To see the other types of publications on this topic, follow the link: Landsat MSS satellite imagery.
Journal articles on the topic 'Landsat MSS satellite imagery'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Landsat MSS satellite imagery.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Dowdeswell, J. A., M. R. Gorman, Yu Ya Macheret, M. Yu Moskalevsky, and J. O. Hagen. "Digital comparison of high resolution Sojuzkarta KFA-1000 imagery of ice masses with Landsat and SPOT data." Annals of Glaciology 17 (1993): 105–12. http://dx.doi.org/10.1017/s0260305500012684.
Full textAbstract:
Russian satellite imagery of the polar regions has recently become available to western scientists through Sojuzkarta. The KFA-1000 photographic camera is of particular interest to glaciologists due to its high resolution (a nominal 5 m). Digitized photographic products from this instrument are compared with digital data from Landsat and SPOT series satellites for a partly glacierized area of northwest Spitsbergen. Comparison of KFA-1000 data with detailed maps of man-made structures at the settlement of Ny Ålesund demonstrates that the resolution of the photographic imagery is about 3 m, but scanner resolution limited our digital data to about 6 m. Significantly less detail can be resolved on Landsat TM imagery and Landsat MSS data fail to resolve any of the structures. KFA-1000 data are compared with Landsat TM and MSS images and SPOT HRV multispectral imagery for several tidewater glaciers in Spitsbergen. KFA-1000 imagery is of a significantly higher geometric resolution than the other sensors, allowing the clear identification of individual crevasses and other ice surface features. KFA-1000 scenes from 1985 and 1988 are used to measure ice marginal fluctuations for several northwest Spitsbergen glaciers, and the onset of a surge can also be identified. This imagery has a 60% overlap between scenes and the heighting accuracy of the stereoscopic data is calculated at 45 m. Radiometric analysis of KFA-1000 data is restricted to relative brightness values, since no absolute calibration is available. The photographic products appear speckled, and the range and standard deviation of normalized pixel brightness values over snow is greater than for equivalent Landsat TM data. The very high spatial resolution of the KFA-1000 camera is its principal attraction for glaciologists.
2
Dowdeswell, J. A., M. R. Gorman, Yu Ya Macheret, M. Yu Moskalevsky, and J. O. Hagen. "Digital comparison of high resolution Sojuzkarta KFA-1000 imagery of ice masses with Landsat and SPOT data." Annals of Glaciology 17 (1993): 105–12. http://dx.doi.org/10.3189/s0260305500012684.
Full textAbstract:
Russian satellite imagery of the polar regions has recently become available to western scientists through Sojuzkarta. The KFA-1000 photographic camera is of particular interest to glaciologists due to its high resolution (a nominal 5 m). Digitized photographic products from this instrument are compared with digital data from Landsat and SPOT series satellites for a partly glacierized area of northwest Spitsbergen. Comparison of KFA-1000 data with detailed maps of man-made structures at the settlement of Ny Ålesund demonstrates that the resolution of the photographic imagery is about 3 m, but scanner resolution limited our digital data to about 6 m. Significantly less detail can be resolved on Landsat TM imagery and Landsat MSS data fail to resolve any of the structures. KFA-1000 data are compared with Landsat TM and MSS images and SPOT HRV multispectral imagery for several tidewater glaciers in Spitsbergen. KFA-1000 imagery is of a significantly higher geometric resolution than the other sensors, allowing the clear identification of individual crevasses and other ice surface features. KFA-1000 scenes from 1985 and 1988 are used to measure ice marginal fluctuations for several northwest Spitsbergen glaciers, and the onset of a surge can also be identified. This imagery has a 60% overlap between scenes and the heighting accuracy of the stereoscopic data is calculated at 45 m. Radiometric analysis of KFA-1000 data is restricted to relative brightness values, since no absolute calibration is available. The photographic products appear speckled, and the range and standard deviation of normalized pixel brightness values over snow is greater than for equivalent Landsat TM data. The very high spatial resolution of the KFA-1000 camera is its principal attraction for glaciologists.
3
Johansen, Bernt, and Stein Rune Karlsen. "Monitoring vegetation changes on Finnmarksvidda, Northern Norway, using Landsat MSS and Landsat TM/ETM+ satellite images." Phytocoenologia 35, no. 4 (December 13, 2005): 969–84. http://dx.doi.org/10.1127/0340-269x/2005/0035-0969.
