantial changes in LST are observed in zones of greater fire severity, which can be explained by the lower emissivity of combustion products found in the burned area and changes in the energy balance related to vegetation removal. As time progresses over the 27 months after fire, LST differences decrease due to vegetation regeneration. The differences in LST and Normalized Difference Vegetation Index (NDVI values between burn severity categories in each image are highly correlated (r = 0.84. Spatial patterns of severity and post-fire LST obtained from Landsat time series enable an evaluation of the relationship between these variables to predict the natural dynamics of burned areas.

A COMPARISON OF HAZE REMOVAL ALGORITHMS AND THEIR IMPACTS ON CLASSIFICATION ACCURACY FOR LANDSAT IMAGERY

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Yang Xiao

Full Text Available The quality of Landsat images in humid areas is considerably degraded by haze in terms of their spectral response pattern, which limits the possibility of their application in using visible and near-infrared bands. A variety of haze removal algorithms have been proposed to correct these unsatisfactory illumination effects caused by the haze contamination. The purpose of this study was to illustrate the difference of two major algorithms (the improved homomorphic filtering (HF and the virtual cloud point (VCP for their effectiveness in solving spatially varying haze contamination, and to evaluate the impacts of haze removal on land cover classification. A case study with exploiting large quantities of Landsat TM images and climates (clear and haze in the most humid areas in China proved that these haze removal algorithms both perform well in processing Landsat images contaminated by haze. The outcome of the application of VCP appears to be more similar to the reference images compared to HF. Moreover, the Landsat image with VCP haze removal can improve the classification accuracy effectively in comparison to that without haze removal, especially in the cloudy contaminated area

Land and Land-use Change in the Climate Sensitive High Plains: An Automated Approach with Landsat

Science.gov (United States)

Goetz, Alexander F.; Williams, D. L. (Technical Monitor)

2002-01-01

The High Plains is an economically important and climatologically sensitive region of the United States and Canada. The High Plains contain 100,000 sq km of Holocene sand dunes and sand sheets that are currently stabilized by natural vegetation. Droughts and the larger threat of global warming are climate phenomena that could cause depletion of natural vegetation and make this region susceptible to sand dune reactivation. The original proposal was directed toward the use of Landsat TM data to establish the state and ongoing changes of the surface in the 1.2 million sq. km, semi-arid High Plains region of the central US, A key objective was to develop a model to predict the reactivation of the 100,000 sq. km of Holocene dunes found on the High Plains during an extended drought. At least one Landsat 5 image per year for 1985, 1988 and 1996 was obtained for 32 scenes on the High Plains to coincide with wet and dry years. Additional Landsat 7 data were acquired for 1999 and 2000 primarily for Colorado and Nebraska. As luck would have it, there was no severe drought during the study period 1985-2000. Attention was focused on developing methods for mapping dry vs. green vegetation on sparsely vegetated rangelands in sandy soils, since these were the areas most susceptible to surface reactivation during a drought.

Discrimination Of The Land Features In Al Hasa Oasi, Saudi Arabia, Using Color Ratio Technique On Land Sat Tm Data

International Nuclear Information System (INIS)

Al Saud, M.B.M.

2003-01-01

Landsat Thematic Mapper (TM) data for Al Rasa Oasis area was processed for delineating characteristic land features represented mainly by sand dunes, sabkhas, cultivated land and urban areas using procedures that take advantage of distinctive spectral reflectance of these land features. The method employs a color ratio technique based on comprising different ratios 2/3, 2/4, 3/4, 3/5, 4/5, 5/6, and 5/7. A number of ratio triplets were processed using a three colored composite ratio. The ratio images (3/4,3/5,5/6,and 5/7) succeeded to distinguish the main land features in the studied arid region and generate detailed maps over wide area by using quantitative reproducible mapping criteria and helping in identifying the characteristics of the different land features

Regional scale net radiation estimation by means of Landsat and TERRA/AQUA imagery and GIS modeling

Science.gov (United States)

Cristóbal, J.; Ninyerola, M.; Pons, X.; Llorens, P.; Poyatos, R.

2009-04-01

Net radiation (Rn) is one of the most important variables for the estimation of surface energy budget and is used for various applications including agricultural meteorology, climate monitoring and weather prediction. Moreover, net radiation is an essential input variable for potential as well as actual evapotranspiration modeling. Nowadays, radiometric measurements provided by Remote Sensing and GIS analysis are the technologies used to compute net radiation at regional scales in a feasible way. In this study we present a regional scale estimation of the daily Rn on clear days, (Catalonia, NE of the Iberian Peninsula), using a set of 22 Landsat images (17 Landsat-5 TM and 5 Landsat-7 ETM+) and 171 TERRA/AQUA images MODIS from 2000 to 2007 period. TERRA/AQUA MODIS images have been downloaded by means of the EOS Gateway. We have selected three different types of products which contain the remote sensing data we have used to model daily Rn: daily LST product, daily calibrated reflectances product and daily atmospheric water vapour product. Landsat-5 TM images have been corrected by means of conventional techniques based on first order polynomials taking into account the effect of land surface relief using a Digital Elevation Model, obtaining an RMS less than 30 m. Radiometric correction of Landsat non-thermal bands has been done following the methodology proposed by Pons and Solé (1994), which allows to reduce the number of undesired artifacts that are due to the effects of the atmosphere or to the differential illumination which is, in turn, due to the time of the day, the location in the Earth and the relief (zones being more illuminated than others, shadows, etc). Atmospheric correction of Landsat thermal band has been carried out by means of a single-channel algorithm improvement developed by Cristóbal et al. (2009) and the land surface emissivity computed by means of the methodology proposed by Sobrino and Raissouni (2000). Rn has been estimated through the

Tamarisk (Salt Cedar) Infestations in Northwestern Nevada Mapped Using Landsat TM Imagery and GIS Layers

Science.gov (United States)

Sengupta, D.; Geraci, C.; Kolkowitz, S.

2004-12-01

Tamarisk, also known as salt cedar (Tamarix sp.) is a prevalent invasive species that has infested many riparian areas in the southwestern United States. Mature salt cedar plants are resistant to high stress environments and fare well in drought conditions, mainly due to their extensive root systems that derive much of their sustenance from the water table rather than surface water and precipitation. The salt cedar root systems have altered hydrological patterns by tapping into underlying aquifers. This has decreased water available for recreational use, regional ecology and plant diversity. Many states have implemented salt cedar monitoring programs at the local level, but the problem of large-scale mapping of this invasive species has continued to be a challenge to land management agencies. Furthermore, inaccessible and unexplored areas continue to be absent in the mapping process. In August 2004, using field data consisting of large areas as training sets for classification of Landsat TM imagery, the DEVELOP student research team at NASA Ames Research Center generated a preliminary map of areas that that were susceptible to salt cedar growth for a region in northwestern Nevada. In addition to the remote sensing-based classification of satellite imagery, the team used the variables of elevation and estimated distance to the water table in conjunction with collected field data and knowledge of salt cedar growth habits to further refine the map. The team has further extended the mapping of key environmental factors of water availability for salt cedar, soil types and species distribution in regions infested by salt cedar. The investigation was carried out by 1) improving an existing GIS layer for water access using a suitable interpolation method, 2) including a GIS layer for soils associated with salt cedar growth and 3) completing field work to evaluate species distribution and regions of presence or absence of salt cedar. The outcome of this project served to

An Object-Based Approach for Fire History Reconstruction by Using Three Generations of Landsat Sensors

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Thomas Katagis

2014-06-01

Full Text Available In this study, the capability of geographic object-based image analysis (GEOBIA in the reconstruction of the recent fire history of a typical Mediterranean area was investigated. More specifically, a semi-automated GEOBIA procedure was developed and tested on archived and newly acquired Landsat Multispectral Scanner (MSS, Thematic Mapper (TM, and Operational Land Imager (OLI images in order to accurately map burned areas in the Mediterranean island of Thasos. The developed GEOBIA ruleset was built with the use of the TM image and then applied to the other two images. This process of transferring the ruleset did not require substantial adjustments or any replacement of the initially selected features used for the classification, thus, displaying reduced complexity in processing the images. As a result, burned area maps of very high accuracy (over 94% overall were produced. In addition to the standard error matrix, the employment of additional measures of agreement between the produced maps and the reference data revealed that “spatial misplacement” was the main source of classification error. It can be concluded that the proposed approach can be potentially used for reconstructing the recent (40-year fire history in the Mediterranean, based on extended time series of Landsat or similar data.

Automated mapping of mineral groups and green vegetation from Landsat Thematic Mapper imagery with an example from the San Juan Mountains, Colorado

Science.gov (United States)

Rockwell, Barnaby W.

2013-01-01

Multispectral satellite data acquired by the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) and Landsat 7 Enhanced Thematic Mapper Plus (TM) sensors are being used to populate an online Geographic Information System (GIS) of the spatial occurrence of mineral groups and green vegetation across the western conterminous United States and Alaska. These geospatial data are supporting U.S. Geological Survey national-scale mineral deposit database development and other mineral resource and geoenvironmental research as a means of characterizing mineral exposures related to mined and unmined hydrothermally altered rocks and mine waste. This report introduces a new methodology for the automated analysis of Landsat TM data that has been applied to more than 180 scenes covering the western United States. A map of mineral groups and green vegetation produced using this new methodology that covers the western San Juan Mountains, Colorado, and the Four Corners Region is presented. The map is provided as a layered GeoPDF and in GIS-ready digital format. TM data analysis results from other well-studied and mineralogically characterized areas with strong hydrothermal alteration and (or) supergene weathering of near-surface sulfide minerals are also shown and compared with results derived from ASTER data analysis.

Nanocrystals of a new complex perovskite dielectric Ba{sub 2}TmSbO{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Nair, V.M. [Department of Physics, University College, Trivandrum 695034, Kerala (India); Jose, R., E-mail: rjose@ump.edu.my [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, 26300 Kuantan (Malaysia); Anil Kumar, G.M. [Noritake Co Ltd, 300 Higashiyama, Miyoshi, Aichi 470-0293 (Japan); Yusoff, Mashitah M. [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, 26300 Kuantan (Malaysia); Wariar, P.R.S. [Department of Physics, University College, Trivandrum 695034, Kerala (India)

2012-01-25

Highlights: Black-Right-Pointing-Pointer A new material, Ba{sub 2}TmSbO{sub 6}, has been synthesized as nanocrystals for the first time. Black-Right-Pointing-Pointer A combustion process, characterized by a one-pot procedure, was adopted to synthesize Ba{sub 2}TmSbO{sub 6} as nanocrystals. Black-Right-Pointing-Pointer Crystal structure and dielectric properties of the Ba{sub 2}TmSbO{sub 6} have been studied and compared with similar materials. - Abstract: Nanocrystals of a new complex perovskites ceramic oxide, barium thulium antimony oxide - Ba{sub 2}TmSbO{sub 6}, were synthesized using a single step auto-ignition combustion process. The combustion product was single phase and composed of aggregates of nanocrystals of sizes in the range 20-50 nm. Ba{sub 2}TmSbO{sub 6} crystallized in cubic perovskite structure with lattice parameter, a = 8.4101 Angstrom-Sign . The polycrystalline fluffy combustion product was sintered to high density ({approx}97%) at {approx}1450 Degree-Sign C for 4 h. Resistivity of the sintered specimen was {approx}5 M{Omega}/cm. The Ba{sub 2}TmSbO{sub 6} has dielectric constant ({epsilon} Prime ) and dielectric loss (tan {delta}) of 17 and {approx}10{sup -4} at 5 MHz; the new material would probably be developed as a low-loss dielectric material.

Automated mapping of persistent ice and snow cover across the western U.S. with Landsat

Science.gov (United States)

Selkowitz, David J.; Forster, Richard R.

2016-01-01

We implemented an automated approach for mapping persistent ice and snow cover (PISC) across the conterminous western U.S. using all available Landsat TM and ETM+ scenes acquired during the late summer/early fall period between 2010 and 2014. Two separate validation approaches indicate this dataset provides a more accurate representation of glacial ice and perennial snow cover for the region than either the U.S. glacier database derived from US Geological Survey (USGS) Digital Raster Graphics (DRG) maps (based on aerial photography primarily from the 1960s–1980s) or the National Land Cover Database 2011 perennial ice and snow cover class. Our 2010–2014 Landsat-derived dataset indicates 28% less glacier and perennial snow cover than the USGS DRG dataset. There are larger differences between the datasets in some regions, such as the Rocky Mountains of Northwest Wyoming and Southwest Montana, where the Landsat dataset indicates 54% less PISC area. Analysis of Landsat scenes from 1987–1988 and 2008–2010 for three regions using a more conventional, semi-automated approach indicates substantial decreases in glaciers and perennial snow cover that correlate with differences between PISC mapped by the USGS DRG dataset and the automated Landsat-derived dataset. This suggests that most of the differences in PISC between the USGS DRG and the Landsat-derived dataset can be attributed to decreases in PISC, as opposed to differences between mapping techniques. While the dataset produced by the automated Landsat mapping approach is not designed to serve as a conventional glacier inventory that provides glacier outlines and attribute information, it allows for an updated estimate of PISC for the conterminous U.S. as well as for smaller regions. Additionally, the new dataset highlights areas where decreases in PISC have been most significant over the past 25–50 years.

Deforestation and Secondary Growth in Rondonia, Brazil from SIR-C SAR and Landsat.SPOT data

Science.gov (United States)

Rignot, Eric; Salas, William A.; Skole, David L.

1996-01-01

Covers problems with existing data collected with high-resolution optical sensors. They say active microwave sensors could complement other sensors in getting through things like cloud cover. They analyzed SIR-C data in combination with Landsat TM data, a 9-year time series of SPOT XS data, and a preliminary field survey. They report findings and draw conclusions, including that SARs operating at long radar wavelengths, with both like and cross-polarizations, are needed for tropical deforestation studies.

Laser-induced, Er3+ trace-sensitized red-to-blue photon avalanche up-conversion in Tm3+-doped LiKYF5 crystals

International Nuclear Information System (INIS)

Jouart, J P; Bouffard, M; Boulma, E; Diaf, M; Vojtenko, E N; Khaidukov, N M

2005-01-01

The results for a spectroscopic study demonstrating that the excited-state absorption(ESA) of Tm 3+ :LiKYF 5 at 648nm is dependent on the purity of starting materials used for synthesizing the crystal are presented. The Er 3+ -free LiKYF 5 crystal doped with Tm 3+ is transparent at 648 nm because the majority of the Tm 3+ ions are in the ground 3 H 6 state whatever the selective excitation intensity, whereas the Er 3+ -contaminated crystal is semi-transparent. In the second case a small increase of the excitation intensity above a certain threshold produces an abrupt enhancement of the ESA process at 648 nm as well as the blue and the green emissions that are detected. All three processes, namely ESA corresponding to the 3 F 4 (2) → 1 G 4 (2) Tm 3+ transition, the blue emission due to the 1 G 4 → 3 H 6 Tm 3+ transition and the green emission from the 4 S 3/2 Er 3+ level, are sensitized with the Tm 3+ → Er 3+ → Tm 3+ energy transfers which promote the conversion of Tm 3+ ions from the 1 G 4 and the 3 H 4 states to the metastable 3 F 4 state

Detection of land-use and land cover changes in Franklin, Gulf, and Liberty Counties, Florida, with multitemporal landsat thematic mapper images

Science.gov (United States)

Shufen Pan; Guiying Li

2007-01-01

Florida Panhandle region has been experiencing rapid land transformation in the recent decades. To quantify land use and land-cover (LULC) changes and other landscape changes in this area, three counties including Franklin, Liberty and Gulf were taken as a case study and an unsupervised classification approach implemented to Landsat TM images acquired from 1985 to 2005...

TREE AGE AS ADJUSTMENT FACTOR TO NDVI

OpenAIRE

Elias Fernando Berra; Denise Cybis Fontana; Tatiana Mora Kuplich

2018-01-01

ABSTRACT This study aimed to increase satellite-derived Normalized Difference Vegetation Index (NDVI) sensitivity to biophysical parameters changes with aid of a forest age-based adjustment factor. This factor is defined as a ratio between stand age and age of rotation, which value multiplied by Landsat-5/TM-derived NDVI generated the so-called adjusted index NDVI_a. Soil Adjusted Vegetation Index (SAVI) was also calculated. The relationship between these vegetation indices (VI) with Eucalypt...

Landsat 8 Operational Land Imager (OLI)_Thermal Infared Sensor (TIRS) V1

Data.gov (United States)

National Aeronautics and Space Administration — Abstract:The Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) are instruments onboard the Landsat 8 satellite, which was launched in February of...

Using Landsat 5 imagery in the assessment of groundwater resources in the crystalline rocks around Dutsin-Ma, northwestern Nigeria

International Nuclear Information System (INIS)

Bala, A. E.; Batelaan, O.; De Smedt, F.

2000-01-01

Landsat's TM imagery of January 1986 covering Dustin - Ma and the surrounding areas in northwestern Nigeria was used for the assessment of groundwater resources in the crystalline rocks (Basement Complex) terrain. Employing ER Mapper (5.2), surface indicator for the occurrence of groundwater such as thriving vegetation in non - irrigated lands, and fracture were identified. These were interpreted vis - a - vis the tectonic development of the are. Lineaments interpreted as fractures show two prominent strike maxima that lie between 0000 and 0300, with the more common lying between 0000 and 0100. These strike maxima correspond to the stress axis of the Pan African orogeny. The lushness of vegetation along these strikes is higher than in the neighbouring areas and indicate the presence of groundwater. On the basis of lineament density and relative lushness of the vegetal cover, the area was divided into three main hydrogeological zones namely, the zones with the highest, intermediate, and least groundwater potential, for which ground truthing is recommended for their confirmation. Geophysical surveys for the siting of boreholes are also recommended parallel to strikes between 270 o and 300 o . It is judged that the groundwater resource for this area is low because of the general lack of moist or seepage areas, the low threshold value. (0.12) of Normalized Difference Vegetation Index (NDVI), and the generally dispersed nature of the vegetation

An assessment of radiance in Landsat TM middle and thermal infrared wavebands for the detection of tropical forest regeneration

International Nuclear Information System (INIS)

Boyd, D.S.; Foody, G.M.; Curran, P.J.; Lucas, R.M.; Honzak, M.

1996-01-01

It has been postulated that tropical forests regenerating after deforestation constitute an unmeasured terrestrial sink of atmospheric carbon, and that the strength of this sink is a function of regeneration stage. Such regeneration stages can be characterized by biophysical properties, such as leaf and wood biomass, which influence the radiance emitted and/or reflected from the forest canopy. Remotely sensed data can therefore be used to estimate these biophysical properties and thereby determine the forest regenerative stage. Studies conducted on temperate forests have related biophysical properties successfully with red and near-infrared radiance, particularly within the Normalized Difference Vegetation Index (NDVI). However, only weak correlations have generally been observed for tropical forests and it is suggested here that the relationship between forest biophysical properties and middle and thermal infrared radiance may be stronger than that between those properties and visible and near-infrared radiance.An assessment of Landsat Thematic Mapper (TM) data revealed that radiance acquired in middle and thermal infrared wavebands contained significant information for the detection of regeneration stages in Amazonian tropical forests. It was demonstrated that tropical forest regeneration stages were most separable using middle infrared and thermal infrared wavebands and that the correlation with regeneration stage was stronger with middle infrared, thermal infrared or combinations of these wavebands than they were with visible, near infrared or combinations of these wavebands. For example, correlation coefficients increased from — 0·26 (insignificant at 95 per cent confidence level) when using the NDVI, to up to 0·93 (significant at 99 per cent confidence level) for a vegetation index containing data acquired in the middle and thermal infrared wavebands. These results point to the value of using data acquired in middle and thermal infrared wavebands for the

Stratifying FIA Ground Plots Using A 3-Year Old MRLC Forest Cover Map and Current TM Derived Variables Selected By "Decision Tree" Classification

Science.gov (United States)

Michael Hoppus; Stan Arner; Andrew Lister

2001-01-01

A reduction in variance for estimates of forest area and volume in the state of Connecticut was accomplished by stratifying FIA ground plots using raw, transformed and classified Landsat Thematic Mapper (TM) imagery. A US Geological Survey (USGS) Multi-Resolution Landscape Characterization (MRLC) vegetation cover map for Connecticut was used to produce a forest/non-...

The global Landsat archive: Status, consolidation, and direction

Science.gov (United States)

Wulder, Michael A.; White, Joanne C.; Loveland, Thomas; Woodcock, Curtis; Belward, Alan; Cohen, Warren B.; Fosnight, Eugene A.; Shaw, Jerad; Masek, Jeffery G.; Roy, David P.

2016-01-01

New and previously unimaginable Landsat applications have been fostered by a policy change in 2008 that made analysis-ready Landsat data free and open access. Since 1972, Landsat has been collecting images of the Earth, with the early years of the program constrained by onboard satellite and ground systems, as well as limitations across the range of required computing, networking, and storage capabilities. Rather than robust on-satellite storage for transmission via high bandwidth downlink to a centralized storage and distribution facility as with Landsat-8, a network of receiving stations, one operated by the U.S. government, the other operated by a community of International Cooperators (ICs), were utilized. ICs paid a fee for the right to receive and distribute Landsat data and over time, more Landsat data was held outside the archive of the United State Geological Survey (USGS) than was held inside, much of it unique. Recognizing the critical value of these data, the USGS began a Landsat Global Archive Consolidation (LGAC) initiative in 2010 to bring these data into a single, universally accessible, centralized global archive, housed at the Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The primary LGAC goals are to inventory the data held by ICs, acquire the data, and ingest and apply standard ground station processing to generate an L1T analysis-ready product. As of January 1, 2015 there were 5,532,454 images in the USGS archive. LGAC has contributed approximately 3.2 million of those images, more than doubling the original USGS archive holdings. Moreover, an additional 2.3 million images have been identified to date through the LGAC initiative and are in the process of being added to the archive. The impact of LGAC is significant and, in terms of images in the collection, analogous to that of having had twoadditional Landsat-5 missions. As a result of LGAC, there are regions of the globe that now have markedly improved

Mapping fractional woody cover in semi-arid savannahs using multi-seasonal composites from Landsat data

Science.gov (United States)

Higginbottom, Thomas P.; Symeonakis, Elias; Meyer, Hanna; van der Linden, Sebastian

2018-05-01

Increasing attention is being directed at mapping the fractional woody cover of savannahs using Earth-observation data. In this study, we test the utility of Landsat TM/ ETM-based spectral-temporal variability metrics for mapping regional-scale woody cover in the Limpopo Province of South Africa, for 2010. We employ a machine learning framework to compare the accuracies of Random Forest models derived using metrics calculated from different seasons. We compare these results to those from fused Landsat-PALSAR data to establish if seasonal metrics can compensate for structural information from the PALSAR signal. Furthermore, we test the applicability of a statistical variable selection method, the recursive feature elimination (RFE), in the automation of the model building process in order to reduce model complexity and processing time. All of our tests were repeated at four scales (30, 60, 90, and 120 m-pixels) to investigate the role of spatial resolution on modelled accuracies. Our results show that multi-seasonal composites combining imagery from both the dry and wet seasons produced the highest accuracies (R2 = 0.77, RMSE = 9.4, at the 120 m scale). When using a single season of observations, dry season imagery performed best (R2 = 0.74, RMSE = 9.9, at the 120 m resolution). Combining Landsat and radar imagery was only marginally beneficial, offering a mean relative improvement of 1% in accuracy at the 120 m scale. However, this improvement was concentrated in areas with lower densities of woody coverage (continue to exploit the Landsat archive, but should aim to use multi-seasonal derived information. When the coarser 120 m pixel scale is adequate, integration of Landsat and SAR data should be considered, especially in areas with lower woody cover densities. The use of multiple seasonal compositing periods offers promise for large-area mapping of savannahs, even in regions with a limited historical Landsat coverage.

Landsat-based monitoring of crop water demand in the San Joaquin Valley

Science.gov (United States)

Johnson, L.; Trout, T.; Wang, D.; Melton, F. S.

2010-12-01

Fresh water resources are becoming increasingly scarce in California due to urbanization, environmental regulation, and groundwater depletion. The strain is projected to worsen under various climate change scenarios and is exacerbated by declining water delivery infrastructure. It is estimated that irrigated agriculture currently commands more than 70% of the state’s water supply, and many growers are striving to improve water use efficiency in order to help maintain the state’s rich agricultural heritage. Remote sensing technology offers the potential to monitor cropland evapotranspiration (ET) regionally, while making farm-based irrigation scheduling more practical, convenient, and possibly more accurate. Landsat5-TM imagery was used in this study to monitor basal crop evapotranspiration (ETcb), which is primarily related to plant transpiration, for several San Joaquin Valley fields throughout the 2008 growing season. A ground-based digital camera was used to measure fractional cover of 48 study fields planted to 18 different crop types (row crops, grains, orchard, and vineyard) of varying maturity over 12 dates coinciding with Landsat overpasses. Landsat L1T terrain-corrected images were atmospherically corrected to surface reflectance by an implementation of the Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS), then converted to normalized difference vegetation index (NDVI) on a per-pixel basis. A strong linear relationship between NDVI and fractional cover was observed (r2=0.96), and a resulting conversion equation was used to transform all imagery to fractional cover. Conversion equations previously developed by use of weighting lysimeters were then used to transform fractional cover to basal crop coefficient (Kcb; ratio of crop transpiration plus a small diffusive soil evaporation component to reference ET). Finally, measurements of grass reference ET (ETo) from the California Irrigation Management Information System were used to

Water Feature Extraction and Change Detection Using Multitemporal Landsat Imagery

Directory of Open Access Journals (Sweden)

Komeil Rokni

2014-05-01

Full Text Available Lake Urmia is the 20th largest lake and the second largest hyper saline lake (before September 2010 in the world. It is also the largest inland body of salt water in the Middle East. Nevertheless, the lake has been in a critical situation in recent years due to decreasing surface water and increasing salinity. This study modeled the spatiotemporal changes of Lake Urmia in the period 2000–2013 using the multi-temporal Landsat 5-TM, 7-ETM+ and 8-OLI images. In doing so, the applicability of different satellite-derived indexes including Normalized Difference Water Index (NDWI, Modified NDWI (MNDWI, Normalized Difference Moisture Index (NDMI, Water Ratio Index (WRI, Normalized Difference Vegetation Index (NDVI, and Automated Water Extraction Index (AWEI were investigated for the extraction of surface water from Landsat data. Overall, the NDWI was found superior to other indexes and hence it was used to model the spatiotemporal changes of the lake. In addition, a new approach based on Principal Components of multi-temporal NDWI (NDWI-PCs was proposed and evaluated for surface water change detection. The results indicate an intense decreasing trend in Lake Urmia surface area in the period 2000–2013, especially between 2010 and 2013 when the lake lost about one third of its surface area compared to the year 2000. The results illustrate the effectiveness of the NDWI-PCs approach for surface water change detection, especially in detecting the changes between two and three different times, simultaneously.

Landsat Remote Sensing Data as an Alternative Approach for ...

African Journals Online (AJOL)

Rungwe Volcanic Province (RVP) is mostly covered by extrusive rocks that overlain the Precambrian basement. The use of Landsat data in this area has revealed the need of effective use of these data in geological mapping programs in Tanzania. Landsat band ratios 5/1, 3/7, 5/7 and 5/4 as well as R: G: B composite ...

Determining the area of influence of depression cone in the vicinity of lignite mine by means of triangle method and LANDSAT TM/ETM+ satellite images.

Science.gov (United States)

Zawadzki, Jarosław; Przeździecki, Karol; Miatkowski, Zygmunt

2016-01-15

Problems with lowering of water table are common all over the world. Intensive pumping of water from aquifers for consumption, irrigation, industrial or mining purposes often causes groundwater depletion and results in the formation of cone of depression. This can severely decrease water pressure, even over vast areas, and can create severe problems such as degradation of agriculture or natural environment sometimes depriving people and animals of water supply. In this paper, the authors present a method for determining the area of influence of a groundwater depression cone resulting from prolonged drainage, by means of satellite images in optical, near infrared and thermal infrared bands from TM sensor (Thematic Mapper) and ETM+ sensor (Enhanced Thematic Mapper +) placed on Landsat 5 and Landsat 7 satellites. The research area was Szczercowska Valley (Pol. Kotlina Szczercowska), Central Poland, located within a range of influence of a groundwater drainage system of the lignite coal mine in Belchatow. It is the biggest lignite coal mine in Poland and one of the largest in Europe exerting an enormous impact on the environment. The main method of satellite data analysis for determining soil moisture, was the so-called triangle method. This method, based on TVDI (Temperature Vegetation Dryness Index) was supported by additional spatial analysis including ordinary kriging used in order to combine fragmentary information obtained from areas covered by meadows. The results obtained are encouraging and confirm the usefulness of the triangle method not only for soil moisture determination but also for assessment of the temporal and spatial changes in the area influenced by the groundwater depression cone. The range of impact of the groundwater depression cone determined by means of above-described remote sensing analysis shows good agreement with that determined by ground measurements. The developed satellite method is much faster and cheaper than in-situ measurements

LBA-ECO LC-24 Landsat ETM+ Forest Cover Classification, Uruara, Para, Brazil: 1999

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set contains a 1999 Landsat ETM+ mosaic image land of cover classification showing forested and deforestation areas in Uruara, Para, Brazil. This...

Landsat Data Continuity Mission

Science.gov (United States)

,

2012-01-01

The Landsat Data Continuity Mission (LDCM) is a partnership formed between the National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS) to place the next Landsat satellite in orbit in January 2013. The Landsat era that began in 1972 will become a nearly 41-year global land record with the successful launch and operation of the LDCM. The LDCM will continue the acquisition, archiving, and distribution of multispectral imagery affording global, synoptic, and repetitive coverage of the Earth's land surfaces at a scale where natural and human-induced changes can be detected, differentiated, characterized, and monitored over time. The mission objectives of the LDCM are to (1) collect and archive medium resolution (30-meter spatial resolution) multispectral image data affording seasonal coverage of the global landmasses for a period of no less than 5 years; (2) ensure that LDCM data are sufficiently consistent with data from the earlier Landsat missions in terms of acquisition geometry, calibration, coverage characteristics, spectral characteristics, output product quality, and data availability to permit studies of landcover and land-use change over time; and (3) distribute LDCM data products to the general public on a nondiscriminatory basis at no cost to the user.

Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

Science.gov (United States)

Potter, Christopher S.

2014-01-01

A detailed geographic record of recent vegetation regrowth and disturbance patterns in forests of the Sierra Nevada remains a gap that can be filled with remote sensing data. Landsat (TM) imagery was analyzed to detect 10 years of recent changes (between 2000 and 2009) in forest vegetation cover for areas burned by wildfires between years of 1995 to 1999 in the region. Results confirmed the prevalence of regrowing forest vegetation during the period 2000 and 2009 over 17% of the combined burned areas.

Landsat Program

Science.gov (United States)

Markham, Brian L.; Arvidson, Terry; Barsi, Julia A.; Choate, Michael; Kaita, Edward; Levy, Raviv; Lubke, Mark; Masek, Jeffrey G.

2016-01-01

Landsat initiated the revolution in moderate resolution Earth remote sensing in the 1970s. With seven successful missions over 40+ years, Landsat has documented - and continues to document - the global Earth land surface and its evolution. The Landsat missions and sensors have evolved along with the technology from a demonstration project in the analog world of visual interpretation to an operational mission in the digital world, with incremental improvements along the way in terms of spectral, spatial, radiometric and geometric performance as well as acquisition strategy, data availability, and products.

The influence of topography on the forest surface temperature retrieved from Landsat TM, ETM C and ASTER thermal channels

Czech Academy of Sciences Publication Activity Database

Hais, M.; Kučera, Tomáš

2009-01-01

Roč. 64, č. 6 (2009), s. 585-591 ISSN 0924-2716 Institutional research plan: CEZ:AV0Z60870520 Keywords : Landsat * surface temperature * topography Subject RIV: EH - Ecology, Behaviour Impact factor: 2.308, year: 2009

Judd–Ofelt analysis of spectra and experimental evaluation of laser performance of Tm3+ doped Lu2SiO5 crystal

International Nuclear Information System (INIS)

Yao Baoquan; Zheng Liangliang; Duan Xiaoming; Zhao Guangjun; Zong Yanhua

2008-01-01

This paper reports that the Tm 3+ :Lu 2 SiO 5 (Tm:LSO) crystal is grown by Czochralski technique. The room-temperature absorption spectra of Tm:LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd–Ofelt intensity parameters Ω 2 = 9.3155 × 10 −20 cm 2 , Ω 4 = 8.4103 × 10 −20 cm 2 ,Ω 6 = 1.5908 × 10 −20 cm 2 , the fluorescence lifetime is calculated to be 2.03 ms for 3 F 4 → 3 H 6 transition, and the integrated emission cross section is 5.81 × 10 −18 cm 2 . Room-temperature laser action near 2μm under diode pumping is experimentally evaluated in Tm:LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuous-wave maximum output power of 0.67 W. The emission wavelengths of Tm:LSO laser are centred around 2.06 μm with spectral bandwidth of ∼13.6 nm. (nuclear physics)

Landsat and agriculture—Case studies on the uses and benefits of Landsat imagery in agricultural monitoring and production

Science.gov (United States)

Leslie, Colin R.; Serbina, Larisa O.; Miller, Holly M.

2017-03-29

production. The USDA has been using Landsat imagery to monitor global agricultural production since the launch of Landsat 1 in 1972. Landsat imagery provides objective, global input for a number of USDA agricultural programs and plays an important role in economic and food security forecasting.U.S. Department of Agriculture—Satellite Imagery Archive.—Highlights a number of the experiences of the USDA in acquiring, sharing, and managing moderate resolution imagery to support the diversity of USDA operational programs. Private sector applications using Landsat imagery for agricultural management are discussed in the Landsat Imagery Use and Benefits in Field-Level Agricultural Production Management section of the report in the following subsections:Field-Level Management.—Provides an introduction to what field-level production management is and how it can be applied to agricultural management. This section explores the concept of zone mapping and how Landsat imagery can be used to identify different conditions within a field. The section also provides a case study of zone-mapping software, developed by GK Technology, Inc., that is used by numerous agricultural consultants.Putting Zone Maps to Work.—Highlights several case studies of private agricultural consultants who have been using Landsat imagery to develop zone maps for farmers. Landsat imagery is helping consultants and farmers optimize agricultural inputs, including fertilizer and seed, which leads to higher yield and economic return for the farmer.Increasing Yield.—Highlights the primary benefit of zone mapping using Landsat imagery. Using 5-year market average prices for a number of commodities, this section provides examples of how yield increases translate into higher returns for farmers.

A SMAP Supervised Classification of Landsat Images for Urban Sprawl Evaluation

Directory of Open Access Journals (Sweden)

Flavia Di Palma

2016-07-01

Full Text Available The negative impacts of land take on natural components and economic resources affect planning choices and territorial policies. The importance of land take monitoring, in Italy, has been only recently considered, but despite this awareness, in the great part of the country, effective monitoring and containment measures have not been started, yet. This research proposes a methodology to map and monitor land use changes. To this end, a time series from 1985–2010, based on the multi-temporal Landsat data Thematic Mapper (TM, has been analyzed in the Vulture Alto-Bradano area, a mountain zone of the Basilicata region (Southern Italy. Results confirm a double potentiality of using these data: on the one hand, the use of multi-temporal Landsat data allows going very back in time, producing accurate datasets that provide a phenomenon trend over time; on the other hand, these data can be considered a first experience of open data in the field of spatial information. The proposed methodology provides agencies, local authorities and practitioners with a valuable tool to implement monitoring actions. This represents the first step to pursue territorial governance methods based on sustainability, limiting the land take.

Mapping afforestation and its carbon stock using time-series Landsat stacks

Science.gov (United States)

Liu, L.; Wu, Y.

2015-12-01

The Three Norths Shelter Forest Programme (TNSFP) is the largest afforestation reconstruction project in the world. Remote sensing is a crucial tool to map land cover and cover changes, but it is still challenging to accurately quantify the plantation and its carbon stock from time-series satellite images. In this paper, the Yulin district, Shaanxi province, representing a typical afforestation area in the TNSFP region, was selected as the study area, and there were twenty-nine Landsat MSS/TM/ETM+ epochs were collected from 1974 to 2012 to reconstruct the forest changes and carbon stock in last 40 years. Firstly, the Landsat ground surface reflectance (GSR) images from 1974 to 2013 were collected and processed based on 6S atmospheric transfer code and a relative reflectance normalization algorithm. Subsequently, we developed a vegetation change tracking method to reconstruct the forest change history (afforestation and deforestation) from the dense time-series Landsat GSR images based on the integrated forest z-score (IFZ) model, and the afforestation age was successfully retrieved from the Landsat time-series stacks in the last forty years and shown to be consistent with the surveyed tree ages, with a RMSE value of 4.32 years and a determination coefficient (R²) of 0.824. Then, the AGB regression models were successfully developed by integrating vegetation indices and tree age. The simple ratio vegetation index (SR) is the best candidate of the commonly used vegetation indices for estimating forest AGB, and the forest AGB model was significantly improved using the combination of SR and tree age, with R² values from 0.50 to 0.727. Finally, the forest AGB images were mapped at eight epochs from 1985 to 2013 using SR and afforestation age. The total forest AGB in six counties of Yulin District increased by 20.8 G kg, from 5.8 G kg in 1986 to 26.6 G kg in 2013, a total increase of 360%. For the forest area since 1974, the forest AGB density increased from 15.72 t

Influence of Al on the magnetic properties of TmCo{sub 4}Al compound, a magnetic and neutron diffraction study

Energy Technology Data Exchange (ETDEWEB)

Laslo, A. [CNRS, Inst. Néel, F-38042 Grenoble (France); Univ. Grenoble Alpes, Inst. Néel, F-38042 Grenoble (France); Babes-Bolyai University, Faculty of Physics, 400084 Cluj-Napoca (Romania); Pop, V. [Babes-Bolyai University, Faculty of Physics, 400084 Cluj-Napoca (Romania); Isnard, O. [CNRS, Inst. Néel, F-38042 Grenoble (France); Univ. Grenoble Alpes, Inst. Néel, F-38042 Grenoble (France)

2015-03-25

Highlights: • The existence of a compensation temperature is found for TmCo{sub 4}Al. • The crystal structure and its thermal evolution are analysed by X-ray and neutron diffraction. • The ferrimagnetic magnetic structure of TmCo{sub 4}Al is established. • Magnetic properties are determined. • Significant coercivity is reported for TmCo{sub 4}Al. - Abstract: The structural and magnetic properties of the TmCo{sub 4}Al compound are presented as deduced from magnetic measurements, X-ray and neutron powder diffraction. The crystal structure is obtained in the light of Rietveld refinement of the neutron powder diffraction pattern. The symmetry of the CaCu{sub 5} structure is preserved and the Al atom is found to substitute the Co one exclusively on the 3g atomic position. Thermal expansion of the crystal lattice is reported, the temperature variation occurring mostly along the basal hexagonal plane. This compound exhibits a ferrimagnetic structure, the Tm and Co magnetic moments being coupled antiparallel. An ordering temperature of 511 K is found. The thermal dependence of the Tm magnetic moment is obtained down to 4 K. A compensation of the two sublattice magnetization is found at 75 K, a feature induced by the Al for Co substitution and not observed in the corresponding TmCo{sub 5} compound. Magnetization curves reveal large coercivity values at low temperature such as 2.48 T at 2 K.

Inventory and change detection of urban land cover in Illinois using Landsat Thematic Mapper data

International Nuclear Information System (INIS)

Cook, E.A.; Iverson, L.R.

