Landsat Thematic Mapper Satellite Data Research Articles

The impact of COVID-19 induced lockdown on the changes of air quality and land surface temperature in Kolkata city, India

The COVID-19 pandemic and related lockdown reduced the pollution level in the major megacities worldwide. The air pollution level of the city directly influences the air temperature and also land surface temperature (LST). In this paper, authors analyzed the impact of lockdown due to COVID-19 pandemic on the pollution level of the city and resulted LST. Single channel algorithm has been used to retrieve LST from Landsat Thematic Mapper satellite data. Pre-lockdown and post-lockdown satellite data has been used to show the changes in LST due to lockdown. The air quality index of pre-lockdown and post-lockdown period of the city estimated based on seven pollutants such as PM2.5, PM10, NO2, NH3, SO2, CO and Ozone. The pollution level of the city and LST significantly decreased after lockdown is enforced. The pollution level of the major portion of the city before lockdown is moderately polluted (95–153 µm) and after lockdown the satisfactory level of pollution level observed (33–45 µm). The mean LST before lockdown is 28.76 °C (13 March, 2020) and it decreased down to 26.56 °C after lockdown (30 April, 2020). There is a sharp decrease of low value of LST observed (23.6–17.35 °C) in the city.

Tuart (Eucalyptus gomphocephala) decline is not associated with other vegetation structure and composition changes

Tree decline affects forests and woodlands on most continents. The loss of canopy species from these landscapes has marked impacts on the surrounding environment. Understanding the consequences of tree mortality on vegetation structure and composition will contribute to developing management strategies for these ecosystems. The tuart (Eucalyptus gomphocephala), once the dominant tree species on the coastal plain in southwest Western Australia, has been cleared extensively and today occurs over less than a third of its former range. Compounding the effects of this clearing, dramatic declines in tree health over the past two decades has been recorded. We examined whether E. gomphocephala decline is reflected in changes to overall vegetation structure and composition. Using Landsat Thematic Mapper satellite data, we identified 12 sites with stable or improving vegetation vigour over the previous 15 years (‘healthy’ sites) and 12 sites with declining vegetation vigour over this time (‘declining’ sites). Health of E. gomphocephala trees, as well as litter, vegetation structure and vegetation composition were compared across these sites. Four health measures indicated that E. gomphocephala trees from healthy and declining sites were statistically distinguishable (p < 0.001). Trees at declining sites showed marked epicormic growth (up to 96% of canopy), evidence of crown dieback, reduced crown density and increased foliage transparency. The canopy changes were reflected in marked reduction in leaf litter for declining sites (p = 0.024). Despite the changes in E. gomphocephala canopy and leaf litter, however, there were no significant differences in vegetation community composition, relative vegetation cover for five height strata, vegetation structural and compositional diversity, presence of coarse woody debris, or overall canopy cover. There were also no differences in soil chemistry between the healthy and declining sites. The agent of tuart decline therefore appears to be specific to Eucalyptus gomphocephala at these sites, or alternatively the changes to other plant species have been too subtle to detect at this stage.

CHROMITITE PROSPECTING USING LANDSAT TM AND ASTER REMOTE SENSING DATA

Abstract. Studying the ophiolite complexes using multispectral remote sensing satellite data are interesting because of high diversity of minerals and the source of podiform chromitites. This research developed an approach to discriminate lithological units and detecting host rock of chromitite bodies within ophiolitic complexes using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) satellite data. Three main ophiolite complexes located in south of Iran have been selected for the study. Spectral transform techniques, including minimum noise fraction (MNF) and specialized band ratio were employed to detect different rock units and the identification of high-potential areas of chromite ore deposits within ophiolitic complexes. A specialized band ratio (4/1, 4/5, 4/7) of ASTER, MNF components and Spectral Angle Mapper (SAM) on ASTER and Landsat TM data were used to distinguish ophiolitic rock units. Results show that the specialized band ratio was able to identify different rock units and serpentinized dunite as host rock of chromitites within ophiolitic complexes, appropriately. MNF components of ASTER and Landsat TM data were suitable to distinguish ophiolitic rock complexes at a regional scale. The integration of SAM and Feature Level Fusion (FLF) used in this investigation discriminated the ophiolitic rock units and prepared detailed geological map for the study area. Accordingly, high potential areas (serpentinite dunite) were identified in the study area for chromite exploration targets.The approach used in this research offers the image processing techniques as a robust, reliable, fast and cost-effective method for detecting serpentinized dunite as host rock of chromitite bodies within vast ophiolite complexes using ASTER and Landsat TM satellite data.