Full text
4
Ferrigno, J. G., and W. G. Gould. "Substantial changes in the coastline of Antarctica revealed by satellite imagery." Polar Record 23, no. 146 (May 1987): 577–83. http://dx.doi.org/10.1017/s003224740000807x.
Full textAbstract:
ABSTRACTNoaa Avhrr and Landsat MSS imagery acquired between January and November 1986 has shown substantial changes in the Antarctic coastline near the Filchner Ice Shelf, Larsen Ice Shelf and Thwaites Glacier. In the Filchner Ice Shelf area some 11,500 km of ice calved from mid-April onward. In the Larsen Ice Shelf area two large bergs calved between February and August. The combined volume of ice from these two events equals approximately three years' normal calving from the entire Antarctic coastline. In the Thwaites Glacier area several changes appear to have occurred at the base of Thwaites Iceberg Tongue and Thwaites Glacier Tongue.
5
Van Niekerk, Elna, and Luke Sandham. "Visual interpretation of ASTER satellite data, Part 1: Geologic mapping in the Cradle of Humankind World Heritage Site." Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie 26, no. 3 (September 21, 2007): 177–95. http://dx.doi.org/10.4102/satnt.v26i3.132.
Full textAbstract:
Since the first earth observing satellite was launched in 1972, remote sensing has become a powerful tool in the arsenal of geoscientists. This satellite became known as Landsat 1 and carried the Multispectral Scanner (MSS) delivering imagery at a spatial resolution of 80, and spectral resolution from blue to near infrared. Ongoing satellite and sensor development to the end of the century produced the Landsat Thematic Mapper (TM) with improved spatial and spectral resolution, as well as the SPOT series of satellites delivering the highest spatial but limited spectral resolution. These developments culminated in the SPOT 4 (1998) and Landsat Enhanced Thematic Mapper (1999) sensors. While Landsat ETM in particular provided much improved spatial and spectral resolutions, on the basis of which a large amount of geoscientific remote sensing was conducted world wide, the data did not provide adequate spectral and spatial sensitivity to be optimally effective for geological mapping at the local scale. On 18 December 1999 the Terra platform was launched, carrying five remote sensing instruments, including ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer). ASTER consists of three separate instrument subsystems, each operating in a different spectral region, and using separate optical systems. These are the Visible and Very Near Infrared (VNIR) subsystem with a 15m-spatial resolution, the Short Wave Infrared (SWIR) subsystem with a 30m-spatial resolution and the Thermal Infrared (TIR) subsystem with a 90m-spatial resolution. ASTER effectively offers an improvement on Landsat MSS, Landsat TM, Landsat ETM+ and SPOT spectral and spatial resolutions. Given the paucity of published research on geological remote sensing at the local scale in South Africa, and particularly on the use of ASTER for geological mapping in South Africa, it is imperative that the value of ASTER be investigated. This article reports on the improved detail and scale achieved in the mapping of litho-stratigraphy, geological structures and mining-related features by the visual interpretation of processed ASTER images. ASTER imagery obtained from the EOS website was subjected to a range of image enhancement and analysis techniques including colour composites, band ratios, normalised difference indices, regression and decorrelation, in order to obtain optimal visual interpretability. Eight images thus obtained could be used for visual analysis, and it became evident that litho-stratigraphy, faults, fracture zones and elements of the regional seam system, as well as remnants of mining activities, were readily identifiable. Some of these were in accordance with the most recent and accurate geological map of the area, but many of them had apparently not been mapped. These features were annotated and were verified by field checks. In all cases the accuracy of detection and location from satellite imagery was confirmed on the ground. The improved detail and accuracy obtained by visual interpretation of processed ASTER satellite data for mapping a section of the Cradle of Humankind World Heritage Site demonstrated the potential value of this data for a variety of other geoscience applications. It appears that the improved accuracy can be ascribed jointly to the higher spatial and spectral resolution provided by ASTER data.
6
Deguchi, C., and S. Sugio. "Estimations for Percentage of Impervious Area by the Use of Satellite Remote Sensing Imagery." Water Science and Technology 29, no. 1-2 (January 1, 1994): 135–44. http://dx.doi.org/10.2166/wst.1994.0659.