1991-01-01

In order to provide information about urban forests and other vegetative land cover in Illinois cities, Landsat TM data from June 17, 1988, were classified for the Chicago metropolitan region and five urban areas of central Illinois. Ten land cover classes were identified, including three types of forestland, cropland, two grassland categories, two urban classes, water, and miscellaneous vegetation. The cities inventoried have a significantly higher proportion of forests and forested residential areas than the surrounding rural areas because of preservation measures and accruement of tree cover from landscaping. Short-term change in land cover for the Chicago region was also assessed by postclassification comparison of the 1988 data with similarly derived data from a June 3, 1985, TM scene. The largest single category of change in the six-county area was cropland to urban land use. A majority of cover loss was conversion of forested tracts to residential areas, and forest cover increase was negligible. 16 refs

ANALYSIS OF RELATIONSHIP BETWEEN URBAN HEAT ISLAND EFFECT AND LAND USE/COVER TYPE USING LANDSAT 7 ETM+ AND LANDSAT 8 OLI IMAGES

Directory of Open Access Journals (Sweden)

N. Aslan

2016-06-01

Full Text Available The main objectives of this study are (i to calculate Land Surface Temperature (LST from Landsat imageries, (ii to determine the UHI effects from Landsat 7 ETM+ (June 5, 2001 and Landsat 8 OLI (June 17, 2014 imageries, (iii to examine the relationship between LST and different Land Use/Land Cover (LU/LC types for the years 2001 and 2014. The study is implemented in the central districts of Antalya. Initially, the brightness temperatures are retrieved and the LST values are calculated from Landsat thermal images. Then, the LU/LC maps are created from Landsat pan-sharpened images using Random Forest (RF classifier. Normalized Difference Vegetation Index (NDVI image, ASTER Global Digital Elevation Model (GDEM and DMSP_OLS nighttime lights data are used as auxiliary data during the classification procedure. Finally, UHI effect is determined and the LST values are compared with LU/LC classes. The overall accuracies of RF classification results were computed higher than 88 % for both Landsat images. During 13-year time interval, it was observed that the urban and industrial areas were increased significantly. Maximum LST values were detected for dry agriculture, urban, and bareland classes, while minimum LST values were detected for vegetation and irrigated agriculture classes. The UHI effect was computed as 5.6 °C for 2001 and 6.8 °C for 2014. The validity of the study results were assessed using MODIS/Terra LST and Emissivity data and it was found that there are high correlation between Landsat LST and MODIS LST data (r2 = 0.7 and r2 = 0.9 for 2001 and 2014, respectively.

Non-equivalent role of TM2 gating hinges in heteromeric Kir4.1/Kir5.1 potassium channels.

Science.gov (United States)

Shang, Lijun; Tucker, Stephen J

2008-02-01

Comparison of the crystal structures of the KcsA and MthK potassium channels suggests that the process of opening a K(+) channel involves pivoted bending of the inner pore-lining helices at a highly conserved glycine residue. This bending motion is proposed to splay the transmembrane domains outwards to widen the gate at the "helix-bundle crossing". However, in the inwardly rectifying (Kir) potassium channel family, the role of this "hinge" residue in the second transmembrane domain (TM2) and that of another putative glycine gating hinge at the base of TM2 remain controversial. We investigated the role of these two positions in heteromeric Kir4.1/Kir5.1 channels, which are unique amongst Kir channels in that both subunits lack a conserved glycine at the upper hinge position. Contrary to the effect seen in other channels, increasing the potential flexibility of TM2 by glycine substitutions at the upper hinge position decreases channel opening. Furthermore, the contribution of the Kir4.1 subunit to this process is dominant compared to Kir5.1, demonstrating a non-equivalent contribution of these two subunits to the gating process. A homology model of heteromeric Kir4.1/Kir5.1 shows that these upper "hinge" residues are in close contact with the base of the pore alpha-helix that supports the selectivity filter. Our results also indicate that the highly conserved glycine at the "lower" gating hinge position is required for tight packing of the TM2 helices at the helix-bundle crossing, rather than acting as a hinge residue.

Change detection by the IR-MAD and kernel MAF methods in Landsat TM data covering a Swedish forest region

DEFF Research Database (Denmark)

Nielsen, Allan Aasbjerg; Olsson, Håkan

2010-01-01

Change over time between two 512 by 512 (25 m by 25 m pixels) multispectral Landsat Thematic Mapper images dated 6 June 1986 and 27 June 1988 respectively covering a forested region in northern Sweden, is here detected by means of the iteratively reweighted multivariate alteration detection (IR-M...

Landsat 7 - A challenge to America

Science.gov (United States)

Colvocoresses, Alden P.

Factors in favor of Landsat 7 are discussed; they include: reasonable cost, a base on which to examine global change, and the need for comprehensive and continuous satellite coverage of the earth at moderate (5-30 m) resolution, in view of various occurrences on the earth's surface, ranging from the Chernobyl disaster to deforestation to the Persian Gulf conflict. Attention is given to proposed parameters for Landsat 7 and suggested actions that should be taken by Congress, the Administration, and the public to implement this space program.

Estimation of land surface temperature based on satellite image data. Paper no. IGEC-1-117

International Nuclear Information System (INIS)

Torii, S.; Yano, T.; Iino, N.

2005-01-01

The aim of the present study is to predict a ground surface temperature (GST) of Kagoshima Prefecture in Kyushu Island, Japan, by using LANDSAT-5/TM and NOAA-11/AVHRR digital data. Image processing procedure is employed to aid in evaluating GST, in which the thermal images of AVHRR bands 4 and 5 are analysed. Emphasis is placed on the prediction accuracy of the existing atmospheric correlation equations taking the atmospheric attenuation effect into account, which are proposed by Tamba et. al., Bates and Diaz, and Sakkaida and Kawamura. It is disclosed that (I) the factor of the zenith angle need to be taken into account when the accurate GST is evaluated by using the atmospheric correction equations, (ii) that of Sakaida and Kawamura has better accuracy, (iii) LANDSAT-5/TM data contains a very high resolution level of the land, the estimated land surface temperature is higher than the measured value, and (iv) improved accuracy of the surface temperature is achieved if LANDSAT-5/TM data are used together with NOAA-11/AVHRR. (author)

Blue and green emissions with high color purity from nanocrystalline Ca2Gd8Si6O26:Ln (Ln = Tm or Er) phosphors

International Nuclear Information System (INIS)

Seeta Rama Raju, G.; Park, Jin Young; Jung, Hong Chae; Pavitra, E.; Moon, Byung Kee; Jeong, Jung Hyun; Yu, Jae Su; Kim, Jung Hwan; Choi, Haeyoung

2011-01-01

Graphical abstract: Highlights: → Nanocrystalline Ca 2 Gd 8 Si 6 O 26 (CGS):Tm 3+ and CGS:Er 3+ phosphors were prepared by solvothermal reaction method. → The visible luminescence properties of phosphors were investigated by exciting with ultraviolet (UV) or near-UV light and low voltage electron beam (0.5-5 kV). → The photoluminescence spectra of CGS:Tm 3+ under 359 nm excitation and CGS:Er 3+ under 380 nm excitation showed the strong blue ( 1 D 2 → 3 F 4 at 456 nm) and green ( 4 S 3/2 → 4 I 15/2 at 550 nm) colors with the color purity 87% and 96%, respectively → The low accelerating voltage cathodoluminescence spectra of CGS:Tm 3+ and CGS:Er 3+ showed the strong blue and green emissions with the high color purity 95% and 96%, respectively. → The obtained results are hint at the promising applications to produce high quality LEDs and FED devices. - Abstract: Blue and green light emissive nanocrystalline Ca 2 Gd 8 Si 6 O 26 (CGS):Tm 3+ and CGS:Er 3+ phosphors with high color purity were prepared by solvothermal reaction method. The structural and morphological properties of these phosphors were evaluated by the powder X-ray diffraction (XRD) and scanning electron microscopy, respectively. From the XRD results, Tm 3+ :CGS and Er 3+ :CGS phosphors had the characteristic peaks of oxyapatite in the hexagonal lattice structure. The visible luminescence properties of phosphors were obtained by ultraviolet (UV) or near-UV light and low voltage electron beam (0.5-5 kV) excitation. The photoluminescence and cathodoluminescence properties were investigated by changing the variation of Tm 3+ or Er 3+ concentrations and the acceleration voltage, respectively. The CGS:Tm 3+ phosphors exhibited the blue emission due to 1 D 2 → 3 F 4 transition, while the CGS:Er 3+ phosphors showed the green emission due to 4 S 3/2 → 4 I 15/2 transition. The color purity and chromaticity coordinates of the fabricated phosphors are comparable to or better than those of standard

NUCLEAR PHYSICS: Judd Ofelt analysis of spectra and experimental evaluation of laser performance of Tm3+ doped Lu2SiO5 crystal

Science.gov (United States)

Yao, Bao-Quan; Zheng, Liang-Liang; Duan, Xiao-Ming; Zhao, Guang-Jun; Zong, Yan-Hua

2008-10-01

This paper reports that the Tm3+:Lu2SiO5 (Tm:LSO) crystal is grown by Czochralski technique. The room-temperature absorption spectra of Tm:LSO crystal are measured on a b-cut sample with 4 at.% thulium. According to the obtained Judd-Ofelt intensity parameters Ω2 = 9.3155 × 10-20 cm2, Ω4 = 8.4103 × 10-20 cm2,Ω6 = 1.5908 × 10-20 cm2, the fluorescence lifetime is calculated to be 2.03 ms for 3F4 → 3H6 transition, and the integrated emission cross section is 5.81 × 10-18 cm2. Room-temperature laser action near 2μm under diode pumping is experimentally evaluated in Tm:LSO. An optical-optical conversion efficiency of 9.1% and a slope efficiency of 16.2% are obtained with continuous-wave maximum output power of 0.67 W. The emission wavelengths of Tm:LSO laser are centred around 2.06 μm with spectral bandwidth of ~13.6 nm.

Seasonal Variation of Colored Dissolved Organic Matter in Barataria Bay, Louisiana, Using Combined Landsat and Field Data

Directory of Open Access Journals (Sweden)

Ishan Joshi

2015-09-01

Full Text Available Coastal bays, such as Barataria Bay, are important transition zones between the terrigenous and marine environments that are also optically complex due to elevated amounts of particulate and dissolved constituents. Monthly field data collected over a period of 15 months in 2010 and 2011 in Barataria Bay were used to develop an empirical band ratio algorithm for the Landsat-5 TM that showed a good correlation with the Colored Dissolved Organic Matter (CDOM absorption coefficient at 355 nm (ag355 (R2 = 0.74. Landsat-derived CDOM maps generally captured the major details of CDOM distribution and seasonal influences, suggesting the potential use of Landsat imagery to monitor biogeochemistry in coastal water environments. An investigation of the seasonal variation in ag355 conducted using Landsat-derived ag355 as well as field data suggested the strong influence of seasonality in the different regions of the bay with the marine end members (lower bay experiencing generally low but highly variable ag355 and the freshwater end members (upper bay experiencing high ag355 with low variability. Barataria Bay experienced a significant increase in ag355 during the freshwater release at the Davis Pond Freshwater Diversion (DPFD following the Deep Water Horizon oil spill in 2010 and following the Mississippi River (MR flood conditions in 2011, resulting in a weak linkage to salinity in comparison to the other seasons. Tree based statistical analysis showed the influence of high river flow conditions, high- and low-pressure systems that appeared to control ag355 by ~28%, 29% and 43% of the time duration over the study period at the marine end member just outside the bay. An analysis of CDOM variability in 2010 revealed the strong influence of the MR in controlling CDOM abundance in the lower bay during the high flow conditions, while strong winds associated with cold fronts significantly increase CDOM abundance in the upper bay, thus revealing the important

Removal of cadmium, copper, nickel, cobalt and mercury from water by Apatite II{sup TM}: Column experiments

Energy Technology Data Exchange (ETDEWEB)

Oliva, Josep [Department of Mining Engineering and Natural Resou-rces, Universitat Politecnica de Catalunya, Bases de Manresa 61-73, 08242 Manresa, Catalonia (Spain); De Pablo, Joan [Department of Chemical Engineering, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Cortina, Jose-Luis, E-mail: jose.luis.cortina@upc.edu [Department of Chemical Engineering, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona, Catalonia (Spain); Water Technology Center, CETaqua, Paseo de los Tilos 3, 08034 Barcelona, Catalonia (Spain); Cama, Jordi; Ayora, Carlos [Institute of Environmental Assessment and Water Research, IDAEA, CSIC, Jordi Girona 18, 08034 Barcelona, Catalonia (Spain)

2011-10-30

Highlights: {yields} The efficiency of Apatite II{sup TM} increases as the acidity decreases, then the application of apatite-based materials for metal removal treatments should be restricted to slightly acid to neutral waters. {yields} Because of the preferred process of using phosphate ions to form metal-phosphate precipitates, the mixture with other sources of alkalinity, such as limestone, is proposed to extend the duration of Apatite II{sup TM}. {yields} Compared with other reactive materials such as limestone and caustic magnesia that exhibit a reduction of porosity Apatite II{sup TM} showed stable hydraulic performance. {yields} The extrapolation of the column durabilities to a 1-m-thick passive treatment suggests that the Apatite II{sup TM} filling can be active between 5 and 10 years for an inflow pH exceeding 5. - Abstract: Apatite II{sup TM}, a biogenic hydroxyapatite, was evaluated as a reactive material for heavy metal (Cd, Cu, Co, Ni and Hg) removal in passive treatments. Apatite II{sup TM} reacts with acid water by releasing phosphates that increase the pH up to 6.5-7.5, complexing and inducing metals to precipitate as metal phosphates. The evolution of the solution concentration of calcium, phosphate and metals together with SEM-EDS and XRD examinations were used to identify the retention mechanisms. SEM observation shows low-crystalline precipitate layers composed of P, O and M. Only in the case of Hg and Co were small amounts of crystalline phases detected. Solubility data values were used to predict the measured column experiment values and to support the removal process based on the dissolution of hydroxyapatite, the formation of metal-phosphate species in solution and the precipitation of metal phosphate. Cd{sub 5}(PO{sub 4}){sub 3}OH(s), Cu{sub 2}(PO{sub 4})OH(s), Ni{sub 3}(PO{sub 4}){sub 2}(s), Co{sub 3}(PO{sub 4}){sub 2}8H{sub 2}O(s) and Hg{sub 3}(PO{sub 4}){sub 2}(s) are proposed as the possible mineral phases responsible for the removal

Requirements, Science, and Measurements for Landsat 10 and Beyond: Perspectives from the Landsat Science Team

Science.gov (United States)

Crawford, C. J.; Masek, J. G.; Roy, D. P.; Woodcock, C. E.; Wulder, M. A.

2017-12-01

The U.S. Geological Survey (USGS) and NASA are currently prioritizing requirements and investing in technology options for a "Landsat 10 and beyond" mission concept as part of the Sustainable Land Imaging (SLI) architecture. Following the successful February 2013 launch of the Landsat 8, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) have now added over 1 million images to the USGS Landsat archive. The USGS and NASA support and co-lead a Landsat Science Team made up largely of university and government experts to offer independent insight and guidance of program activities and directions. The rapid development of Landsat 9 reflects, in part, strong input from the 2012-2017 USGS Landsat Science Team (LST). During the last two years of the LST's tenure, individual LST members and within LST team working groups have made significant contributions to Landsat 10 and beyond's science traceability and future requirements justification. Central to this input, has been an effort to identify a trade space for enhanced measurement capabilities that maintains mission continuity with eight prior multispectral instruments, and will extend the Landsat Earth observation record beyond 55+ years with an approximate launch date of 2027. The trade space is framed by four fundamental principles in remote sensing theory and practice: (1) temporal resolution, (2) spatial resolution, (3) radiometric resolution, and (4) spectral coverage and resolution. The goal of this communication is to provide a synopsis of past and present 2012-2017 LST contributions to Landsat 10 and beyond measurement science and application priorities. A particular focus will be to document the links between new science and societal benefit areas with potential technical enhancements to the Landsat mission.

Spatiotemporal Dynamics of Surface Water Extent from Three Decades of Seasonally Continuous Landsat Time Series at Subcontinental Scale

Science.gov (United States)

Tulbure, M. G.; Broich, M.; Stehman, Stephen V.

2016-06-01

Surface water is a critical resource in semi-arid areas. The Murray-Darling Basin (MDB) of Australia, one of the largest semi-arid basins in the world is aiming to set a worldwide example of how to balance multiple interests (i.e. environment, agriculture and urban use), but has suffered significant water shrinkages during the Millennium Drought (1999-2009), followed by extensive flooding. Baseline information and systematic quantification of surface water (SW) extent and flooding dynamics in space and time are needed for managing SW resources across the basin but are currently lacking. To synoptically quantify changes in SW extent and flooding dynamics over MDB, we used seasonally continuous Landsat TM and ETM+ data (1986 - 2011) and generic machine learning algorithms. We further mapped flooded forest at a riparian forest site that experienced severe tree dieback due to changes in flooding regime. We used a stratified sampling design to assess the accuracy of the SW product across time. Accuracy assessment yielded an overall classification accuracy of 99.94%, with producer's and user's accuracy of SW of 85.4% and 97.3%, respectively. Overall accuracy was the same for Landsat 5 and 7 data but user's and producer's accuracy of water were higher for Landsat 7 than 5 data and stable over time. Our validated results document a rapid loss in SW bodies. The number, size, and total area of SW showed high seasonal variability with highest numbers in winter and lowest numbers in summer. SW extent per season per year showed high interannual and seasonal variability, with low seasonal variability during the Millennium Drought. Examples of current uses of the new dataset will be presented and include (1) assessing ecosystem response to flooding with implications for environmental water releases, one of the largest investment in environment in Australia; (2) quantifying drivers of SW dynamics (e.g. climate, human activity); (3) quantifying changes in SW dynamics and

Application of 1-ethyl-3-(2,5-dihydro-4-(3,5-dimethyl-1H-pyrazol-4-yl) -5-oxo-1H-pyrazol-3-yl)thiourea as sensing material for construction of Tm3+-PVC membrane sensor

International Nuclear Information System (INIS)

Zamani, Hassan Ali; Feizyzadeh, Babak; Faridbod, Farnoush; Ganjali, Mohammad Reza

2011-01-01

A thulium(III) membrane sensor was made using 2% sodium tetraphenyl borate (NaTPB), 65% dibutylphthalate (DBP), 30% poly(vinyl chloride) (PVC) and 3% 1-ethyl-3-(2,5-dihydro-4-(3,5-dimethyl-1H-pyrazol-4-yl) -5-oxo-1H-pyrazol-3-yl)thiourea (ET) as an ionophore. Conductometric study shows selectivity of the Et toward Tm 3+ ions. Nernstian response of 19.6 ± 0.4 mV per decade of thulium concentration was observed, and the electrode worked well in concentration range of 1.0 x 10 -6 to 1.0 x 10 -2 mol L -1 with a lower detection limit (LDL) of 7.2 x 10 -7 mol L -1 , in a pH range of 4.3-10.4. The selectivity of the sensor over alkaline, alkaline earth, transition and heavy metal ions was also found to be in a satisfactory range. To check the analytical applicability of the proposed Tm 3+ sensor, it was successfully used as an indicator electrode in analysis of thulium in certified reference materials. - Research highlights: → This work reports development of polymeric membrane sensor for Tm3+ determination in certified reference materials. → The novelty of this work is based on the high affinity of the ionophore toward the Tm3+ ions which causes the high selectivity of the sensor. → The newly developed sensor is superior to the formerly reported Tm3+ sensors in terms of selectivity and detection limit.

Landsat and water: case studies of the uses and benefits of landsat imagery in water resources

Science.gov (United States)

Serbina, Larisa O.; Miller, Holly M.

2014-01-01

The Landsat program has been collecting and archiving moderate resolution earth imagery since 1972. The number of Landsat users and uses has increased exponentially since the enactment of a free and open data policy in 2008, which made data available free of charge to all users. Benefits from the information Landsat data provides vary from improving environmental quality to protecting public health and safety and informing decision makers such as consumers and producers, government officials and the public at large. Although some studies have been conducted, little is known about the total benefit provided by open access Landsat imagery. This report contains a set of case studies focused on the uses and benefits of Landsat imagery. The purpose of these is to shed more light on the benefits accrued from Landsat imagery and to gain a better understanding of the program’s value. The case studies tell a story of how Landsat imagery is used and what its value is to different private and public entities. Most of the case studies focus on the use of Landsat in water resource management, although some other content areas are included.

Estimation of watershed-level distributed forest structure metrics relevant to hydrologic modeling using LiDAR and Landsat

Science.gov (United States)

Varhola, Andrés; Coops, Nicholas C.

2013-04-01

SummaryA detailed characterization of vegetation structure is fundamental for physically-based hydrologic models to simulate various processes that determine rates of snow accumulation and ablation, evapotranspiration and water dynamics. However, major efforts focused on developing complex equations to describe hydrologic processes as a function of vegetation structure at the plot level have not been accompanied by corresponding attempts to adequately extrapolate these metrics over the wider landscape in order to parameterize fully-distributed models. Recent advances in remote sensing technologies offer alternatives to overcome these difficulties and therefore improve our capacity to monitor vegetation and hydrologic processes extensively. Airborne Laser Scanning (ALS) stands out as the most promising tool to provide detailed, 3-dimensional representations of vegetation from which a wide array of structural metrics can be estimated. On the other hand, moderate scale optical remote sensing imagery such as Landsat Thematic Mapper (TM) offers the capacity to extrapolate these metrics across the landscape by virtue of its spatial and temporal resolutions. Here we correlate ALS-derived forest cover (FC), tree height (H), leaf area index (LAI) and sky view-factor (SVF) - the four main structural parameters used by hydrologic models - with a suite of spectral indices obtained from six spectral bands of a Landsat 5 TM image. Despite numerous sources of variation that affect the relationships between 2-dimensional spectral indices and three-dimensional structural metrics, models to predict FC, H, LAI and SVF with reasonable accuracy were developed. The extrapolation of these variables across a watershed in British Columbia severely affected by insect disturbance resulted in highly-detailed 30 m spatial resolution maps and frequency distributions consistent with the natural variation ranges of each metric - a major improvement compared to traditional approaches that use

Whole-body retention studies of /sup 167/Tm--citrate. Estimation of radiation dose to humans from /sup 167/Tm--citrate

Energy Technology Data Exchange (ETDEWEB)

Hiraki, T; Ando, A [Kanazawa Univ. (Japan). School of Paramedicine; Mori, H; Ando, I; Sakamoto, K

1978-02-01

For the purpose of calculating absorbed dose to humans from /sup 167/Tm-citrate, the whole-body retention studies using 5 rats were carried out. Up to 40 days following intravenous injection of /sup 167/Tm-citrate, the whole-body counts were monitored with an animal counter. The whole-body retention curve was obtained with three exponential components. Namely, the 26% of the injected /sup 167/Tm-citrate had a biological half-time of 3.4 hours, 12.5% had a biological half-time of 99 hours and 61.5% had a biological half-time of 106 days. These results indicate, that three components consist of the rapid clearance from the kidneys, the retention in the liver and other soft tissues with relatively long half-time and the retention in the bones with long half-time. Based on these biological data and the MIRD Committee method, the average dose estimates to the bone and whole-body from intravenous administration of 1 mCi /sup 167/Tm-citrate were 7.08 rads and 1.28 rads, respectively.

Comparison of satellite imagery and infrared aerial photography as vegetation mapping methods in an arctic study area: Jameson Land, East Greenland

DEFF Research Database (Denmark)

Hansen, Birger Ulf; Mosbech, Anders

1994-01-01

Remote Sensing, vegetation mapping, SPOT, Landsat TM, aerial photography, Jameson Land, East Greenland......Remote Sensing, vegetation mapping, SPOT, Landsat TM, aerial photography, Jameson Land, East Greenland...

Spectroscopy and microchip laser operation of Tm, Ho:KYW crystals with different Ho concentrations

Science.gov (United States)

Gusakova, N. V.; Kurilchik, S. V.; Yasukevich, A. S.; Kisel, V. E.; Dashkevich, V. I.; Orlovich, V. A.; Pavlyuk, A. A.; Vatnik, S. M.; Bagaev, S. N.; Kuleshov, N. V.

2018-02-01

The spectroscopic properties of Tm, Ho:KYW crystals with different Ho concentrations were investigated. The diode-pumped microchip laser operation of Tm (5 at.%), Ho (0.5 at.%):KYW and Tm (5 at.%), Ho (1 at.%):KYW was demonstrated. The highest, to our knowledge, output power of 480 mW with slope efficiency of 31% for CW Tm (5 at.%), Ho (0.5 at.%):KYW microchip laser was obtained.

Effect of co-doping Tm3+ ions on the emission properties of Dy3+ ions in tellurite glasses

International Nuclear Information System (INIS)

Sasikala, T.; Rama Moorthy, L.; Mohan Babu, A.; Srinivasa Rao, T.

2013-01-01

The present work reports the absorption, photoluminescence and decay properties of singly doped Dy 3+ and co-doped Dy 3+ /Tm 3+ ions in TeO 2 +ZnO+K 2 O+CaO (TZKC) glasses prepared by the melt quenching technique. The glassy nature of the host glass has been confirmed by X-ray diffraction analysis and the primary vibrational modes were determined from the Raman spectrum. Judd–Ofelt (JO) analysis has been used to calculate the radiative transition rates, branching ratios and radiative lifetime of the emitting 4 F 9/2 state. The effect of co-doping of different concentrations of Tm 3+ ions on the emission properties of Dy 3+ ions has been investigated. The decay profiles of the 4 F 9/2 level were fitted to double exponential as well as Inokuti–Hirayama (IH) model to determine the energy transfer rates between Dy 3+ and Tm 3+ ions. The energy transfer rates found to increase with the increase of Tm 3+ ions concentration. The chromaticity coordinates and color purity of the emitted light for all glasses were determined. - Graphical abstract: The graphical abstract shows the emission spectra of Dy 3+ , Tm 3+ and Dy 3+ /Tm 3+ co-doped TZKC glasses recorded by exciting at 355 nm wavelength. - Highlights: • Zinc tellurite glasses doped with Dy 3+ , Tm 3+ and Dy 3+ /Tm 3+ ions were prepared. • XRD, DTA and Raman spectral measurements were recorded to know the nature of host. • Energy transfer occurs from Dy 3+ ions to Tm 3+ ions. • The color purity of the emitted light was determined

Spatiotemporal Built-up Land Density Mapping Using Various Spectral Indices in Landsat-7 ETM+ and Landsat-8 OLI/TIRS (Case Study: Surakarta City)

Science.gov (United States)

Risky, Yanuar S.; Aulia, Yogi H.; Widayani, Prima

2017-12-01

Spectral indices variations support for rapid and accurate extracting information such as built-up density. However, the exact determination of spectral waves for built-up density extraction is lacking. This study explains and compares the capabilities of 5 variations of spectral indices in spatiotemporal built-up density mapping using Landsat-7 ETM+ and Landsat-8 OLI/TIRS in Surakarta City on 2002 and 2015. The spectral indices variations used are 3 mid-infrared (MIR) based indices such as the Normalized Difference Built-up Index (NDBI), Urban Index (UI) and Built-up and 2 visible based indices such as VrNIR-BI (visible red) and VgNIR-BI (visible green). Linear regression statistics between ground value samples from Google Earth image in 2002 and 2015 and spectral indices for determining built-up land density. Ground value used amounted to 27 samples for model and 7 samples for accuracy test. The classification of built-up density mapping is divided into 9 classes: unclassified, 0-12.5%, 12.5-25%, 25-37.5%, 37.5-50%, 50-62.5%, 62.5-75%, 75-87.5% and 87.5-100 %. Accuracy of built-up land density mapping in 2002 and 2015 using VrNIR-BI (81,823% and 73.235%), VgNIR-BI (78.934% and 69.028%), NDBI (34.870% and 74.365%), UI (43.273% and 64.398%) and Built-up (59.755% and 72.664%). Based all spectral indices, Surakarta City on 2000-2015 has increased of built-up land density. VgNIR-BI has better capabilities for built-up land density mapping on Landsat-7 ETM + and Landsat-8 OLI/TIRS.

Crystalline phase, profile characteristics and spectroscopic properties of Er3+/Tm3+-diffusion-codoped LiNbO3 crystal

International Nuclear Information System (INIS)

Sun, Wen-Bao; Zhang, Zi-Bo; Sun, Hong-Xue; Wong, Wing-Han; Yu, Dao-Yin; Pun, Edwin Yue-Bun

2017-01-01

Er 3+ /Tm 3+ -codoped LiNbO 3 crystal was prepared by co-diffusion of stacked Er and Tm metal films coated onto surface of off-congruent, Li-deficient LiNbO 3 substrate produced by Li-poor vapor transport equilibration technique. The crystalline phase on the diffused surface was analyzed by X-ray single-crystal diffraction. The Er 3+ and Tm 3+ profile characteristics were studied by secondary ion mass spectrometry. The emission spectra were measured under the 980 or 795 nm wavelength excitation, and the emission and absorption cross section spectra were calculated based upon McCumber theory. The lifetimes of some emissions were measured. The results show that the Er 3+ and Tm 3+ ions presence is in the form of LiNbO 3 phase. Both ions obey to Gaussian profile with a diffusion depth 21.5 μm. In the codoping case, both ions keep their respective spectroscopic features of only doping case and do not affect each other. The codoping enables to combine the wavelength emissions of both ions and the resultant emission band in the telecommunication window around 1.5 μm is as wide as 150 nm, providing the possibility of S+C+L broadband amplification by employing commercial 980 and 795 nm laser diodes as the pump sources. The Er 3+ /Tm 3+ -codoped LN is a promising host material for integrated optics. - Graphical abstract: Er 3+ /Tm 3+ -codoped LiNbO 3 crystal was prepared by co-diffusion of stacked Er and Tm metal films. The crystalline phase, diffusion profile and cross section spectra of Er 3+ and Tm 3+ ions in the diffusion layer have been investigated. The results show that the presence of Er 3+ and Tm 3+ ions is in the LiNbO 3 phase. Both ions follow Gaussian profile with a diffusion depth 21.5 μm. Both ions keep their respective spectroscopic features of only doping case. Excited state absorption is the dominant process for 795-nm-upconvered fluorescence of Tm 3+ . The codoping enables to combine the wavelength emissions of both ions and provide the possibility of S

Landsat Science Team meeting: Winter 2015

Science.gov (United States)

Schroeder, Todd A.; Loveland, Thomas; Wulder, Michael A.; Irons, James R.

2015-01-01

The summer meeting of the joint U.S. Geological Survey (USGS)–NASA Landsat Science Team (LST) was held at the USGS’s Earth Resources Observation and Science (EROS) Center July 7-9, 2015, in Sioux Falls, SD. The LST co-chairs, Tom Loveland [EROS—Senior Scientist] and Jim Irons [NASA’s Goddard Space Flight Center (GSFC)—Landsat 8 Project Scientist], opened the three-day meeting on an upbeat note following the recent successful launch of the European Space Agency’s Sentinel-2 mission on June 23, 2015 (see image on page 14), and the news that work on Landsat 9 has begun, with a projected launch date of 2023.With over 60 participants in attendance, this was the largest LST meeting ever held. Meeting topics on the first day included Sustainable Land Imaging and Landsat 9 development, Landsat 7 and 8 operations and data archiving, the Landsat 8 Thermal Infrared Sensor (TIRS) stray-light issue, and the successful Sentinel-2 launch. In addition, on days two and three the LST members presented updates on their Landsat science and applications research. All presentations are available at landsat.usgs.gov/science_LST_Team_ Meetings.php.

Change Detection Analysis in Urban and Suburban Areas Using Landsat Thematic Mapper data: Case of Huntsville, Alabama

Science.gov (United States)

Kuan, Dana; Fahsi, A.; Steinfeld S.; Coleman, T.

1998-01-01

Two Landsat Thematic Mapper (TM) images, from July 1984 and July 1992, were used to identify land use/cover changes in the urban and suburban fringe of the city of Huntsville, Alabama. Image difference was the technique used to quantify the change between the two dates. The eight-year period showed a 16% change, mainly from agricultural lands to urban areas generated by the settlement of industrial, commercial, and residential areas. Visual analysis of the change map (i.e., difference image) supported this phenomenon by showing that most changes were occurring in the vicinity of the major roads and highways across the city.

TM0416, a Hyperthermophilic Promiscuous Nonphosphorylated Sugar Isomerase, Catalyzes Various C5 and C6 Epimerization Reactions.

Science.gov (United States)

Shin, Sun-Mi; Cao, Thinh-Phat; Choi, Jin Myung; Kim, Seong-Bo; Lee, Sang-Jae; Lee, Sung Haeng; Lee, Dong-Woo

2017-05-15

There is currently little information on nonphosphorylated sugar epimerases, which are of potential interest for producing rare sugars. We found a gene (the TM0416 gene) encoding a putative d-tagatose-3-epimerase-related protein from the hyperthermophilic bacterium Thermotoga maritima We overexpressed the TM0416 gene in Escherichia coli and purified the resulting recombinant protein for detailed characterization. Amino acid sequence alignment and a structural similarity search revealed that TM0416 is a putative nonphosphorylated sugar epimerase. The recombinant enzyme exhibited maximal C-3 epimerization of l-ribulose to l-xylulose at ∼80°C and pH 7 in the presence of 1 mM Mn 2+ In addition, this enzyme showed unusually high activity for the epimerization of d-tagatose to d-sorbose, with a conversion yield of 20% after 6 h at 80°C. Remarkably, the enzyme catalyzed the isomerization of d-erythrose or d-threose to d-erythrulose significantly, with conversion yields of 71% and 54.5%, respectively, after 6 h at 80°C at pH 7. To further investigate the substrate specificity of TM0416, we determined its crystal structures in complex with divalent metal ions and l-erythrulose at resolutions of 1.5 and 1.6 Å. Detailed inspection of the structural features and biochemical data clearly demonstrated that this metalloenzyme, with a freely accessible substrate-binding site and neighboring hydrophobic residues, exhibits different and promiscuous substrate preferences, compared with its mesophilic counterparts. Therefore, this study suggests that TM0416 can be functionally classified as a novel type of l-ribulose 3-epimerase (R3E) with d-erythrose isomerase activity. IMPORTANCE Rare sugars, which occur naturally in small amounts, have attracted considerable attention in the food and drug industries. However, there is little information on nonphosphorylated sugar epimerases, which might potentially be applied for the production of rare sugars. This study describes the

Suppression of vegetation in LANDSAT ETM+ remote sensing images

Science.gov (United States)

Yu, Le; Porwal, Alok; Holden, Eun-Jung; Dentith, Michael

2010-05-01

Vegetation cover is an impediment to the interpretation of multispectral remote sensing images for geological applications, especially in densely vegetated terrains. In order to enhance the underlying geological information in such terrains, it is desirable to suppress the reflectance component of vegetation. One form of spectral unmixing that has been successfully used for vegetation reflectance suppression in multispectral images is called "forced invariance". It is based on segregating components of the reflectance spectrum that are invariant with respect to a specific spectral index such as the NDVI. The forced invariance method uses algorithms such as software defoliation. However, the outputs of software defoliation are single channel data, which are not amenable to geological interpretations. Crippen and Blom (2001) proposed a new forced invariance algorithm that utilizes band statistics, rather than band ratios. The authors demonstrated the effectiveness of their algorithms on a LANDSAT TM scene from Nevada, USA, especially in open canopy areas in mixed and semi-arid terrains. In this presentation, we report the results of our experimentation with this algorithm on a densely to sparsely vegetated Landsat ETM+ scene. We selected a scene (Path 119, Row 39) acquired on 18th July, 2004. Two study areas located around the city of Hangzhou, eastern China were tested. One of them covers uninhabited hilly terrain characterized by low rugged topography, parts of the hills are densely vegetated; another one covers both inhabited urban areas and uninhabited hilly terrain, which is densely vegetated. Crippen and Blom's algorithm is implemented in the following sequential steps: (1) dark pixel correction; (2) vegetation index calculation; (3) estimation of statistical relationship between vegetation index and digital number (DN) values for each band; (4) calculation of a smooth best-fit curve for the above relationships; and finally, (5) selection of a target average DN

Mapping caribou habitat north of the 51st parallel in Québec using Landsat imagery

Directory of Open Access Journals (Sweden)

Stéphanie Chalifoux

2003-04-01

Full Text Available A methodology using Landsat Thematic Mapper (TM images and vegetation typology, based on lichens as the principal component of caribou winter diet, was developed to map caribou habitat over a large and diversified area of Northern Québec. This approach includes field validation by aerial surveys (helicopter, classification of vegetation types, image enhancement, visual interpretation and computer assisted mapping. Measurements from more than 1500 field sites collected over six field campaigns from 1989 to 1996 represented the data analysed in this study. As the study progressed, 14 vegetation classes were defined and retained for analyses. Vegetation classes denoting important caribou habitat included six classes of upland lichen communities (Lichen, Lichen-Shrub, Shrub-Lichen, Lichen-Graminoid-Shrub, Lichen-Woodland, Lichen-Shrub-Woodland. Two classes (Burnt-over area, Regenerating burnt-over area are related to forest fire, and as they develop towards lichen communities, will become important for caribou. The last six classes are retained to depict remaining vegetation cover types. A total of 37 Landsat TM scenes were geocoded and enhanced using two methods: the Taylor method and the false colour composite method (bands combination and stretching. Visual inter¬pretation was chosen as the most efficient and reliable method to map vegetation types related to caribou habitat. The 43 maps produced at the scale of 1:250 000 and the synthesis map (1:2 000 000 provide a regional perspective of caribou habitat over 1200 000 km2 covering the entire range of the George river herd. The numerical nature of the data allows rapid spatial analysis and map updating.

Application of 1-ethyl-3-(2,5-dihydro-4-(3,5-dimethyl-1H-pyrazol-4-yl) -5-oxo-1H-pyrazol-3-yl)thiourea as sensing material for construction of Tm{sup 3+}-PVC membrane sensor

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali, E-mail: haszamani@yahoo.com [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Feizyzadeh, Babak [Department of Applied Chemistry, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of); Faridbod, Farnoush; Ganjali, Mohammad Reza [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

2011-10-10

A thulium(III) membrane sensor was made using 2% sodium tetraphenyl borate (NaTPB), 65% dibutylphthalate (DBP), 30% poly(vinyl chloride) (PVC) and 3% 1-ethyl-3-(2,5-dihydro-4-(3,5-dimethyl-1H-pyrazol-4-yl) -5-oxo-1H-pyrazol-3-yl)thiourea (ET) as an ionophore. Conductometric study shows selectivity of the Et toward Tm{sup 3+} ions. Nernstian response of 19.6 {+-} 0.4 mV per decade of thulium concentration was observed, and the electrode worked well in concentration range of 1.0 x 10{sup -6} to 1.0 x 10{sup -2} mol L{sup -1} with a lower detection limit (LDL) of 7.2 x 10{sup -7} mol L{sup -1}, in a pH range of 4.3-10.4. The selectivity of the sensor over alkaline, alkaline earth, transition and heavy metal ions was also found to be in a satisfactory range. To check the analytical applicability of the proposed Tm{sup 3+} sensor, it was successfully used as an indicator electrode in analysis of thulium in certified reference materials. - Research highlights: {yields} This work reports development of polymeric membrane sensor for Tm3+ determination in certified reference materials. {yields} The novelty of this work is based on the high affinity of the ionophore toward the Tm3+ ions which causes the high selectivity of the sensor. {yields} The newly developed sensor is superior to the formerly reported Tm3+ sensors in terms of selectivity and detection limit.

Landsat eyes help guard the world's forests

Science.gov (United States)

Campbell, Jon

2017-03-03

SummaryThe Landsat program is a joint effort between the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA), but the partner agencies have distinct roles. NASA develops remote-sensing instruments and spacecraft, launches satellites, and validates their performance in orbit. The USGS owns and operates Landsat satellites in space and manages their data transmissions, including ground reception, archiving, product generation, and public distribution. In 2008, with support from the U.S. Department of the Interior, the USGS made its Landsat data free to anyone in the world.The current satellites in the Landsat program, Landsat 7 (launched in 1999) and Landsat 8 (launched in 2013), provide complete coverage of the Earth every eight days. A Landsat 9 satellite is scheduled for launch in late 2020.

A one year Landsat 8 conterminous United States study of spatial and temporal patterns of cirrus and non-cirrus clouds and implications for the long term Landsat archive.

Science.gov (United States)

Kovalskyy, V.; Roy, D. P.

2014-12-01

The successful February 2013 launch of the Landsat 8 satellite is continuing the 40+ year legacy of the Landsat mission. The payload includes the Operational Land Imager (OLI) that has a new 1370 mm band designed to monitor cirrus clouds and the Thermal Infrared Sensor (TIRS) that together provide 30m low, medium and high confidence cloud detections and 30m low and high confidence cirrus cloud detections. A year of Landsat 8 data over the Conterminous United States (CONUS), composed of 11,296 acquisitions, was analyzed comparing the spatial and temporal incidence of these cloud and cirrus states. This revealed (i) 36.5% of observations were detected with high confidence cloud with spatio-temporal patterns similar to those observed by previous Landsat 7 cloud analyses, (ii) 29.2% were high confidence cirrus, (iii) 20.9% were both high confidence cloud and high confidence cirrus, (iv) 8.3% were detected as high confidence cirrus but not as high confidence cloud. The results illustrate the value of the cirrus band for improved Landsat 8 terrestrial monitoring but imply that the historical CONUS Landsat archive has a similar 8% of undetected cirrus contaminated pixels. The implications for long term Landsat time series records, including the global Web Enabled Landsat Data (WELD) product record, are discussed.