Analysing spatio-temporal footprints of urbanization on environment of Surat city using satellite-derived bio-physical parameters

Our study examines the relationships among various environmental variables in Surat city using remote sensing. Landsat Thematic Mapper satellite data were used in conjugation with geospatial techniques to study urbanization and correlation among satellite-derived biophysical parameters namely, normalized difference vegetation index (NDVI), normalized difference built-up index (NDBI), normalized difference water index (NDWI), normalized difference bareness index (NDBaI) and land surface temperature (LST). A modified NDWI (MNDWI) was used for extracting areas under water. Land use/land cover classification was performed using hierarchical decision tree classification technique using ERDAS IMAGINE Expert classifier with an accuracy of 90.4% for 1990 and 85% for 2009. It was found that city has expanded over 42.75 sq.km within two decades. Built-up, fallow and sediment land use classes exhibited high dynamics with increase of nearly 200% and 50% and decrease of 55% respectively from 1990 to 2009. Vegetation and water classes were less dynamic with 20% decrease and 15% increase. The transformation of land parcels from vegetation to built-up, vegetation to fallow and fallow to built-up has resulted in increase of LST by 5.5 ± 2.6°C, 6.7 ± 3°C and 3.5 ± 2.9°C, respectively.

Spatio-temporal footprints of urbanisation in Surat, the Diamond City of India (1990–2009)

Urbanisation is a ubiquitous phenomenon with greater prominence in developing nations. Urban expansion involves land conversions from vegetated moisture-rich to impervious moisture-deficient land surfaces. The urban land transformations alter biophysical parameters in a mode that promotes development of heat islands and degrades environmental health. This study elaborates relationships among various environmental variables using remote sensing dataset to study spatio-temporal footprint of urbanisation in Surat city. Landsat Thematic Mapper satellite data were used in conjugation with geo-spatial techniques to study urbanisation and correlation among various satellite-derived biophysical parameters, [Normalised Difference Vegetation Index, Normalised Difference Built-up Index, Normalised Difference Water Index, Normalised Difference Bareness Index, Modified NDWI and land surface temperature (LST)]. Land use land cover was prepared using hierarchical decision tree classification with an accuracy of 90.4% (kappa = 0.88) for 1990 and 85% (kappa = 0.81) for 2009. It was found that the city has expanded over 42.75km(2) within a decade, and these changes resulted in elevated surface temperatures. For example, transformation from vegetation to built-up has resulted in 5.5 ± 2.6°C increase in land surface temperature, vegetation to fallow 6.7 ± 3°C, fallow to built-up is 3.5 ± 2.9°C and built-up to dense built-up is 5.3 ± 2.8°C. Directional profiling for LST was done to study spatial patterns of LST in and around Surat city. Emergence of two new LST peaks for 2009 was observed in N-S and NE-SW profiles.

Comparing ten classification methods for burned area mapping in a Mediterranean environment using Landsat TM satellite data

Various methods have been developed during the past three decades to improve the classification accuracy in burned area mapping using satellite data captured by different sensors. In this article, we compare ten such classification approaches using Landsat Thematic Mapper (TM) imagery on three Mediterranean test sites by evaluating the classification accuracy using (i) a traditional pixel-based approach, (ii) the concept of the Pareto boundary of efficient solution and (iii) linear regression analysis. Additionally, we make a discrimination of errors depending on their distribution and causal factor. The classification approaches compared resulted in not statistically significant differences in the accuracy of the burned area maps. Differences between the methods were also observed when considering the accuracy along the edges of the burned patches; however, again these were not statistically significant. The findings of our study in a Mediterranean environment clearly demonstrate that, for the selection of the most suitable classification approach, other factors could be given more weight, such as computational resources, imagery characteristics, availability of ancillary data, available software and the analyst's experience. Maybe the most important finding of our work is that the variance imposed by the methods is less than the variance imposed by factors differentiated locally in the three study sites since the between-group variance of the overall accuracy is higher than that of the within groups.