Full textAbstract:
This study aims to evaluate the applicability of satellite imagery in estimating the percentage of impervious area in urbanized areas. Two methods of estimation are proposed and applied to a small urbanized watershed in Japan. The area is considered under two different cases of subdivision; i.e., 14 zones and 17 zones. The satellite imageries of LANDSAT-MSS (Multi-Spectral Scanner) in 1984, MOS-MESSR(Multi-spectral Electronic Self-Scanning Radiometer) in 1988 and SPOT-HRV(High Resolution Visible) in 1988 are classified. The percentage of imperviousness in 17 zones is estimated by using these classification results. These values are compared with the ones obtained from the aerial photographs. The percent imperviousness derived from the imagery agrees well with those derived from aerial photographs. The estimation errors evaluated are less than 10%, the same as those obtained from aerial photographs.
7
Dede, Moh, Millary Agung Widiawaty, Nurhanifah Nurhanifah, Arif Ismail, Ajeng Randhita Prabatiwakya Artati, Amniar Ati, and Yanuar Rizky Ramadhan. "Estimasi Perubahan Kualitas Udara Berbasis Citra Satelit Penginderaan Jauh Di Sekitar PLTU Cirebon." Jambura Geoscience Review 2, no. 2 (June 14, 2020): 78–87. http://dx.doi.org/10.34312/jgeosrev.v2i2.5951.
Full textAbstract:
Steam power plant construction and operation is an effort to meet electricity needs. In Indonesia, two steam power plants were built and changed the landscape in Cirebon. The presence of Cirebon steam power plants has disturbed the community and potential to decrease air quality. This study aims to estimate air quality changes around the power plants based on remote sensing satellite imageries. The main data in this study obtained from Landsat-8 OLI (2019) and Landsat-7 ETM (2004) satellite imageries were processed with four parameters of air quality algorithm namely PM10, CO, SO2, and NOx on AOI with ranging of 2000 m from the source point. Validation uses comparative data from MODIS and Sentinel-2 MSS satellite imageries in the same period. Changes analysis in air quality used the Mann-Whitney method (U-Test). This research shows that the Landsat series satellite imagery is suitable to be used as the main data for estimating air quality because it has a similar pattern to comparable data. The Cirebon PLTU operation caused a significant increase in CO levels of 1.25 mg/l on a wide range. In other air quality parameters such as PM10, SO2 and NOx were decreased.
8
Hall, R. J., A. R. Kruger, W. C. Moore, J. Scheffer, and S. J. Titus. "A Statistical Evaluation of LANDSAT TM and MSS Data for Mapping Forest Cutovers." Forestry Chronicle 65, no. 6 (December 1, 1989): 441–49. http://dx.doi.org/10.5558/tfc65441-6.
Full textAbstract:
The cutover area and boundary placement mapping accuracies from currently used air photo techniques and LANDSAT TM and MSS imagery were determined for Alberta forestry conditions. Overall area accuracies for the air photo techniques. LANDSAT TM, and MSS images were 86.7%, 89.5%, and 86.9%, respectively. The influence of increasing accuracy with increasing cutover size, however, must be kept in perspective. Although interpreted cutover areas were generally smaller compared with their actual areas, the deviation was systematic and could therefore be corrected by regression techniques. Overall boundary placement errors for air photo techniques. LANDSAT TM, and MSS images were 30.1, 24.9, and 38.3 m, respectively. Most of the LANDSAT TM errors were in the 20-m range and were within 5 m of the target 15-20 m desired by the Alberta Forest Service. Improvements to this may be achieved by using larger scale satellite images. The base map scale of 1:20 000 was a limiting factor to this study, however, as it was too small with both plotting errors and pen line widths contributing to existing map errors. LANDSAT TM images offered a 12:1 cost savings in data acquisition and are more efficient in comparison with conventional air photos. Use of either medium scale air photos or LANDSAT TM images can be recommended depending on the level of timber commitment accuracy requirements and is presented in the paper as an operational cutover update mapping strategy. Keywords: Forest inventory, update, LANDSAT, change detection, mapping, accuracy analysis, remote sensing.
9
Onuigbo, I. C., and J. Y. Jwat. "Change Detection Analysis Using Surveying and Geoinformatics Techniques." Nigerian Journal of Environmental Sciences and Technology 2, no. 1 (March 2018): 28–38. http://dx.doi.org/10.36263/nijest.2018.01.0051.