Sealing ability of grar MTA AngelusTM, CPM TM and MBPc used as apical plugs

Directory of Open Access Journals (Sweden)

Fernando Accorsi Orosco

2008-02-01

Full Text Available This study evaluated the sealing ability of apical plugs fabricated with gray MTA AngelusTM sealer, CPM TM sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with an ISO 50 until an ISO 90 could be visualized 1 mm beyond the apex. After root canal preparation, the external surface of each root was rendered impermeable and roots were assigned to 3 experimental groups (n = 30, which received a 5-mm thick apical plug of gray MTA AngelusTM, CPM TM and MBPc, and two control groups (n=4. The remaining portion of the canal in the experimental groups was filled by the lateral condensation technique. The teeth of each group, properly identified, were fixed on utility wax by their crowns and were placed in plastic flasks, leaving the apex free and facing upward. The flasks were filled with 0.2% Rhodamine B solution, pH 7.0, so as to completely cover the root apex of all teeth. The sealing ability was analyzed by measuring 0.2% Rhodamine B leakage after all groups had been maintained in this solution for 48 hours. Data were analyzed statistically by Kruskal-Wallis test and Dunn test with a=5%. The results showed that, among the tested materials used for fabrication of apical plugs, MBPc sealer had the least amount of leakage with statistically significant difference (p<0.05.

Landsat 6 contract signed

Science.gov (United States)

Maggs, William Ward

A new agreement provides $220 million for development and construction of the Landsat 6 remote sensing satellite and its ground systems. The contract, signed on March 31, 1988, by the Department of Commerce (DOC) and the Earth Observation Satellite (EOSAT) Company of Lanham, Md., came just days after approval of DOC's Landsat commercialization plan by subcommittees of the House and Senate appropriations committees.The Landsat 6 spacecraft is due to be launched into orbit on a Titan II rocket in June 1991 from Vandenburg Air Force Base, Calif. The satellite will carry an Enhanced Thematic Mapper (ETM) sensor, an instrument sensitive to electromagnetic radiation in seven ranges or bands of wavelengths. The satellite's payload will also include the Sea Wide Field Sensor (Sea-WiFS), designed to provide information on sea surface temperature and ocean color. The sensor is being developed in a cooperative effort by EOSAT and the National Aeronautics and Space Administration (NASA). A less certain passenger is a proposed 5-m resolution, three-band sensor sensitive to visible light. EOSAT is trying to find both private financing for the device and potential buyers of the high-resolution imagery that it could produce. The company has been actively courting U.S. television networks, which have in the past used imagery from the European Système Probatoire d'Observation de la Terre (SPOT) satellite for news coverage.

Tetratricopeptide repeat domain 9A is an interacting protein for tropomyosin Tm5NM-1

International Nuclear Information System (INIS)

Cao, Shenglan; Ho, Gay Hui; Lin, Valerie CL

2008-01-01

Tetratricopeptide repeat domain 9A (TTC9A) protein is a recently identified protein which contains three tetratricopeptide repeats (TPRs) on its C-terminus. In our previous studies, we have shown that TTC9A was a hormonally-regulated gene in breast cancer cells. In this study, we found that TTC9A was over-expressed in breast cancer tissues compared with the adjacent controls (P < 0.00001), suggesting it might be involved in the breast cancer development process. The aim of the current study was to further elucidate the function of TTC9A. Breast samples from 25 patients including the malignant breast tissues and the adjacent normal tissues were processed for Southern blot analysis. Yeast-two-hybrid assay, GST pull-down assay and co-immunoprecipitation were used to identify and verify the interaction between TTC9A and other proteins. Tropomyosin Tm5NM-1 was identified as one of the TTC9A partner proteins. The interaction between TTC9A and Tm5NM-1 was further confirmed by GST pull-down assay and co-immunoprecipitation in mammalian cells. TTC9A domains required for the interaction were also characterized in this study. The results suggested that the first TPR domain and the linker fragment between the first two TPR domains of TTC9A were important for the interaction with Tm5NM-1 and the second and the third TPR might play an inhibitory role. Since the primary function of tropomyosin is to stabilize actin filament, its interaction with TTC9A may play a role in cell shape and motility. In our previous results, we have found that progesterone-induced TTC9A expression was associated with increased cell motility and cell spreading. We speculate that TTC9A acts as a chaperone protein to facilitate the function of tropomyosins in stabilizing microfilament and it may play a role in cancer cell invasion and metastasis

Use of LANDSAT data to define soil boundaries in Carroll County, Missouri

Science.gov (United States)

Davidson, S. E.

1981-01-01

Bands 4, 5 and 7 false color composite photographs were prepared using data from LANDSAT scenes acquired during April 1977 and April 1981 on computer compatible tapes, and these color composites were compared with band 7 black and white photographs prepared for the entire county. Delineations of soil boundaries at the soil association level were achieved using LANDSAT spectral reflectance data and slope maps for a portion of Carroll County, Missouri. Forty two spectral reflectance classes from April 1977 LANDSAT data were overlaid on digitized slope maps of nine USGS 7.5 minute series topographic quadrangle slope maps to achieve boundary delineations of the soil associations.

Perspective View with Landsat Overlay, Costa Rica

Science.gov (United States)

2002-01-01

This perspective view shows the Caribbean coastal plain of Costa Rica, with the Cordillera Central rising in the background and the Pacific Ocean in the distance. The prominent river in the center of the image is the Rio Sucio, which merges with the Rio Sarapiqui at the bottom of the image and eventually joins with Rio San Juan on the Nicaragua border.Like much of Central America, Costa Rica is generally cloud covered so very little satellite imagery is available. The ability of the Shuttle Radar Topography Mission (SRTM) instrument to penetrate clouds and make three-dimensional measurements will allow generation of the first complete high-resolution topographic map of the entire region. These data were used to generate the image.This three-dimensional perspective view was generated using elevation data from SRTM and an enhanced false-color Landsat 7 satellite image. Colors are from Landsat bands 5, 4, and 2 as red, green and blue, respectively. Topographic expression is exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, S.D.Elevation data used in this image was acquired by the SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices

An Effort to Map and Monitor Baldcypress Forest Areas in Coastal Louisiana, Using Landsat, MODIS, and ASTER Satellite Data

Science.gov (United States)

Spruce, Joseph P.; Sader, Steve; Smoot, James

2012-01-01

This presentation discusses a collaborative project to develop, test, and demonstrate baldcypress forest mapping and monitoring products for aiding forest conservation and restoration in coastal Louisiana. Low lying coastal forests in the region are being negatively impacted by multiple factors, including subsidence, salt water intrusion, sea level rise, persistent flooding, hydrologic modification, annual insect-induced forest defoliation, timber harvesting, and conversion to urban land uses. Coastal baldcypress forests provide invaluable ecological services in terms of wildlife habitat, forest products, storm buffers, and water quality benefits. Before this project, current maps of baldcypress forest concentrations and change did not exist or were out of date. In response, this project was initiated to produce: 1) current maps showing the extent and location of baldcypress dominated forests; and 2) wetland forest change maps showing temporary and persistent disturbance and loss since the early 1970s. Project products are being developed collaboratively with multiple state and federal agencies. Products are being validated using available reference data from aerial, satellite, and field survey data. Results include Landsat TM- based classifications of baldcypress in terms of cover type and percent canopy cover. Landsat MSS data was employed to compute a circa 1972 classification of swamp and bottomland hardwood forest types. Landsat data for 1972-2010 was used to compute wetland forest change products. MODIS-based change products were applied to view and assess insect-induced swamp forest defoliation. MODIS, Landsat, and ASTER satellite data products were used to help assess hurricane and flood impacts to coastal wetland forests in the region.

Landsat-8 Sensor Characterization and Calibration

Directory of Open Access Journals (Sweden)

Brian Markham

2015-02-01

Full Text Available Landsat-8 was launched on 11 February 2013 with two new Earth Imaging sensors to provide a continued data record with the previous Landsats. For Landsat-8, pushbroom technology was adopted, and the reflective bands and thermal bands were split into two instruments. The Operational Land Imager (OLI is the reflective band sensor and the Thermal Infrared Sensor (TIRS, the thermal. In addition to these fundamental changes, bands were added, spectral bandpasses were refined, dynamic range and data quantization were improved, and numerous other enhancements were implemented. As in previous Landsat missions, the National Aeronautics and Space Administration (NASA and United States Geological Survey (USGS cooperated in the development, launch and operation of the Landsat-8 mission. One key aspect of this cooperation was in the characterization and calibration of the instruments and their data. This Special Issue documents the efforts of the joint USGS and NASA calibration team and affiliates to characterize the new sensors and their data for the benefit of the scientific and application users of the Landsat archive. A key scientific use of Landsat data is to assess changes in the land-use and land cover of the Earth’s surface over the now 43-year record. [...

Generating Daily Synthetic Landsat Imagery by Combining Landsat and MODIS Data.

Science.gov (United States)

Wu, Mingquan; Huang, Wenjiang; Niu, Zheng; Wang, Changyao

2015-09-18

Owing to low temporal resolution and cloud interference, there is a shortage of high spatial resolution remote sensing data. To address this problem, this study introduces a modified spatial and temporal data fusion approach (MSTDFA) to generate daily synthetic Landsat imagery. This algorithm was designed to avoid the limitations of the conditional spatial temporal data fusion approach (STDFA) including the constant window for disaggregation and the sensor difference. An adaptive window size selection method is proposed in this study to select the best window size and moving steps for the disaggregation of coarse pixels. The linear regression method is used to remove the influence of differences in sensor systems using disaggregated mean coarse reflectance by testing and validation in two study areas located in Xinjiang Province, China. The results show that the MSTDFA algorithm can generate daily synthetic Landsat imagery with a high correlation coefficient (R) ranged from 0.646 to 0.986 between synthetic images and the actual observations. We further show that MSTDFA can be applied to 250 m 16-day MODIS MOD13Q1 products and the Landsat Normalized Different Vegetation Index (NDVI) data by generating a synthetic NDVI image highly similar to actual Landsat NDVI observation with a high R of 0.97.

Detecting long-term changes to vegetation in northern Canada using the Landsat satellite image archive

International Nuclear Information System (INIS)

Fraser, R H; Olthof, I; Carrière, M; Deschamps, A; Pouliot, D

2011-01-01

Analysis of coarse resolution (∼1 km) satellite imagery has provided evidence of vegetation changes in arctic regions since the mid-1980s that may be attributable to climate warming. Here we investigate finer-scale changes to northern vegetation over the same period using stacks of 30 m resolution Landsat TM and ETM + satellite images. Linear trends in the normalized difference vegetation index (NDVI) and tasseled cap indices are derived for four widely spaced national parks in northern Canada. The trends are related to predicted changes in fractional shrub and other vegetation covers using regression tree classifiers trained with plot measurements and high resolution imagery. We find a consistent pattern of greening (6.1–25.5% of areas increasing) and predicted increases in vascular vegetation in all four parks that is associated with positive temperature trends. Coarse resolution (3 km) NDVI trends were not detected in two of the parks that had less intense greening. A range of independent studies and observations corroborate many of the major changes observed.

Crystalline phase, profile characteristics and spectroscopic properties of Er{sup 3+}/Tm{sup 3+}-diffusion-codoped LiNbO{sub 3} crystal

Energy Technology Data Exchange (ETDEWEB)

Sun, Wen-Bao [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Zhang, Zi-Bo [Department of Engineering, Pierre and Marie Curie University (University of Paris VI), 4 place Jussieu, 75005 Paris (France); Sun, Hong-Xue [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Wong, Wing-Han, E-mail: eewhwong@cityu.edu.hk [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Yu, Dao-Yin [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education (Tianjin University), Tianjin 300072 (China); Pun, Edwin Yue-Bun [Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); and others

2017-04-15

Er{sup 3+}/Tm{sup 3+}-codoped LiNbO{sub 3} crystal was prepared by co-diffusion of stacked Er and Tm metal films coated onto surface of off-congruent, Li-deficient LiNbO{sub 3} substrate produced by Li-poor vapor transport equilibration technique. The crystalline phase on the diffused surface was analyzed by X-ray single-crystal diffraction. The Er{sup 3+} and Tm{sup 3+} profile characteristics were studied by secondary ion mass spectrometry. The emission spectra were measured under the 980 or 795 nm wavelength excitation, and the emission and absorption cross section spectra were calculated based upon McCumber theory. The lifetimes of some emissions were measured. The results show that the Er{sup 3+} and Tm{sup 3+} ions presence is in the form of LiNbO{sub 3} phase. Both ions obey to Gaussian profile with a diffusion depth 21.5 μm. In the codoping case, both ions keep their respective spectroscopic features of only doping case and do not affect each other. The codoping enables to combine the wavelength emissions of both ions and the resultant emission band in the telecommunication window around 1.5 μm is as wide as 150 nm, providing the possibility of S+C+L broadband amplification by employing commercial 980 and 795 nm laser diodes as the pump sources. The Er{sup 3+}/Tm{sup 3+}-codoped LN is a promising host material for integrated optics. - Graphical abstract: Er{sup 3+}/Tm{sup 3+}-codoped LiNbO{sub 3} crystal was prepared by co-diffusion of stacked Er and Tm metal films. The crystalline phase, diffusion profile and cross section spectra of Er{sup 3+} and Tm{sup 3+} ions in the diffusion layer have been investigated. The results show that the presence of Er{sup 3+} and Tm{sup 3+} ions is in the LiNbO{sub 3} phase. Both ions follow Gaussian profile with a diffusion depth 21.5 μm. Both ions keep their respective spectroscopic features of only doping case. Excited state absorption is the dominant process for 795-nm-upconvered fluorescence of Tm{sup 3+}. The

The role of upstream sequences in selecting the reading frame on tmRNA

Directory of Open Access Journals (Sweden)

Dewey Jonathan D

2008-06-01

Full Text Available Abstract Background tmRNA acts first as a tRNA and then as an mRNA to rescue stalled ribosomes in eubacteria. Two unanswered questions about tmRNA function remain: how does tmRNA, lacking an anticodon, bypass the decoding machinery and enter the ribosome? Secondly, how does the ribosome choose the proper codon to resume translation on tmRNA? According to the -1 triplet hypothesis, the answer to both questions lies in the unique properties of the three nucleotides upstream of the first tmRNA codon. These nucleotides assume an A-form conformation that mimics the codon-anticodon interaction, leading to recognition by the decoding center and choice of the reading frame. The -1 triplet hypothesis is important because it is the most credible model in which direct binding and recognition by the ribosome sets the reading frame on tmRNA. Results Conformational analysis predicts that 18 triplets cannot form the correct structure to function as the -1 triplet of tmRNA. We tested the tmRNA activity of all possible -1 triplet mutants using a genetic assay in Escherichia coli. While many mutants displayed reduced activity, our findings do not match the predictions of this model. Additional mutagenesis identified sequences further upstream that are required for tmRNA function. An immunoblot assay for translation of the tmRNA tag revealed that certain mutations in U85, A86, and the -1 triplet sequence result in improper selection of the first codon and translation in the wrong frame (-1 or +1 in vivo. Conclusion Our findings disprove the -1 triplet hypothesis. The -1 triplet is not required for accommodation of tmRNA into the ribosome, although it plays a minor role in frame selection. Our results strongly disfavor direct ribosomal recognition of the upstream sequence, instead supporting a model in which the binding of a separate ligand to A86 is primarily responsible for frame selection.

An assessment of land-use/land-cover change of Bistrishko branishte biosphere reserve using Landsat data

International Nuclear Information System (INIS)

Filchev, L; Feilong, L; Panayotov, M

2014-01-01

Land-Use/Land-Cover (LU/LC) change detection using satellite data has gained momentum with the advance of the pre-operational phase of regional and global earth observation programmes such as GEOS, GMES, and GOFC-GOLD to name but a few. Present study aims at revealing LU/LC change of Bistrishko branishte biosphere reserve using Landsat 5 TM and Landsat 7 ETM+ radiometer satellite data. The LU/LC classification of the study area is done for the period 2007-2012, and difference images, between LU/LC maps, have been created. The classification scheme follows CORINE2000 Level 3 with few additional classes introduced to map changes. The methods used in the study are geoinformation, cartography, and statistical. The results show that in effect of 2012 wildfire 0.72 km 2 from reserve territory was devastated. The temporal changes which are taking place after the 60 ha windthrow in 2001, the 200 ha bark-beetle outbreak in 2003–2011 and the wildfire from June 2012 were further investigated using ASD HH FS spectrometer in 2011. As a result the increase in '331 Broad-leaved forest' and '312 Coniferous forest' LU/LC classes is attributed to the increase of the territory of deciduous species after a large bark beetle outbreak, which took place between 2003 and 2011, which devastated most of the old Picea abies trees, while the decrease of 'Outbreak' and '332 Bare rock' LU/LC classes is mainly due to the wildfire which took place in June 2012

A novel high color purity blue-emitting phosphor: CaBi{sub 2}B{sub 2}O{sub 7}:Tm{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Li, Jiangong, E-mail: lijiangong01@gmail.com [Department of Electronic Science and Engineering, Huanghuai University, Zhumadian 463000 (China); Yan, Huifang [Department of Foreign Languages and Literature, Huanghuai University, Zhumadian 463000 (China); Yan, Fengmei [Department of Chemistry and Chemical Engineering, Huanghuai University, Zhumadian 463000 (China)

2016-07-15

Graphical abstract: - Highlights: • A series of Tm{sup 3+}-doped CaBi{sub 2}B{sub 2}O{sub 7} blue-emitting phosphors were prepared. • The optimum doping content of Tm{sup 3+} ions was found. • The critical distance and concentration quenching mechanism was discussed. • The color purity of as prepared sample was analyzed and compared. - Abstract: A series of Tm{sup 3+}-doped CaBi{sub 2−x}B{sub 2}O{sub 7}:xTm{sup 3+} (0.02 ≤ x ≤ 0.12) blue-emitting phosphors with high color purity were prepared by solid-state reaction method. The crystal structure and luminescence properties of the as-prepared phosphors were studied. This phosphor shows a satisfactory blue performance (peak at 453 nm) due to the {sup 1}D{sub 2} → {sup 3}F{sub 4} transition of Tm{sup 3+} excited by 357 nm light. Investigation of Tm{sup 3+} content dependent emission spectra indicates that x = 0.04 is the optimum doping content of Tm{sup 3+} ions in the CaBi{sub 2}B{sub 2}O{sub 7} host. The critical distance and the concentration quenching mechanism were also investigated. In particular, the color purity of as prepared sample was analyzed and the result shows that the color purity of CaBi{sub 2}B{sub 2}O{sub 7}:Tm{sup 3+} is higher than the commercial blue phosphor BaMgAl{sub 10}O{sub 17}:Eu{sup 2+} (BAM:Eu{sup 2+}) and the latest reported Tm{sup 3+} doped blue phosphors. The present work suggests that the CaBi{sub 2}B{sub 2}O{sub 7}:Tm{sup 3+} phosphor is a potential blue-emitting candidate for the application in the near-UV WLEDs.

Integrated Cu-based TM-pass polarizer using CMOS technology platform

KAUST Repository

Ng, Tien Khee

2010-01-01

A transverse-magnetic-pass (TM-pass) copper (Cu) polarizer is proposed and analyzed using the previously published two-dimensional Method-of-Lines beam-propagation model. The proposed polarizer exhibits a simulated high-pass filter characteristics, with TM0 and TE0 mode transmissivity of >70% and <5%, respectively, in the wavelength regime of 1.2-1.6 μm. The polarization extinction ratio (PER) given by 10 log10 (PTM0)/(PTE0) is +11.5 dB across the high-pass wavelength regime. To the best of the authors\\' knowledge, we report here the smallest footprint CMOS-platform compatible TM-polarizer.

∼2 μm fluorescence radiative dynamics and energy transfer between Er3+ and Tm3+ ions in silicate glass

International Nuclear Information System (INIS)

Li, Ming; Liu, Xueqiang; Guo, Yanyan; Hao, Wei; Hu, Lili; Zhang, Junjie

2014-01-01

Graphical abstract: - Highlights: • A Er 3+ /Tm 3+ co-doped silicate glass with good thermal stability (k gl = 0.402 for STE glass) is prepared. • Efficient ∼2 μm emission is observed under 808 nm and 980 nm laser excitation. • The glass structure and spectroscopic properties are confirmed by optical absorption, IR transmission, Raman and fluorescence studies. • The content of OH groups deceases efficiently after fluorine ions are introduced. • The energy transfer coefficient from Er 3+ to Tm 3+ in STFE glass is 13.39 × 10 −40 cm 6 /s. - Abstract: A Er 3+ /Tm 3+ co-doped silicate glass with good thermal stability is prepared by melt-quenching method. An efficient emission of ∼2 μm is observed under different selective laser excitations. The optical absorption and transmission spectra, Raman spectra, and emission spectra are tested to characterize ∼2 μm emission properties of Er 3+ /Tm 3+ co-doped silicate glasses and a reasonable energy transfer mechanism of ∼2 μm emission between Er 3+ and Tm 3+ ions is proposed. Based on the optical absorption spectra, the Judd–Ofelt parameters and radiative properties were calculated. Intense ∼2 μm emission is obtained from Er 3+ /Tm 3+ co-doped silicate glasses due to the efficient energy transfer from Er 3+ to Tm 3+ ions. The energy transfer coefficient from Er 3+ to Tm 3+ ions can reach as high as 13.39 × 10 −40 cm 6 /s. In addition, the population of the OH groups is decreased and the ∼2 μm emission is effectively enhanced with fluoride introduction. The emission property, together with good thermal property, indicates that Er 3+ /Tm 3+ co-doped silicate glass is a potential kind of laser glass for efficient ∼2 μm laser

Geospatial Method for Computing Supplemental Multi-Decadal U.S. Coastal Land-Use and Land-Cover Classification Products, Using Landsat Data and C-CAP Products

Science.gov (United States)

Spruce, J. P.; Smoot, James; Ellis, Jean; Hilbert, Kent; Swann, Roberta

2012-01-01

This paper discusses the development and implementation of a geospatial data processing method and multi-decadal Landsat time series for computing general coastal U.S. land-use and land-cover (LULC) classifications and change products consisting of seven classes (water, barren, upland herbaceous, non-woody wetland, woody upland, woody wetland, and urban). Use of this approach extends the observational period of the NOAA-generated Coastal Change and Analysis Program (C-CAP) products by almost two decades, assuming the availability of one cloud free Landsat scene from any season for each targeted year. The Mobile Bay region in Alabama was used as a study area to develop, demonstrate, and validate the method that was applied to derive LULC products for nine dates at approximate five year intervals across a 34-year time span, using single dates of data for each classification in which forests were either leaf-on, leaf-off, or mixed senescent conditions. Classifications were computed and refined using decision rules in conjunction with unsupervised classification of Landsat data and C-CAP value-added products. Each classification's overall accuracy was assessed by comparing stratified random locations to available reference data, including higher spatial resolution satellite and aerial imagery, field survey data, and raw Landsat RGBs. Overall classification accuracies ranged from 83 to 91% with overall Kappa statistics ranging from 0.78 to 0.89. The accuracies are comparable to those from similar, generalized LULC products derived from C-CAP data. The Landsat MSS-based LULC product accuracies are similar to those from Landsat TM or ETM+ data. Accurate classifications were computed for all nine dates, yielding effective results regardless of season. This classification method yielded products that were used to compute LULC change products via additive GIS overlay techniques.

Powernext Day-AheadTM. Powernext futuresTM. Activity report - 2004

International Nuclear Information System (INIS)

2004-01-01

The introduction of a power exchange in France is a direct response to the opening up of the European electricity markets. Powernext SA is a Multilateral Trading Facility in charge of managing the French power exchange through an optional and anonymous organised exchange offering: - Day-ahead contracts for the management of volume risk on Powernext Day-Ahead TM since 21 November 2001, - Medium term contracts for the management of price risk on Powernext Futures TM since 18 June 2004. This document is the 2004 activity report of Powernext SA, it presents the key figures of the power market and of Powernext in 2004: - Increasing volumes: Powernext Day-Ahead TM 's traded volumes increased by 89%, from 7.48 to 14.18 TWh. Powernext Futures TM kicks off to a promising debut with 12.86 TWh traded in less than 7 months. - Less volatile prices: During 2004, the base price averaged 28.13 euro/MWh, and the peak prices averaged 33.71 euro/MWh. Compared to 2003, these prices decreased by an average of 3.7% on base-load and 10.9% on peak-load. In comparison to the two previous years, the daily volatility has noticeably settled down with 27% on base-load and 37% on peak-load. - Increasing liquidity: 10 new members joined Powernext Day-Ahead TM in 2004. The activity level of the members remains very high as 89% of them trade on an actual daily basis during 2004. The market resiliency stays strong. In December, an additional market 50 MW order on each hour resulted in a balance price variation of only 0.16 euro/MWh, or 0.53% of this balance price. For a 100 MW order, the resiliency is 0.32 euro/MWh, or 1.07% of the balance price. Thus, in 2004, Powernext Day-Ahead TM consolidates its role as a short term reference price. Moreover, in 2004, Powernext launched a futures market, Powernext Futures TM . This new market segment proposes contracts tradable up to 2 years ahead of delivery

Scintillation characteristics of Tm3+ in Ca3(BO3)2 crystals

International Nuclear Information System (INIS)

Fujimoto, Yutaka; Yanagida, Takayuki; Yokota, Yuui; Kawaguchi, Noriaki; Fukuda, Kentaro; Totsuka, Daisuke; Watanabe, Kenichi; Yamazaki, Atsushi; Yoshikawa, Akira

2011-01-01

Basic optical properties and radiation responses of undoped, Tm 3+ 1.0% and 2.0% activated Ca 3 (BO 3 ) 2 (CBO) crystalline scintillator prepared by the micro-pulling down (μ-PD) method are reported. Tm 3+ : CBO crystals showed three weak absorption bands around 190, 260 and 350 nm, owing to the Tm 3+ 4f–4f transition. Strong blue luminescence peaks at 360 and 460 nm which are ascribed to the 1 D 2 – 3 H 6 and 1 D 2 – 3 F 4 transitions of Tm 3+ respectively were observed under 241 Am 5.5 MeV α-ray excitation. The scintillation light yield of 2.0% Tm 3+ -doped CBO crystal was evaluated to be about 250 ph/n from the 252 Cf excited pulse height spectrum.

Measurement of the 209Bi(n ,4 n )206Bi and 169Tm(n ,3 n )167Tm cross sections between 23.5 and 30.5 MeV relevant to reaction-in-flight neutron studies at the National Ignition Facility

Science.gov (United States)

Gooden, M. E.; Bredeweg, T. A.; Champine, B.; Combs, D. C.; Finch, S.; Hayes-Sterbenz, A.; Henry, E.; Krishichayan, Rundberg, R.; Tornow, W.; Wilhelmy, J.; Yeamans, C.

2017-08-01

At the National Ignition Facility, experiments are being performed to measure charged-particle stopping powers in the previously unexplored warm dense plasma regime. These measurements are done using reaction-in-flight (RIF) neutrons from an inertial confinement fusion system. RIF neutrons are produced with a continuum of energies up to 30 MeV. By making activation measurements utilizing threshold reactions for neutrons in the energy range of 15 Tm(n ,3 n )167Tm reaction has been used. However, in an effort to provide a secondary complimentary measurement, efforts are underway to make use of the 209Bi(n ,4 n )206Bi reaction, with a threshold of 22.5 MeV. The cross sections were measured at the 10 MV tandem Van De Graaff accelerator at the Triangle Universities Nuclear Laboratory with quasimonoenergetic neutrons between 23.5 and 30.5 MeV, where few previous measurements have been made. Cross-section data are compared to calculations and other available measurements.

The tmRDB and SRPDB resources

DEFF Research Database (Denmark)

Andersen, Ebbe Sloth; Rosenblad, Magnus Alm; Larsen, Niels

2006-01-01

Maintained at the University of Texas Health Science Center at Tyler, Texas, the tmRNA database (tmRDB) is accessible at the URL http://psyche.uthct.edu/dbs/tmRDB/tmRDB.html with mirror sites located at Auburn University, Auburn, Alabama (http://www.ag.auburn.edu/mirror/tmRDB/) and the Royal...

Comparative analysis of different sensor data (Landsat-TM and MOMS) for earth observation and impact on future sensor development

International Nuclear Information System (INIS)

Bodechtel, J.; Zilger, J.; Salomonson, V.V.

1986-01-01

The missions of the German Modular Optoelectronic Multispectral Scanner (MOMS) aboard two flights of the United States Space Transportation System STS demonstrated the feasibility of a novel concept with regard to both technical and scientific objectives. On account of the successful missions a cooperative study was instituted for comparing MOMS observations with the more familiar operational Landsat-Thematic Mapper data over selected testsites as a means of obtaining some relative measure of performance. This paper summarizes the results obtained and presents the MOMS-02

Magnetic ordering in TmGa

DEFF Research Database (Denmark)

Cadogan, J.M.; Stewart, G.A.; Muños Pérez, S.

2014-01-01

We have determined the magnetic structure of the intermetallic compound TmGa by high-resolution neutron powder diffraction and 169Tm Mössbauer spectroscopy. This compound crystallizes in the orthorhombic (Cmcm) CrB-type structure and its magnetic structure is characterized by magnetic order...... of the Tm sublattice along the a-axis. The initial magnetic ordering occurs at 15(1) K and yields an incommensurate antiferromagnetic structure described by the propagation vector k1 = [0 0.275(2) 0]. At 12 K the dominant ferromagnetic ordering of the Tm sublattice along the a-axis develops in what appears...... to be a first-order transition. At 3 K the magnetic structure of TmGa is predominantly ferromagnetic but a weakened incommensurate component remains. The ferromagnetic Tm moment reaches 6.7(2) μB at 3 K and the amplitude of the remaining incommensurate component is 2.7(4) μB. The 169Tm hyperfine magnetic field...

IceTrendr: a linear time-series approach to monitoring glacier environments using Landsat

Science.gov (United States)

Nelson, P.; Kennedy, R. E.; Nolin, A. W.; Hughes, J. M.; Braaten, J.

2017-12-01

Arctic glaciers in Alaska and Canada have experienced some of the greatest ice mass loss of any region in recent decades. A challenge to understanding these changing ecosystems, however, is developing globally-consistent, multi-decadal monitoring of glacier ice. We present a toolset and approach that captures, labels, and maps glacier change for use in climate science, hydrology, and Earth science education using Landsat Time Series (LTS). The core step is "temporal segmentation," wherein a yearly LTS is cleaned using pre-processing steps, converted to a snow/ice index, and then simplified into the salient shape of the change trajectory ("temporal signature") using linear segmentation. Such signatures can be characterized as simple `stable' or `transition of glacier ice to rock' to more complex multi-year changes like `transition of glacier ice to debris-covered glacier ice to open water to bare rock to vegetation'. This pilot study demonstrates the potential for interactively mapping, visualizing, and labeling glacier changes. What is truly innovative is that IceTrendr not only maps the changes but also uses expert knowledge to label the changes and such labels can be applied to other glaciers exhibiting statistically similar temporal signatures. Our key findings are that the IceTrendr concept and software can provide important functionality for glaciologists and educators interested in studying glacier changes during the Landsat TM timeframe (1984-present). Issues of concern with using dense Landsat time-series approaches for glacier monitoring include many missing images during the period 1984-1995 and that automated cloud mask are challenged and require the user to manually identify cloud-free images. IceTrendr is much more than just a simple "then and now" approach to glacier mapping. This process is a means of integrating the power of computing, remote sensing, and expert knowledge to "tell the story" of glacier changes.

Geologic mapping using LANDSAT data

Science.gov (United States)

Siegal, B. S.; Abrams, M. J.

1976-01-01

The feasibility of automated classification for lithologic mapping with LANDSAT digital data was evaluated using three classification algorithms. The two supervised algorithms analyzed, a linear discriminant analysis algorithm and a hybrid algorithm which incorporated the Parallelepiped algorithm and the Bayesian maximum likelihood function, were comparable in terms of accuracy; however, classification was only 50 per cent accurate. The linear discriminant analysis algorithm was three times as efficient as the hybrid approach. The unsupervised classification technique, which incorporated the CLUS algorithm, delineated the major lithologic boundaries and, in general, correctly classified the most prominent geologic units. The unsupervised algorithm was not as efficient nor as accurate as the supervised algorithms. Analysis of spectral data for the lithologic units in the 0.4 to 2.5 microns region indicated that a greater separability of the spectral signatures could be obtained using wavelength bands outside the region sensed by LANDSAT.

Translation-Memory (TM) Research

DEFF Research Database (Denmark)

Schjoldager, Anne Gram; Christensen, Tina Paulsen

2010-01-01

to be representative of the research field as a whole. Our analysis suggests that, while considerable knowledge is available about the technical side of TMs, more research is needed to understand how translators interact with TM technology and how TMs influence translators' cognitive translation processes.......  It is no exaggeration to say that the advent of translation-memory (TM) systems in the translation profession has led to drastic changes in translators' processes and workflow, and yet, though many professional translators nowadays depend on some form of TM system, this has not been the object...... of much research. Our paper attempts to find out what we know about the nature, applications and influences of TM technology, including translators' interaction with TMs, and also how we know it. An essential part of the analysis is based on a selection of empirical TM studies, which we assume...

Analysis of CMOS Compatible Cu-Based TM-Pass Optical Polarizer

KAUST Repository

Ng, Tien Khee

2012-02-10

A transverse-magnetic-pass (TM-pass) optical polarizer based on Cu complementary metal-oxide-semiconductor technology platform is proposed and analyzed using the 2-D method-of-lines numerical model. In designing the optimum configuration for the polarizer, it was found that the metal-insulator-metal (MIM) polarizer structure is superior compared to the insulator-metal-insulator polarizer structure due to its higher polarization extinction ratio (PER) and low insertion loss. An optimized MIM TM-pass polarizer exhibits simulated long wavelength pass filter characteristics of > ?1.2 ?m, with fundamental TM 0 and TE 0 mode transmissivity of >70% and <5%, respectively, and with PER ?11.5 dB in the wavelength range of 1.2-1.6 ?m. The subwavelength and submicrometer features of this TM-polarizer are potentially suitable for compact and low power photonics integrated circuit implementation on silicon-based substrates. © 1989-2012 IEEE.

Analysis of land degradation processes on a tiger bush plateau in South West Niger using MODIS and LANDSAT TM/ETM+ data

Science.gov (United States)

Fiorillo, Edoardo; Maselli, Fabio; Tarchiani, Vieri; Vignaroli, Patrizio

2017-10-01

Remote sensing digital image analysis has been applied to monitor land clearing and degradation processes on a plateau covered by tiger bush near Niamey in South West Niger, where signs of severe landscape degradation due to fuelwood supply have been observed in the last decades. A MODIS NDVI dataset (2000-2015) and five LANDSAT images (1986-2012) were used to identify spatial and temporal dynamics and to emphasize areas of greater degradation. The study indicates that the land clearing found by previous investigations in the second part of the 20th century is still ongoing, with a decreasing trend of MODIS NDVI values recorded in the period 2000-2015. This trend appeared to be linked to an increase in bare soil areas that was demonstrated by analysis of LANDSAT SAVI images. The investigation also indicated that rates of degradation are stronger in more deteriorated areas like those located nearer Niamey; degradation patterns also tend to increase from the inner areas to the edges of the plateau. These results attest to the urgency to develop effective environmental preservation policies and find alternative solutions for domestic energy supply.

Water Quality Determination of Küçükçekmece Lake, Turkey by Using Multispectral Satellite Data

Directory of Open Access Journals (Sweden)

Erhan Alparslan

2009-01-01

Full Text Available This study focuses on the analysis of the Landsat-5 TM + SPOT-Pan (1992, IRS-1C/D LISS + Pan (2000, and Landsat-5 TM (2006 satellite images that reflect the drastic land use/land cover changes in the Küçükçekmece Lake region, Istanbul. Landsat-5 TM satellite data dated 2006 was used for mapping water quality. A multiple regression analysis was carried out between the unitless planetary reflectance values derived from the satellite image and in situ water quality parameters chlorophyll a, total phosphorus, total nitrogen, turbidity, and biological and chemical oxygen demand measured at a number of stations homogenously distributed over the lake surface. The results of this study provided valuable information to local administrators on the water quality of Küçükçekmece Lake, which is a large water resource of the Istanbul Metropolitan Area. Results also show that such a methodology structured by use of reflectance values provided from satellite imagery, in situ water quality measurements, and basin land use/land cover characteristics obtained from images can serve as a powerful and rapid monitoring tool for the drinking water basins that suffer from rapid urbanization and pollution, all around the world.

Landsat-D thematic mapper simulator

Science.gov (United States)

Flanagan, G. F.; Tilton, E. L., III

The design and testing program for the airborne Landsat-D thematic-mapper simulator (TMS) is summarized. The TMS is intended to provide data similar enough to those expected from Landsat-D to facilitate the development of data-processing software. The design process comprised mainly modifications on the existing MSS-simulator fiber optics, dichroics, and detectors to provide 7-channel coverage of the 0.45-12.3-micron range at 60-deg angle of view, corresponding to a 418-element, 13.8-km-wide ground swath. The TMS is carried on a Lear 23 aircraft operating at 750 km/h and 12-m altitude and equipped with a 15.2-cm aerial mapping camera and a ground-updated inertial navigational system. Agricultural, forestry, and geological trial applications are reviewed, and some sample results are given. The significant improvements predicted for the Landsat-D thematic mapper (relative to the Landsat MSS) are seen as confirmed, with the possible exception of the 120-m-resolution version of channel 7.

Crystal growth and characterization of Tm doped mixed rare-earth aluminum perovskite

Energy Technology Data Exchange (ETDEWEB)

Totsuka, Daisuke, E-mail: totsuka@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Nihon Kessho Kogaku Co., Ltd., 810-5 Nobe-cho, Tatebayashi, Gunma 374-0047 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Sugiyama, Makoto; Fujimoto, Yutaka; Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

2012-04-15

Highlights: Black-Right-Pointing-Pointer (Lu{sub x}Gd{sub y}Y{sub 0.99-x-y}Tm{sub 0.01})AP single crystals were grown by the {mu}-PD method. Black-Right-Pointing-Pointer The grown crystals were single phase with perovskite structure (Pbnm). Significant segregation of Lu and Gd was detected in the growth direction. Black-Right-Pointing-Pointer Some absorption bands due to Tm{sup 3+}, Gd{sup 3+} and color centers were exhibited. Black-Right-Pointing-Pointer Radioluminescence spectra showed several emission peaks ascribed to Tm{sup 3+} and Gd{sup 3+}. -- Abstract: In this work, we present results of structural characterization and optical properties including radio luminescence of (Lu{sub x}Gd{sub y}Y{sub 0.99-x-y}Tm{sub 0.01})AP single crystal scintillators for (x, y) = (0.30, 0.19), (0, 0.19) and (0, 0) grown by the micro-pulling-down ({mu}-PD) method. The grown crystals were single phase materials with perovskite structure (Pbnm) as confirmed by XRD and had a good crystallinity. The distribution of the crystal constituents in growth direction was evaluated, and significant segregation of Lu and Gd was detected in (Lu{sub 0.30}Gd{sub 0.19}Y{sub 0.50}Tm{sub 0.01})AP sample. The crystals demonstrated 70% transmittance in visible wavelength range and some absorption bands due to Tm{sup 3+}, Gd{sup 3+} and color centers were exhibited in 190-900 nm. The radioluminescence measurement under X-ray irradiation demonstrated several emission peaks ascribed to 4f-4f transitions of Tm{sup 3+} and Gd{sup 3+}. The ratio of emission intensity in longer wavelength range was increased when Y was replaced by Lu or Gd.

NASA 3D Models: Landsat 7

Data.gov (United States)

National Aeronautics and Space Administration — The Landsat Program is a series of Earth-observing satellite missions jointly managed by NASA and the U.S. Geological Survey. Since 1972, Landsat satellites have...

Online Global Land Surface Temperature Estimation from Landsat

Directory of Open Access Journals (Sweden)

David Parastatidis

2017-11-01

Full Text Available This study explores the estimation of land surface temperature (LST for the globe from Landsat 5, 7 and 8 thermal infrared sensors, using different surface emissivity sources. A single channel algorithm is used for consistency among the estimated LST products, whereas the option of using emissivity from different sources provides flexibility for the algorithm’s implementation to any area of interest. The Google Earth Engine (GEE, an advanced earth science data and analysis platform, allows the estimation of LST products for the globe, covering the time period from 1984 to present. To evaluate the method, the estimated LST products were compared against two reference datasets: (a LST products derived from ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer, as higher-level products based on the temperature-emissivity separation approach; (b Landsat LST data that have been independently produced, using different approaches. An overall RMSE (root mean square error of 1.52 °C was observed and it was confirmed that the accuracy of the LST product is dependent on the emissivity; different emissivity sources provided different LST accuracies, depending on the surface cover. The LST products, for the full Landsat 5, 7 and 8 archives, are estimated “on-the-fly” and are available on-line via a web application.