Estimating the Effects of Map Error on Habitat Delineation for the California Spotted Owl in Southern California

The reliability of habitat maps that have been generated using Geographic Information Systems (GIS) and image processing of remotely sensed data can be overestimated. Habitat suitability and spatially explicit population viability models are often based on these products without explicit knowledge of the effects of these mapping errors on model results. While research has considered errors in population modeling assumptions, there is no standardized method for measuring the effects of inaccuracies resulting from errors in landscape classification. Using landscape-scale maps of existing vegetation developed for the USDA Forest Service in southern California from Landsat Thematic Mapper satellite data and GIS modeling, we performed a sensitivity analysis to estimate how mapping errors in vegetation type, forest canopy cover, and tree crown size might affect delineation of suitable habitat for the California spotted owl (Strix occidentalis occidentalis). The resulting simulated uncertainty maps showed an increase in the estimated area of suitable habitat types. Further analysis measuring the fragmentation of the additional patches showed that they were too small to be useful as habitat areas.

Assessing Water Quality in Catawba River Reservoirs Using Landsat Thematic Mapper Satellite Data

ABSTRACT This study investigates the potential of satellite-based remote sensing to assess water quality in the 11 reservoirs of the Catawba River basin. Near-simultaneous acquisition of both Landsat TM (Thematic Mapper) data and in situ water quality observations (turbidity, secchi disk depth, chlorophyll and surface temperature), in May of 1995, provided a statistical foundation for the development of algorithms that convert TM reflectance to each water quality parameter. The conversion models defined for turbidity, secchi disk depth, chlorophyll (power law function) and temperature (linear function) were used to produce digital cartographic products that depict the distribution of each parameter in the 11 reservoirs. A analysis of error demonstrates that accurate quantitative data products can be produced from Landsat TM imagery for the surface waters of the major reservoirs in this system with a spatial resolution of 30 m for turbidity and secchi disk depth, and a 120-m resolution for surface temperature. Landsat TM appeared to have an inadequate spectral resolution for the quantitative assessment of chlorophyll. In this study, an additional experiment was performed in October 1995 to evaluate the applicability of the reflectance-based conversion algorithms to TM data acquired at other times and from other reservoirs. Though not quantitatively conclusive, the predicted values derived by the conversion algorithms were as consistent with ground observations for all water quality parameters except chlorophyll as that seen in the initial experiment.

Spectral mixture analysis for mapping land degradation in semi-arid areas

Spectral mixture analysis (SMA) is an image-processing technique used for the analysis of airborne hyperspectral remote-sensing data which consist of a large number of spectral bands, typically over 100. In this paper the possibilities are examined of using SMA for the analysis of Landsat Thematic Mapper satellite data with only six bands in the visible to shortwave-infrared wavelength. We use data from a semi-arid area in the Sanmatenga province of Burkina Faso, an area known to experience land-degradation problems. In SMA, we assume that pixels in an image consist of one or more homogeneous (uniform in character) or pure surfaces, the so called end-members. The end-members were derived from the image data on the basis of specific image characteristics. Field data was collected to describe the characteristics of these end-members in terms of land cover, soil and degradation phenomena. The end-members derived from the image analysis, although statistically pure in terms of image spectral characteristics, prove to be mixtures at a field scale. This lack of purity is explained by the nature of semi-arid areas which is more heterogeneous than that of most other areas. The SMA yielded cover percentages for the end-members from which an unsupervised classification was made. Comparison of the classification with the results of SMA shows that the latter provides information on the amount and spatial distribution of land characteristics such as land degradation.