Determination of dosimetric characteristics of OptiSeedTM a plastic brachytherapy 103Pd source

International Nuclear Information System (INIS)

Wang Zhonglu; Hertel, Nolan E.

2005-01-01

A new 103 Pd plastic brachytherapy source, OptiSeed TM Model 1032P, is being introduced by International Brachytherapy sa (IBt). Measurements of the dose distributions about the source were performed using LiF thermoluminescent dosimeters (TLD-100) in Virtual Water TM . MCNP5 calculations were performed to determine the dose distributions in Virtual Water TM and liquid water. The source dose rate constant, radial dose function, anisotropy function and anisotropy factor have been determined following the updated AAPM TG-43 recommendations. The measured dose rate constant in the Virtual Water TM phantom was determined to be 0.727±6.9% cGy h -1 U -1 , and the computed value is 0.716±2.1% cGy h -1 U -1 . The Monte-Carlo simulation yielded a dose rate constant of 0.665±2.1% cGy h -1 U -1 in water. The measured dose rate constant in water is 0.675±7.5% cGy h -1 U -1 . It is determined by multiplying the dose rate constant measured in the Virtual Water TM phantom with the ratio of the value calculated in water to that in Virtual Water TM . The average of the measured and calculated dose rate constant is 0.670±5.5% cGy h -1 U -1 . The radial dose functions of the new source were measured for distances ranging from 1 to 7 cm in a Virtual Water TM phantom. The anisotropy functions in Virtual Water TM phantom were measured for distances of 2, 3, 5, and 7 cm. The Monte-Carlo computed radial dose functions, anisotropy functions, and anisotropy factors in both Virtual Water TM phantom and water are reported

Crystal growth, spectroscopic and laser properties of Tm:LuAG crystal

Science.gov (United States)

Xu, X. D.; Wang, X. D.; Lin, Z. F.; Cheng, Y.; Li, D. Z.; Cheng, S. S.; Wu, F.; Zhao, Z. W.; Gao, C. Q.; Gao, M. W.; Xu, J.

2009-11-01

Tm:Lu3Al5O12 (Tm:LuAG) crystal was grown by the Czochralski method. The segregation coefficient was measured by Inductively Coupled Plasma Atomic Emission Spectrometer. The cell parameters were analyzed with X-ray powder diffraction experiments. The absorption and fluorescence spectra of Tm:LuAG crystal at room temperature were investigated. With a 20 W fiber-coupled diode laser as pump source, the continuous-wave (CW) laser action of Tm:LuAG crystal was demonstrated. The maximum output power at 2020 nm was obtained to be 3.04 W, and the slope efficiency was 25.3%.

2.05 xB5m emission properties and energy transfer mechanism of germanate glass doped with Ho3+, Tm3+, and Er3+

Science.gov (United States)

Xu, Rongrong; Wang, Meng; Tian, Ying; Hu, Lili; Zhang, Junjie

2011-03-01

A new GeO2-Ga2O3-Na2O-BaO-La2O3 germanate glass doped with Ho2O3, Tm2O3, and Er2O3 has been investigated for application as a laser material at the 2 μm region. The spectroscopic properties and energy transfer mechanisms of Ho3+ sensitized by Tm3+ and Er3+ are analyzed. Based on the measurement of absorption spectra, the Judd-Ofelt intensity parameters, radiation emission probability, branching ratio, and lifetime of Ho3+ are calculated to evaluate the spectroscopic properties. The maximum value of emission cross section of Ho3+ around 2.05 μm is 8.003×10-21 cm2, which indicates that the germanate glass may provide high gain as a good medium in high-power level laser system. It is also found that the 2.05 μm emission of Ho3+:5I7→5I8 can be greatly enhanced by adding the proper amount of Er2O3 and Tm2O3 under excitation at 808 nm. With the large energy transfer coefficient, the high efficient energy transfer process among Ho3+, Tm3+, and Er3+ ions is proven.

Remote sensing of the earth's surface; Proceedings of the Symposium 2, Topical Meeting, and Workshop I of the 27th COSPAR Plenary Meeting, Espoo, Finland, July 18-29, 1988

Science.gov (United States)

Salomonson, V. V. (Editor); Walter, L. S. (Editor); Maetzler, C. (Editor); Rott, H. (Editor)

1989-01-01

The present conference discusses topics in the spaceborne study of the earth's surface, crust, and lithosphere, recent results from SPOT and Landsat TM investigations, and microwave observations of snowpack and soil properties. Attention is given to airborne and satellite-borne gravimetry, stereoviewing from space, TM studies of volcanism and tectonism in central Mexico, remote sensing of volcanoes, the uses of SPOT in forest management, the tectonics of the central Andes, and the application of VLBI to crustal movement studies. Also discussed are Landsat TM band ratios for soil investigations, snow dielectric measurements, the microwave radiometry of snow, microwave signatures of bare soil, the estimation of Alpine snow properties from Landsat TM data, and an experimental study of vegetable canopy microwave emissions.

Analyzing spatial and temporal trends in Aboveground Biomass within the Acadian New England Forests using the complete Landsat Archive

Science.gov (United States)

Kilbride, J. B.; Fraver, S.; Ayrey, E.; Weiskittel, A.; Braaten, J.; Hughes, J. M.; Hayes, D. J.

2017-12-01

Forests within the New England states and Canadian Maritime provinces, here described as the Acadian New England (ANE) forests, have undergone substantial disturbances due to insect, fire, and anthropogenic factors. Through repeated satellite observations captures by USGS's Landsat program, 45 years of disturbance information can be incorporated into modeling efforts to better understand the spatial and temporal trends in forest above ground biomass (AGB). Using Google's Earth Engine, annual mosaics were developed for the ANE study area and then disturbance and recovery metrics were developed using the temporal segmentation algorithm VeRDET. Normalization procedures were developed to incorporate the Landsat Multispectral Scanner (MSS, 1972 - 1985) data alongside the modern era of Landsat Thematic Mapper (TM, 1984-2013), Enhanced Thematic Mapper plus (ETM+, 1999 - present), and Operational Land Imager (OLI, 2013- present) data products. This has enabled the creation of a dataset with an unprecedented spatial and temporal view of forest landscape change. Model training was performed using was the Forest Inventory Analysis (FIA) and New Brunswick Permanent Sample Plot data datasets. Modeling was performed using parametric techniques such as mixed effects models and non-parametric techniques such as k-NN imputation and generalized boosted regression. We compare the biomass estimate and model accuracy to other inventory and modeling studies produced within this study area. The spatial and temporal patterns of stock changes are analyzed against resource policy, land ownership changes, and forest management.

LBA-ECO ND-01 Watershed Deforestation from Landsat TM Series, Rondonia, Brazil: 1999

Data.gov (United States)

National Aeronautics and Space Administration — ABSTRACT: This data set provides estimates of watershed deforestation, as a proportion of the total area of watersheds, in Rondonia, Brazil for 1999. Deforestation...

Kansas Satellite Image Database (KSID) 2004-2005

Data.gov (United States)

Kansas Data Access and Support Center — The Kansas Satellite Image Database (KSID) 2004-2005 consists of terrain-corrected, precision rectified spring, summer, and fall Landsat 5 Thematic Mapper (TM)...

Thematic mapper data analysis

Science.gov (United States)

Settle, M.; Chavez, P.; Kieffer, H. H.; Everett, J. R.; Kahle, A. B.; Kitcho, C. A.; Milton, N. M.; Mouat, D. A.

1983-01-01

The geological applications of remote sensing technology are discussed, with emphasis given to the analysis of data from the Thematic Mapper (TM) instrument onboard the Landsat 4 satellite. The flight history and design characteristics of the Landsat 4/TM are reviewed, and some difficulties endountered in the interpretation of raw TM data are discussed, including: the volume of data; residual noise; detector-to-detector striping; and spatial misregistration between measurements. Preliminary results of several geological, lithological, geobotanical mapping experiments are presented as examples of the geological applications of the TM, and some areas for improving the guality of TM imagery are identified.

The accessibility in the external part of the TM5 of the glutamate transporter EAAT1 is conformationally sensitive during the transport cycle.

Directory of Open Access Journals (Sweden)

Xiuping Zhang

Full Text Available BACKGROUND: Excitatory amino acid transporter 1 (EAAT1 is a glutamate transporter which is a key element in the termination of the synaptic actions of glutamate. It serves to keep the extracellular glutamate concentration below neurotoxic level. However the functional significance and the change of accessibility of residues in transmembrane domain (TM 5 of the EAAT1 are not clear yet. METHODOLOGY/PRINCIPAL FINDINGS: We used cysteine mutagenesis with treatments with membrane-impermeable sulfhydryl reagent MTSET [(2-trimethylammonium methanethiosulfonate] to investigate the change of accessibility of TM5. Cysteine mutants were introduced from position 291 to 300 of the cysteine-less version of EAAT1. We checked the activity and kinetic parameters of the mutants before and after treatments with MTSET, furthermore we analyzed the effect of the substrate and blocker on the inhibition of the cysteine mutants by MTSET. Inhibition of transport by MTSET was observed in the mutants L296C, I297C and G299C, while the activity of K300C got higher after exposure to MTSET. V(max of L296C and G299C got lower while that of K300C got higher after treated by MTSET. The L296C, G299C, K300C single cysteine mutants showed a conformationally sensitive reactivity pattern. The sensitivity of L296C to MTSET was potentiated by glutamate and TBOA,but the sensitivity of G299C to MTSET was potentiated only by TBOA. CONCLUSIONS/SIGNIFICANCE: All these facts suggest that the accessibility of some positions of the external part of the TM5 is conformationally sensitive during the transport cycle. Our results indicate that some residues of TM5 take part in the transport pathway during the transport cycle.

Mapping and characterization of wheat stem rust resistance genes SrTm5 and Sr60 from Triticum monococcum.

Science.gov (United States)

Chen, Shisheng; Guo, Yan; Briggs, Jordan; Dubach, Felix; Chao, Shiaoman; Zhang, Wenjun; Rouse, Matthew N; Dubcovsky, Jorge

2018-03-01

The new stem rust resistance gene Sr60 was fine-mapped to the distal region of chromosome arm 5A m S, and the TTKSK-effective gene SrTm5 could be a new allele of Sr22. The emergence and spread of new virulent races of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici; Pgt), including the Ug99 race group, is a serious threat to global wheat production. In this study, we mapped and characterized two stem rust resistance genes from diploid wheat Triticum monococcum accession PI 306540. We mapped SrTm5, a previously postulated gene effective to Ug99, on chromosome arm 7A m L, completely linked to Sr22. SrTm5 displayed a different race specificity compared to Sr22 indicating that they are distinct. Sequencing of the Sr22 homolog in PI 306540 revealed a novel haplotype. Characterization of the segregating populations with Pgt race QFCSC revealed an additional resistance gene on chromosome arm 5A m S that was assigned the official name Sr60. This gene was also effective against races QTHJC and SCCSC but not against TTKSK (a Ug99 group race). Using two large mapping populations (4046 gametes), we mapped Sr60 within a 0.44 cM interval flanked by sequenced-based markers GH724575 and CJ942731. These two markers delimit a 54.6-kb region in Brachypodium distachyon chromosome 4 and a 430-kb region in the Chinese Spring reference genome. Both regions include a leucine-rich repeat protein kinase (LRRK123.1) that represents a potential candidate gene. Three CC-NBS-LRR genes were found in the colinear Brachypodium region but not in the wheat genome. We are currently developing a Bacterial Artificial Chromosome library of PI 306540 to determine which of these candidate genes are present in the T. monococcum genome and to complete the cloning of Sr60.

Tm-doped TiO2 and Tm2Ti2O7 pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase.

Science.gov (United States)

De Los Santos, Desiré M; Navas, Javier; Aguilar, Teresa; Sánchez-Coronilla, Antonio; Fernández-Lorenzo, Concha; Alcántara, Rodrigo; Piñero, Jose Carlos; Blanco, Ginesa; Martín-Calleja, Joaquín

2015-01-01

Tm-doped TiO2 nanoparticles were synthesized using a water-controlled hydrolysis reaction. Analysis was performed in order to determine the influence of the dopant concentration and annealing temperature on the phase, crystallinity, and electronic and optical properties of the resulting material. Various characterization techniques were utilized such as X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and UV-vis spectroscopy. For the samples annealed at 773 and 973 K, anatase phase TiO2 was obtained, predominantly internally doped with Tm(3+). ICP-AES showed that a doping concentration of up to 5.8 atom % was obtained without reducing the crystallinity of the samples. The presence of Tm(3+) was confirmed by X-ray photoelectron spectroscopy and UV-vis spectroscopy: the incorporation of Tm(3+) was confirmed by the generation of new absorption bands that could be assigned to Tm(3+) transitions. Furthermore, when the samples were annealed at 1173 K, a pyrochlore phase (Tm2Ti2O7) mixed with TiO2 was obtained with a predominant rutile phase. The photodegradation of methylene blue showed that this pyrochlore phase enhanced the photocatalytic activity of the rutile phase.

Perspective View with Landsat Overlay, Salt Lake City, Utah

Science.gov (United States)

2002-01-01

Most of the population of Utah lives just west of the Wasatch Mountains in the north central part of the state. This broad east-northeastward view shows that region with the cities of Ogden, Salt Lake City, and Provo seen from left to right. The Great Salt Lake (left) and Utah Lake (right) are quite shallow and appear greenish in this enhanced natural color view. Thousands of years ago ancient Lake Bonneville covered all of the lowlands seen here. Its former shoreline is clearly seen as a wave-cut bench and/or light colored 'bathtub ring' at several places along the base of the mountain front - evidence seen from space of our ever-changing planet.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM), a Landsat 5 satellite image mosaic, and a false sky. Topographic expression is exaggerated four times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif

Landsat Science Team: 2017 Winter Meeting Summary

Science.gov (United States)

Schroeder, Todd A.; Loveland, Thomas; Wulder, Michael A.; Irons, James R.

2017-01-01

The summer meeting of the joint U.S. Geological Survey (USGS)-NASA Landsat Science Team (LST) was held July 26-28, 2016, at South Dakota State University (SDSU) in Brookings, SD. LST co-chair Tom Loveland [USGS’s Earth Resources Observation and Science Center (EROS)] and Kevin Kephart [SDSU] welcomed more than 80 participants to the three-day meeting. That attendance at such meetings continues to increase—likely due to the development of new data products and sensor systems—further highlights the growing interest in the Landsat program. The main objectives of this meeting were to provide a status update on Landsat 7 and 8, review team member research activities, and to begin identifying priorities for future Landsat missions.

Assessing the role of climate and resource management on groundwater dependent ecosystem changes in arid environments with the Landsat archive

Science.gov (United States)

Huntington, Justin; McGwire, Kenneth C.; Morton, Charles; Snyder, Keirith A.; Peterson, Sarah; Erickson, Tyler; Niswonger, Richard G.; Carroll, Rosemary W.H.; Smith, Guy; Allen, Richard

2016-01-01

Groundwater dependent ecosystems (GDEs) rely on near-surface groundwater. These systems are receiving more attention with rising air temperature, prolonged drought, and where groundwater pumping captures natural groundwater discharge for anthropogenic use. Phreatophyte shrublands, meadows, and riparian areas are GDEs that provide critical habitat for many sensitive species, especially in arid and semi-arid environments. While GDEs are vital for ecosystem services and function, their long-term (i.e. ~ 30 years) spatial and temporal variability is poorly understood with respect to local and regional scale climate, groundwater, and rangeland management. In this work, we compute time series of NDVI derived from sensors of the Landsat TM, ETM +, and OLI lineage for assessing GDEs in a variety of land and water management contexts. Changes in vegetation vigor based on climate, groundwater availability, and land management in arid landscapes are detectable with Landsat. However, the effective quantification of these ecosystem changes can be undermined if changes in spectral bandwidths between different Landsat sensors introduce biases in derived vegetation indices, and if climate, and land and water management histories are not well understood. The objective of this work is to 1) use the Landsat 8 under-fly dataset to quantify differences in spectral reflectance and NDVI between Landsat 7 ETM + and Landsat 8 OLI for a range of vegetation communities in arid and semiarid regions of the southwestern United States, and 2) demonstrate the value of 30-year historical vegetation index and climate datasets for assessing GDEs. Specific study areas were chosen to represent a range of GDEs and environmental conditions important for three scenarios: baseline monitoring of vegetation and climate, riparian restoration, and groundwater level changes. Google's Earth Engine cloud computing and environmental monitoring platform is used to rapidly access and analyze the Landsat archive

Detecting wetland changes in Shanghai, China using FORMOSAT and Landsat TM imagery

Energy Technology Data Exchange (ETDEWEB)

Tian, Bo; Zhou, Yun-xuan; Thom, Ronald M.; Diefenderfer, Heida L.; Yuan, Qing

2015-07-14

Understanding the state of wetland ecosystems and their changes at the national and local levels is critical for wetland conservation, management, decision-making, and policy development practices. This study analyzed the wetlands in Shanghai, a province-level city, using remote sensing, image processing, and geographic information systems (GIS) techniques based on the Chinese national wetland inventory procedure and standards. FORMOSAT imagery acquired in 2012 and Navy nautical charts of the Yangtze estuarine area were used in conjunction with object-oriented segmentation, expert interpretation, and field validation to determine wetland status. Landsat imagery from 1985, 1995, 2000, 2003 and 2013 as well as social-economic data collected from 1985 to 2013 were used to further assess wetland changes. In 2013, Shanghai contained 376,970.6 ha of wetlands, and 78.8% of all wetlands were in marine or estuarine systems. Estuarine waters comprised the single largest wetland category. Between the first national wetland inventory in 2003 and the second national wetland inventory in 2013, Shanghai lost 50,519.13 ha of wetlands, amounting to a mean annual loss rate of 1.2% or an 11.8% loss over the decade. Declines were proportionately higher in marine and estuarine wetlands, with an annual loss of 1.8%, while there was a sharp increase of 1882.6% in constructed water storage areas for human uses. Diking, filling, impoundment and reclamation, which are all attributable to the economic development and urbanization associated with population increases, were the major factors that explained the gain and loss of wetlands. Additional factors affecting wetland losses and gains include sediment trapping by the hydropower system, which reduces supply to the estuary and erodes wetlands, and sediment trapping by the jetties, spur dikes, and diversion bulwark associated with a navigation channel deepening project, which has the converse effect, increasing saltmarsh wetland area at

Multispectral Landsat images of Antartica

Energy Technology Data Exchange (ETDEWEB)

Lucchitta, B.K.; Bowell, J.A.; Edwards, K.L.; Eliason, E.M.; Fergurson, H.M.

1988-01-01

The U.S. Geological Survey has a program to map Antarctica by using colored, digitally enhanced Landsat multispectral scanner images to increase existing map coverage and to improve upon previously published Landsat maps. This report is a compilation of images and image mosaic that covers four complete and two partial 1:250,000-scale quadrangles of the McMurdo Sound region.

Perspective View with Landsat Overlay, Lakes Managua and Nicaragua

Science.gov (United States)

2002-01-01

This perspective view shows Lakes Managua and Nicaragua near the Pacific coast of Nicaragua. Lake Managua is the 65-kilometer (40-mile)-long fresh water lake in the foreground of this south-looking view, emptying via the Tipitapa River into the much larger Lake Nicaragua in the distance. The capital city of Managua, with a population of more than 500,000, is located along the southern shore of Lake Managua, the area with the highest population density in Nicaragua.The physical setting of Lake Managua is dominated by the numerous volcanic features aligned in a northwest-southeast axis. The cone-like feature in the foreground is Momotombo, a 1,280-meter (4,199-foot)-high stratovolcano located on the northwest end of the lake. Two water-filled volcanic craters (Apoyegue and Jiloa volcanoes) reside on the Chiltepe Peninsula protruding into the lake from the west. Two volcanoes can also be seen on the island of Ometepe in Lake Nicaragua: El Maderas rising to 1,394 meters (4,573 feet) and the active El Conception at 1,610 meters (5,282 feet).This three-dimensional perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) and an enhanced false-color Landsat 7 satellite image. Colors are from Landsat bands 5, 4, and 2 as red, green and blue, respectively. Topographic expression is exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, S.D.Elevation data used in this image was acquired by the SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar

The impact of landsat satellite monitoring on conservation biology.

Science.gov (United States)

Leimgruber, Peter; Christen, Catherine A; Laborderie, Alison

2005-07-01

Landsat 7's recent malfunctioning will result in significant gaps in long-term satellite monitoring of Earth, affecting not only the research of the Earth science community but also conservation users of these data. To determine whether or how important Landsat monitoring is for conservation and natural resource management, we reviewed the Landsat program's history with special emphasis on the development of user groups. We also conducted a bibliographic search to determine the extent to which conservation research has been based on Landsat data. Conservation biologists were not an early user group of Landsat data because a) biologists lacked technical capacity--computers and software--to analyze these data; b) Landsat's 1980s commercialization rendered images too costly for biologists' budgets; and c) the broad-scale disciplines of conservation biology and landscape ecology did not develop until the mid-to-late 1980s. All these conditions had changed by the 1990s and Landsat imagery became an important tool for conservation biology. Satellite monitoring and Landsat continuity are mandated by the Land Remote Sensing Act of 1992. This legislation leaves open commercial options. However, past experiments with commercial operations were neither viable nor economical, and severely reduced the quality of monitoring, archiving and data access for academia and the public. Future satellite monitoring programs are essential for conservation and natural resource management, must provide continuity with Landsat, and should be government operated.

High-power diode-end-pumped Tm:YLF slab laser delivering 189 W at 1890 nm

CSIR Research Space (South Africa)

Koen, W

2010-09-01

Full Text Available Laser Delivering 189 W at 1890 nm W. Koen, H.J. Strauss, C. Bollig and M.J.D. Esser CSIR National Laser Centre, Meiring Naude Road, Brummeria, Pretoria, 0001 wkoen@csir.co.za Abstract: We present a high-power Tm:YLF slab laser double...

PHMB: Utilización del apósito de espuma antimicrobiana (AMD KendallTM (PHMB 0,5% en el tratamiento de las heridas crónicas PHMB: The role ok KendallTM AMD Antimicrobial Foam Dressing (0.5% PHMB in the treatment of wounds

Directory of Open Access Journals (Sweden)

John Timmons

2010-03-01

Full Text Available Abordamos la parte más problemática del tratamiento de las heridas crónicas o agudas, de acuerdo con los profesionales especializados es la infección de la herida. La sobrecarga bacteriana puede retardar la curación de la herida y disminuir la calidad del paciente como consecuencia del aumento del dolor, del exudado y del posible mal olor. Se han recopilado casos clínicos durante los últimos 6 meses en una unidad especializada en el cuidado de heridas de los hospitales Doncaster y Bassetlaw, RU. Estos casos ilustran la variedad de tipos de herida que pueden tratarse con éxito con el nuevo apósito de Espuma antimicrobiano KendallTM AMD (PHMB 0,5%. Se pudo concluir que el apósito de Espuma KendallTM AMD actúa bien como antimicrobiano y como producto de vendaje moderno. Su utilización disminuye la carga bacteriana al tiempo que consigue la absorción del exudado y el mantenimiento de un ambiente óptimo para la curación de la herida.The most troublesome part of wound healing according to the care practitioners is the Wound infection. The presence of excess bacteria in the wound can lead to delayed healing that lead to a reduced quality of life for the patient due to increased pain, higher exudates levels and potential malodor. The following patient case report have been collated over the past six months in a specialist wound care clinic in Doncaster and Bassetlaw, UK. These cases illustrate the range of wound types that have been successfully treated with the new KendallTM AMD Antimicrobial Foam dressing (PHMB 0,5%. The conclusion was that KendallTM AMD Foam dressing functions well as an antimicrobial and a modern wound dressing product. This resulted in consistent lowering of the wound bioburden, absorption of exudates and maintenance of an optimal wound healing environment.

Filling Landsat ETM+ SLC-off gaps using a segmentation model approach

Science.gov (United States)

Maxwell, Susan

2004-01-01

The purpose of this article is to present a methodology for filling Landsat Scan Line Corrector (SLC)-off gaps with same-scene spectral data guided by a segmentation model. Failure of the SLC on the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instrument resulted in a loss of approximately 25 percent of the spectral data. The missing data span across most of the image with scan gaps varying in size from two pixels near the center of the image to 14 pixels along the east and west edges. Even with the scan gaps, the radiometric and geometric qualities of the remaining portions of the image still meet design specifications and therefore contain useful information (see http:// landsat7.usgs.gov for additional information). The U.S. Geological Survey EROS Data Center (EDC) is evaluating several techniques to fill the gaps in SLC-off data to enhance the usability of the imagery (Howard and Lacasse 2004) (PE&RS, August 2004). The method presented here uses a segmentation model approach that allows for same-scene spectral data to be used to fill the gaps. The segment model is generated from a complete satellite image with no missing spectral data (e.g., Landsat 5, Landsat 7 SLCon, SPOT). The model is overlaid on the Landsat SLC-off image, and the missing data within the gaps are then estimated using SLC-off spectral data that intersect the segment boundary. A major advantage of this approach is that the gaps are filled using spectral data derived from the same SLC-off satellite image.

[Application of small remote sensing satellite constellations for environmental hazards in wetland landscape mapping: taking Liaohe Delta, Liaoning Province of Northeast China as a case].

Science.gov (United States)

Yang, Yuan-Zheng; Chang, Yu; Hu, Yuan-Man; Liu, Miao; Li, Yue-Hui

2011-06-01

To timely and accurately acquire the spatial distribution pattern of wetlands is of significance for the dynamic monitoring, conservation, and sustainable utilization of wetlands. The small remote sensing satellite constellations A/B stars (HJ-1A/1B stars) for environmental hazards were launched by China for monitoring terrestrial resources, which could provide a new data source of remote sensing image acquisition for retrieving wetland types. Taking Liaohe Delta as a case, this paper compared the accuracy of wetland classification map and the area of each wetland type retrieved from CCD data (HJ CCD data) and TM5 data, and validated and explored the applicability and the applied potential of HJ CCD data in wetland resources dynamic monitoring. The results showed that HJ CCD data could completely replace Landsat TM5 data in feature extraction and remote sensing classification. In real-time monitoring, due to its 2 days of data acquisition cycle, HJ CCD data had the priority to Landsat TM5 data (16 days of data acquisition cycle).

Updating stand-level forest inventories using airborne laser scanning and Landsat time series data

Science.gov (United States)

Bolton, Douglas K.; White, Joanne C.; Wulder, Michael A.; Coops, Nicholas C.; Hermosilla, Txomin; Yuan, Xiaoping

2018-04-01

Vertical forest structure can be mapped over large areas by combining samples of airborne laser scanning (ALS) data with wall-to-wall spatial data, such as Landsat imagery. Here, we use samples of ALS data and Landsat time-series metrics to produce estimates of top height, basal area, and net stem volume for two timber supply areas near Kamloops, British Columbia, Canada, using an imputation approach. Both single-year and time series metrics were calculated from annual, gap-free Landsat reflectance composites representing 1984-2014. Metrics included long-term means of vegetation indices, as well as measures of the variance and slope of the indices through time. Terrain metrics, generated from a 30 m digital elevation model, were also included as predictors. We found that imputation models improved with the inclusion of Landsat time series metrics when compared to single-year Landsat metrics (relative RMSE decreased from 22.8% to 16.5% for top height, from 32.1% to 23.3% for basal area, and from 45.6% to 34.1% for net stem volume). Landsat metrics that characterized 30-years of stand history resulted in more accurate models (for all three structural attributes) than Landsat metrics that characterized only the most recent 10 or 20 years of stand history. To test model transferability, we compared imputed attributes against ALS-based estimates in nearby forest blocks (>150,000 ha) that were not included in model training or testing. Landsat-imputed attributes correlated strongly to ALS-based estimates in these blocks (R2 = 0.62 and relative RMSE = 13.1% for top height, R2 = 0.75 and relative RMSE = 17.8% for basal area, and R2 = 0.67 and relative RMSE = 26.5% for net stem volume), indicating model transferability. These findings suggest that in areas containing spatially-limited ALS data acquisitions, imputation models, and Landsat time series and terrain metrics can be effectively used to produce wall-to-wall estimates of key inventory attributes, providing an

TM-pass polarizer based on multilayer graphene polymer waveguide

Science.gov (United States)

Cai, Ke-su; Li, Yue-e.; Wei, Wen-jing; Mu, Xi-jiao; Ma, A.-ning; Wang, Zhong; Song, Dan-ming

2018-05-01

A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed. The mode properties, the extinction ratio, the insertion loss and the bandwidth are also discussed. The results show that a TM-pass polarizer, which only guides the TM mode, can be achieved by multilayer graphene polymer waveguide. With length of 150 μm, the proposed polarizer can achieve extinction ratio of 33 dB and insertion loss of 0.5 dB at optical wavelength of 1.55 μm. This device has an excellent performance, including large extinction ratio and low insertion loss within the spectral range from 1.45 μm to 1.6 μm.

Change detection using Landsat images and an analysis of the linkages between the change and property tax values in the Istanbul Province of Turkey.

Science.gov (United States)

Canaz, Sibel; Aliefendioğlu, Yeşim; Tanrıvermiş, Harun

2017-09-15

In this study, the Istanbul Province was monitored using Landsat 5 TM, MSS, Landsat 7 ETM+, and Landsat 8 OLI imagery from the years 1986, 2000, 2009, 2011, 2013, and 2015 in order to assess land cover changes in the province. The aim of the study was to classify manmade structures, land, green, and water areas, and to observe the changes in the province using satellite images. After classification, the images were compared in selected years to observe land cover. Moreover, these changes were correlated with the property tax values of Istanbul by years. The findings of the study showed that manmade structure areas increased while vegetation areas decreased due to rapid population growth, urbanization, and industrial and commercial development in Istanbul. These changes also explain the transformation of land from rural and natural areas to residential use, and serve as a tool with which to assess land value increments. Land value capturing is critical for the analysis of the linkages between the changes in land cover, and for assessing land transformation and urban growth. Due to inadequate market data, real estate tax values were used to analyze the linkages between detection changes, land cover, and taxation. In fact, the declared tax values of land owners are generally lower than the actual market values and therefore it is not possible to transfer the value increasing of land in urban areas by using property taxation from the owner to local and central governments. The research results also show that the integration of remote sensing results with real estate market data give us to determine the tax base values of real estate more realistically. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uso de imagens orbitais como base de dados para projetos de reforma agrária The use of orbital images as subsidies to agrarian reform projects

Directory of Open Access Journals (Sweden)

Marina de Fátima Vilela

2005-08-01

Full Text Available Análises técnica e econômica foram realizadas em imagens dos sensores IKONOS, TM/Landsat 5, ETM+/Landsat 7 e CCD/CBERS, objetivando a verificação da viabilidade destas como base de dados em projetos de reforma agrária. Essas análises efetuadas e a situação de mercado indicaram que a imagem IKONOS apresenta excelente desempenho técnico, mas o custo de aquisição inviabiliza sua utilização como base de dados para a reforma agrária. A imagem do Landsat 7, com baixo custo de aquisição, apresentou grande viabilidade técnica para fins de reforma agrária. No entanto, a perda do contato com a plataforma Landsat 7 inviabilizou a compra de novas imagens do sensor ETM+. A imagem CCD/CBERS apresentou a segunda maior similaridade com a verdade de campo e o menor índice Kappa para a classificação. Apesar do baixo índice de exatidão para a classificação, as análises de custo, o lançamento do CBERS-2 e a possibilidade de correção dos problemas de radiometria podem tornar as imagens da plataforma CBERS-2 concorrentes de peso no mercado e, ainda, preencher a lacuna deixada pela perda do Landsat 7. A imagem do Landsat 5 apresentou o mais baixo desempenho técnico nas análises efetuadas. Entretanto, seu potencial como base de dados é amplamente reconhecido pelo INCRA, que ainda utiliza tais imagens. O declínio da vida útil do Landsat-5 atribui mais importância ao lançamento do CBERS-2.Technical and economical analyses were performed on IKONOS, Landsat TM 5 and Landsat ETM+ 7 and CCD/CBERS data in order to verify their feasibilities to subsidy agrarian reform projects. Results showed that IKONOS data presented excellent technical viability but its high cost prevents its use. Landsat ETM+ 7 data, with low cost, presented good technical viability, however due to the problems occurring in the satellite operation, its use was also prevented . CCD/CBERS data presented the second best similarity with the ground truth data, although it

Detection of soil erosion with Thematic Mapper (TM) satellite data within Pinyon-Juniper woodlands

Science.gov (United States)

Price, Kevin Paul

1987-01-01

Pinyon-Juniper woodlands dominate approximately 24.3 million hectares (60 million acres) in the western United States. The overall objective was to test the sensitivity of the LANDSAT Thematic Mapper (TM) spectral data for detecting varying degrees of soil erosion within the Pinyon-Juniper woodlands. A second objective was to assess the potential of the spectral data for assigning the Universal Soil Loss Equation (USLE) crop management (C) factor values to varying cover types within the woodland. Thematic Mapper digital data for June 2, 1984 on channels 2, 3, 4, and 5 were used. Digital data analysis was performed using the ELAS software package. Best results were achieved using CLUS, an unsupervised clustering algorithm. Fifteen of the 40 Pinyon-Juniper signatures were identified as being relatively pure Pinyon-Juniper woodland. Final analysis resulted in the grouping of the 15 signatures into three major groups. Ten study sites were selected from each of the three groups and located on the ground. At each site the following field measurements were taken: percent tree canopy and percent understory cover, soil texture, total soil loss, and soil erosion rate estimates. A technique for measuring soil erosion within Pinyon-Juniper woodlands was developed. A theoretical model of site degradation after Pinyon-Juniper invasion is presented.

Determination of turbidity patterns in Lake Chicot from LANDSAT MSS imagery

Science.gov (United States)

Lecroy, S. R.

1982-01-01

A historical analysis of all the applicable LANDSAT imagery was conducted on the turbidity patterns of Lake Chicot, located in the southeastern corner of Arkansas. By examining the seasonal and regional turbidity patterns, a record of sediment dynamics and possible disposition can be obtained. Sketches were generated from the suitable imagery, displaying different intensities of brightness observed in bands 5 and 7 of LANDSAT's multispectral scanner data. Differences in and between bands 5 and 7 indicate variances in the levels of surface sediment concentrations. High sediment loads are revealed when distinct patterns appear in the band 7 imagery. Additionally, the upwelled signal is exponential in nature and saturates in band 5 at low wavelengths for large concentrations of suspended solids.

Comparative Spectroscopic Investigation of Tm3+:Tellurite Glasses for 2-μm Lasing Applications

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Huseyin Cankaya

2018-02-01

Full Text Available We performed a comparative spectroscopic analysis on three novel Tm3+:tellurite-based glasses with the following compositions Tm2O3:TeO2-ZnO (TeZnTm, Tm2O3:TeO2-Nb2O5 (TeNbTm, and Tm3+:TeO2-K2O-Nb2O5 (TeNbKTm, primarily for 2-μm laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of Tm3+ ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies. By performing Judd–Ofelt analysis, we determined the average radiative lifetimes of the 3H4 level to be 2.55 ± 0.07 ms, 2.76 ± 0.03 ms and 2.57 ± 0.20 ms for the TeZnTm, TeNbTm and TeNbKTm samples, respectively. We clearly observed the effect of the cross-relaxation, which becomes significant at higher Tm2O3 concentrations, leading to the quenching of 1460-nm emission and enhancement of 1860-nm emission. Furthermore, with increasing Tm2O3 concentrations, we observed a decrease in the fluorescence lifetimes as a result of the onset of non-radiative decay. For the 3H4 level, the highest obtained quantum efficiency was 32% for the samples with the lowest Tm2O3 ion concentration. For the 1860-nm emission band, the average emission cross section was determined to measure around 6.33 ± 0.34 × 10−21 cm2, revealing the potential of thulium-doped tellurite gain media for 2-μm laser applications in bulk and fiber configurations.

Global 30m 2000-2014 Surface Water Dynamics Map Derived from All Landsat 5, 7, and 8

Science.gov (United States)

Hudson, A.; Hansen, M.

2015-12-01

Water is critical for human life, agriculture, and ecosystems. A better understanding of where it is and how it is changing will enable better management of this valuable resource and guide protection of sensitive ecological areas. Global water maps have typically been representations of surface water at one given time. However, there is both seasonal and interannual variability: rivers meander, lakes disappear, floods arise. To address this ephemeral nature of water, in this study University of Maryland has developed a method that analyzes every Landsat 5, 7, and 8 scene from 1999-2015 to produce global seasonal maps (Winter, Spring, Summer, Fall) of surface water dynamics from 2000-2014. Each Landsat scene is automatically classified into land, water, cloud, haze, shadow, and snow via a decision tree algorithm. The land and water observations are aggregated per pixel into percent occurrence of water in a 3 year moving window for each meteorological season. These annual water percentages form a curve for each season that is discretized into a continuous 3 band RGB map. Frequency of water observation and type of surface water change (loss, gain, peak, or dip) is clearly seen through brightness and hue respectively. Additional data layers include: the year the change began, peak year, minimum year, and the year the change process ended. Currently these maps have been created for 18 1°x1° test tiles scattered around the world, and a portion of the September-November map over Bangladesh is shown below. The entire Landsat archive from 1999-2015 will be processed through a partnership with Google Earth Engine to complete the global product in the coming months. In areas where there is sufficient satellite data density (e.g. the United States), this project could be expanded to 1984-2015. This study provides both scientific researchers and the public an understandable, temporally rich, and globally consistent map showing surface water changes over time.

Tectolinear interpretation of a 1:5,000,000 Landsat-1 mosaic compared with the structure of central and eastern United States

Science.gov (United States)

Kutina, Jan; Carter, William D.

1978-01-01

The pattern of lineaments and curvilinear features interpreted from a 1:5,000,000 mosaic of satellite images (Landsat-1 was superimposed on a simplified version of the Geological Map of the United States, 1:2,500,000 scale, showing the structural scheme of Central and Eastern United States. A comparison of the above two patterns, shown in Fig. 1, is presented in this paper.

Analysis of Coastline Extraction from Landsat-8 OLI Imagery

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Yaolin Liu

2017-10-01

Full Text Available Coastline extraction is a fundamental work for coastal resource management, coastal environmental protection and coastal sustainable development. Due to the free access and long-term record, Landsat series images have the potential to be used for coastline extraction. However, dynamic features of different types of coastlines (e.g., rocky, sandy, artificial, caused by sea level fluctuation from tidal, storm and reclamation, make it difficult to be accurately extracted with coarse spatial resolution, e.g., 30 m, of Landsat images. To access this problem, we analyze the performance of coastline extraction by integrating downscaling, pansharpening and water index approaches in increasing the accuracy of coastline extraction from the latest Landsat-8 Operational Land Imager (OLI imagery. In order to prove the availability of the proposed method, we designed three strategies: (1 Strategy 1 uses the traditional water index method to extract coastline directly from original 30 m Landsat-8 OLI multispectral (MS image; (2 Strategy 2 extracts coastlines from 15 m fused MS images generated by integrating 15 m panchromatic (PAN band and 30 m MS image with ten pansharpening algorithms; (3 Strategy 3 first downscales the PAN band to a finer spatial resolution (e.g., 7.5 m band, and then extracts coastlines from pansharpened MS images generated by integrating downscaled spatial resolution PAN band and 30 m MS image with ten pansharpening algorithms. Using the coastline extracted from ZiYuan-3 (ZY-3 5.8 m MS image as reference, accuracies of coastlines extracted from MS images in three strategies were validated visually and quantitatively. The results show that, compared with coastline extracted directly from 30 m Landsat-8 MS image (strategy 1, strategy 3 achieves the best accuracies with optimal mean net shoreline movement (MNSM of −2.54 m and optimal mean absolute difference (MAD of 11.26 m, followed by coastlines extracted in strategy 2 with optimal MNSM

An analysis of Landsat-4 Thematic Mapper geometric properties

Science.gov (United States)

Walker, R. E.; Zobrist, A. L.; Bryant, N. A.; Gohkman, B.; Friedman, S. Z.; Logan, T. L.

1984-01-01

Landsat-4 Thematic Mapper data of Washington, DC, Harrisburg, PA, and Salton Sea, CA were analyzed to determine geometric integrity and conformity of the data to known earth surface geometry. Several tests were performed. Intraband correlation and interband registration were investigated. No problems were observed in the intraband analysis, and aside from indications of slight misregistration between bands of the primary versus bands of the secondary focal planes, interband registration was well within the specified tolerances. A substantial number of ground control points were found and used to check the images' conformity to the Space Oblique Mercator (SOM) projection of their respective areas. The means of the residual offsets, which included nonprocessing related measurement errors, were close to the one pixel level in the two scenes examined. The Harrisburg scene residual mean was 28.38 m (0.95 pixels) with a standard deviation of 19.82 m (0.66 pixels), while the mean and standard deviation for the Salton Sea scene were 40.46 (1.35 pixels) and 30.57 m (1.02 pixels), respectively. Overall, the data were judged to be a high geometric quality with errors close to those targeted by the TM sensor design specifications.

Landsat science team meeting: Summer 2015

Science.gov (United States)

Schroeder, Todd; Loveland, Thomas; Wulder, Michael A.; Irons, James R.

2015-01-01

The summer meeting of the joint U.S. Geological Survey (USGS)–NASA Landsat Science Team (LST) was held at the USGS’s Earth Resources Observation and Science (EROS) Center July 7-9, 2015, in Sioux Falls, SD. The LST co-chairs, Tom Loveland [EROS—Senior Scientist] and Jim Irons [NASA’s Goddard Space Flight Center (GSFC)—Landsat 8 Project Scientist], opened the three-day meeting on an upbeat note following the recent successful launch of the European Space Agency’s Sentinel-2 mission on June 23, 2015 (see image on page 14), and the news that work on Landsat 9 has begun, with a projected launch date of 2023.

Single-phased CaAl2Si2O8:Tm3+, Dy3+ white-light phosphors under ultraviolet excitation

International Nuclear Information System (INIS)

Yang, Penghui; Yu, Xue; Xu, Xuhui; Jiang, Tingming; Yu, Hongling; Zhou, Dacheng; Yang, Zhengwen; Song, Zhiguo; Qiu, Jianbei

2013-01-01

A novel white-light-emitting phosphor CaAl 2 Si 2 O 8 :Tm, Dy was synthesized in ambient atmosphere by solid-state reaction. The energy transfer from Tm 3+ to Dy 3+ ions via a dipole–quadrupole reaction was observed and investigated. Upon UV excitation, white light emission was achieved by integrating a blue emission band located at 455 nm and an orange one located at 574 nm attributed to Tm 3+ and Dy 3+ ions, respectively. In addition, the energy-transfer efficiency and critical distance were calculated. Results suggested that the phosphor might be promising as a single-phased white-light-emitting phosphor for UV white-light LED. - Graphical abstract: The results indicate the existence of energy transfer from Tm 3+ to Dy 3+ . By tuning the concentration of Dy 3+ , single-phased white light can be realized. - Highlights: ► Energy transfer from Tm 3+ to Dy 3+ was investigated. ► Color tunable from blue to white can be achieved. ► White light can be realized in CaAl 2 Si 2 O 8 :Tm 3+ , Dy 3+ phosphor

Detecting areal changes in tidal flats after sea dike construction ...

Indian Academy of Sciences (India)

The main objective of this study was to estimate changes in the area of tidal flats that occurred after sea dike construction on the western coast of South Korea using Landsat-TM images. Applying the ISODATA method of unsupervised classification for Landsat-TM images, the tidal flats were identified, and the resulting areas ...

Modeling a Hypothetical 170Tm Source for Brachytherapy Applications

International Nuclear Information System (INIS)

Enger, Shirin A.; D'Amours, Michel; Beaulieu, Luc

2011-01-01

Purpose: To perform absorbed dose calculations based on Monte Carlo simulations for a hypothetical 170 Tm source and to investigate the influence of encapsulating material on the energy spectrum of the emitted electrons and photons. Methods: GEANT4 Monte Carlo code version 9.2 patch 2 was used to simulate the decay process of 170 Tm and to calculate the absorbed dose distribution using the GEANT4 Penelope physics models. A hypothetical 170 Tm source based on the Flexisource brachytherapy design with the active core set as a pure thulium cylinder (length 3.5 mm and diameter 0.6 mm) and different cylindrical source encapsulations (length 5 mm and thickness 0.125 mm) constructed of titanium, stainless-steel, gold, or platinum were simulated. The radial dose function for the line source approximation was calculated following the TG-43U1 formalism for the stainless-steel encapsulation. Results: For the titanium and stainless-steel encapsulation, 94% of the total bremsstrahlung is produced inside the core, 4.8 and 5.5% in titanium and stainless-steel capsules, respectively, and less than 1% in water. For the gold capsule, 85% is produced inside the core, 14.2% inside the gold capsule, and a negligible amount ( 170 Tm source is primarily a bremsstrahlung source, with the majority of bremsstrahlung photons being generated in the source core and experiencing little attenuation in the source encapsulation. Electrons are efficiently absorbed by the gold and platinum encapsulations. However, for the stainless-steel capsule (or other lower Z encapsulations) electrons will escape. The dose from these electrons is dominant over the photon dose in the first few millimeter but is not taken into account by current standard treatment planning systems. The total energy spectrum of photons emerging from the source depends on the encapsulation composition and results in mean photon energies well above 100 keV. This is higher than the main gamma-ray energy peak at 84 keV. Based on our

Landsat 8 Data Modeled as DGGS Data Cubes

Science.gov (United States)

Sherlock, M. J.; Tripathi, G.; Samavati, F.

2016-12-01

In the context of tracking recent global changes in the Earth's landscape, Landsat 8 provides high-resolution multi-wavelength data with a temporal resolution of sixteen days. Such a live dataset can benefit novel applications in environmental monitoring. However, a temporal analysis of this dataset in its native format is a challenging task mostly due to the huge volume of geospatial images and imperfect overlay of different day Landsat 8 images. We propose the creation of data cubes derived from Landsat 8 data, through the use of a Discrete Global Grid System (DGGS). DGGS referencing of Landsat 8 data provides a cell-based representation of the pixel values for a fixed area on earth, indexed by keys. Having the calibrated cell-based Landsat 8 images can speed up temporal analysis and facilitate parallel processing using distributed systems. In our method, the Landsat 8 dataset hosted on Amazon Web Services (AWS) is downloaded using a web crawler and stored on a filesystem. We apply the cell-based DGGS referencing (using Pyxis SDK) to Landsat 8 images which provide a rhombus based tessellation of equal area cells for our use-case. After this step, the cell-images which overlay perfectly on different days, are stacked in the temporal dimension and stored into data cube units. The depth of the cube represents the number of temporal images of the same cell and can be updated when new images are received each day. Harnessing the regular spatio-temporal structure of data cubes, we want to compress, query, transmit and visualize big Landsat 8 data in an efficient way for temporal analysis.

Detection of NASBA amplified bacterial tmRNA molecules on SLICSel designed microarray probes

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Toome Kadri

2011-02-01

Full Text Available Abstract Background We present a comprehensive technological solution for bacterial diagnostics using tmRNA as a marker molecule. A robust probe design algorithm for microbial detection microarray is implemented. The probes were evaluated for specificity and, combined with NASBA (Nucleic Acid Sequence Based Amplification amplification, for sensitivity. Results We developed a new web-based program SLICSel for the design of hybridization probes, based on nearest-neighbor thermodynamic modeling. A SLICSel minimum binding energy difference criterion of 4 kcal/mol was sufficient to design of Streptococcus pneumoniae tmRNA specific microarray probes. With lower binding energy difference criteria, additional hybridization specificity tests on the microarray were needed to eliminate non-specific probes. Using SLICSel designed microarray probes and NASBA we were able to detect S. pneumoniae tmRNA from a series of total RNA dilutions equivalent to the RNA content of 0.1-10 CFU. Conclusions The described technological solution and both its separate components SLICSel and NASBA-microarray technology independently are applicative for many different areas of microbial diagnostics.

Detection of tmRNA molecules on microarrays at low temperatures using helper oligonucleotides

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Palta Priit

2010-04-01

Full Text Available Abstract Background The hybridization of synthetic Streptococcus pneumoniae tmRNA on a detection microarray is slow at 34°C resulting in low signal intensities. Results We demonstrate that adding specific DNA helper oligonucleotides (chaperones to the hybridization buffer increases the signal strength at a given temperature and thus makes the specific detection of Streptococcus pneumoniae tmRNA more sensitive. No loss of specificity was observed at low temperatures compared to hybridization at 46°C. The effect of the chaperones can be explained by disruption of the strong secondary and tertiary structure of the target RNA by the selective hybridization of helper molecules. The amplification of the hybridization signal strength by chaperones is not necessarily local; we observed increased signal intensities in both local and distant regions of the target molecule. Conclusions The sensitivity of the detection of tmRNA at low temperature can be increased by chaperone oligonucleotides. Due to the complexity of RNA secondary and tertiary structures the effect of any individual chaperone is currently not predictable.

Detection of NASBA amplified bacterial tmRNA molecules on SLICSel designed microarray probes

LENUS (Irish Health Repository)

Scheler, Ott

2011-02-28

Abstract Background We present a comprehensive technological solution for bacterial diagnostics using tmRNA as a marker molecule. A robust probe design algorithm for microbial detection microarray is implemented. The probes were evaluated for specificity and, combined with NASBA (Nucleic Acid Sequence Based Amplification) amplification, for sensitivity. Results We developed a new web-based program SLICSel for the design of hybridization probes, based on nearest-neighbor thermodynamic modeling. A SLICSel minimum binding energy difference criterion of 4 kcal\\/mol was sufficient to design of Streptococcus pneumoniae tmRNA specific microarray probes. With lower binding energy difference criteria, additional hybridization specificity tests on the microarray were needed to eliminate non-specific probes. Using SLICSel designed microarray probes and NASBA we were able to detect S. pneumoniae tmRNA from a series of total RNA dilutions equivalent to the RNA content of 0.1-10 CFU. Conclusions The described technological solution and both its separate components SLICSel and NASBA-microarray technology independently are applicative for many different areas of microbial diagnostics.

Reconstructing the Spatio-Temporal Development of Irrigation Systems in Uzbekistan Using Landsat Time Series

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Thomas Koellner

2012-12-01

Full Text Available The expansion of irrigated agriculture during the Soviet Union (SU era made Central Asia a leading cotton production region in the world. However, the successor states of the SU in Central Asia face on-going environmental damages and soil degradation that are endangering the sustainability of agricultural production. With Landsat MSS and TM data from 1972/73, 1977, 1987, 1998, and 2000 the expansion and densification of the irrigated cropland could be reconstructed in the Kashkadarya Province of Uzbekistan, Central Asia. Classification trees were generated by interpreting multitemporal normalized difference vegetation index data and crop phenological knowledge. Assessments based on image-derived validation samples showed good accuracy. Official statistics were found to be of limited use for analyzing the plausibility of the results, because they hardly represent the area that is cropped in the very dry study region. The cropping area increased from 134,800 ha in 1972/73 to 470,000 ha in 2009. Overlaying a historical soil map illustrated that initially sierozems were preferred for irrigated agriculture, but later the less favorable solonchaks and solonetzs were also explored, illustrating the strategy of agricultural expansion in the Aral Sea Basin. Winter wheat cultivation doubled between 1987 and 1998 to approximately 211,000 ha demonstrating its growing relevance for modern Uzbekistan. The spatial-temporal approach used enhances the understanding of natural conditions before irrigation is employed and supports decision-making for investments in irrigation infrastructure and land cultivation throughout the Landsat era.

Plastic Muscles TM as lightweight, low voltage actuators and sensors

Science.gov (United States)

Bennett, Matthew; Leo, Donald; Duncan, Andrew

2008-03-01

Using proprietary technology, Discover Technologies has developed ionomeric polymer transducers that are capable of long-term operation in air. These "Plastic Muscle TM" transducers are useful as soft distributed actuators and sensors and have a wide range of applications in the aerospace, robotics, automotive, electronics, and biomedical industries. Discover Technologies is developing novel fabrication methods that allow the Plastic Muscles TM to be manufactured on a commercial scale. The Plastic Muscle TM transducers are capable of generating more than 0.5% bending strain at a peak strain rate of over 0.1 %/s with a 3 V input. Because the Plastic Muscles TM use an ionic liquid as a replacement solvent for water, they are able to operate in air for long periods of time. Also, the Plastic Muscles TM do not exhibit the characteristic "back relaxation" phenomenon that is common in water-swollen devices. The elastic modulus of the Plastic Muscle TM transducers is estimated to be 200 MPa and the maximum generated stress is estimated to be 1 MPa. Based on these values, the maximum blocked force at the tip of a 6 mm wide, 35 mm long actuator is estimated to be 19 mN. Modeling of the step response with an exponential series reveals nonlinearity in the transducers' behavior.

Effect of silica surface coating on the luminescence lifetime and upconversion temperature sensing properties of semiconductor zinc oxide doped with gallium(III) and sensitized with rare earth ions Yb(III) and Tm(III).

Science.gov (United States)

Li, Yuemei; Li, Yongmei; Wang, Rui; Zheng, Wei

2018-02-26

Optical sensing of temperature by measurement of the ratio of the intensities of the 700 nm emission and the 800 nm emission of Ga(III)-doped ZnO (GZO) nanoparticles (NPs) and of GZO NPs coated with a silica shell are demonstrated at 980 nm excitation. It is found that the relative sensitivity of SiO 2 @Yb/Tm/GZO is 6.2% K -1 at a temperature of 693 K. This is ~3.4 times higher than that of Yb/Tm/GZO NPs. Obviously, the SiO 2 shell structure decreases the rate of the nonradiative decay. The decay time of the 800 nm emission of the Yb/Tm/GZO NPs (15 mol% Ga; 7 mol% Yb; 0.5 mol% Tm) displays a biexponential decay with a dominant decay time of 148 μs and a second decay time of ~412 μs. The lifetime of the Yb/Tm/GZO NPs at 293 K, and of the SiO 2 @Yb/Tm/GZO NPs are ~412 μs. Both the Yb/Tm/GZO and SiO 2 @Yb/Tm/GZO can be used up to 693 K. These results indicate that the SiO 2 shell on the Yb/Tm/GZO is beneficial in terms of sensitivity and resolution. Graphical abstract The enhancement the decay time and thermal sensitivity in the SiO 2 @Yb/Tm/GZO shell@core structure have been studied compared to the Ga(III)-doped Yb/Tm-doped ZnO (Yb/Tm/GZO). The SiO 2 @Yb/Tm/GZO have good thermal accuracy up to 693 °C.

Development of the Landsat Data Continuity Mission Cloud Cover Assessment Algorithms

Science.gov (United States)

Scaramuzza, Pat; Bouchard, M.A.; Dwyer, John L.

2012-01-01

The upcoming launch of the Operational Land Imager (OLI) will start the next era of the Landsat program. However, the Automated Cloud-Cover Assessment (CCA) (ACCA) algorithm used on Landsat 7 requires a thermal band and is thus not suited for OLI. There will be a thermal instrument on the Landsat Data Continuity Mission (LDCM)-the Thermal Infrared Sensor-which may not be available during all OLI collections. This illustrates a need for CCA for LDCM in the absence of thermal data. To research possibilities for full-resolution OLI cloud assessment, a global data set of 207 Landsat 7 scenes with manually generated cloud masks was created. It was used to evaluate the ACCA algorithm, showing that the algorithm correctly classified 79.9% of a standard test subset of 3.95 109 pixels. The data set was also used to develop and validate two successor algorithms for use with OLI data-one derived from an off-the-shelf machine learning package and one based on ACCA but enhanced by a simple neural network. These comprehensive CCA algorithms were shown to correctly classify pixels as cloudy or clear 88.5% and 89.7% of the time, respectively.

Small forest cuttings mapped with Landsat digital data

Science.gov (United States)

Bryant, E.; Dodge, A. G.; Eger, M. J. E.

1979-01-01

The Cooperative Landsat Applications Research Group used computer classification of Landsat digital data to map forest cuttings (clearcuts) in northern New Hampshire. Cuttings as small as 3 hectares were identified. Several ages or conditions of clearcuts could be distinguished. Progress in two methods of duplicating classification categories from one Landsat pass to another are discussed. One method was used in making maps of areas in 1973, 1975, and 1978.

Assessment of dynamic softening mechanisms in Allvac 718Plus{sup TM} by EBSD analysis

Energy Technology Data Exchange (ETDEWEB)

Mitsche, Stefan, E-mail: stefan.mitsche@felmi-zfe.at [Institute for Electron Microscopy, Graz University of Technology, Steyrergasse 17, Graz (Austria); Sommitsch, Christof [Institute for Material Science and Welding, Christian Doppler Laboratory for Materials Modelling and Simulation, Graz University of Technology, Graz (Austria); Huber, Daniel; Stockinger, Martin [Boehler Schmiedetechnik GmbH and Co KG, Kapfenberg (Austria); Poelt, Peter [Institute for Electron Microscopy, Graz University of Technology, Steyrergasse 17, Graz (Austria)

2011-04-25

Research highlights: {yields} EBSD investigations of hot deformed superalloy Allvac 718Plus{sup TM}. {yields} Dynamic softening (recovery, DDRX and CDRX) in dependence on the temperature and strain rate. {yields} At high temperature (1050 deg. C) and high strain rate (10 s{sup -1}) mainly DDRX. {yields} At high temperature (1050 deg. C) and low strain rate (0.1 s{sup -1}) combination of DDRX, CDRX and recovery. - Abstract: The nickel-based superalloy Allvac 718Plus{sup TM} is a future candidate for turbine disc applications, as this new material combines the formability and cost advantages of Alloy 718 with the higher temperature capability of Waspaloy. Due to the strong influence of the microstructure on the final mechanical properties, a fundamental knowledge of the dynamic recrystallization mechanism of Allvac 718Plus{sup TM} is of great importance in order to develop precise microstructure evolution models for this material. Compression tests were performed at temperatures of 900 deg. C to 1050 deg. C and strain rates between 0.1 s{sup -1} and 10 s{sup -1}. The microstructures obtained were analyzed by electron backscatter diffraction (EBSD) to evaluate the influence of the different hot forming parameters on the dynamic softening processes of Allvac 718Plus{sup TM}.

Quality Assessment of Landsat Surface Reflectance Products Using MODIS Data

Science.gov (United States)

Feng, Min; Huang, Chengquan; Channan, Saurabh; Vermote, Eric; Masek, Jeffrey G.; Townshend, John R.

2012-01-01

Surface reflectance adjusted for atmospheric effects is a primary input for land cover change detection and for developing many higher level surface geophysical parameters. With the development of automated atmospheric correction algorithms, it is now feasible to produce large quantities of surface reflectance products using Landsat images. Validation of these products requires in situ measurements, which either do not exist or are difficult to obtain for most Landsat images. The surface reflectance products derived using data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), however, have been validated more comprehensively. Because the MODIS on the Terra platform and the Landsat 7 are only half an hour apart following the same orbit, and each of the 6 Landsat spectral bands overlaps with a MODIS band, good agreements between MODIS and Landsat surface reflectance values can be considered indicators of the reliability of the Landsat products, while disagreements may suggest potential quality problems that need to be further investigated. Here we develop a system called Landsat-MODIS Consistency Checking System (LMCCS). This system automatically matches Landsat data with MODIS observations acquired on the same date over the same locations and uses them to calculate a set of agreement metrics. To maximize its portability, Java and open-source libraries were used in developing this system, and object-oriented programming (OOP) principles were followed to make it more flexible for future expansion. As a highly automated system designed to run as a stand-alone package or as a component of other Landsat data processing systems, this system can be used to assess the quality of essentially every Landsat surface reflectance image where spatially and temporally matching MODIS data are available. The effectiveness of this system was demonstrated using it to assess preliminary surface reflectance products derived using the Global Land Survey (GLS) Landsat

Thermal and optical properties of Tm3+ doped tellurite glasses.

Science.gov (United States)

Ozen, G; Demirata, B; Oveçoğlu, M L; Genç, A

2001-02-01

Ultraviolet, visible (UV/VIS) and differential thermal analysis (DTA) measurements were carried out in order to investigate the optical and thermal properties of various 0.5 mol.% Tm2O3 containing (1 - x)TeO2 + xLiCl glasses in molar ratio. The samples were prepared by fusing the mixture of their respective reagent grade powders in a platinum cricuble at 750 degrees C for 30 min. DTA curves taken in the 23-600 degrees C temperature range with a heating rate of 10 degrees C/min reveal a change in the value of the glass transition temperature, Tg, while melting was not observed for the glasses containing LiCl content less than 50 mol.%. These glasses were found to be moisture-resistant. However, the glasses with LiCl content higher than 50 mol.%, in which a melting peak was observed at Tc = 401 degrees C, were moisture-sensitive. Absorption measurements in the UV/VIS region of the glasses without Tm2O3 content show that the Urbach cutoff occurs at about 320 nm and, is relatively independent of the LiCl content. Six absorption bands were observed in the Tm2O3 doped glasses corresponding to the absorption of the 1G4, 3F2, 3F3 and 3F4, 3H5 and 3H4 levels from the 3H6 ground level of Tm3+ ions. The spectra also show that the integrated absorption cross-section of each band depends on the glass composition. Judd-Ofelt theory was used to determine the Judd-Ofelt parameters as well as the radiative transition probabilities for the metastable levels of Tm3+ ions in (0.3)LiCl + (0.7) TeO2: 0.01 Tm2O3 glass which is moisture-resistant.

Landsat Science: 40 Years of Innovation and Opportunity

Science.gov (United States)

Cook, Bruce D.; Irons, James R.; Masek, Jeffrey G.; Loveland, Thomas R.

2012-01-01

Landsat satellites have provided unparalleled Earth-observing data for nearly 40 years, allowing scientists to describe, monitor and model the global environment during a period of time that has seen dramatic changes in population growth, land use, and climate. The success of the Landsat program can be attributed to well-designed instrument specifications, astute engineering, comprehensive global acquisition and calibration strategies, and innovative scientists who have developed analytical techniques and applications to address a wide range of needs at local to global scales (e.g., crop production, water resource management, human health and environmental quality, urbanization, deforestation and biodiversity). Early Landsat contributions included inventories of natural resources and land cover classification maps, which were initially prepared by a visual interpretation of Landsat imagery. Over time, advances in computer technology facilitated the development of sophisticated image processing algorithms and complex ecosystem modeling, enabling scientists to create accurate, reproducible, and more realistic simulations of biogeochemical processes (e.g., plant production and ecosystem dynamics). Today, the Landsat data archive is freely available for download through the USGS, creating new opportunities for scientists to generate global image datasets, develop new change detection algorithms, and provide products in support of operational programs such as Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD). In particular, the use of dense (approximately annual) time series to characterize both rapid and progressive landscape change has yielded new insights into how the land environment is responding to anthropogenic and natural pressures. The launch of the Landsat Data Continuity Mission (LDCM) satellite in 2012 will continue to propel innovative Landsat science.

SUPPORT VECTOR MACHINE CLASSIFICATION OF OBJECT-BASED DATA FOR CROP MAPPING, USING MULTI-TEMPORAL LANDSAT IMAGERY

Directory of Open Access Journals (Sweden)

R. Devadas

2012-07-01

Full Text Available Crop mapping and time series analysis of agronomic cycles are critical for monitoring land use and land management practices, and analysing the issues of agro-environmental impacts and climate change. Multi-temporal Landsat data can be used to analyse decadal changes in cropping patterns at field level, owing to its medium spatial resolution and historical availability. This study attempts to develop robust remote sensing techniques, applicable across a large geographic extent, for state-wide mapping of cropping history in Queensland, Australia. In this context, traditional pixel-based classification was analysed in comparison with image object-based classification using advanced supervised machine-learning algorithms such as Support Vector Machine (SVM. For the Darling Downs region of southern Queensland we gathered a set of Landsat TM images from the 2010–2011 cropping season. Landsat data, along with the vegetation index images, were subjected to multiresolution segmentation to obtain polygon objects. Object-based methods enabled the analysis of aggregated sets of pixels, and exploited shape-related and textural variation, as well as spectral characteristics. SVM models were chosen after examining three shape-based parameters, twenty-three textural parameters and ten spectral parameters of the objects. We found that the object-based methods were superior to the pixel-based methods for classifying 4 major landuse/land cover classes, considering the complexities of within field spectral heterogeneity and spectral mixing. Comparative analysis clearly revealed that higher overall classification accuracy (95% was observed in the object-based SVM compared with that of traditional pixel-based classification (89% using maximum likelihood classifier (MLC. Object-based classification also resulted speckle-free images. Further, object-based SVM models were used to classify different broadacre crop types for summer and winter seasons. The influence of

Assessing, monitoring and mapping forest resources in the Blue Nile Region of Sudan using an object-based image analysis approach

OpenAIRE

Mahmoud El-Abbas Mustafa, Mustafa

2015-01-01

Following the hierarchical nature of forest resource management, the present work focuses on the natural forest cover at various abstraction levels of details, i.e. categorical land use/land cover (LU/LC) level and a continuous empirical estimation of local operational level. As no single sensor presently covers absolutely all the requirements of the entire levels of forest resource assessment, multisource imagery (i.e. RapidEye, TERRA ASTER and LANDSAT TM), in addition to other data and know...

Development and Application of an Annual Vegetation-Monitoring Tool in Gishwati Forest Reserve using MODIS NDVI product and Landsat-5 and 7

Science.gov (United States)

Makar, N. I.; Butler, K.; Fox, T.; Geddes, Q. A.; Janse van Vuuren, L.; Li, A.; Sharma, A.

2012-12-01

As the most densely populated country in Africa, Rwanda relies heavily on a limited supply of natural resources to sustain its agrarian economy. Population pressures, economic policy, and the aftermath of the genocide have placed particular stress on the Gishwati Forest in Rwanda's Western Province. Deforestation for agricultural purposes and fuel consumption has disrupted the local climate, soil structure, and topography, leading to increased erosion, landslides and flooding. Once 280 km2, by 1995 the Gishwati Forest was only 6 km2. The Rwandan government and international NGOs have started initiatives to reverse deforestation, which would benefit from monitoring and evaluation using remote sensing technology. This study filled the gaps in the tumultuous history of Gishwati Forest since 1982 using NASA's Earth Observing System, specifically Landsat 5 and AVHRR. In collaboration with partner organizations, we developed a robust, yet simple to use, forest monitoring tool employing MODIS NDVI product and Landsat that provide annual estimates of the forest's health.

DC Stark addressing for quantum memory in Tm:YAG

Science.gov (United States)

Gerasimov, Konstantin; Minnegaliev, Mansur; Urmancheev, Ravil; Moiseev, Sergey

2017-10-01

We observed a linear DC Stark effect for 3H6 - 3H4 optical transition of Tm3+ ions in Y3Al5O12. We observed that application of electric field pulse suppresses the two-pulse photon echo signal. If we then apply a second electric pulse of opposite polarity the echo signal is restored again, which indicates the linear nature of the observed effect. The effect is present despite the D2 symmetry of the Tm3+ sites that prohibits a linear Stark effect. Experimental data analysis shows that the observed electric field influence can be attributed to defects that break the local crystal field symmetry near Tm3+ ions. Using this effect we demonstrate selective retrieval of light pulses in two-pulse photon echo.

Pool boiling performance of NovecTM 649 engineered fluid

International Nuclear Information System (INIS)

Forrest, Eric; Buongiorno, Jacopo; McKrell, Thomas; Hu, Lin-Wen

2009-01-01

A new fluorinated ketone, C 2 F 5 C(O)CF(CF 3 ) 2 , is currently being considered as an environmentally friendly alternative for power electronics cooling applications due to its high dielectric strength and low global warming potential (GWP). Sold commercially by the 3M Company as Novec TM 649 Engineered Fluid, C 2 F 5 C(O)CF(CF 3 ) 2 exhibits very low acute toxicity while maintaining long-term stability. To assess the general two-phase heat transfer performance of Novec TM 649, pool boiling tests were conducted by resistively heating a 0.01 in. diameter nickel wire at the fluid's atmospheric saturation temperature of 49 deg C. The nucleate boiling heat transfer coefficient and critical heat flux (CHF) obtained for the fluorinated ketone compare favorably with results obtained for FC-72, a fluorocarbon widely used for the direct cooling of electronic devices. Initial results indicate that Novec TM 649 may prove to be a viable alternative to FC-72 and other halo alkanes for the cooling of high power density electronic devices. (author)

Inverse modelling of national and European CH4 emissions using the atmospheric zoom model TM5

Directory of Open Access Journals (Sweden)

P. Bergamaschi

2005-01-01

Full Text Available A synthesis inversion based on the atmospheric zoom model TM5 is used to derive top-down estimates of CH4 emissions from individual European countries for the year 2001. We employ a model zoom over Europe with 1° × 1° resolution that is two-way nested into the global model domain (with resolution of 6° × 4°. This approach ensures consistent boundary conditions for the zoom domain and thus European top-down estimates consistent with global CH4 observations. The TM5 model, driven by ECMWF analyses, simulates synoptic scale events at most European and global sites fairly well, and the use of high-frequency observations allows exploiting the information content of individual synoptic events. A detailed source attribution is presented for a comprehensive set of 56 monitoring sites, assigning the atmospheric signal to the emissions of individual European countries and larger global regions. The available observational data put significant constraints on emissions from different regions. Within Europe, in particular several Western European countries are well constrained. The inversion results suggest up to 50-90% higher anthropogenic CH4 emissions in 2001 for Germany, France and UK compared to reported UNFCCC values (EEA, 2003. A recent revision of the German inventory, however, resulted in an increase of reported CH4 emissions by 68.5% (EEA, 2004, being now in very good agreement with our top-down estimate. The top-down estimate for Finland is distinctly smaller than the a priori estimate, suggesting much smaller CH4 emissions from Finnish wetlands than derived from the bottom-up inventory. The EU-15 totals are relatively close to UNFCCC values (within 4-30% and appear very robust for different inversion scenarios.

Mapping Impervious Surfaces Globally at 30m Resolution Using Landsat Global Land Survey Data

Science.gov (United States)

Brown de Colstoun, E.; Huang, C.; Wolfe, R. E.; Tan, B.; Tilton, J.; Smith, S.; Phillips, J.; Wang, P.; Ling, P.; Zhan, J.; Xu, X.; Taylor, M. P.

2013-12-01

Impervious surfaces, mainly artificial structures and roads, cover less than 1% of the world's land surface (1.3% over USA). Regardless of the relatively small coverage, impervious surfaces have a significant impact on the environment. They are the main source of the urban heat island effect, and affect not only the energy balance, but also hydrology and carbon cycling, and both land and aquatic ecosystem services. In the last several decades, the pace of converting natural land surface to impervious surfaces has increased. Quantitatively monitoring the growth of impervious surface expansion and associated urbanization has become a priority topic across both the physical and social sciences. The recent availability of consistent, global scale data sets at 30m resolution such as the Global Land Survey from the Landsat satellites provides an unprecedented opportunity to map global impervious cover and urbanization at this resolution for the first time, with unprecedented detail and accuracy. Moreover, the spatial resolution of Landsat is absolutely essential to accurately resolve urban targets such a buildings, roads and parking lots. With long term GLS data now available for the 1975, 1990, 2000, 2005 and 2010 time periods, the land cover/use changes due to urbanization can now be quantified at this spatial scale as well. In the Global Land Survey - Imperviousness Mapping Project (GLS-IMP), we are producing the first global 30 m spatial resolution impervious cover data set. We have processed the GLS 2010 data set to surface reflectance (8500+ TM and ETM+ scenes) and are using a supervised classification method using a regression tree to produce continental scale impervious cover data sets. A very large set of accurate training samples is the key to the supervised classifications and is being derived through the interpretation of high spatial resolution (~2 m or less) commercial satellite data (Quickbird and Worldview2) available to us through the unclassified

Comparison of winter wheat growth with multi-temporal remote sensing imagery

International Nuclear Information System (INIS)

Xiaoyu, Song; Bei, Cui; Guijun, Yang; Haikuan, Feng

2014-01-01

Leaf area index (LAI) is an important index for crop growth monitoring. This paper focused on estimation of winter wheat LAI dynamics in different growth stages based on Landsat TM data. In order to retrieve wheat LAI from remote sensing data, LAI measurements were initiated when Landsat satellite pass over the study region. Three Landsat5 TM images were acquired on April 15, May 17, and June 2, 2009, corresponding to jointing stage, flowering stage and milking stage of wheat. LAI was measured at each stage in thirty wheat fields distributed in Beijing suburb. Based on the TM images, spectral indices including NDVI, MSAVI, SAVI, RDVI, SR, ISR, MSR and NLI were calculated. Univariate correlation analysis was then conducted between LAI data and corresponding TM spectral variables. The analysis results indicated that TM ISR on April 15, TM Band4 on May17, and TM ISR on June 2 were very significantly correlated with LAI, and the coefficient values were 0.736, 0.548 and 0.493, respectively. LAI map of winter wheat for whole study area was produced based on optimal non-linear correlation models. The three LAI maps were used to winter wheat growth analysis and comparison of different growth stages. Study results indicated that from April 15 to May 17, LAI value for 14.88% of winter wheat fields (9131ha) increased less than 1, 64.43 % (39421 ha) increased between 1 to 2, 20.67 % (12685 ha) increased more than 2. LAI decreased from May 17 to June 2. 45.34% of winter wheat fields (27828 ha) decreased less than1, 45.20 % (27738 ha) decreased between 1 to 2, 9.33% (5725.42 ha) decreased more than 2

Structural, photoluminescence and XPS properties of Tm3þ ions in ZnO nanostructures

CSIR Research Space (South Africa)

Kabongo, GL

2017-07-01

Full Text Available of photoluminescence (PL) spectroscopy. Finally, Tm 4d core level was detected in ZnO: 0.5 mol% Tm(sup3+) sample from high resolution X-Ray Photoelectron Spectroscopy (XPS) scan....

Formation and characterization of ZnO : Tm+ optical waveguides fabricated by Tm+ and O+ ion implantation

International Nuclear Information System (INIS)

Ming Xianbing; Lu Fei; Liu Hanping; Chen Ming; Wang Lei

2009-01-01

Planar optical waveguides were formed in ZnO crystal by Tm + and O + ion implantation. The distributions of Tm + in as-implanted and annealed ZnO samples were investigated by the RBS technique. A shift of the Tm + peak towards the sample surface and out diffusion were observed after thermal treatment and subsequent O + ion implantation. Waveguide formation was determined after O + implantation in Tm + -implanted ZnO crystal. By using the prism-coupling method two guided modes were detected. The refractive index profile in the implanted waveguide was reconstructed according to the SRIM and RCM simulation. The RBS/channelling measurements show that the lattice structure of ZnO did not suffer detectable damage after O + implantation.

PLUS7TM In-Reactor Operating Performance and Economics

International Nuclear Information System (INIS)

Kim, Kyutae; Jang, Youngki; Choi, Joonhyung; Lee, Jinseok; Kim, Yoonho; Suh, Jungmin

2006-01-01

KNFC has developed an advanced fuel, PLUS7 TM , for the Korean Standard Nuclear Power Plants(KSNPs) through the joint development program with Westinghouse. With the help of various out-of-pile tests, it is found that the PLUS7 TM shows much better performance than the current fuel, GUARDIAN TM from the safety and economy points of view. Now four Lead Test Assembles(LTAs) of the PLUS7 TM are being irradiated for the 3 rd cycle after the successful completion of the 1 st and 2 nd irradiation cycles. During the 1 st and 2 nd irradiation cycles, no fuel failure was observed at LTAs and their nuclear-related parameters matched their design values well. During the overhaul period, on the other hand, pool side examinations were performed for four LTAs to generate key in-reactor fuel performance data such as fuel rod and assembly growths, fuel rod-to-top nozzle gap, fuel assembly bow and twist, fuel rod bow, spacer grid width, fuel rod diameter and fuel rod oxide layer thickness. It is found that all measured values are bounded by upper and lower predicted ones. The detailed economic analyses have shown that significant fuel cycle cost can be reduced by more than one million dollars per cycle of one KSNP with the introduction of the PLUS7 TM assembly. Furthermore, more than one hundred million dollars with power up-rating of 5% can be saved annually for currently operating eight KSNPs, which is easily and safety achievable with the PLUS7 TM assembly

Forest cover change and fragmentation using Landsat data in Maçka State Forest Enterprise in Turkey.

Science.gov (United States)

Cakir, Günay; Sivrikaya, Fatih; Keleş, Sedat

2008-02-01

Monitoring forest cover change and understanding the dynamic of forest cover is increasingly important in sustainable development and management of forest ecosystems. This paper uses remote sensing (RS) techniques to monitor forest cover change in Maçka State Forest Enterprise (MSFE) located in NE of Turkey through 1975 to 2000 and then analyses spatial and temporal changes in forest cover by Geographical Information Systems (GIS) and FRAGSTATStrade mark. Forest cover changes were detected from a time series of satellite images of Landsat MSS in 1975, Landsat TM in 1987, and Landsat ETM+ in 2000 using RS and GIS. The results showed that total forest area, productive forest area and degraded forest area increased while broadleaf forest area and non forest area decreased. Mixed forest and degraded forest increased during the first (1975-1987) period, but decreased during the second (1987-2000) period. During the whole study period, the annual forestation rate was 152 ha year(-1), equivalent to 0.27% year(-1) using the compound-interest-rate formula. The total number of patches increased from 36,204 to 48,092 (33%), and mean size of forest patch (MPS) decreased from 2.8 ha to 2.1 ha during a 25 year period. Number of smaller patches (patches in 0-100 ha size class) increased, indicating more fragmented landscape over time that might create a risk for the maintenance of biodiversity of the area. While total population increased from 1975 to 2000 (3.7%), rural population constantly decreased. The increase of forest areas may well be explained by the fact that demographic movement of rural areas concentrated into Maçka City Center. These figures also indicated that decrease in the rural population might likely lead to the release of human pressure to forest areas, probably resulting in a positive development of forest areas.

Temperature dependence of LRE-HRE-TM thin films

Science.gov (United States)

Li, Zuoyi; Cheng, Xiaomin; Lin, Gengqi; Li, Zhen; Huang, Zhixin; Jin, Fang; Wang, Xianran; Yang, Xiaofei

2003-04-01

Temperature dependence of the properties of RE-TM thin films is very important for MO recording. In this paper, we studied the temperature dependence of the magnetic and magneto-optical properties of the amorphous LRE-HRE-TM single layer thin films and LRE-HRE-TM/HRE-TM couple-bilayered thin films. For LRE-HRE-TM single layer thin films, the temperature dependence of the magnetization was investigated by using the mean field theory. The experimental and theoretical results matched very well. With the LRE substitution in HRE-TM thin film, the compensation temperature Tcomp decreased and the curie temperature Tc remained unchanged. Kerr rotation angle became larger and the saturation magnetization Ms at room temperature increased. For LRE-HRE-TM/HRE-TM couple-bilayered thin films, comparisons of the temperature dependences of the coercivities and Kerr rotation angles were made between isolated sublayers and couple-bilayered thin film.

SRTM Perspective View with Landsat Overlay: San Jose, Costa Rica

Science.gov (United States)

2001-01-01

This perspective view shows the capital city of San Jose, Costa Rica, in the right center of the image (gray area). Rising behind it are the volcanoes Irazu, 3402 meters high (11,161 feet) and Turrialba, 3330 meters high (10,925 feet.)Irazu is the highest volcano in Costa Rica and is located in the Irazu Volcano National Park, established in 1955. There have been at least 23 eruptions of Irazu since 1723, the most recent during 1963 to 1965. This activity sent tephra and secondary mudflows into cultivated areas, caused at least 40 deaths, and destroyed 400 houses and some factories.This image was generated in support of the Central American Commission for Environment and Development through an agreement with NASA. The Commission involves eight nations working to develop the Mesoamerican Biological Corridor, an effort to study and preserve some of the most biologically diverse regions of the planet.This three-dimensional perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) and an enhanced false-color Landsat 7 satellite image. Colors are from Landsat bands 5, 4, and 2 as red, green and blue, respectively. Topographic expression is exaggerated 2X.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM

Measurement of absorbed dose for high energy electron using CaSO4: Tm-PTFE TLD

International Nuclear Information System (INIS)

Park, Myeong Hwan; Kim, Do Sung

2000-01-01

In this study, the highly sensitive CaSO 4 : Tm-PTFE TLDs has been fabricated for the purpose of measurement of high energy electron. CaSO 4 : Tm phosphor powder was mixed with polytetrafluoroethylene(PTFE) powder and moulded in a disk type(diameter 8.5mm, thickness 90mg/cm 2 ) by cold pressing. The absorbed dose distribution and ranges for high energy electron were measured by using the CaSO 4 : Tm-PTFE TLDs. The ranges determined were R 100 =3D14.5mm, R 50 =3D24.1mm and R p =3D31.8mm, respectively and the beam flatness, the variation of relative dose in 80% of the field size, was 4.5%. The fabricated CaSO 4 : Tm-PTFE TLDs may be utilized in radiation dosimetry for personal, absorbed dose and environmental monitoring.=20

Measurement of the 169Tm (n ,3 n ) 167Tm cross section and the associated branching ratios in the decay of 167Tm

Science.gov (United States)

Champine, B.; Gooden, M. E.; Krishichayan, Norman, E. B.; Scielzo, N. D.; Stoyer, M. A.; Thomas, K. J.; Tonchev, A. P.; Tornow, W.; Wang, B. S.