A remote sensing approach to alteration mapping: AVIRIS data and extension-related potassium metasomatism, Socorro, New Mexico

Miocene crustal extension in the south-western United States was accompanied by potassium metasomatism, a type of alteration marked by addition of large amounts of potassium at the expense of other constituents, notably sodium. The fluids responsible for the potassic alteration may have played a role in triggering extensional fault motion; one way to determine this is to compare the geographic distribution of the alteration to fault and sedimentary facies maps. Despite the large impact on rock composition, however, the alteration is visually subtle and difficult to map in the field. In this paper we present a preliminary alteration map of the Lemitar Mountains near Socorro, New Mexico, within the Rio Grande rift. This map was created from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data. The potential to discriminate potassium metasomatism in Landsat Thematic Mapper satellite data is part of the motivation for this study, since such data are widely available. Although the potassic minerals do not exhibit spectral features in the visible and near-infrared, iron was mobilized during potassium metasomatism, and the distribution of haematite thus serves as a proxy for the potassium. Evidence supporting the proxy relationship between haematite and metasomatism include (a) published reports by previous workers stating that haematite is added to rocks during K-metasomatism; (b) limited chemical evidence that samples collected from areas displaying a distinctive spectral response are strongly metasomatized; (c) the presence of large amounts of haematite in metasomatized rocks, observed petrographically and with an EDAX microprobe; and (d) the coincidence of the southern edge of the K-anomaly in the Lemitar Mountains as defined by chemical analysis and the southernmost occurrence of the anomalous spectral response. No other significant source of haematite has been reported from this area. Manganese oxide, occurring as localized veins or as rock varnish, is black in colour and highly absorptive, resulting in a distinctly different spectral response than the metasomatism-related haematite. This work shows that K-metasomatism can be mapped using AVIRIS data. The spectral response is not subtle, and can be observed in Landsat Thematic Mapper data; it is likely that K-metasomatism can be mapped, at least to some significant degree, from the Landsat data. Ongoing work is focusing on calibrating the strength of the spectral response to the intensity of alteration.

Airborne Magnetic, Radiometric and Satellite Imagery for Regolith Mapping in the Yilgarn Craton of Western Australia

The integrated use of airborne magnetic and radiometric data, and SPOT Panchromatic and LANDSAT Thematic Mapper satellite data has proved effective for regolith mapping in the Yilgarn Craton of Western Australia. They can form the basis for designing appropriate soil sampling and regional exploration drilling in gold exploration programs.Horizontal derivative filters have been applied to airborne magnetic line data to enhance short wavelength magnetic responses of maghemite-rich lateritic weathering products within the regolith profile. Magnetised maghemite-rich pisolites often occur in buried Tertiary palaeo-drainage channels or within residual laterite horizons, and their distribution can be delineated with these filters. Anew filter for magnetic data (REGMAG) is described that maps the distribution of short-wavelength responses and has proved effective in mapping magnetic structures in the regolith.Ratios of airborne radiometric potassium and thorium channels, and ternary images of potassium, thorium and uranium, are useful in highlighting the radiometric signatures of various weathering products in the regolith. A new ratio normalisation algorithm improves the resolution of ratioed data.Combined SPOT Panchromatic and LANDSAT Thematic Mapper satellite data are useful for landform mapping. Ratios of LANDSAT Thematic Mapper bands provide discrimination of various weathering products such as saprolite, pisolitic/nodular goethite and hematite-rich laterite, quartz and kaolinite rich alluvial cover, and red-earth calcareous clays.Examples from the Archaean Yilgarn Craton of Western Australia show how these processing techniques can reveal valuable information from remotely sensed data which can assist with regolith mapping.

Forest cover types derived from Landsat Thematic Mapper imagery for Changbai Mountain area of China

The distributions of various forest cover types on Changbai Mountain of northeastern China were examined by interpreting Landsat Thematic Mapper satellite data. The area studied consists of the Changbai Nature Reserve plus an 8 km wide buffer zone. The dominant forest cover types were mixed Korean pine (Pinuskoraiensis Sieb. &amp; Zucc.) hardwood forest below 1100 m above sea level (asl) and evergreen coniferous forest between 1100 and 1650 m asl. These two forest cover types accounted for about 70% of the area inside the reserve, and 50% of the area outside the reserve. Other forest cover types included aspen (Populusdavidiana Dode) –white birch (Betulaplatyphylla Sukachev) forest, hardwood forest, larch (Larixolgensis A. Henry) forest, sparse forest land, and mountain birch (Betulaermanii Cham.) forest. Above the forest line (1950 m asl), a zone of tundra was distributed on the top of Changbai Mountain. The mountain birch forest was located between tundra and the evergreen forest. Human-altered areas, including forest clearcuts and urban areas, accounted for only 10% of the whole study area. More than 90% (in area) of the human-altered areas was found in the zone surrounding the reserve. To better protect the old-growth forest ecosystems inside and outside Changbai Nature Reserve, conservation planning for the reserve and forest management for the surrounding area need to be modified.