2016-01-01

The cross section for the 169Tm(n ,3 n ) 167Tm reaction was measured from 17 to 22 MeV using quasimonoenergetic neutrons produced by the 2H(d ,n ) 3He reaction. This energy range was studied to resolve the discrepancy between previous (n ,3 n ) cross-section measurements. In addition, the absolute γ -ray branching ratios following the electron-capture decay of 167Tm were measured. These results provide more reliable nuclear data for an important diagnostic that is used at the National Ignition Facility to estimate the yield of reaction-in-flight neutrons produced via the inertial-confinement-fusion plasma in deuterium-tritium capsules.

Comparison of Landsat-8 and Sentinel-2A reflectance and normalized difference vegetation index

Science.gov (United States)

Zhang, H.; Roy, D. P.; Yan, L.; Li, Z.; Huang, H.

2017-12-01

The moderate spatial resolution satellite data from the polar-orbiting Landsat-8 (launched 2013) and Sentinel-2A (launched 2015) sensors provide 10 m to 30 m multi-spectral global coverage with a better than 5-day revisit. Although a national laboratory traceable cross-calibration comparison of the Landsat-8 Operational Land Imager (OLI) and the Sentinel-2A MultiSpectral Instrument (MSI) was undertaken pre-launch, there are a number of other sensor differences, notably due to spectral, spatial and angular differences. To examine these in a comprehensive way, Landsat-8 and Sentinel-2A data for approximately 20° × 10° of southern Africa acquired in the summer (January to March) and winter (July to September) of 2016 were compared. Only Landsat-8 and Sentinel-2A observations acquired within one-day apart were considered. The sensor data were registered and then each orbit projected into 30 m fixed global Web Enabled Landsat Data (GWELD) tiles defined in the MODIS sinusoidal equal area projection. Only corresponding sensor observations of each 30 m tile pixel that were flagged as cloud and snow-free, unsaturated, and that had no significant change in their one day separation, were compared. Both the Landsat-8 and Sentinel-2A data were atmospherically corrected using the Landsat Surface Reflectance Code (LaSRC) and were also corrected to nadir BRDF adjusted reflectance (NBAR). Top of atmosphere and surface reflectance for the spectrally corresponding visible, near infrared and shortwave infrared OLI and MSI bands, and derived normalized difference vegetation index (NDVI), were compared and their differences quantified using regression analyses. The resulting statistical transformations may be used to improve the consistency between the Landsat-8 OLI and Sentinel-2A MSI data. The importance and sensitivity of the results to correct filtering, atmospheric correction and adjustment to NBAR is demonstrated.

Landsat-based trend analysis of lake dynamics across northern permafrost regions

Science.gov (United States)

Nitze, Ingmar; Grosse, Guido; Jones, Benjamin M.; Arp, Christopher D.; Ulrich, Mathias; Federov, Alexander; Veremeeva, Alexandra

2017-01-01

Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here we present, a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM,ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e. upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

Research Article Special Issue

African Journals Online (AJOL)

2018-01-15

Jan 15, 2018 ... This study examines the spatial and temporal changes of land use and land ... industry, etc.). .... In this study, the Landsat images (l 1-5 MSS, l 4-5TM) with 30 m ..... GIS: A case study of Ilorin and its environs in Kwara, State.

Perspectives on monitoring gradual change across the continuity of Landsat sensors using time-series data

Science.gov (United States)

Vogelmann, James; Gallant, Alisa L.; Shi, Hua; Zhu, Zhe

2016-01-01

There are many types of changes occurring over the Earth's landscapes that can be detected and monitored using Landsat data. Here we focus on monitoring “within-state,” gradual changes in vegetation in contrast with traditional monitoring of “abrupt” land-cover conversions. Gradual changes result from a variety of processes, such as vegetation growth and succession, damage from insects and disease, responses to shifts in climate, and other factors. Despite the prevalence of gradual changes across the landscape, they are largely ignored by the remote sensing community. Gradual changes are best characterized and monitored using time-series analysis, and with the successful launch of Landsat 8 we now have appreciable data continuity that extends the Landsat legacy across the previous 43 years. In this study, we conducted three related analyses: (1) comparison of spectral values acquired by Landsats 7 and 8, separated by eight days, to ensure compatibility for time-series evaluation; (2) tracking of multitemporal signatures for different change processes across Landsat 5, 7, and 8 sensors using anniversary-date imagery; and (3) tracking the same type of processes using all available acquisitions. In this investigation, we found that data representing natural vegetation from Landsats 5, 7, and 8 were comparable and did not indicate a need for major modification prior to use for long-term monitoring. Analyses using anniversary-date imagery can be very effective for assessing long term patterns and trends occurring across the landscape, and are especially good for providing insights regarding trends related to long-term and continuous trends of growth or decline. We found that use of all available data provided a much more comprehensive level of understanding of the trends occurring, providing information about rate, duration, and intra- and inter-annual variability that could not be readily gleaned from the anniversary date analyses. We observed that using all

Thermal stability and glass-forming ability of amorphous Nd-Al-TM (TM=Fe, Co, Ni or Cu) alloys

International Nuclear Information System (INIS)

Inoue, A.; Zhang Tao

1997-01-01

Bulk amorphous alloys were prepared for Nd 70 Al 10 TM 20 and Nd 60 Al 10 TM 30 (TM=Fe or Co) alloys by copper mold casting. The maximum sample thickness for glass formation reaches 15 mm for the Nd-Al-Fe alloys and 5 mm for the Nd-Al-Co alloys. A significant difference in the phase transition upon heating is recognized between the Fe- and Co-containing alloys. No glass transition before crystallization is observed for the Nd-Al-Fe alloys, but the Nd-Al-Co alloys exhibit the glass transition. The ΔT x (=T x -T g ) and T g /T m are 40-55 K and 0.65-0.67, respectively, for the latter alloys. The absence of supercooled liquid for the former alloys is different from those for all bulk amorphous alloys reported up to date. The T x /T m and ΔT m (=T m -T x ) are 0.85-0.89 and 88-137 K, respectively, for the Nd-Al-Fe alloys and, hence, the large glass-forming ability is presumably due to the high T x /T m and small ΔT m values. (orig.)

Assessment of The trophic state and Chlorophyll-a concentrations using Landsat OLI in Karaoun reservoir, Lebanon

Directory of Open Access Journals (Sweden)

Ali Fadel

2016-12-01

Full Text Available Fadel, A., Faour G. and Slim K. 2016. Assessment of the trophic state and chlorophyll-a concentrations using Landsat OLI in Karaoun reservoir, Lebanon. Lebanese Science Journal, 17(2: 130-145. Harmful algal blooms have become a worldwide environmental problem. A regular and cost-effective monitoring of these blooms is highly needed by lakes managers. Satellite remote sensing imagery like Landsat Operational Land Imager (OLI can be used to assess and monitor chlorophyll-a in water bodies over large areas in a cost-effective way. In this study, the accuracy of Landsat OLI to estimate chlorophyll-a was examined. Four field campaigns and cloud free images of Landsat OLI with 30 m resolution (01 May 2013, 21 August 2013, 10 July 2015, and 11 August 2015 were used in this study to determine the accuracy of Landsat OLI in estimating chlorophyll-a in a 12 km2 freshwater body, Karaoun reservoir. After atmospheric correction of these images, reflectance of single and multiple band combinations were compared to field chlorophyll-a data. Results of field campaigns showed that the trophic state of Karaoun reservoir is still eutrophic to hypereutrophic with high nutrient concentration and low phytoplankton biodiversity, dominated by cyanobacteria species, Microcystis aeruginosa and Aphanizomenon ovalisporum. On single band level, the in situ chlorophyll-a measurement correlated best with band 5 (0.85 - 0.88 µm, with R=0.75 and R2=0.57. Highest correlation (R=0.84 and R2=0.72 was obtained using band combination, B2:B4 band ratio multiplied by B5. Results indicated that Landsat OLI can be used effectively to determine chlorophyll-a concentration in lakes and reservoirs. We recommend the application of Landsat OLI as a satisfactory and cost effective method for monitoring chlorophyll-a in other lakes through-out the world

Influence of Tm+3 concentration on the non-linear optical effects of the BiB3O6 : Tm3+ glass nanoparticle-doped polymer

International Nuclear Information System (INIS)

Majchrowski, A; Ebothe, J; Ozga, K; Kityk, I V; Reshak, A H; Lukasiewicz, T; Brik, M G

2010-01-01

It is shown that BiB 3 O 6 : Tm 3+ glass nanoparticles incorporated into polymethylmethacrylate (PMMA) and polycarbonate (PC) polymer matrices show good second-order susceptibilities under bicolour coherent laser treatment. It is found that only during incorporation into highly polarized PC matrices could one observe an enhancement of the second-order susceptibilities with increasing laser treated power densities. The main increase is observed for all samples at power densities equal to about 0.4 GW cm -2 . After passing this value there is a saturation of the output susceptibilities and even an abrupt decrease. The most striking feature is the achievement of second-order susceptibilities equal to about 5 pm V -1 for samples containing 4% nanoparticle (NP) content in the PC matrix. A further increase in the NP concentration to 6% leads to a decrease in susceptibility to 15%. In the case of PMMA matrices these changes do not exceed the background. The same situation is present for the pure BIBO and low-doped Tm materials. The effect is maximal for a low concentration of Tm-about 0.75%. In the case of bulk glasses the intensity dependences of the second-harmonic generation unambiguously show that the achieved maximal values of second-order susceptibilities do not exceed 3 pm V -1 for 0.5% Tm concentration.

Virally encoded 7TM receptors

DEFF Research Database (Denmark)

Rosenkilde, M M; Waldhoer, M; Lüttichau, H R

2001-01-01

expression of this single gene in certain lymphocyte cell lineages leads to the development of lesions which are remarkably similar to Kaposi's sarcoma, a human herpesvirus 8 associated disease. Thus, this and other virally encoded 7TM receptors appear to be attractive future drug targets.......A number of herpes- and poxviruses encode 7TM G-protein coupled receptors most of which clearly are derived from their host chemokine system as well as induce high expression of certain 7TM receptors in the infected cells. The receptors appear to be exploited by the virus for either immune evasion...

Bridging the Divide: Translating Landsat Research Into Usable Science

Science.gov (United States)

Rocchio, L. E.; Davis, A. L.

2006-12-01

Science has long served humankind. Breakthroughs in medicine have increased longevity and advances in technology have made modern-day conveniences possible. Yet, social benefits begotten by the environmental sciences, although critical for the survival of humanity, have not always been as widely recognized or used. To benefit today's rapidly growing population, the divides between environmental research, applied environmental science, and use of this information by decision makers must be bridged. Lessons about the translation from research to usable science can be learned from the four decades of Landsat history, and these lessons can serve as useful models for bridging the gaps between new technology, scientific research, and the use of that research and technology in real-world problem solving. In 1965, William Pecora, then-director of the U.S. Geological Survey, proposed the idea of a remote sensing satellite program to gather facts about natural resources of Earth. For the next seven years, an intense campaign showing the depth and diversity of satellite imagery applications was waged. This led to the 1972 launch of the first civilian land-observing satellite, Landsat 1. By 1975, successful application research based on Landsat 1 imagery prompted then-NASA Administrator Dr. James Fletcher to proclaim that if one space age development would save the world, it would be Landsat and its successor satellites. Thirty-four years of continual Landsat imaging and related-research has lead to the implementation of many socially beneficial applications, such as improved water management techniques, crop insurance fraud reduction, illicit crop inventories, natural disaster relief planning, continent-scale carbon estimates, and extensive cartographic advances. Despite these successes, the challenge of translating Landsat research into realized social benefits remains. Even in this geospatially-savvy era, the utility of Landsat largely escapes policymakers. Here, in an

Perspective with Landsat Overlay, Mount Kilimanjaro, Tanzania

Science.gov (United States)

2002-01-01

Mount Kilimanjaro (Kilima Njaro or 'shining mountain' in Swahili), the highest point in Africa, reaches 5,895 meters (19,340 feet) above sea level, tall enough to maintain a permanent snow cap despite being just 330 kilometers (210 miles) south of the equator. It is the tallest free-standing mountain on the Earth's land surface world, rising about 4,600 meters (15,000 feet) above the surrounding plain. Kilimanjaro is a triple volcano (has three peaks) that last erupted perhaps more than 100,000 years ago but still exudes volcanic gases. It is accompanied by about 20 other nearby volcanoes, some of which are seen to the west (left) in this view, prominently including Mount Meru, which last erupted only about a century ago. The volcanic mountain slopes are commonly fertile and support thick forests, while the much drier grasslands of the plains are home to elephants, lions, and other savanna wildlife.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM), a Landsat 7 satellite image, and a false sky. Topographic expression is vertically exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and

Automated Method for Monitoring Water Quality Using Landsat Imagery

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D. Clay Barrett

2016-06-01

Full Text Available Regular monitoring of water quality is increasingly necessary to keep pace with rapid environmental change and protect human health and well-being. Remote sensing has been suggested as a potential solution for monitoring certain water quality parameters without the need for in situ sampling, but universal methods and tools are lacking. While many studies have developed predictive relationships between remotely sensed surface reflectance and water parameters, these relationships are often unique to a particular geographic region and have little applicability in other areas. In order to remotely monitor water quality, these relationships must be developed on a region by region basis. This paper presents an automated method for processing remotely sensed images from Landsat Thematic Mapper (TM and Enhanced Thematic Mapper Plus (ETM+ and extracting corrected reflectance measurements around known sample locations to allow rapid development of predictive water quality relationships to improve remote monitoring. Using open Python scripting, this study (1 provides an openly accessible and simple method for processing publicly available remote sensing data; and (2 allows determination of relationships between sampled water quality parameters and reflectance values to ultimately allow predictive monitoring. The method is demonstrated through a case study of the Ozark/Ouchita-Appalachian ecoregion in eastern Oklahoma using data collected for the Beneficial Use Monitoring Program (BUMP.

Consistency of land surface reflectance data: presentation of a new tool and case study with Formosat-2, SPOT-4 and Landsat-5/7/8 data

Science.gov (United States)

Claverie, M.; Vermote, E.; Franch, B.; Huc, M.; Hagolle, O.; Masek, J.

2013-12-01

Maintaining consistent dataset of Surface Reflectance (SR) data derived from the large panel of in-orbit sensors is an important challenge to ensure long term analysis of earth observation data. Continuous validation of such SR products through comparison with a reference dataset is thus an important challenge. Validating with in situ or airborne SR data is not easy since the sensors rarely match completely the same spectral, spatial and directional characteristics of the satellite measurement. Inter-comparison between satellites sensors data appears as a valuable tool to maintain a long term consistency of the data. However, satellite data are acquired at various times of the day (i.e., variation of the atmosphere content) and within a relative large range of geometry (view and sun angles). Also, even if band-to-band spectral characteristics of optical sensors are closed, they rarely have identical spectral responses. As the results, direct comparisons without consideration of these differences are poorly suitable. In this study, we suggest a new systematic method to assess land optical SR data from high to medium resolution sensors. We used MODIS SR products (MO/YD09CMG) which benefit from a long term calibration/validation process, to assess SR from 3 sensors data: Formosat-2 (280 scenes 24x24km - 5 sites), SPOT-4 (62 scenes 120x60km - 1 site) and Landsat-5/7 (104 180x180km scenes - 50 sites). The main issue concerns the difference in term of geometry acquisition between MODIS and compared sensors data. We used the VJB model (Vermote et al. 2009, TGRS) to correct MODIS SR from BRDF effects and to simulate SR at the corresponding geometry (view and sun angles) of each pixel of the compared sensor data. The comparison is done at the CMG spatial resolution (0.05°) which ensures a constant field-of-view and negligible geometrical errors. Figure 1 displays the summary of the NIR results through APU graphs where metrics A, P and U stands for Accuracy, Precision and

The Landsat Phenology Study (LaPS): Preliminary CONUS Results for 2008

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Henebry, Geoffrey M.; Roy, David P.; Ju, Junchang; Kovalskyy, Valeriy

2010-05-01

Most studies of land surface phenology (LSP) have used time series derived from moderate spatial resolution satellite sensor data (e.g., AVHRR, MODIS, VEGETATION) because these data are freely available and because they provide an acceptable trade-off between higher, near daily, temporal frequency of observation needed to reduce cloud contamination against lower (500m-5km) spatial resolution. The recent opening of the USGS Landsat archive to web-enabled access presents the opportunity to explore how well Landsat time series can portray LSPs at high spatial resolution. The NASA Web-enabled Landsat data (WELD) project (http://landsat.usgs.gov/WELD.php) has produced 30m composited mosaics for all the conterminous US (CONUS) from Landsat 7 ETM+ data. The composited mosaics are generated on monthly, seasonal, and annual basis and include spectral reflectance, normalized difference vegetation index (NDVI), and the acquisition date of each composited pixel. The WELD compositing approach is designed to select valid land surface observations with minimal cloud, snow, and atmospheric contamination. We extracted 30m pixel time series from the twelve monthly WELD composited mosaics for 2008 at 320 locations across the CONUS where we have ground phenological observations that are heterogeneous with respect to the types of plants observed, the phenophases recorded (predominantly spring green-up) and the ground sampling protocols used. The ground data came from several sources, including the cloned lilac/honeysuckle network, the Phenocam network, five LTER sites (H.J. Andrews, Harvard Forest, Jornada, Konza Prairie, and Sevilleta), and a private woodlot in Maine. Temporal profiles of the 30m WELD Landsat NDVI, the green NDVI (GNDVI), the normalized difference infrared index (NDII) derived from the composited reflectances, are compared to the ground observations. Results show that (i) inclusion of the Landsat acquisition date for each pixel improves the characterization of the LSP

Lake Area Analysis Using Exponential Smoothing Model and Long Time-Series Landsat Images in Wuhan, China

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Gonghao Duan

2018-01-01

Full Text Available The loss of lake area significantly influences the climate change in a region, and this loss represents a serious and unavoidable challenge to maintaining ecological sustainability under the circumstances of lakes that are being filled. Therefore, mapping and forecasting changes in the lake is critical for protecting the environment and mitigating ecological problems in the urban district. We created an accessible map displaying area changes for 82 lakes in the Wuhan city using remote sensing data in conjunction with visual interpretation by combining field data with Landsat 2/5/7/8 Thematic Mapper (TM time-series images for the period 1987–2013. In addition, we applied a quadratic exponential smoothing model to forecast lake area changes in Wuhan city. The map provides, for the first time, estimates of lake development in Wuhan using data required for local-scale studies. The model predicted a lake area reduction of 18.494 km2 in 2015. The average error reached 0.23 with a correlation coefficient of 0.98, indicating that the model is reliable. The paper provided a numerical analysis and forecasting method to provide a better understanding of lake area changes. The modeling and mapping results can help assess aquatic habitat suitability and property planning for Wuhan lakes.

Valuing geospatial information: Using the contingent valuation method to estimate the economic benefits of Landsat satellite imagery

Science.gov (United States)

Loomis, John; Koontz, Steve; Miller, Holly M.; Richardson, Leslie A.

2015-01-01

While the U.S. government does not charge for downloading Landsat images, the images have value to users. This paper demonstrates a method that can value Landsat and other imagery to users. A survey of downloaders of Landsat images found: (a) established US users have a mean value of $912 USD per scene; (b) new US users and users returning when imagery became free have a mean value of $367 USD per scene. Total US user benefits for the 2.38 million scenes downloaded is $1.8 billion USD. While these benefits indicate a high willingness-to-pay among many Landsat downloaders, it would be economically inefficient for the US government to charge for Landsat imagery. Charging a price of $100 USD a scene would result in an efficiency loss of $37.5 million a year. This economic information should be useful to policy-makers who must decide about the future of this and similar remote sensing programs.

Tropical forest plantation biomass estimation using RADARSAT-SAR and TM data of south china

Science.gov (United States)

Wang, Chenli; Niu, Zheng; Gu, Xiaoping; Guo, Zhixing; Cong, Pifu

2005-10-01

Forest biomass is one of the most important parameters for global carbon stock model yet can only be estimated with great uncertainties. Remote sensing, especially SAR data can offers the possibility of providing relatively accurate forest biomass estimations at a lower cost than inventory in study tropical forest. The goal of this research was to compare the sensitivity of forest biomass to Landsat TM and RADARSAT-SAR data and to assess the efficiency of NDVI, EVI and other vegetation indices in study forest biomass based on the field survey date and GIS in south china. Based on vegetation indices and factor analysis, multiple regression and neural networks were developed for biomass estimation for each species of the plantation. For each species, the better relationships between the biomass predicted and that measured from field survey was obtained with a neural network developed for the species. The relationship between predicted and measured biomass derived from vegetation indices differed between species. This study concludes that single band and many vegetation indices are weakly correlated with selected forest biomass. RADARSAT-SAR Backscatter coefficient has a relatively good logarithmic correlation with forest biomass, but neither TM spectral bands nor vegetation indices alone are sufficient to establish an efficient model for biomass estimation due to the saturation of bands and vegetation indices, multiple regression models that consist of spectral and environment variables improve biomass estimation performance. Comparing with TM, a relatively well estimation result can be achieved by RADARSAT-SAR, but all had limitations in tropical forest biomass estimation. The estimation results obtained are not accurate enough for forest management purposes at the forest stand level. However, the approximate volume estimates derived by the method can be useful in areas where no other forest information is available. Therefore, this paper provides a better

Tm:GGAG crystal for 2μm tunable diode-pumped laser

Science.gov (United States)

Šulc, Jan; Boháček, Pavel; Němec, Michal; Fibrich, Martin; Jelínková, Helena; Trunda, Bohumil; Havlák, Lubomír.; Jurek, Karel; Nikl, Martin

2016-04-01

The spectroscopy properties and wavelength tunability of diode pumped laser based on Tm-doped mixed gadolinium-gallium-aluminium garnet Gd3(GaxAl1-x)5O12 (Tm:GGAG) single crystal were investigated for the first time. The crystal was grown by Czochralski method in a slightly oxidative atmosphere using an iridium crucible. The tested Tm:GGAG sample was cut from the grown crystal boule perpendicularly to growth direction (c-axis). The composition of sample was determined using electron microprobe X-ray elemental analysis. For spectroscopy and laser experiments 3.5mm thick plane-parallel face-polished plate (without AR coatings) with composition Gd2.76Tm0.0736Ga2.67Al2.50O12 (2.67 at.% Tm/Gd) was used. A fiber (core diameter 400 μm, NA= 0.22) coupled laser diode (emission wavelength 786 nm) was used for longitudinal Tm:GGAG pumping. The laser diode was operating in the pulsed regime (10 ms pulse length, 10 Hz repetition rate, maximum power amplitude 18 W). The 145mm long semi-hemispherical laser resonator consisted of a flat pumping mirror (HR @ 1.8- 2.10 μm, HT @ 0.78 μm) and curved (r = 150mm) output coupler with a reflectivity of » 97% @ 1.8- 2.10 µm. The maximum laser output power amplitude 1.14W was obtained at wavelength 2003nm for absorbed pump power amplitude 4.12W. The laser slope efficiency was 37% in respect to absorbed pumping power. Wavelength tuning was accomplished by using 2mm thick MgF2 birefringent filter placed inside the laser resonator at the Brewster angle. The laser was continuously tunable over 180nm in a spectral region from 1856nm to 2036 nm.

Identifying Spatial Units of Human Occupation in the Brazilian Amazon Using Landsat and CBERS Multi-Resolution Imagery

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Maria Isabel Sobral Escada

2012-01-01

Full Text Available Every spatial unit of human occupation is part of a network structuring an extensive process of urbanization in the Amazon territory. Multi-resolution remote sensing data were used to identify and map human presence and activities in the Sustainable Forest District of Cuiabá-Santarém highway (BR-163, west of Pará, Brazil. The limits of spatial units of human occupation were mapped based on digital classification of Landsat-TM5 (Thematic Mapper 5 image (30m spatial resolution. High-spatial-resolution CBERS-HRC (China-Brazil Earth Resources Satellite-High-Resolution Camera images (5 m merged with CBERS-CCD (Charge Coupled Device images (20 m were used to map spatial arrangements inside each populated unit, describing intra-urban characteristics. Fieldwork data validated and refined the classification maps that supported the categorization of the units. A total of 133 spatial units were individualized, comprising population centers as municipal seats, villages and communities, and units of human activities, such as sawmills, farmhouses, landing strips, etc. From the high-resolution analysis, 32 population centers were grouped in four categories, described according to their level of urbanization and spatial organization as: structured, recent, established and dependent on connectivity. This multi-resolution approach provided spatial information about the urbanization process and organization of the territory. It may be extended into other areas or be further used to devise a monitoring system, contributing to the discussion of public policy priorities for sustainable development in the Amazon.

[Study of serum thrombomodulin(TM) levels in patients with hyper- or hypo- thyroidism].

Science.gov (United States)

Soma, M; Maeda, Y; Matsuura, R; Sasaki, I; Kasakura, S; Saeki, Y; Ikekubo, K; Ishihara, T; Kurahachi, H; Sasaki, S; Tagami, T; Nakao, K

1997-01-01

We studies a relationship between the serum levels of thrombomodulin(TM) and the thyroid functions. Serum TM levels were measured in 48 patients with Graves' disease, 17 patients with primary hypothyroidism, 7 patients with subacute thyroiditis, 5 patients with painless thyroiditis and 2 patients with systematic Refetoff syndrome. These patients did not have malignant tumor, kidney failure, or blood vessel injury. Control sera were obtained from 42 healthy subjects. Serum levels of TM in patients with untreated Graves' disease were significantly higher(p thyroid function(FT3, FT4 and TH) in patients with Graves' disease during treatment showed that both the serum levels of TM and thyroid hormones (FT3 and FT4) lowered progressively during treatment. After normalization of serum FT3 and FT4, the serum TM levels returned to normal. However, the serum levels of TM in patients with destructive thyroiditis and Refetoff syndrome were normal in spite of high serum levels of thyroid hormones. These data suggest that an increase in serum levels of TM is not the direct result of thyroid hormones themselves but is the result of the prolonged hypermetabolic state induced by their peripheral activities. Thyroid hormones may stimulate the synthesis or metabolism of TM on the surface of vascular endothelial cells in the patients with Graves' disease.

Comparison of Sentinel-2A and Landsat-8 Nadir BRDF Adjusted Reflectance (NBAR) over Southern Africa

Science.gov (United States)

Li, J.; Roy, D. P.; Zhang, H.

2016-12-01

The Landsat satellites have been providing moderate resolution imagery of the Earth's surface for over 40 years with continuity provided by the Landsat 8 and planned Landsat 9 missions. The European Space Agency Sentinel-2 satellite was successfully launched into a polar sun-synchronous orbit in 2015 and carries the Multi Spectral Instrument (MSI) that has Landsat-like bands and acquisition coverage. These new sensors acquire images at view angles ± 7.5° (Landsat) and ± 10.3° (Sentinel-2) from nadir that result in small directional effects in the surface reflectance. When data from adjoining paths, or from long time series are used, a model of the surface anisotropy is required to adjust observations to a uniform nadir view (primarily for visual consistency, vegetation monitoring, or detection of subtle surface changes). Recently a generalized approach was published that provides consistent Landsat view angle corrections to provide nadir BRDF-adjusted reflectance (NBAR). Because the BRDF shapes of different terrestrial surfaces are sufficiently similar over the narrow 15° Landsat field of view, a fixed global set of MODIS BRDF spectral model parameters was shown to be adequate for Landsat NBAR derivation with little sensitivity to the land cover type, condition, or surface disturbance. This poster demonstrates the application of this methodology to Sentinel-2 data over a west-east transect across southern Africa. The reflectance differences between adjacent overlapping paths in the forward and backward scatter directions are quantified for both before and after BRDF correction. Sentinel-2 and Landsat-8 reflectance and NBAR inter-comparison results considering different stages of cloud and saturation filtering, and filtering to reduce surface state differences caused by acquisition time differences, demonstrate the utility of the approach. The relevance and limitations of the corrections for providing consistent moderate resolution reflectance are discussed.

Comparison of NMR and crystal structures for the proteins TM1112 and TM1367

International Nuclear Information System (INIS)

Mohanty, Biswaranjan; Serrano, Pedro; Pedrini, Bill; Jaudzems, Kristaps; Geralt, Michael; Horst, Reto; Herrmann, Torsten; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

2010-01-01

NMR structures of the proteins TM1112 and TM1367 solved by the JCSG in solution at 298 K could be superimposed with the corresponding crystal structures at 100 K with r.m.s.d. values of <1.0 Å for the backbone heavy atoms. For both proteins the structural differences between multiple molecules in the asymmetric unit of the crystals correlated with structural variations within the bundles of conformers used to represent the NMR solution structures. A recently introduced JCSG NMR structure-determination protocol, which makes use of the software package UNIO for extensive automation, was further evaluated by comparison of the TM1112 structure obtained using these automated methods with another NMR structure that was independently solved in another PSI center, where a largely interactive approach was applied. The NMR structures of the TM1112 and TM1367 proteins from Thermotoga maritima in solution at 298 K were determined following a new protocol which uses the software package UNIO for extensive automation. The results obtained with this novel procedure were evaluated by comparison with the crystal structures solved by the JCSG at 100 K to 1.83 and 1.90 Å resolution, respectively. In addition, the TM1112 solution structure was compared with an NMR structure solved by the NESG using a conventional largely interactive methodology. For both proteins, the newly determined NMR structure could be superimposed with the crystal structure with r.m.s.d. values of <1.0 Å for the backbone heavy atoms, which provided a starting platform to investigate local structure variations, which may arise from either the methods used or from the different chemical environments in solution and in the crystal. Thereby, these comparative studies were further explored with the use of reference NMR and crystal structures, which were computed using the NMR software with input of upper-limit distance constraints derived from the molecular models that represent the results of structure

Landsat-8: Science and product vision for terrestrial global change research

Science.gov (United States)

Roy, David P.; Wulder, M.A.; Loveland, Thomas R.; Woodcock, C.E.; Allen, R. G.; Anderson, M. C.; Helder, D.; Irons, J.R.; Johnson, D.M.; Kennedy, R.; Scambos, T.A.; Schaaf, Crystal B.; Schott, J.R.; Sheng, Y.; Vermote, E. F.; Belward, A.S.; Bindschadler, R.; Cohen, W.B.; Gao, F.; Hipple, J. D.; Hostert, Patrick; Huntington, J.; Justice, C.O.; Kilic, A.; Kovalskyy, Valeriy; Lee, Z. P.; Lymburner, Leo; Masek, J.G.; McCorkel, J.; Shuai, Y.; Trezza, R.; Vogelmann, James; Wynne, R.H.; Zhu, Z.

2014-01-01

Landsat 8, a NASA and USGS collaboration, acquires global moderate-resolution measurements of the Earth's terrestrial and polar regions in the visible, near-infrared, short wave, and thermal infrared. Landsat 8 extends the remarkable 40 year Landsat record and has enhanced capabilities including new spectral bands in the blue and cirrus cloud-detection portion of the spectrum, two thermal bands, improved sensor signal-to-noise performance and associated improvements in radiometric resolution, and an improved duty cycle that allows collection of a significantly greater number of images per day. This paper introduces the current (2012–2017) Landsat Science Team's efforts to establish an initial understanding of Landsat 8 capabilities and the steps ahead in support of priorities identified by the team. Preliminary evaluation of Landsat 8 capabilities and identification of new science and applications opportunities are described with respect to calibration and radiometric characterization; surface reflectance; surface albedo; surface temperature, evapotranspiration and drought; agriculture; land cover, condition, disturbance and change; fresh and coastal water; and snow and ice. Insights into the development of derived ‘higher-level’ Landsat products are provided in recognition of the growing need for consistently processed, moderate spatial resolution, large area, long-term terrestrial data records for resource management and for climate and global change studies. The paper concludes with future prospects, emphasizing the opportunities for land imaging constellations by combining Landsat data with data collected from other international sensing systems, and consideration of successor Landsat mission requirements.

White light emission from Tm3+/Dy3+ co-doped oxyfluoride germanate glasses under UV light excitation

International Nuclear Information System (INIS)

Lakshminarayana, G.; Yang Hucheng; Qiu Jianrong

2009-01-01

In this paper, we report on the absorption and photoluminescence properties of Tm 3+ /Dy 3+ ions co-doped oxyfluoride germanate glasses for white light emission. The X-ray diffraction (XRD) and differential thermal analysis (DTA) profiles of the host glass have been carried out to confirm its structure and thermal stability. From the measured absorption spectra, Judd-Ofelt (J-O) intensity parameters (Ω 2 , Ω 4 and Ω 6 ) have been evaluated for Tm 3+ and Dy 3+ ions. A combination of blue, yellow and red emissions has emerged in these glasses, which allows the observation of bright white light when the glasses are excited by the ultraviolet light. The white light luminescence colour could be changed by varying the excitation wavelength. Also, various colours of luminescence, including white light, can be easily tuned by adjusting the concentrations of Tm 3+ or Dy 3+ ions in the co-doped glasses. Concentration quenching effect was also investigated and possible energy transfer mechanism from Dy 3+ →Tm 3+ ions was explained which is also confirmed by the decay lifetime measurements. - Graphical Abstract: A combination of blue, yellow and red emissions has emerged from Tm 3+ /Dy 3+ co-doped glasses, which allows the observation of bright white light and makes them as excellent candidates applicable in the solid-state multi-colour three-dimensional display.

Cartografía mediante imágenes Landsat de suelos salinos en la tierra de Medina (Valladolid

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García Rodríguez, M. P.

2010-07-01

Full Text Available The main goal of this study is the mapping of saline soils (solonchaks, solonetzs and luvisols with salic phases in «Tierra de Medina» (Valladolid using images of the TM and ETM sensors of the Landsat satellites. The spectral signatures of these soils show very high digital values, which allows to differentiate them from other types of soils and superficial covers. The highest values correspond to those which have salt efflorescences and the lowest values to soils affected by hydromorphic processes. The images obtained with the NDVI do not allow a clear discrimination of saline soils, but they allow to interpret the changes in their use. In these soils the values of NDVI are very low, due to their scarce vegetation. There is a remarkable vegetation reduction between years 1987 and 2001, which implies a structure deterioration and a great loss of vegetal cover; many of soils affected by salinization have not been cultivated any more.

El objetivo del estudio es cartografiar los suelos salinos (solonchaks, solonetzs y luvisoles con fases sálicas en la Tierra de Medina (Valladolid utilizado imágenes de los sensores TM y ETM de los satélites Landsat. Las signaturas espectrales de estos suelos muestran valores digitales muy altos, lo que permite diferenciarlos de otros tipos de suelos y cubiertas superficiales. Los valores más altos corresponden a los que tienen eflorescencias salinas en superficie y los más bajos a los suelos afectados por hidromorfismo. Las imágenes obtenidas con el NDVI no permiten una clara discriminación de los suelos salinos, pero sí interpretar los cambios en su uso. En estos suelos los valores de NDVI son muy bajos, acordes con su escasa vegetación. Hay un notable descenso entre los años 1987 y 2001, lo que implica un deterioro de su estructura y una gran pérdida de cubierta vegetal; muchos de los suelos afectados por salinización se han dejado de cultivar. [fr] L’objectif de l’étude est

Assessment of the Trophic State and Chlorophyll-A Concentrations using Landsat OLI in Karaoun Reservoir Lebanon

International Nuclear Information System (INIS)

Fadel, A.; Faour, GH.; Slim, K.

2016-01-01

Harmful algal blooms have become a worldwide environmental problem. A regular and cost -effective monitoring of these blooms is highly needed by lakes managers. Satellite remote sensing imagery like Landsat Operational Land Imager (OLI) can be used to assess and monitor chlorophyll-a in water bodies over large areas in a cost-effective way. In this study, the accuracy of Landsat OLI to estimate chlorophyll-a was examined. Four field campaigns and cloud free images of Landsat OLI with 30 m resolution (01 May 2013, 21 August 2013, 10 July 2015, and 11 August 2015) were used in this study to determine the accuracy of Landsat OLI in estimating chlorophyll-a in a 12 km2 fresh water body, Karaoun reservoir. After atmospheric correction of these images, reflectance of single and multiple band combinations were compared to field chlorophyll-a data. Results of field campaigns showed that the trophic state of Karaoun reservoir is still eutrophic to hypereutrophic withhigh nutrient concentration andlow phytoplankton biodiversity, dominatedby cyanobacteria species, Microcystis aeruginosa and Aphanizomenon ovalisporum. On single band level, the n situ chlorophyll-a measurement correlated best with band 5 (0.85 -0.88 μm), with R=0.75 and R2=0.57.Highest correlation (R=0.84 and R2=0.72) was obtained using band combination, B2:B4 band ratio multiplied by B5. Results indicated that Landsat OLI can be used effectively to determine chlorophyll-a concentration in lakes and reservoirs. We recommend the application of Landsat OLI as a satisfactory and cost effective method for monitoring chlorophyll-a in other lakes through-out the world. (author)

SRTM Perspective View with Landsat Overlay: Costa Rica Coastal Plain

Science.gov (United States)

2001-01-01

This perspective view shows the northern coastal plain of Costa Rica with the Cordillera Central, composed of a number of active and dormant volcanoes, rising in the background. This view looks toward the south over the Rio San Juan, which marks the boundary between Costa Rica and Nicaragua. The smaller river joining Rio San Juan in the center of the image is Rio Sarapiqui, which is navigable upstream as far inland as Puerto Viejo (Old Port) de Sarapiqui at the mountain's base. This river was an important transportation route for those few hardy settlers who first moved into this region, although as recently as 1953 a mere three thatched-roof houses were all that comprised the village of Puerto Viejo.This coastal plain is a sedimentary basin formed about 50 million years ago composed of river alluvium and lahar (mud and ash flow) deposits from the volcanoes of the Cordillera Central. It comprises the province of Heredia (the smallest of Costa Rica's seven) and demonstrates a wide range of climatic conditions, from warm and humid lowlands to cool and damp highlands, and including the mild but seasonally wet and dry Central Valley.This image was generated in support of the Central American Commission for Environment and Development through an agreement with NASA. The Commission involves eight nations working to develop the Mesoamerican Biological Corridor, an effort to study and preserve some of the most biologically diverse regions of the planet.This three-dimensional perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) and an enhanced false-color Landsat 7 satellite image. Colors are from Landsat bands 5, 4, and 2 as red, green and blue, respectively. Topographic expression is exaggerated 2X.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat

Landsat and water pollution

Science.gov (United States)

Castruccio, P.; Fowler, T.; Loats, H., Jr.

1979-01-01

Report presents data derived from satellite images predicting pollution loads after rainfall. It explains method for converting Landsat images of Eastern United States into cover maps for Baltimore/five county region.

Intracellular distribution of TM4SF1 and internalization of TM4SF1-antibody complex in vascular endothelial cells

International Nuclear Information System (INIS)

Sciuto, Tracey E.; Merley, Anne; Lin, Chi-Iou; Richardson, Douglas; Liu, Yu; Li, Dan; Dvorak, Ann M.; Dvorak, Harold F.; Jaminet, Shou-Ching S.

2015-01-01

Transmembrane-4 L-six family member-1 (TM4SF1) is a small plasma membrane-associated glycoprotein that is highly and selectively expressed on the plasma membranes of tumor cells, cultured endothelial cells, and, in vivo, on tumor-associated endothelium. Immunofluorescence microscopy also demonstrated TM4SF1 in cytoplasm and, tentatively, within nuclei. With monoclonal antibody 8G4, and the finer resolution afforded by immuno-nanogold transmission electron microscopy, we now demonstrate TM4SF1 in uncoated cytoplasmic vesicles, nuclear pores and nucleoplasm. Because of its prominent surface location on tumor cells and tumor-associated endothelium, TM4SF1 has potential as a dual therapeutic target using an antibody drug conjugate (ADC) approach. For ADC to be successful, antibodies reacting with cell surface antigens must be internalized for delivery of associated toxins to intracellular targets. We now report that 8G4 is efficiently taken up into cultured endothelial cells by uncoated vesicles in a dynamin-dependent, clathrin-independent manner. It is then transported along microtubules through the cytoplasm and passes through nuclear pores into the nucleus. These findings validate TM4SF1 as an attractive candidate for cancer therapy with antibody-bound toxins that have the capacity to react with either cytoplasmic or nuclear targets in tumor cells or tumor-associated vascular endothelium. - Highlights: • Anti-TM4SF1 antibody 8G4 was efficiently taken up by cultured endothelial cells. • TM4SF1–8G4 internalization is dynamin-dependent but clathrin-independent. • TM4SF1–8G4 complexes internalize along microtubules to reach the perinuclear region. • Internalized TM4SF1–8G4 complexes pass through nuclear pores into the nucleus. • TM4SF1 is an attractive candidate for ADC cancer therapy

Intracellular distribution of TM4SF1 and internalization of TM4SF1-antibody complex in vascular endothelial cells

Energy Technology Data Exchange (ETDEWEB)

Sciuto, Tracey E.; Merley, Anne; Lin, Chi-Iou [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States); Richardson, Douglas [Department of Molecular and Cellular Biology, Harvard University (United States); Liu, Yu [Department of Pharmacology, Shanxi Medical University, Xinjiannanlu 56, Shanxi Province, Taiyuan 030001 (China); Li, Dan; Dvorak, Ann M. [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States); Dvorak, Harold F., E-mail: hdvorak@bidmc.harvard.edu [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States); Jaminet, Shou-Ching S., E-mail: sjaminet@bidmc.harvard.edu [Center for Vascular Biology Research and Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School (United States)

2015-09-25

Transmembrane-4 L-six family member-1 (TM4SF1) is a small plasma membrane-associated glycoprotein that is highly and selectively expressed on the plasma membranes of tumor cells, cultured endothelial cells, and, in vivo, on tumor-associated endothelium. Immunofluorescence microscopy also demonstrated TM4SF1 in cytoplasm and, tentatively, within nuclei. With monoclonal antibody 8G4, and the finer resolution afforded by immuno-nanogold transmission electron microscopy, we now demonstrate TM4SF1 in uncoated cytoplasmic vesicles, nuclear pores and nucleoplasm. Because of its prominent surface location on tumor cells and tumor-associated endothelium, TM4SF1 has potential as a dual therapeutic target using an antibody drug conjugate (ADC) approach. For ADC to be successful, antibodies reacting with cell surface antigens must be internalized for delivery of associated toxins to intracellular targets. We now report that 8G4 is efficiently taken up into cultured endothelial cells by uncoated vesicles in a dynamin-dependent, clathrin-independent manner. It is then transported along microtubules through the cytoplasm and passes through nuclear pores into the nucleus. These findings validate TM4SF1 as an attractive candidate for cancer therapy with antibody-bound toxins that have the capacity to react with either cytoplasmic or nuclear targets in tumor cells or tumor-associated vascular endothelium. - Highlights: • Anti-TM4SF1 antibody 8G4 was efficiently taken up by cultured endothelial cells. • TM4SF1–8G4 internalization is dynamin-dependent but clathrin-independent. • TM4SF1–8G4 complexes internalize along microtubules to reach the perinuclear region. • Internalized TM4SF1–8G4 complexes pass through nuclear pores into the nucleus. • TM4SF1 is an attractive candidate for ADC cancer therapy.

Using the Landsat data archive to assess long-term regional forest dynamics assessment in Eastern Europe, 1985-2012

Science.gov (United States)

Turubanova, S.; Potapov, P.; Krylov, A.; Tyukavina, A.; McCarty, J. L.; Radeloff, V. C.; Hansen, M. C.

2015-04-01

Dramatic political and economic changes in Eastern European countries following the dissolution of the "Eastern Bloc" and the collapse of the Soviet Union greatly affected land-cover and land-use trends. In particular, changes in forest cover dynamics may be attributed to the collapse of the planned economy, agricultural land abandonment, economy liberalization, and market conditions. However, changes in forest cover are hard to quantify given inconsistent forest statistics collected by different countries over the last 30 years. The objective of our research was to consistently quantify forest cover change across Eastern Europe from 1985 until 2012 using the complete Landsat data archive. We developed an algorithm for processing imagery from different Landsat platforms and sensors (TM and ETM+), aggregating these images into a common set of multi-temporal metrics, and mapping annual gross forest cover loss and decadal gross forest cover gain. Our results show that forest cover area increased from 1985 to 2012 by 4.7% across the region. Average annual gross forest cover loss was 0.41% of total forest cover area, with a statistically significant increase from 1985 to 2012. Most forest disturbance recovered fast, with only 12% of the areas of forest loss prior to 1995 not being recovered by 2012. Timber harvesting was the main cause of forest loss. Logging area declined after the collapse of socialism in the late 1980s, increased in the early 2000s, and decreased in most countries after 2007 due to the global economic crisis. By 2012, Central and Baltic Eastern European countries showed higher logging rates compared to their Western neighbours. Comparing our results with official forest cover and change estimates showed agreement in total forest area for year 2010, but with substantial disagreement between Landsat-based and official net forest cover area change. Landsat-based logging areas exhibit strong relationship with reported roundwood production at national

Calibration and Validation of Landsat Tree Cover in the Taiga−Tundra Ecotone

Directory of Open Access Journals (Sweden)

Paul Mannix Montesano

2016-06-01

Full Text Available Monitoring current forest characteristics in the taiga−tundra ecotone (TTE at multiple scales is critical for understanding its vulnerability to structural changes. A 30 m spatial resolution Landsat-based tree canopy cover map has been calibrated and validated in the TTE with reference tree cover data from airborne LiDAR and high resolution spaceborne images across the full range of boreal forest tree cover. This domain-specific calibration model used estimates of forest height to determine reference forest cover that best matched Landsat estimates. The model removed the systematic under-estimation of tree canopy cover >80% and indicated that Landsat estimates of tree canopy cover more closely matched canopies at least 2 m in height rather than 5 m. The validation improved estimates of uncertainty in tree canopy cover in discontinuous TTE forests for three temporal epochs (2000, 2005, and 2010 by reducing systematic errors, leading to increases in tree canopy cover uncertainty. Average pixel-level uncertainties in tree canopy cover were 29.0%, 27.1% and 31.1% for the 2000, 2005 and 2010 epochs, respectively. Maps from these calibrated data improve the uncertainty associated with Landsat tree canopy cover estimates in the discontinuous forests of the circumpolar TTE.

M5TM alloy high burnup behavior and worldwide licensing

International Nuclear Information System (INIS)

Mardon, J.P.; Hoffmann, P.B.; Garner, G.L.

2005-01-01

The in-reactor behavior of advanced PWR Zirconium alloys at burnups equal to or below licensing limits has been widely reported. Specifically, the advanced alloy M5 has demonstrated impressive improvements over Zircaloy-4 for fuel rod cladding and fuel assembly structural components. To demonstrate superiority of the alloy at burnups beyond current licensing limits, M5 has been operated in PWR at burnups exceeding 71 GWd/tU in the United States and 78 GWd/tU in Europe. Two extensive irradiation programs have been performed in the United States to demonstrate alloy M5 performance beyond current licensing limits. Four M5 TM fuel rods were exposed to four 24-month cycles in a 15x15 reactor beginning in 1995. Additionally, one 17x17 lead assembly containing M5 fuel rods and guide tubes was operated for four 18-month cycles beginning from 1997. Post-irradiation examinations (PIE) performed after all four cycles in the 15x15 demonstration program revealed excellent performance in the licensed burnup and in the high burnup stages of the experience. Examination of the 4th cycle 17x17 assembly will be accomplished in two stages the first of which is scheduled for June 2005. Moreover, several irradiation campaigns have been performed in Europe in order to confirm the excellent M5 in-pile behavior in demanding PWRs irradiation conditions with regard to void fraction, heat flux, lithium content and temperature. Results from the high burnup fuel examinations verify that the excellent performance achieved up to 62 GWd/tU was continued into higher burnup. The results of high burnup PIE campaigns for European and American PWR's are presented in this paper. Measured performance indicators include fuel assembly dimensional stability parameters (assembly length, fuel rod length, assembly bow, fuel rod bow, fuel rod radial creep and spacer grid width), oxidation measurements (fuel rod and guide tube) and hydrogen pick-up data (fuel rod). In the framework of PCI studies, power ramp

Use of landsat ETM+ SLC-off segment-based gap-filled imagery for crop type mapping

Science.gov (United States)

Maxwell, S.K.; Craig, M.E.

2008-01-01

Failure of the Scan Line Corrector (SLC) on the Landsat ETM+ sensor has had a major impact on many applications that rely on continuous medium resolution imagery to meet their objectives. The United States Department of Agriculture (USDA) Cropland Data Layer (CDL) program uses Landsat imagery as the primary source of data to produce crop-specific maps for 20 states in the USA. A new method has been developed to fill the image gaps resulting from the SLC failure to support the needs of Landsat users who require coincident spectral data, such as for crop type mapping and monitoring. We tested the new gap-filled method for a CDL crop type mapping project in eastern Nebraska. Scan line gaps were simulated on two Landsat 5 images (spring and late summer 2003) and then gap-filled using landscape boundary models, or segment models, that were derived from 1992 and 2002 Landsat images (used in the gap-fill process). Various date combinations of original and gap-filled images were used to derive crop maps using a supervised classification process. Overall kappa values were slightly higher for crop maps derived from SLC-off gap-filled images compared to crop maps derived from the original imagery (0.3–1.3% higher). Although the age of the segment model used to derive the SLC-off gap-filled product did not negatively impact the overall agreement, differences in individual cover type agreement did increase (−0.8%–1.6% using the 2002 segment model to −5.0–5.1% using the 1992 segment model). Classification agreement also decreased for most of the classes as the size of the segment used in the gap-fill process increased.

Linkage studies on 13 biochemical loci and 2 coat color loci in a [(BN x TM) x TM] backcross progeny of the rat (Rattus norvegicus).

Science.gov (United States)

Yamada, J; Hamada, S; Bender, K; Adams, M

1986-10-01

In a [(BN X TM) X TM] backcross progeny of rats, nine significant linkage associations were found among 105 pairwise combinations of 15 loci. After comparing this with other published data and data of personal communications, we considered that the d gene we tentatively designated may be identical to the gene for pink-eyed dilution (p), and that the associations of Gc-Hbb, RT1-h, and Gc-Fh were due to chance rather than real linkage. The linkages obtained in this study, therefore, were Hbb-p (26.5 +/- 5.5) in LG I, Mup-1-Acon-1 (12.5 +/- 4.1) in LG II, Hao-1-Svp-1 (23.8 +/- 6.6) in LG IV, Es-1-Es-3 (17.2 +/- 4.7) in LG V, h-Gc (10.9 +/- 3.3) in LG VI, and Fh-Pep-3 (32.3 +/- 5.9) in LG X.

Family C 7TM receptor dimerization and activation

DEFF Research Database (Denmark)

Bonde, Marie Mi; Sheikh, Søren P; Hansen, Jakob Lerche

2006-01-01

The family C seven transmembrane (7TM) receptors constitutes a small and especially well characterized subfamily of the large 7TM receptor superfamily. Approximately 50% of current prescription drugs target 7TM receptors, this biologically important family represents the largest class of drug...... to be fully defined. This review presents the biochemical support for family C 7TM receptor dimerization and discusses its importance for receptor biosynthesis, surface expression, ligand binding and activation, since lessons learnt here may well be applicable to the whole superfamily of 7TM receptors.......-targets today. It is well established that family C 7TM receptors form homo- or hetero-dimers on the cell surface of living cells. The large extra-cellular domains (ECD) have been crystallized as a dimer in the presence and absence of agonist. Upon agonist binding, the dimeric ECD undergoes large conformational...

River morphodynamics from space: the Landsat frontier

Science.gov (United States)

Schwenk, Jon; Khandelwal, Ankush; Fratkin, Mulu; Kumar, Vipin; Foufoula-Georgiou, Efi

2017-04-01

NASA's Landsat family of satellites have been observing the entire globe since 1984, providing over 30 years of snapshots with an 18 day frequency and 30 meter resolution. These publicly-available Landsat data are particularly exciting to researchers interested in river morphodynamics, who are often limited to use of historical maps, aerial photography, and field surveys with poor and irregular time resolutions and limited spatial extents. Landsat archives show potential for overcoming these limitations, but techniques and tools for accurately and efficiently mining the vault of scenes must first be developed. In this PICO presentation, we detail the problems we encountered while mapping and quantifying planform dynamics of over 1,300 km of the actively-migrating, meandering Ucayali River in Peru from Landsat imagery. We also present methods to overcome these obstacles and introduce the Matlab-based RivMAP (River Morphodynamics from Analysis of Planforms) toolbox that we developed to extract banklines and centerlines, compute widths, curvatures, and angles, identify cutoffs, and quantify planform changes via centerline migration and erosion/accretion over large spatial domains with high temporal resolution. Measurement uncertainties were estimated by analyzing immobile, abandoned oxbow lakes. Our results identify hotspots of planform changes, and combined with limited precipitation, stage, and topography data, we parse three simultaneous controls on river migration: climate, sediment, and meander cutoff. Overall, this study demonstrates the vast potential locked within Landsat archives to identify multi-scale controls on river migration, observe the co-evolution of width, curvature, discharge, and migration, and discover and develop new geomorphic insights.

Anaglyph, Landsat Overlay: Wellington, New Zealand

Science.gov (United States)

2000-01-01

Wellington, the capital city of New Zealand, is located on the shores of Port Nicholson, a natural harbor at the south end of North Island. The city was founded in 1840 by British emigrants and now has a regional population of more than 400,000 residents. As seen here, the natural terrain imposes strong control over the urban growth pattern. Rugged hills generally rising to 300 meters (1,000 feet) help protect the city and harbor from strong winter winds.New Zealand is seismically active and faults are readily seen in the topography. The Wellington Fault forms the straight northwestern (upper left) shoreline of the harbor. Toward the southwest (lower left) the fault crosses through the city, then forms linear canyons in the hills before continuing offshore. Toward the northeast (upper right) the fault forms the sharp mountain front along the northern edge of the heavily populated Hutt Valley.This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar Topography Mission, then using the topographic data to create two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter (99 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) data Center, Sioux Falls, South Dakota.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour

Use of Landsat thermal imagery for dynamically monitoring spontaneous combustion of Datong Jurassic coalfields in China

Science.gov (United States)

Xue, Yongan; Liu, Jin; Li, Jun; Shang, Changsheng; Zhao, Jinling; Zhang, Mingmei

2018-06-01

It is highly helpful and necessary to investigate and monitor the status of coal seam. Fortunately, remote sensing has facilitated the identification and dynamical monitoring of spontaneous combustion for a large area coal mining area, especially using the time series remotely-sensed datasets. In this paper, Datong Jurassic coal mining area is used as the study area, China, and an exclusion method and a multiple-factor analysis method are jointly used to identify the spontaneous combustion, including land surface temperature (LST), burnt rocks, and land use and land cover change (LUCC). The LST is firstly retrieved using a single-window algorithm due to a thermal infrared band of Landsat-5 TM (Thematic Mapper). Burnt rocks is then extracted using a decision-tree classification method based on a high-resolution SPOT-5 image. The thermal anomaly areas are identified and refined by the spatial overlay analysis of the above affecting factors. Three-period maps of coal fire areas are obtained and dynamically analyzed in 2007, 2009 and 2010. The results show that a total of 12 coal fire areas have been identified, which account for more than 1% of the total area of the study area. In general, there is an increasing trend yearly and a total of 771,970 m2 is increased. The average annual increase is 257,320 m2, the average annual growth rate is 3.78%, and the dynamic degree is 11.29%.

Digital color analysis of color-ratio composite LANDSAT scenes. [Nevada

Science.gov (United States)

Raines, G. L.

1977-01-01

A method is presented that can be used to calculate approximate Munsell coordinates of the colors produced by making a color composite from three registered images. Applied to the LANDSAT MSS data of the Goldfield, Nevada, area, this method permits precise and quantitative definition of the limonitic areas originally observed in a LANDSAT color ratio composite. In addition, areas of transported limonite can be discriminated from the limonite in the hydrothermally altered areas of the Goldfield mining district. From the analysis, the numerical distinction between limonitic and nonlimonitic ground is generally less than 3% using the LANDSAT bands and as much as 8% in ratios of LANDSAT MSS bands.

Agricultural land-use change and disappearance of farmlands in ...

African Journals Online (AJOL)

The four imageries (Landsat MSS 1980, Landsat TM 1990, Landsat ETM+ 2005 and Nigeria Sat X 2012) used were classified and compared to understand the rate and extent of agricultural land-use change during the different periods. The findings revealed that the study area experienced a significant reduction in

A MultiSite GatewayTM vector set for the functional analysis of genes in the model Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Nagels Durand Astrid

2012-09-01

Full Text Available Abstract Background Recombinatorial cloning using the GatewayTM technology has been the method of choice for high-throughput omics projects, resulting in the availability of entire ORFeomes in GatewayTM compatible vectors. The MultiSite GatewayTM system allows combining multiple genetic fragments such as promoter, ORF and epitope tag in one single reaction. To date, this technology has not been accessible in the yeast Saccharomyces cerevisiae, one of the most widely used experimental systems in molecular biology, due to the lack of appropriate destination vectors. Results Here, we present a set of three-fragment MultiSite GatewayTM destination vectors that have been developed for gene expression in S. cerevisiae and that allow the assembly of any promoter, open reading frame, epitope tag arrangement in combination with any of four auxotrophic markers and three distinct replication mechanisms. As an example of its applicability, we used yeast three-hybrid to provide evidence for the assembly of a ternary complex of plant proteins involved in jasmonate signalling and consisting of the JAZ, NINJA and TOPLESS proteins. Conclusion Our vectors make MultiSite GatewayTM cloning accessible in S. cerevisiae and implement a fast and versatile cloning method for the high-throughput functional analysis of (heterologous proteins in one of the most widely used model organisms for molecular biology research.

Overview of Nintendo WiiTM use and potential applications for the Microsoft KinectTM in residential facilities

NARCIS (Netherlands)

C.A: Greenlay; H.R. Marston; J. van Hoof

2013-01-01

Marston, H.R., Greenlay, C.A., van Hoof, J. (2013) Overview of Nintendo WiiTM use and potential applications for the Microsoft KinectTM in residential facilities. Technology and Disability 25(2):77-85 doi: 10.3233/TAD-130369

Theoretical and experimental determination of dosimetric characteristics for ADVANTAGE{sup TM} Pd-103 brachytherapy source

Energy Technology Data Exchange (ETDEWEB)

Meigooni, Ali S. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States)]. E-mail: alimeig@uky.edu; Dini, Sharifeh A. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Awan, Shahid B. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Dou, Kai [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States); Koona, Rafiq A. [Department of Radiation Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536 (United States)

2006-08-15

ADVANTAGE{sup TM} Pd-103 brachytherapy source has been recently introduced by IsoAid{sup TM} for prostate permanent implants. Dosimetric characteristics (Dose rate constant, radial dose function, 2D-, and 1D-anisotropy functions) of this source model have been determined using both theoretical and experimental methods, following the updated TG-43U1 protocol. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with the 1999 Standards. Measurements were performed in Solid Water{sup TM} using LiF TLD chips and the theoretical calculations were performed in Solid Water{sup TM} and liquid water phantom materials using PTRAN Monte Carlo code. The results of the Monte Carlo simulation have shown a dose rate constant of 0.69 cGy h{sup -1} U{sup -1} in liquid water and 0.67 cGy h{sup -1} U{sup -1} in Solid Water{sup TM} medium. The measured dose rate constant in Solid Water{sup TM} was found to be 0.68{+-}8% cGy h{sup -1} U{sup -1}, which is in a good agreement (within {+-}5%) to the Monte Carlo simulated data. The 2D- and 1D-anisotropy functions of the ADVANTAGE{sup TM} Pd-103 source were calculated for radial distances ranging from 0.5 to 5.0 cm. Radial dose function was determined for radial distances ranging from 0.2 to 8.0 cm using line source approximation. All these calculations are based on L {sub eff} equal to 3.61 cm, calculated following TG-43U1 recommendations. The tabulated data for 2D-anisotropy function, 1D-anisotropy function, dose rate constant and radial dose function have been produced for clinical application of this source model.

Rare Functional Variant in TM2D3 is Associated with Late-Onset Alzheimer's Disease.

Directory of Open Access Journals (Sweden)

Johanna Jakobsdottir

2016-10-01

Full Text Available We performed an exome-wide association analysis in 1393 late-onset Alzheimer's disease (LOAD cases and 8141 controls from the CHARGE consortium. We found that a rare variant (P155L in TM2D3 was enriched in Icelanders (~0.5% versus <0.05% in other European populations. In 433 LOAD cases and 3903 controls from the Icelandic AGES sub-study, P155L was associated with increased risk and earlier onset of LOAD [odds ratio (95% CI = 7.5 (3.5-15.9, p = 6.6x10-9]. Mutation in the Drosophila TM2D3 homolog, almondex, causes a phenotype similar to loss of Notch/Presenilin signaling. Human TM2D3 is capable of rescuing these phenotypes, but this activity is abolished by P155L, establishing it as a functionally damaging allele. Our results establish a rare TM2D3 variant in association with LOAD susceptibility, and together with prior work suggests possible links to the β-amyloid cascade.

On the state of the TM 71 extensometer monitoring in Slovenia: seven years of micro-tectonic displacement measurements

Czech Academy of Sciences Publication Activity Database

Gosar, A.; Šebela, S.; Košťák, Blahoslav; Stemberk, Josef

2011-01-01

Roč. 8, č. 4 (2011), s. 389-402 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30460519 Keywords : geodynamics * TM 71 extensometer * micro-tectonic displacements Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/abstracts/AGG/04_11/2_Gosar.pdf

From Landsat through SLI: Ball Aerospace Instrument Architecture for Earth Surface Monitoring

Science.gov (United States)

Wamsley, P. R.; Gilmore, A. S.; Malone, K. J.; Kampe, T. U.; Good, W. S.

2017-12-01

The Landsat legacy spans more than forty years of moderate resolution, multi-spectral imaging of the Earth's surface. Applications for Landsat data include global environmental change, disaster planning and recovery, crop and natural resource management, and glaciology. In recent years, coastal water science has been greatly enhanced by the outstanding on-orbit performance of Landsat 8. Ball Aerospace designed and built the Operational Land Imager (OLI) instrument on Landsat 8, and is in the process of building OLI 2 for Landsat 9. Both of these instruments have the same design however improved performance is expected from OLI 2 due to greater image bit depth (14 bit on OLI 2 vs 12 bit on OLI). Ball Aerospace is currently working on two novel instrument architectures applicable to Sustainable Land Imaging for Landsat 10 and beyond. With increased budget constraints probable for future missions, technological improvements must be included in future instrument architectures to enable increased capabilities at lower cost. Ball presents the instrument architectures and associated capabilities enabling new science in past, current, and future Landsat missions.

Pool boiling performance of Novec{sup TM} 649 engineered fluid

Energy Technology Data Exchange (ETDEWEB)

Forrest, Eric; Buongiorno, Jacopo; McKrell, Thomas [Massachusetts Institute of Technology, Cambridge (United States). Dept. of Nuclear Science and Engineering; Hu, Lin-Wen [Massachusetts Institute of Technology, Cambridge (United States). Nuclear Reactor Lab.], e-mail: lwhu@mit.edu

2009-07-01

A new fluorinated ketone, C{sub 2}F{sub 5}C(O)CF(CF{sub 3}){sub 2}, is currently being considered as an environmentally friendly alternative for power electronics cooling applications due to its high dielectric strength and low global warming potential (GWP). Sold commercially by the 3M Company as Novec{sup TM} 649 Engineered Fluid, C{sub 2}F{sub 5}C(O)CF(CF{sub 3}){sub 2} exhibits very low acute toxicity while maintaining long-term stability. To assess the general two-phase heat transfer performance of Novec{sup TM} 649, pool boiling tests were conducted by resistively heating a 0.01 in. diameter nickel wire at the fluid's atmospheric saturation temperature of 49 deg C. The nucleate boiling heat transfer coefficient and critical heat flux (CHF) obtained for the fluorinated ketone compare favorably with results obtained for FC-72, a fluorocarbon widely used for the direct cooling of electronic devices. Initial results indicate that Novec{sup TM} 649 may prove to be a viable alternative to FC-72 and other halo alkanes for the cooling of high power density electronic devices. (author)

Georgia resource assessment project: Institutionalizing LANDSAT and geographic data base techniques

Science.gov (United States)

Pierce, R. R.; Rado, B. Q.; Faust, N.

1981-01-01

Digital data from LANDSAT for each 1.1-acre cell in Georgia were processed and the land cover conditions were categorized. Several test cases were completed and an operational hardware and software processing capability was established at the Georgia Institute of Technology. The operational capability was developed to process the entire state (60,000 sq. miles and 14 LANDSAT scenes) in a cooperative project between eleven divisions and agencies at the regional, state, and federal levels. Products were developed for State agencies such as in both mapped and statistical formats. A computerized geographical data base was developed for management programs. To a large extent the applications of the data base evolved as users of LANDSAT information requested that other data (i.e., soils, slope, land use, etc.) be made compatible with LANDSAT for management programs. To date, geographic data bases incorporating LANDSAT and other spatial data deal with elements of the municipal solid waste management program, and reservoir management for the Corps of Engineers. LANDSAT data are also being used for applications in wetland, wildlife, and forestry management.

An Analysis of the High Frequency Vibrations in Early Thematic Mapper Scenes

Science.gov (United States)

Kogut, J.; Larduinat, E.

1985-01-01

The motion of the mirrors in the thematic mapper (TM) and multispectral scanner (MSS) instruments, and the motion of other devices, such as the TDRSS antenna drive, and solar array drives onboard LANDSAT-4 cause vibrations to propagate through the spacecraft. These vibrations as well as nonlinearities in the scanning motion of the TM mirror can cause the TM detectors to point away from their nominal positions. Two computer programs, JITTER and SCDFT, were developed as part of the LANDSAT-D Assessment System (LAS), Products and Procedures Analysis (PAPA) program to evaluate the potential effect of high frequency vibrations on the final TM image. The maximum overlap and underlap which were observed for early TM scenes are well within specifications for the ground processing system. The cross scan and scan high frequency vibrations are also within the specifications cited for the flight system.

Diode-pumped efficient laser operation and spectroscopy of Tm,Ho:YVO 4

Science.gov (United States)

Li, G.; Yao, B. Q.; Meng, P. B.; Duan, X. M.; Ju, Y. L.; Wang, Y. Z.

2011-04-01

Spectroscopic characterization of co-doped Tm,Ho:YVO 4 crystal grown by the Czochralski method has been performed including absorption spectrum, emitting spectrum and luminescence decay lifetime. The polarization emitting spectrum around 2 μm is accomplished by exciting a singly Ho 3+ doped YVO 4 crystal to exclude the influence of Tm 3+3F 4- 3H 6 transition and the emission cross section is deduced from both Fuchtbauer-Ladenburg (F-L) equation and reciprocity method (RM). In addition, we report up to 10.4 W continuous wave (CW) output with a conversion efficiency of 40% and 10.3 W Q-Switch output with 12.5 kHz pulse repetition rate of diode-pumped cryogenic Tm,Ho:YVO 4 laser. For Q-Switch operation, the minimum pulse width of 28.2 ns is obtained, all of which demonstrate that the Tm,Ho:YVO 4 is excellent laser material for 2 μm radiation.

Lyme Disease and YouTube TM: A Cross-Sectional Study of Video Contents.

Science.gov (United States)

Basch, Corey H; Mullican, Lindsay A; Boone, Kwanza D; Yin, Jingjing; Berdnik, Alyssa; Eremeeva, Marina E; Fung, Isaac Chun-Hai

2017-08-01

Lyme disease is the most common tick-borne disease. People seek health information on Lyme disease from YouTube TM videos. In this study, we investigated if the contents of Lyme disease-related YouTube TM videos varied by their sources. Most viewed English YouTube TM videos (n = 100) were identified and manually coded for contents and sources. Within the sample, 40 videos were consumer-generated, 31 were internet-based news, 16 were professional, and 13 were TV news. Compared with consumer-generated videos, TV news videos were more likely to mention celebrities (odds ratio [OR], 10.57; 95% confidence interval [CI], 2.13-52.58), prevention of Lyme disease through wearing protective clothing (OR, 5.63; 95% CI, 1.23-25.76), and spraying insecticides (OR, 7.71; 95% CI, 1.52-39.05). A majority of the most popular Lyme disease-related YouTube TM videos were not created by public health professionals. Responsible reporting and creative video-making facilitate Lyme disease education. Partnership with YouTube TM celebrities to co-develop educational videos may be a future direction.

Compact self-Q-switched Tm:YLF laser at 1.91 μm

Science.gov (United States)

Zhang, B.; Li, L.; He, C. J.; Tian, F. J.; Yang, X. T.; Cui, J. H.; Zhang, J. Z.; Sun, W. M.

2018-03-01

We report self-Q-switching operation in a diode-pumped Tm:YLF bulk laser by exploiting saturable re-absorption under the quasi-three-level regime. Robust self-Q-switched pulse output at 1.91 μm in fundamental mode is demonstrated experimentally with 1.5 at.% doped Tm:YLF crystal. At maximum absorbed pump power of 4.5 W, the average output power and pulse energy are obtained as high as 610 mW and 29 μJ, respectively, with the corresponding slope efficiency of 22%. Pulse repetition rate is tunable in the range of 3-21 kHz with changing the pump power. The dynamics of self-Q-switching of Tm:YLF laser are discussed with the help of a rate equation model showing good agreement with the experiment. The compact self-Q-switched laser near 2 μm has potential application in laser radar systems for accurate wind velocity measurements.

Analyses of TmAl{sub 2} and ErAl{sub 2} composite for use as an active magnetic regenerator close to liquid helium temperature

Energy Technology Data Exchange (ETDEWEB)

Souza, M.V. de, E-mail: marcos_vinicios@hotmail.com [Núcleo de Pós-Graduação em Física, Campus prof. José Aluísio de Campos, UFS, 49100-000, São Cristóvão, SE (Brazil); Silva, J.A. da [Núcleo de Pós-Graduação em Física, Campus prof. José Aluísio de Campos, UFS, 49100-000, São Cristóvão, SE (Brazil); Silva, L.S. [Núcleo de Pós-Graduação em Física, Campus prof. José Aluísio de Campos, UFS, 49100-000, São Cristóvão, SE (Brazil); Instituto Federal de Tocantins, IFTO – Campus Colinas do Tocantins, AV. Bernardo Sayao S/N, Chácara Raio de Sol, Setor Santa Maria, CEP 77760-000, Colinas do Tocantins, TO (Brazil)

2017-07-01

Highlights: • Modeling of the thermodynamics quantities in RAl{sub 2} (R = Er, Tm) single crystal and polycrystal. • An optimal hybrid magnetocaloric material using TmAl{sub 2} and ErAl{sub 2} compounds. • Suppression of the ferromagnetic canted order in the compound TmAl{sub 2} in single crystal form. - Abstract: We report the thermodynamic properties of selected intermetallic RAl{sub 2} (R = Er, Tm) compounds calculated by using a model Hamiltonian, including the Zeeman-exchange interactions and the crystalline electrical field, which are responsible for the magnetic anisotropy. The relationship between the behavior of the temperature-dependent magnetization, calculated in different crystallographic directions for several magnetic fields, and the influence of spin reorientation on the magnetocaloric effect, is discussed. In order to validate the obtained theoretical results, experimental data are compared to calculated data. Also, an optimum molar fraction of the ErAl{sub 2} and TmAl{sub 2} composite was determined theoretically, showing a high potential for use in a regenerative thermal cycle, especially close to the liquid helium temperature range.

Does the use of Nintendo Wii SportsTM improve arm function? Trial of WiiTM in Stroke: a randomized controlled trial and economics analysis.

Science.gov (United States)

Adie, Katja; Schofield, Christine; Berrow, Margie; Wingham, Jennifer; Humfryes, John; Pritchard, Colin; James, Martin; Allison, Rhoda

2017-02-01

The Trial of Wii™ in Stroke investigated the efficacy of using the Nintendo Wii Sports™ (Wii TM ) to improve affected arm function after stroke. Multicentre, pragmatic, parallel group, randomized controlled trial. Home-based rehabilitation. A total of 240 participants aged 24-90 years with arm weakness following a stroke within the previous six months. Participants were randomly assigned to exercise daily for six weeks using the Wii TM or arm exercises at home. Primary outcome was change in the affected arm function at six weeks follow-up using the Action Research Arm Test. Secondary outcomes included occupational performance, quality of life, arm function at six months and a cost effectiveness analysis. The study was completed by 209 participants (87.1%). There was no significant difference in the primary outcome of affected arm function at six weeks follow-up (mean difference -1.7, 95% CI -3.9 to 0.5, p = 0.12) and no significant difference in secondary outcomes, including occupational performance, quality of life or arm function at six months, between the two groups. No serious adverse events related to the study treatment were reported. The cost effectiveness analysis showed that the Wii TM was more expensive than arm exercises £1106 (SD 1656) vs. £730 (SD 829) (probability 0.866). The trial showed that the Wii TM was not superior to arm exercises in home-based rehabilitation for stroke survivors with arm weakness. The Wii TM was well tolerated but more expensive than arm exercises.

Continuous fields of land cover for the conterminous United States using Landsat data: First results from the Web-Enabled Landsat Data (WELD) project

Science.gov (United States)

Hansen, M.C.; Egorov, Alexey; Roy, David P.; Potapov, P.; Ju, J.; Turubanova, S.; Kommareddy, I.; Loveland, Thomas R.

2011-01-01

Vegetation Continuous Field (VCF) layers of 30 m percent tree cover, bare ground, other vegetation and probability of water were derived for the conterminous United States (CONUS) using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data sets from the Web-Enabled Landsat Data (WELD) project. Turnkey approaches to land cover characterization were enabled due to the systematic WELD Landsat processing, including conversion of digital numbers to calibrated top of atmosphere reflectance and brightness temperature, cloud masking, reprojection into a continental map projection and temporal compositing. Annual, seasonal and monthly WELD composites for 2008 were used as spectral inputs to a bagged regression and classification tree procedure using a large training data set derived from very high spatial resolution imagery and available ancillary data. The results illustrate the ability to perform Landsat land cover characterizations at continental scales that are internally consistent while retaining local spatial and thematic detail.

ScoutTM, a portable MCA system

International Nuclear Information System (INIS)

Cheng, A.Y.; Ziemba, F.P.; Browning, J.E.; Szluk, N.

1998-01-01

Quantrad Sensor's hand-held multichannel analyzer (MCA), the Scout TM , has evolved considerably from the initial licensing from Pacific Northwest Laboratories (operated by Battelle Memorial Institute for the U.S. DOE). The Scout TM has grown into a flexible MCA system with alpha-, gamma-, X-ray and neutron detection capabilities with wide ranging applications. The development philosophy is discussed along with specific examples of design choices in areas such as manufacturability, upgradability, probe interchangability and software user interface. Recently introduced products include: software enhancements, additional probes, customized software and a second generation instrument, the Scout512 TM , that boasts increased capabilities. Future developments are also discussed. (author)

Ab initio structures and stabilities of HeTM3+ (TM=Sc-Cu)

International Nuclear Information System (INIS)

Wilson, David J.D.; Marsden, Colin J.; Nagy-Felsobuki, Ellak I. von

2002-01-01

The electronic structure and molecular properties of triply charged transition metal helides, HeTM 3+ (where TM = Sc-Cu), have been investigated employing CCSD(T), MCSCF and MRCI methods. Dissociation energies and harmonic vibrational frequencies have also been determined. For all the triply charged helides, the ground state is dominated by the 3d n electronic configuration. In addition, states with configurations that have holes in the metal 3d σ orbital exhibit greater binding energies. The suitability of single-reference methods and diagnostics for this series has been investigated, with the MCSCF wave function being the most reliable diagnostic tool for the applicability of SCF methods

Vegetation burn severity mapping using Landsat-8 and WorldView-2

Science.gov (United States)

Wu, Zhuoting; Middleton, Barry R.; Hetzler, Robert; Vogel, John M.; Dye, Dennis G.

2015-01-01

We used remotely sensed data from the Landsat-8 and WorldView-2 satellites to estimate vegetation burn severity of the Creek Fire on the San Carlos Apache Reservation, where wildfire occurrences affect the Tribe's crucial livestock and logging industries. Accurate pre- and post-fire canopy maps at high (0.5-meter) resolution were created from World- View-2 data to generate canopy loss maps, and multiple indices from pre- and post-fire Landsat-8 images were used to evaluate vegetation burn severity. Normalized difference vegetation index based vegetation burn severity map had the highest correlation coefficients with canopy loss map from WorldView-2. Two distinct approaches - canopy loss mapping from WorldView-2 and spectral index differencing from Landsat-8 - agreed well with the field-based burn severity estimates and are both effective for vegetation burn severity mapping. Canopy loss maps created with WorldView-2 imagery add to a short list of accurate vegetation burn severity mapping techniques that can help guide effective management of forest resources on the San Carlos Apache Reservation, and the broader fire-prone regions of the Southwest.

Evaluation of the performance of a Ho: Sc2SiO5 laser pumped by a Tm:YAP laser

Science.gov (United States)

Yang, Xiao-tao; Xie, Wen-qiang; Li, Wen-hui; Li, Xue-min

2016-05-01

A continuous-wave 0.5 % Ho3+-doped Ho:Sc2SiO5 (Ho:SSO) laser output at 2112 nm pumped by a Tm:YAP laser is reported. The Ho:SSO bulk crystal was grown by the Czochralski technique. A maximum laser power of 3.72 W was obtained with a slope efficiency of 32.9%, when the transmittance of output mirror was 30%. In this experiment, two output mirrors with different transmittance were also researched. The output spectra of Ho:SSO laser with different output mirrors are also given. The M 2 factor is found to be 1.29. In addition, the absorption and emission spectra are given in this paper.

Evaluation of the performance of a Ho: Sc2SiO5 laser pumped by a Tm:YAP laser

International Nuclear Information System (INIS)

Yang, Xiao-tao; Xie, Wen-qiang; Li, Wen-hui; Li, Xue-min

2016-01-01

A continuous-wave 0.5 % Ho 3+ -doped Ho:Sc 2 SiO 5 (Ho:SSO) laser output at 2112 nm pumped by a Tm:YAP laser is reported. The Ho:SSO bulk crystal was grown by the Czochralski technique. A maximum laser power of 3.72 W was obtained with a slope efficiency of 32.9%, when the transmittance of output mirror was 30%. In this experiment, two output mirrors with different transmittance were also researched. The output spectra of Ho:SSO laser with different output mirrors are also given. The M 2 factor is found to be 1.29. In addition, the absorption and emission spectra are given in this paper. (paper)

Increased wetness confounds Landsat-derived NDVI trends in the central Alaska North Slope region, 1985-2011

Science.gov (United States)

Raynolds, Martha K.; Walker, Donald A.

2016-08-01

Satellite data from the circumpolar Arctic have shown increases in vegetation indices correlated to warming air temperatures (e.g. Bhatt et al 2013 Remote Sensing 5 4229-54). However, more information is needed at finer scales to relate the satellite trends to vegetation changes on the ground. We examined changes using Landsat TM and ETM+ data between 1985 and 2011 in the central Alaska North Slope region, where the vegetation and landscapes are relatively well-known and mapped. We calculated trends in the normalized difference vegetation index (NDVI) and tasseled-cap transformation indices, and related them to high-resolution aerial photographs, ground studies, and vegetation maps. Significant, mostly negative, changes in NDVI occurred in 7.3% of the area, with greater change in aquatic and barren types. Large reflectance changes due to erosion, deposition and lake drainage were evident. Oil industry-related changes such as construction of artificial islands, roads, and gravel pads were also easily identified. Regional trends showed decreases in NDVI for most vegetation types, but increases in tasseled-cap greenness (56% of study area, greatest for vegetation types with high shrub cover) and tasseled-cap wetness (11% of area), consistent with documented degradation of polygon ice wedges, indicating that increasing cover of water may be masking increases in vegetation when summarized using the water-sensitive NDVI.

Use of Landsat data to predict the trophic state of Minnesota lakes

Science.gov (United States)

Lillesand, T. M.; Johnson, W. L.; Deuell, R. L.; Lindstrom, O. M.; Meisner, D. E.

1983-01-01

Near-concurrent Landsat Multispectral Scanner (MSS) and ground data were obtained for 60 lakes distributed in two Landsat scene areas. The ground data included measurement of secchi disk depth, chlorophyll-a, total phosphorous, turbidity, color, and total nitrogen, as well as Carlson Trophic State Index (TSI) values derived from the first three parameters. The Landsat data best correlated with the TSI values. Prediction models were developed to classify some 100 'test' lakes appearing in the two analysis scenes on the basis of TSI estimates. Clouds, wind, poor image data, small lake size, and shallow lake depth caused some problems in lake TSI prediction. Overall, however, the Landsat-predicted TSI estimates were judged to be very reliable for the secchi-derived TSI estimation, moderately reliable for prediction of the chlorophyll-a TSI, and unreliable for the phosphorous value. Numerous Landsat data extraction procedures were compared, and the success of the Landsat TSI prediction models was a strong function of the procedure employed.