Transformed Vegetation Index for Measuring Spatial Variation in Drought Impacted Biomass on Konza Prairie, Kansas

Landsat thematic mapper satellite data were found to offer potential for regular monitoring of the Konza Prairie tallgrass prairie ecosystem. Data from two Landsat thematic mapper channels derived from an August 1989 scene were analyzed using a transformed vegetation index relative to above ground biomass samples on burned and unburned watersheds for Florence and Clime soils. In addition transformed vegetation index (TV 1) values were analyzed relative to watersheds experiencing different burning frequency. Despite drought conditions during 1989, the combination of using Landsat thematic mapper in a transformed vegetation index provided a suitable measure of spatial variation in above ground biomass for diverse burning strategies and soil conditions. Traditional techniques for estimating the productivity of grasslands under varying treatments and soil conditions are time consuming, costly, and do not lend themselves to evaluation of geographically large areas. Vegetation indices, derived using satellite data, however, offer the potential for extrapolating limited ground samples to watershed units. Since the early success of the Landsat system in the early 1970's, scientists from throughout the world have explored the question of measuring vegetation dynamics with remote sensing digital data. In 1982 and 1984, N.A.S.A. launched the Landsat thematic mapper sensor on the Landsat satellite which offered improved spatial resolution with additional improvements in the spectral band resolutions from the Landsat multispectral scanner. The objective of this paper is to explore the use of Landsat thematic mapper data for understanding the condition of various watersheds on the Konza Prairie This content downloaded from 157.55.39.199 on Tue, 21 Feb 2017 20:02:43 UTC All use subject to http://about.jstor.org/terms 94 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE

Detecting Soil Information on a Native Prairie Using Landsat TM and SPOT Satellite Data

AbstractComputer pattern recognition techniques were used to discriminate soil information from the Landsat Thematic Mapper (TM) and the French Systeme Probatoire d'Observation de le Terre (SPOT) satellite data on a native prairie near Manhattan, KS. Digital Elevation Model (DEM) data were merged to Landsat TM and SPOT data to delineate soil mapping units within the study area. Soil mapping units from a conventional soil survey were compared with a classified soil spectral map obtained from Landsat TM or SPOT, and DEM derived elevation, slope, and aspect data, using an overall accuracy assessment. The overall accuracy of soil spectral classes from TM and SPOT data was improved after DEM data were merged. A higher average accuracy for soil mapping units was obtained with a low frequency filtering transformation of the data. For Landsat TM data, Band 5 (middle infrared, 1.55–1.75 µm) was most useful for soil information extraction, and a higher overall accuracy was obtained in the dormant season compared with the accuracy in the growing season. The overall accuracy (about 57%) from SPOT data was slightly higher than the accuracy (about 53%) from Landsat TM at a similar wavelength range. Our results indicate that high resolution Landsat TM and SPOT satellite data can be used to aid second‐order soil surveys in areas where the dominant land use is rangeland.

Multiple dipole eddies in the Alaska Coastal Current detected with Landsat thematic mapper data

Seventeen dipole eddies, including five large, well‐formed ones, three second‐generation eddies, and two double eddies, were observed in the Alaska Coastal Current near Kayak Island in one single scene of the Landsat thematic mapper (TM) on April 22, 1985. The digital Landsat TM satellite data were computer analyzed to extract details in the near coastal circulation in the northern Gulf of Alaska. Enhancement techniques were applied to the visible and thermal IR bands. The features are evident only in the visible bands because of the ability of these bands to detect the distribution of sediments in the near surface. These eddies did not have a significant thermal signature. The sources of these sediments are the glacial streams found throughout the Gulf of Alaska coast. Eddies of this configuration and frequency have never been observed here previously. However, the oceanographic and meteorological conditions are typical for this time of year. These eddies should be important to the cross‐shelf mixing processes in the Alaska Coastal Current and are an indicator that the flow here can be unstable at certain times of the year.