Laboratory panel and radiometer calibration

CSIR Research Space (South Africa)

Deadman, AJ

2011-07-01

Full Text Available stream_source_info Griffith1_2011.pdf.txt stream_content_type text/plain stream_size 16659 Content-Encoding ISO-8859-1 stream_name Griffith1_2011.pdf.txt Content-Type text/plain; charset=ISO-8859-1 LABORATORY PANEL... of Land surface imaging through a ground reference standard test site?, on http://qa4eo.org/documentation.html, 2009. [2] K. J. Thome, D. L. Helder, D. Aaron, and J. D. Dewald, ?Landsat-5 TM and Landsat-7 ETM+ Absolute Radiometric Calibration Using...

IHC-TM connect-disconnect and efferent control V.

Science.gov (United States)

Crane, H D

1982-07-01

Four previous papers in this series have explored how the idea of a set of disconnected inner hair cells (IHCs) that can "impact" the tectorial membrane (TM) is consistent with psychophysical data. This paper extends the model and explores the potential for mechanical interaction between the IHCs and outer hair cells (OHCs). In particular, it is speculated that the advantage of IHC-TM disconnect is extended dynamic range, and that movement of the movement of the OHCs and TM, under efferent control, constitutes a mechanical servo system for adjusting IHC-TM spacing along the cochlear partition to achieve this extended range.

The spectroscopy investigation of ZnWO{sub 4}:Tm{sup 3+} single crystal

Energy Technology Data Exchange (ETDEWEB)

Yang Fugui, E-mail: ruopiao@fjirsm.ac.cn [Department of Electronic Information Science, Fujian Jiangxia University, Fuzhou, Fujian 350108 (China); Tu Chaoyang [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2012-09-15

Highlights: Black-Right-Pointing-Pointer The spectroscopy and refractive index of single crystal ZnWO{sub 4}:Tm{sup 3+} are investigated systematically. Black-Right-Pointing-Pointer The Judd-Ofelt parameters are obtained. Black-Right-Pointing-Pointer The gain cross sections at {approx}2 {mu}m are estimated by reciprocity method (RM). Black-Right-Pointing-Pointer The laser operation at {approx}2 {mu}m is discussed. - Abstract: The single crystal ZnWO{sub 4}:Tm{sup 3+} has been grown by Czochralski method. The XRD, refractive index, absorption and fluorescence spectra are measured. The Judd-Ofelt parameters{Omega}{sub 2}, {Omega}{sub 4}, {Omega}{sub 6} are obtained to be 6.3 Multiplication-Sign 10{sup -20}, 1.3 Multiplication-Sign 10{sup -20}, 1.4 Multiplication-Sign 10{sup -20} cm{sup 2}, respectively. The fluorescence decay time of the {sup 3}H{sub 4} level is measured to be 0.113 ms and the quantum efficiency is 57%. The gain cross sections corresponding to {sup 3}F{sub 4}{yields}{sup 3}H{sub 6} transition at {approx}2 {mu}m are estimated by the reciprocity method (RM). The strong gain at {approx}2 {mu}m indicates that the ZnWO{sub 4}:Tm{sup 3+} crystal is a promising laser host for {approx}2 {mu}m laser.

Remote Sensing and Mapping of Tamarisk along the Colorado River, USA: A Comparative Use of Summer-Acquired Hyperion, Thematic Mapper and QuickBird Data

Directory of Open Access Journals (Sweden)

Jerry A. Griffith

2009-07-01

Full Text Available Tamarisk (Tamarix spp., saltcedar is a well-known invasive phreatophyte introduced from Asia to North America in the 1800s. This report compares the efficacy of Landsat 5 Thematic Mapper (TM5, QuickBird (QB and EO-1 Hyperion data in discriminating tamarisk populations near De Beque, Colorado, USA. As a result of highly correlated reflectance among the spectral bands provided by each sensor, relatively standard image analysis methods were employed. Multispectral data at high spatial resolution (QB, 2.5 m Ground Spatial Distance or GSD proved more effective in tamarisk delineation than either multispectral (TM5 or hyperspectral (Hyperion data at moderate spatial resolution (30 m GSD.

Affinity of 167Tm-citrate for tumor and liver tissue

International Nuclear Information System (INIS)

Ando, A.; Ando, I.; Hiraki, T.

1983-01-01

Strong affinity of 167 Tm-citrate for tumor tissue was reconfirmed by using Ehrlich tumor. Excellent tumor imaging was obtained with 167 Tm-citrate because of its strong tumor affinity and because of the suitable physical characteristics of 167 Tm. A large amount of 167 Tm had accumulated in the connective tissue which contained inflammatory tissue, quite large amounts were found in areas containing viable and necrotic tumor tissue, and small amounts were present in viable tumor tissue. 167 Tm was not seen in necrotic tumor tissue. It was concluded that lysosomes did not play a major role in the tumor concentration of 167 Tm, but played an important role in the liver concentration of this nuclide. In the case of hepatoma AH109A, it was presumed that lysosomes played a considerably important role in the tumor concentration of 167 Tm, hepatoma AH109A possessing some residual features of the liver. 167 Tm was bound to acid mucopolysaccharides and transposed by the acid mucopolysaccharides in the tumor tissues and liver. The acid mucopolysaccharides to which 167 Tm were bound in tumor and liver, were heparan sulfate, chondroitin sulfate (or keratosulfate) and heparin (or keratosulfate). (orig.)

Evaluating the Effectiveness of the 2002-2003 NASA SCIence Files(TM) Program

Science.gov (United States)

Pinelli, Thomas E.; Lambert, Matthew A.; Williams, Amy C.

2004-01-01

NASA SCIence Files (tm) is a research-, inquiry-, and standards-based, integrated mathematics, science, and technology series of 60-minute instructional distance learning (television and web-based) programs for students in grades 3-5. Respondents who evaluated the programs in the 2002-2003 NASA SCIence Files (tm) series reported that (1) they used the programs in the series; (2) the goals and objectives for the series were met; (3) the programs were aligned with the national mathematics, science, and technology standards; (4) the program content was developmentally appropriate for grade level; and (5) the programs in the series enhanced and enriched the teaching of mathematics, science, and technology.

Precise Plan in the analysis of volume precision in SynergyTM conebeam CT image

International Nuclear Information System (INIS)

Bai Sen; Xu Qingfeng; Zhong Renming; Jiang Xiaoqin; Jiang Qingfeng; Xu Feng

2007-01-01

Objective: A method of checking the volume precision in Synergy TM conebeam CT image. Methods: To scan known phantoms (big, middle, small spheres, cubes and cuniform cavum) at different positions (CBCT centre and departure centre from 5, 8, 10 cm along the accelerator G-T way)with conebeam CT, the phantom volume of reconstructed images were measure. Then to compared measured volume of Synergy TM conebeam CT with fanbeam CT results and nominal values. Results: The middle spheres had 1.5% discrepancy in nominal values and metrical average values at CBCT centre and departure from centre 5, 8 cm along accelerator G-T way. The small spheres showed 8.1%, with 0.8 % of the big cube and 2.9% of small cube, in nominal values and metrical average values at CBCT centre and departure from centre 5, 8, 10 cm along the accelerator G-T way. Conclusion: In valid scan range of Synergy TM conebeam CT, reconstructed precision is independent of the distance deviation from the center. (authors)

Perspective View with Landsat Overlay, Salt Lake City Olympics Venues, Utah

Science.gov (United States)

2002-01-01

The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This computer generated perspective image provides a northward looking 'view from space' that includes all of these Olympic sites. In the south, next to Utah Lake, Provo hosts the ice hockey competition. In the north, northeast of the Great Salt Lake, Ogden hosts curling, and the nearby Snow Basin ski area hosts the downhill events. In between, southeast of the Great Salt Lake, Salt Lake City hosts the Olympic Village and the various skating events. Further east, across the Wasatch Mountains, the Park City area ski resorts host the bobsled, ski jumping, and snowboarding events. The Winter Olympics are always hosted in mountainous terrain. This view shows the dramatic landscape that makes the Salt Lake City region a world-class center for winter sports.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) and a Landsat 5 satellite image mosaic. Topographic expression is exaggerated four times.For a full-resolution, annotated version of this image, please select Figure 1, below: [figure removed for brevity, see original site] Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60

LANDSAT-8 OPERATIONAL LAND IMAGER CHANGE DETECTION ANALYSIS

Directory of Open Access Journals (Sweden)

W. Pervez

2017-05-01

Full Text Available This paper investigated the potential utility of Landsat-8 Operational Land Imager (OLI for change detection analysis and mapping application because of its superior technical design to previous Landsat series. The OLI SVM classified data was successfully classified with regard to all six test classes (i.e., bare land, built-up land, mixed trees, bushes, dam water and channel water. OLI support vector machine (SVM classified data for the four seasons (i.e., spring, autumn, winter, and summer was used to change detection results of six cases: (1 winter to spring which resulted reduction in dam water mapping and increases of bushes; (2 winter to summer which resulted reduction in dam water mapping and increase of vegetation; (3 winter to autumn which resulted increase in dam water mapping; (4 spring to summer which resulted reduction of vegetation and shallow water; (5 spring to autumn which resulted decrease of vegetation; and (6 summer to autumn which resulted increase of bushes and vegetation . OLI SVM classified data resulted higher overall accuracy and kappa coefficient and thus found suitable for change detection analysis.

Fluorescent labeling of NASBA amplified tmRNA molecules for microarray applications

Directory of Open Access Journals (Sweden)

Kaplinski Lauris

2009-05-01

Full Text Available Abstract Background Here we present a novel promising microbial diagnostic method that combines the sensitivity of Nucleic Acid Sequence Based Amplification (NASBA with the high information content of microarray technology for the detection of bacterial tmRNA molecules. The NASBA protocol was modified to include aminoallyl-UTP (aaUTP molecules that were incorporated into nascent RNA during the NASBA reaction. Post-amplification labeling with fluorescent dye was carried out subsequently and tmRNA hybridization signal intensities were measured using microarray technology. Significant optimization of the labeled NASBA protocol was required to maintain the required sensitivity of the reactions. Results Two different aaUTP salts were evaluated and optimum final concentrations were identified for both. The final 2 mM concentration of aaUTP Li-salt in NASBA reaction resulted in highest microarray signals overall, being twice as high as the strongest signals with 1 mM aaUTP Na-salt. Conclusion We have successfully demonstrated efficient combination of NASBA amplification technology with microarray based hybridization detection. The method is applicative for many different areas of microbial diagnostics including environmental monitoring, bio threat detection, industrial process monitoring and clinical microbiology.

Louisiana Air Quality - Using ASTER, Landsat 5, and MODIS to Assess the Impact of Sugar Cane and Marsh Burning Practices on Local Air Quality

Science.gov (United States)

Clark, Robert; Reahard, Ross; Robin, Chad; Zeringue, Jared

2010-01-01

Biomass burning is an event that occurs globally and encompasses both human-initiated and naturally-occurring fires. It is estimated that 3 billion metric tons of biomass are burned every year worldwide (Curtis 2002). Societies have used these burning techniques for cooking and heating, clearing land for agricultural use, and removing excess biomass from grazing and croplands (Levine 1991). Our study focuses on the state of Louisiana and its commonly occurring methods of sugarcane and marsh biomass burning (LSU Ag.Center 2000; Nyman and Chabreck 1995). Over the centuries, the sugarcane industry in this state has steadily grown to surpass all other agriculture commodities. To promote efficiency within this large industry, burning excess biomass takes place throughout the harvesting period (LSU Ag.Center 2000). In addition to sugarcane, Louisiana contains 30% of the total coastal marsh of the United States (LSU Ag.Center 2000). The periodic burning of such marshes is an ecologically important management tool that is practiced throughout the Atlantic and Gulf Coasts (Nyman and Chabreck 1995). In most biomass burning instances, the leading by-product is particulate matter that is less than 10 microns in diameter (PM10). Through past research, this fine material has been shown to have negative health effects on surrounding populations (Boopathy2001). While burning guidelines have been set into place by the Louisiana Department of Agriculture and Forestry (LDAF) to reduce health effects, the guidelines are voluntary (LDAF 2000). To help quantify emission estimates, we will focus on Iberia Parish for sugarcane burning and Cameron Parish for marsh burning. Through analysis of ASTER, Landsat 5 TM, and MODIS data, our goal is to determine the amount and location of land area burned for the years 2008 and 2009 due to these practices. With emissions algorithms from Seiler and Crutzen, 1980, total acreage burned can be used to estimate emissions. This information will help to

Regional estimates of reef carbonate dynamics and productivity Using Landsat 7 ETM+, and potential impacts from ocean acidification

Science.gov (United States)

Moses, C.S.; Andrefouet, S.; Kranenburg, C.; Muller-Karger, F. E.

2009-01-01

Using imagery at 30 m spatial resolution from the most recent Landsat satellite, the Landsat 7 Enhanced Thematic Mapper Plus (ETM+), we scale up reef metabolic productivity and calcification from local habitat-scale (10 -1 to 100 km2) measurements to regional scales (103 to 104 km2). Distribution and spatial extent of the North Florida Reef Tract (NFRT) habitats come from supervised classification of the Landsat imagery within independent Landsat-derived Millennium Coral Reef Map geomorphologic classes. This system minimizes the depth range and variability of benthic habitat characteristics found in the area of supervised classification and limits misclassification. Classification of Landsat imagery into 5 biotopes (sand, dense live cover, sparse live cover, seagrass, and sparse seagrass) by geomorphologic class is >73% accurate at regional scales. Based on recently published habitat-scale in situ metabolic measurements, gross production (P = 3.01 ?? 109 kg C yr -1), excess production (E = -5.70 ?? 108 kg C yr -1), and calcification (G = -1.68 ?? 106 kg CaCO 3 yr-1) are estimated over 2711 km2 of the NFRT. Simple models suggest sensitivity of these values to ocean acidification, which will increase local dissolution of carbonate sediments. Similar approaches could be applied over large areas with poorly constrained bathymetry or water column properties and minimal metabolic sampling. This tool has potential applications for modeling and monitoring large-scale environmental impacts on reef productivity, such as the influence of ocean acidification on coral reef environments. ?? Inter-Research 2009.

Magnetism in RRhGe (R = Tb, Dy, Er, Tm): An experimental and theoretical study

Energy Technology Data Exchange (ETDEWEB)

Gupta, Sachin [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Suresh, K.G., E-mail: suresh@phy.iitb.ac.in [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Nigam, A.K. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Lukoyanov, A.V. [Institute of Metal Physics, Russian Academy of Sciences, Ural Branch, Yekaterinburg 620137 (Russian Federation); Ural Federal University, Yekaterinburg 620002 (Russian Federation)

2015-08-15

Highlights: • RRhGe (R = Tb, Dy, Er, Tm) compounds show low temperature antiferromagnetic ordering. • All compounds show field induced metamagnetic transitions. • Some of these compounds show large magnetocaloric effect and magnetoresistance. • Change of sign in MR take place on temperature variation. - Abstract: RRhGe (R = Tb, Dy, Er, Tm) compounds have been studied by different experimental probes and theoretical ab initio calculations. These compounds show very interesting magnetic and transport properties. All the compounds are antiferromagnetic with some of them showing spin-reorientation transition at low temperatures. The magnetocaloric effect estimated from magnetization data shows high values in all these compounds. Magnetoresistance is negative near the ordering temperatures and positive at low temperatures. The electronic structure calculations accounting for electronic correlations in the 4f rare-earth shell reveal the closeness of the antiferromagnetic ground state and other types of magnetic orderings in the rare-earth sublattice. These calculations are also in agreement with the experimental results.

Comparative evaluation of two methods for 172Tm production in nuclear reactors

International Nuclear Information System (INIS)

Cohen, I.M.; Hayes, Alejandro; Melcer, Elsa

2016-01-01

A comparative evaluation of two methods for the production of 172 Tm in nuclear reactors is carried out. They are respectively based on two chains of double neutron capture reactions, 170 Er(n,γ) 171 Er(n,γ) 172 Er(β - ) 172 Tm and 170 Er(n,γ) 171 Er(β - ) 171 Tm(n,γ) 172 Tm, and a chain of triple neutron capture: 169 Tm(n,γ) 170 Tm(n,γ) 71 Tm(n,γ) 172 Tm. Theoretical considerations with respect to both ways of production are formulated and the mathematical equation are solved. Experiments of irradiation of Er 2 O 3 and Tm 2 O 3 were performed. Advantages and drawbacks of both methods are discussed. (author)

Enhancing photovoltaic performance of dye-sensitized solar cell by rare-earth doped oxide of Lu2O3:(Tm3+, Yb3+)

International Nuclear Information System (INIS)

Li Qingbei; Lin Jianming; Wu Jihuai; Lan Zhang; Wang Yue; Peng Fuguo; Huang Miaoliang

2011-01-01

Highlights: → Tm 3+ /Yb 3+ codoped oxide is introduced into the TiO 2 film in dye-sensitized solar cell. → The RE improves light harvest via conversion luminescence and increases photocurrent. → The RE elevates the oxide film energy level and increases the cell photovoltage. → The cell efficiency is increased by 11.1% compared to the cell lacking of RE doping. - Abstract: In order to increase of the photocurrent, photovoltage and energy conversion efficiency of dye-sensitized solar cell (DSSC), rare-earth doped oxide of Lu 2 O 3 :(Tm 3+ , Yb 3+ ) is prepared and introduced into the TiO 2 film in the DSSC. As a luminescence medium, Lu 2 O 3 :(Tm 3+ , Yb 3+ ) improves incident light harvest via a conversion luminescence process and increases photocurrent; as a p-type dopant, the rare-earth ions elevate the energy level of the oxide film and increase the photovoltage. Under a simulated solar light irradiation of 100 mW cm -2 , the light-to-electric energy conversion efficiency of the DSSC with Lu 2 O 3 :(Tm 3+ , Yb 3+ ) doping reaches 6.63%, which is increased by 11.1% compared to the DSSC without Lu 2 O 3 :(Tm 3+ , Yb 3+ ) doping.

Field applications of the ScoutTM portable MCA

International Nuclear Information System (INIS)

Cheng, A.Y.; Ziemba, F.P.; Browning, J.E.

1998-01-01

The use of Quantrad Sensor's Scout TM in field type applications is described. The portability of the Scout TM enables the user to obtain more accurate information in the field versus a survey meter. Isotopic identification is possible when ancillary information is combined with built-in software libraries. Data from the Scout TM in remediation at Stanford Linear Accelerator (SLAC), NORM (Naturally Occurring Radioactive Material) measurements in California's Central Valley oil fields, medical isotope identification at nuclear pharmaceutical company and emergency response applications are presented. Additionally, custom software enabled the use of the Scout TM in identification, qualification and detection of Special Nuclear Materials (SNM) in illicit trafficking and portal monitoring applications. (author)

Interplay between magnetic order at Mn and Tm sites alongside the structural distortion in multiferroic films of o -TmMn O3

Science.gov (United States)

Windsor, Y. W.; Ramakrishnan, M.; Rettig, L.; Alberca, A.; Bothschafter, E. M.; Staub, U.; Shimamoto, K.; Hu, Y.; Lippert, T.; Schneider, C. W.

2015-06-01

We employ resonant soft x-ray diffraction to individually study the magnetic ordering of the Mn and the Tm sublattices in single-crystalline films of orthorhombic (o -) TmMn O3 . The same magnetic ordering wave vector of (0 q 0 ) with q ≈0.46 is found for both ionic species, suggesting that the familiar antiferromagnetic order of the Mn ions induces a magnetic order on the Tm unpaired 4 f electrons. Indeed, intensity variations of magnetic reflections with temperature corroborate this scenario. Calculated magnetic fields at the Tm sites are used as a model magnetic structure for the Tm, which correctly predicts intensity variations at the Tm resonance upon azimuthal rotation of the sample. The model allows ruling out a b c -cycloid modulation of the Mn ions as the cause for the incommensurate ordering, as found in TbMn O3 . The structural distortion, which occurs in the ferroelectric phase below TC, was followed through nonresonant diffraction of structural reflections forbidden by the high-temperature crystal symmetry. The (0 q 0 ) magnetic reflection appears at the Mn resonance well above TC, indicating that this reflection is sensitive also to the intermediate sinusoidal magnetic phase. The model presented suggests that the Tm 4 f electrons are polarized well above the ferroelectric transition and are possibly not affected by the transition at TC. The successful description of the induced order observed at the Tm resonance is a promising example for future element-selective studies in which "spectator" ions may allow access to previously unobtainable information about other constituent ions.

Relaxation phenomena and host exchange parameters in Tm van Vleck compounds

International Nuclear Information System (INIS)

Zevin, V.; Levin, R.; Shaltiel, D.; Baberschke, K.; Davidov, D.

1977-01-01

The ESR linewidth of Gd in TmP (measured by Sugawara et al (Phys. Rev.; B11 (1975)) TmSb and TmBi (measured in the present work and by Davidov and Baberschke (Phys. Lett.; A51:144 (1975)) exhibits an appreciable temperature dependence. This behaviour is attributed to the fluctuation spectra of the host Tm ions. The previous theory (Davidov et al (Phys. Rev.; B15:2771 (1977)) for impurity relaxation in weakly coupled van Vleck paramagnets based on the Bloch-Redfield kinetic equation is extended here and applied to the interpretation of the ESR linewidth in the Tm pnictides. In particular the second moment calculation of the host fluctuation spectra has been extended to include both pair correlation and autocorrelation contributions. Explicit expressions are given for Tm and Pr cubic van Vleck compounds. Using the crystalline field as extracted from independent neutron scattering techniques and the Gd-Tm exchange from the ESR g shift, the Tm-Tm host exchange has been estimated by fitting theory to the experimental results. The host exchange parameter in TmSb is very small confirming previous studies on this compound. (author)

Study of thermal environment in Jingjintang urban agglomeration based on WRF model and Landsat data

International Nuclear Information System (INIS)

Huang, Q N; Cao, Z Q; Guo, H D; Xi, X H; Li, X W

2014-01-01

In recent decades, unprecedented urban expansion has taken place in developing countries resulting in the emergence of megacities or urban agglomeration. It has been highly concerned by many countries about a variety of urban environmental issues such as greenhouse gas emissions and urban heat island phenomenon associated with urbanization. Generally, thermal environment is monitored by remote sensing satellite data. This method is usually limited by weather and repeated cycle. Another approach is relied on numerical simulation based on models. In the study, these two means are combined to study the thermal environment of Jingjintang urban agglomeration. The high temperature processes of the study area in 2009 and 1990s are simulated by using WRF (the Weather Research and Forecasting Model) coupled with UCM (Urban Canopy Model) and the urban impervious surface estimated from Landsat-5 TM data using support vector machine. Results show that the trend of simulated air temperature (2 meter) is in accord with observed air temperature. Moreover, it indicates the differences of air temperature and Land Surface Temperature caused by the urbanization efficiently. The UHI effect at night is stronger than that in the day. The maximum difference of LST reaches to 8–10°C for new build-up area at night. The method provided in this research can be used to analyze impacts on urban thermal environment caused by urbanization and it also provides means on thermal environment monitoring and prediction which will benefit the coping capacity of extreme event

Fire monitoring capability of the joint Landsat and Sentinel 2 constellation

Science.gov (United States)

Murphy, S.; Wright, R.

2017-12-01

Fires are a global hazard. Landsat and Sentinel 2 can monitor the Earth's surface every 2 - 4 days. This provides an important opportunity to complement the operational (lower resolution) fire monitoring systems. Landsat-class sensors can detect small fires that would be missed by MODIS-classed sensors. All large fires start out as small fires. We analyze fire patterns in California from 1984 to 2017 and compare the performance of Landsat-type and MODIS-type sensors. Had an operational Landsat-Sentinel 2 fire detection system been in place at the time of the Soberanes fire last year (i.e. August 2016), the cost of suppressing of this fire event (US $236 million) could potentially have been reduced by an order of magnitude.

Cloud detection algorithm comparison and validation for operational Landsat data products

Science.gov (United States)

Foga, Steven Curtis; Scaramuzza, Pat; Guo, Song; Zhu, Zhe; Dilley, Ronald; Beckmann, Tim; Schmidt, Gail L.; Dwyer, John L.; Hughes, MJ; Laue, Brady

2017-01-01

Clouds are a pervasive and unavoidable issue in satellite-borne optical imagery. Accurate, well-documented, and automated cloud detection algorithms are necessary to effectively leverage large collections of remotely sensed data. The Landsat project is uniquely suited for comparative validation of cloud assessment algorithms because the modular architecture of the Landsat ground system allows for quick evaluation of new code, and because Landsat has the most comprehensive manual truth masks of any current satellite data archive. Currently, the Landsat Level-1 Product Generation System (LPGS) uses separate algorithms for determining clouds, cirrus clouds, and snow and/or ice probability on a per-pixel basis. With more bands onboard the Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS) satellite, and a greater number of cloud masking algorithms, the U.S. Geological Survey (USGS) is replacing the current cloud masking workflow with a more robust algorithm that is capable of working across multiple Landsat sensors with minimal modification. Because of the inherent error from stray light and intermittent data availability of TIRS, these algorithms need to operate both with and without thermal data. In this study, we created a workflow to evaluate cloud and cloud shadow masking algorithms using cloud validation masks manually derived from both Landsat 7 Enhanced Thematic Mapper Plus (ETM +) and Landsat 8 OLI/TIRS data. We created a new validation dataset consisting of 96 Landsat 8 scenes, representing different biomes and proportions of cloud cover. We evaluated algorithm performance by overall accuracy, omission error, and commission error for both cloud and cloud shadow. We found that CFMask, C code based on the Function of Mask (Fmask) algorithm, and its confidence bands have the best overall accuracy among the many algorithms tested using our validation data. The Artificial Thermal-Automated Cloud Cover Algorithm (AT-ACCA) is the most accurate

A Harmonized Landsat-Sentinel-2 Surface Reflectance product: a resource for Agricultural Monitoring

Science.gov (United States)

Masek, J. G.; Claverie, M.; Ju, J.; Vermote, E.; Justice, C. O.

2015-12-01

The combination of Landsat and Sentinel-2 data offers a unique opportunity to observe globally the land every 2-3 days at medium (reflectance data from Landsat and Sentinel-2 missions and to deliver them to the community in a combined, seamless form. The HLS will be beneficial for global agricultural monitoring applications that require medium spatial resolution and weekly or more frequent observations. In particular, the provided opportunity to track crop phenology at the scale of individual fields will support detailed mapping of crop type and type-specific vegetation conditions. To create a compatible set of radiometric measurements, the HLS product relies on rigorous pre- and post-launch cross-calibration (Landsat-8 OLI and Sentinel-2 MSI) activities. The processing chain includes the following components: atmospheric correction, cloud/shadow masking, nadir BRDF-adjustment, spectral-adjustment, regridding, and temporal composite. The atmospheric correction and cloud masking is based on the OLI atmospheric correction developed at NASA-GSFC and has been adapted to the MSI data. The BRDF-adjustment is based on a disaggregation technique using MODIS-based BRDF coefficients. The technique has been evaluated using the multi-angular acquisition from the SPOT 4 and 5 (Take5) experiments. The spectral-adjustment relies on a linear regression that has been calibrated and evaluated using synthetic data and surface reflectance processed from a large number of hyperspectral EO-1 Hyperion scenes. Finally, significant effort is placed on product validation and evaluation. The delivered data set will include surface reflectance products at different levels: Using the native gridding, i.e. UTM, 30m for Landsat-8, and UTM, 10-20m for Sentinel-2 Using a common global gridding (Sinusoidal, 30m) Temporal composite (Sinusoidal, 30m, 5-day) During the first year of operation of Sentinel-2A, the HLS will be prototyped over a selection of 30 sites that includes some of the JECAM sites

Temporal-Spatial Evolution Analysis of Lake Size-Distribution in the Middle and Lower Yangtze River Basin Using Landsat Imagery Data

Directory of Open Access Journals (Sweden)

Lin Li

2015-08-01

Full Text Available Four natural lakes in the middle and lower reaches of the Yangtze River—Dongting Lake, Poyang Lake, Chaohu Lake and Taihu Lake—play a key role in the climate, environment, and ecology of this area. Upstream of these lakes, the Three Gorges Dam Project has been storing water for 12 years. Future monitoring and management of rivers and lakes can certainly benefit from research on the patterns of variation of natural lakes downstream of the Three Gorges Project. This research applies Landsat TM/ETM data to evaluate water area changes in the four lakes from 2002 to 2013. The water area is estimated using AWEI (Automated Water Extraction Index from satellite images. The average areas decreased respectively 452, 11, and 5 km2 (29.6%, 1.4% and 0.2% from 2002 to 2013 for Dongting, Chaohu, and Taihu Lakes. Meanwhile, it increased 300 km2 (11.0% for Poyang Lake. Precipitation and changes in river inflow may account for the fluctuation in the surface area to a large degree, especially between 2009 and 2013. The present study was undertaken to characterize the evolution of lakes and to explore the potential driving force of variation in order to assist the management of dams upstream in the river basin.

Theoretical and experimental determination of dosimetric characteristics for brachyseedTM Pd-103, model Pd-1, source

International Nuclear Information System (INIS)

Meigooni, A.S.; Zhang Hualin; Perry, Candace; Dini, S.A.; Koona, R.A.

2003-01-01

Dosimetric characteristics of the BrachySeed TM Pd-103, Model Pd-1 source have been determined using both theoretical and experimental methods. Dose rate constant, radial dose function, and anisotropy functions of the source have been obtained following the TG-43 recommendations. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with their 1999 Standard. Measurements were performed in Solid Water TM using LiF TLD chips. Theoretical simulation calculations were performed in both Solid Water TM and water phantom materials using MCNP4C2 Monte Carlo code using DLC-200 interaction data. The results of the Monte Carlo simulation indicated a dose rate constant of 0.65 cGy h -1 U -1 and 0.61 cGy h -1 U -1 in water and Solid Water TM , respectively. The measured dose rate constant in Solid Water TM was found to be 0.63±7% cGy h -1 U -1 , which is within the experimental uncertainty of the Monte-Carlo simulated results. The anisotropy functions of the source were calculated in both water and in Solid Water TM at the radial distances of 1 to 7 cm. Measurements were made in Solid Water TM at distances of 2, 3, 5, and 7 cm. The Monte-Carlo calculated anisotropy constant of the new source was found to be 0.98 in water. The tabulated data and 5th order polynomial fit coefficients for the radial dose function along with the dose rate constant and anisotropy functions are provided to support clinical use of this source

Investigations of LRE-HRE-TM thin films for hybrid recording

Science.gov (United States)

Li, Zuoyi; Cheng, Xiaomin; Jin, Fang; Li, Zhen; Lin, Gengqi; Yang, Xiaofei

2005-09-01

Light rare earth-heavy rare earth-transition metal (LRE-HRE-TM) thin films are a kind of important recording media. A lot of researches have been carried out on the LRE-HRE-TM thin films to improve its properties for data storage application and fruitful results have been achieved. This report gives a glance on the evolution of the research on LRE-HRE-TM recording media. At the same time, combined with the hybrid recording technology, some experimental results obtained on LRE-HRE-TM recording media are discussed, which suggest the promising prospect of the LRE-HRE-TM media in hybrid recording application.

Remote sensing of species diversity using Landsat 8 spectral variables

Science.gov (United States)

Madonsela, Sabelo; Cho, Moses Azong; Ramoelo, Abel; Mutanga, Onisimo

2017-11-01

The application of remote sensing in biodiversity estimation has largely relied on the Normalized Difference Vegetation Index (NDVI). The NDVI exploits spectral information from red and near infrared bands of Landsat images and it does not consider canopy background conditions hence it is affected by soil brightness which lowers its sensitivity to vegetation. As such NDVI may be insufficient in explaining tree species diversity. Meanwhile, the Landsat program also collects essential spectral information in the shortwave infrared (SWIR) region which is related to plant properties. The study was intended to: (i) explore the utility of spectral information across Landsat-8 spectrum using the Principal Component Analysis (PCA) and estimate alpha diversity (α-diversity) in the savannah woodland in southern Africa, and (ii) define the species diversity index (Shannon (H‧), Simpson (D2) and species richness (S) - defined as number of species in a community) that best relates to spectral variability on the Landsat-8 Operational Land Imager dataset. We designed 90 m × 90 m field plots (n = 71) and identified all trees with a diameter at breast height (DbH) above 10 cm. H‧, D2 and S were used to quantify tree species diversity within each plot and the corresponding spectral information on all Landsat-8 bands were extracted from each field plot. A stepwise linear regression was applied to determine the relationship between species diversity indices (H‧, D2 and S) and Principal Components (PCs), vegetation indices and Gray Level Co-occurrence Matrix (GLCM) texture layers with calibration (n = 46) and test (n = 23) datasets. The results of regression analysis showed that the Simple Ratio Index derivative had a higher relationship with H‧, D2 and S (r2= 0.36; r2= 0.41; r2= 0.24 respectively) compared to NDVI, EVI, SAVI or their derivatives. Moreover the Landsat-8 derived PCs also had a higher relationship with H‧ and D2 (r2 of 0.36 and 0.35 respectively) than the

Analysis of n+165Ho and 169Tm reactions

International Nuclear Information System (INIS)

Young, P.G.; Arthur, E.D.; Philis, C.; Nagel, P.; Collin, M.

1982-09-01

Experimental data for neutron-induced reactions on 165 Ho and 169 Tm have been theoretically analyzed in preparation for calculations on the unstable isotopes of Tm. A set of deformed optical model parameters was determined from measurements of s- and p-wave neutron strength functions, total cross sections, elastic angular distributions, and 16-MeV proton scattering to the 165 Ho ground and first excited states. The parameters for the 165 Ho and 169 Tm nuclei were linked by means of an isospin term in the real and imaginary well depths, together with adjustment of the ν 2 and ν 4 deformation parameters based on systematics in this mass region. Transmission coefficients from this analysis were used in Hauser-Feshbach statistical model calculations of the 169 Tm(n,ν) cross section as well as the 169 Tm(n,2n) and (n,3n) cross sections to 23 MeV, after application of suitable preequilibrium corrections. The results of these calculations are in good agreement with most of the available experimental data on 165 Ho and 169 Tm

A Cubesat enabled Spatio-Temporal Enhancement Method (CESTEM) utilizing Planet, Landsat and MODIS data

KAUST Repository

Houborg, Rasmus; McCabe, Matthew

2018-01-01

using a multi-scale target sampling scheme that draws Landsat 8 reference data from a series of scenes by using MODIS-consistent surface reflectance time series to quantify relative changes in Landsat-scale reflectances over given Landsat

Global Human Built-up And Settlement Extent (HBASE) Dataset From Landsat

Data.gov (United States)

National Aeronautics and Space Administration — The Global Human Built-up And Settlement Extent (HBASE) Dataset from Landsat is a global map of HBASE derived from the Global Land Survey (GLS) Landsat dataset for...

Landsat: A global land-imaging mission

Science.gov (United States)

,

2012-01-01

Across four decades since 1972, Landsat satellites have continuously acquired space-based images of the Earth's land surface, coastal shallows, and coral reefs. The Landsat Program, a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA), was established to routinely gather land imagery from space. NASA develops remote-sensing instruments and spacecraft, then launches and validates the performance of the instruments and satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground reception, data archiving, product generation, and distribution. The result of this program is a long-term record of natural and human induced changes on the global landscape.

LANDSAT-1 data, its use in a soil survey program

Science.gov (United States)

Westin, F. C.; Frazee, C. J.

1975-01-01

The following applications of LANDSAT imagery were investigated: assistance in recognizing soil survey boundaries, low intensity soil surveys, and preparation of a base map for publishing thematic soils maps. The following characteristics of LANDSAT imagery were tested as they apply to the recognition of soil boundaries in South Dakota and western Minnesota: synoptic views due to the large areas covered, near-orthography and lack of distortion, flexibility of selecting the proper season, data recording in four parts of the spectrum, and the use of computer compatible tapes. A low intensity soil survey of Pennington County, South Dakota was completed in 1974. Low intensity inexpensive soil surveys can provide the data needed to evaluate agricultural land for the remaining counties until detailed soil surveys are completed. In using LANDSAT imagery as a base map for publishing thematic soil maps, the first step was to prepare a mosaic with 20 LANDSAT scenes from several late spring passes in 1973.

STRUCTURE AND DYNAMICS OF BOREAL ECOSYSTEMS: ANOTHER APPROACH TO LANDSAT IMAGERY CLASSIFICATION

Directory of Open Access Journals (Sweden)

P. Litinsky

2017-01-01

Full Text Available An alternative approach to information extraction from Landsat TM/ETM+ imagery is proposed. It involves transformation the image space into visible 3D form and comparing location in this space the segments of the ecosystem types with expressed graphically typology of forest and mire cover (biogeocenotic scheme. The model is built in LC1-LC2-MSI axis (the two first principal components of the image matrix in logarithmic form and moisture stress index. Comparing to Tasseled Cap, this transformation is more suitable for study area (north taiga zone of Eastern Fennoscandia. The spectral segments of mature and old-growth forests line up from the ecological optimum (moraine hills along two main environmental gradients: i lack of water and nutrition (fluvioglacial sands bedrock and ii degree of paludication (lacustrine plains. Thus, the biogeocenotic complexes are identified. The succession trajectories of forest regeneration through spectral space are also associated with the type of Quaternary deposits. For mire ecosystems spectral classes accurately reflect the type of water and mineral nutrition (ombrotrophic or mesotrophic. Spectral space model created using measured by the scanner physical ecosystem characteristics can be the base for developing objective classification of boreal ecosystems, where one of the most significant clustering criterions is the position in the spectral space.

Trapping processes in CaS:Eu2+,Tm3+

International Nuclear Information System (INIS)

Jia, Dongdong; Jia, Weiyi; Evans, D. R.; Dennis, W. M.; Liu, Huimin; Zhu, Jing; Yen, W. M.

2000-01-01

CaS:Eu 2+ ,Tm 3+ is a persistent red phosphor. Thermoluminescence was measured under different excitation and thermal treatment conditions. The results reveal that the charge defects, created by substituting Tm 3+ for Ca 2+ , serve as hole traps for the afterglow at room temperature. Tm 3+ plays the role of deep electron trapping centers, capturing electrons either through the conduction band or directly from the excited Eu 2+ ions. These two processes, in which two different sites of Tm 3+ are involved, correspond to two traps with different depths. (c) 2000 American Institute of Physics

Wavelength switchable high-power diode-side-pumped rod Tm:YAG Laser around 2µm.

Science.gov (United States)

Wang, Caili; Du, Shifeng; Niu, Yanxiong; Wang, Zhichao; Zhang, Chao; Bian, Qi; Guo, Chuan; Xu, Jialin; Bo, Yong; Peng, Qinjun; Cui, Dafu; Zhang, Jingyuan; Lei, Wenqiang; Xu, Zuyan

2013-03-25

We report a high-power diode-side-pumped rod Tm:YAG laser operated at either 2.07 or 2.02 µm depending on the transmission of pumped output coupler. The laser yields 115W of continuous-wave output power at 2.07 µm with 5% output coupling, which is the highest output power for all solid-state 2.07 μm cw rod Tm:YAG laser reported so far. With an output coupler of 10% transmission, the center wavelength of the laser is switched to 2.02 μm with an output power of 77.1 W. This is the first observation of high-power wavelength switchable diode-side-pumped rod Tm:YAG laser around 2 µm.

A conserved aromatic lock for the tryptophan rotameric switch in TM-VI of seven-transmembrane receptors

DEFF Research Database (Denmark)

Holst, Birgitte; Nygaard, Rie; Hansen, Louise Valentin

2010-01-01

simulations in rhodopsin demonstrated that rotation around the chi1 torsion angle of Trp-VI:13 brings its side chain close to the equally highly conserved Phe-V:13 (Phe-5.47) in TM-V. In the ghrelin receptor, engineering of high affinity metal-ion sites between these positions confirmed their close spatial...... degree as observed in the constructs where Trp-VI:13 itself was mutated, but again without affecting agonist potency. In a proposed active receptor conformation generated by molecular simulations, where the extracellular segment of TM-VI is tilted inwards in the main ligand-binding pocket, Trp-VI:13......The conserved tryptophan in position 13 of TM-VI (Trp-VI:13 or Trp-6.48) of the CWXP motif located at the bottom of the main ligand-binding pocket in TM-VI is believed to function as a rotameric microswitch in the activation process of seven-transmembrane (7TM) receptors. Molecular dynamics...