Full textAbstract:
The study was on change detection using Surveying and Geoinformatics techniques. For effective research study, Landsat satellite images and Quickbird imagery of Minna were acquired for three periods, 2000, 2005 and 2012. The research work demonstrated the possibility of using Surveying and Geoinformatics in capturing spatial-temporal data. The result of the research work shows a rapid growth in built-up land between 2000 and 2005, while the periods between 2005 and 2012 witnessed a reduction in this class. It was also observed that change by 2020 may likely follow the trend in 2005 – 2012 all things being equal. Built up area may increase to 11026.456 hectares, which represent 11% change. The study has shown clearly the extent to which MSS imagery and Landsat images together with extensive ground- truthing can provide information necessary for land use and land cover mapping. Attempt was made to capture as accurate as possible four land use and land cover classes as they change through time.
10
Boyce, Mark, Evelyn Merrill, and Ronald Marrs. "Relationships between Climatic Variation and Grassland Biomass on the Northern Range of Yellowstone National Park." UW National Parks Service Research Station Annual Reports 11 (January 1, 1987): 153–59. http://dx.doi.org/10.13001/uwnpsrc.1987.2655.
Full textAbstract:
Summer range is not thought to be limiting to elk because abundant, high quality forage is available whereas a shortage of forage usually exists on elk winter ranges. Nevertheless, summer nutrition and fat reserves acquired on summer ranges influence growth, survival and reproduction of ungulates (Klein 1965, Verme 1963, 1965, Julander et al. 1961). The enormous area of summer range for the Northern Yellowstone elk herd renders detailed field surveys impractical. This study was initiated to evaluate the feasibility of using LANDSAT satellite imagery to (1) characterize vegetation communities on summer range from LANDSAT multispectral scanner (MSS) data and digitized vegetation maps of Yellowstone National Park, (2) predict plant production within grassland types and (3) correlate elk population characteristics with fluctuations in plant production and weather.
11
Vickery, P. J., M. J. Hill, and G. E. Donald. "Satellite derived maps of pasture growth status: association of classification with botanical composition." Australian Journal of Experimental Agriculture 37, no. 5 (1997): 547. http://dx.doi.org/10.1071/ea97014.
Full textAbstract:
Summary. Spectral data from the green, red and near-infrared bands of Landsat MSS and Landsat TM satellite imagery acquired in mid-spring were classified into 3 and 6 pasture growth classes respectively. The classifications were compared with a site database of botanical composition for the Northern Tablelands of New South Wales to examine the association between spectral growth class and pasture composition. Pastures ranged in composition from unimproved native perennial grasses through semi-improved mixtures of native and naturalised grasses and legumes to highly improved temperate perennial grasses and legumes. For 3 years of MSS data, the fast growth class had a mean botanical composition of about 80% improved perennial grass and 0% native; medium growth class averaged 46% improved perennial grass and 14% native; while the slow growth class had about 60% native and 1% improved perennial grass when averaged over 3 years of MSS data. For the 6 class TM data from a single year, a predictive logistic regression of cumulative probability was developed for percentage of ‘very fast’ growth pixels and ordered 10 percentile categories of improved perennial grass or native grass. Differences in patch characteristics between classes with MSS disappeared with TM reclassified to the same 3 class level. Most probable pasture type was inferred from 3 class MSS and TM data using Bayesian probability analysis. The resulting maps were similar in general appearance but detail was better with the TM data. The pasture growth classification identified highly improved perennial grass pastures and native pastures but sensitivity to intermediate pasture types was poor. Future improvement will come from direct measurement of biophysical characteristics using vegetation indices or inversion of reflectance models.
12
G. Ferrigno, Jane, and Bruce F. Molnia. "Evaluation Of Landsat, Spot, and Sojuzkarta Data Of Antarctica For Ice and Climate Research." Annals of Glaciology 14 (1990): 333–34. http://dx.doi.org/10.1017/s0260305500008946.
Full textAbstract:
Satellite data have proved suitable and cost-effective for ice and climate research in Antarctica. They have been used in numerous research efforts, including: monitoring coastal change, determining velocities of outlet glaciers, defining blue ice areas, tracking the movement of icebergs, and as a base for overlaying radar and other data. This paper reviews the data acquired since 1972 by the Landsat, SPOT and Sojuzkarta space systems and illustrates where good-quality (±10% cloud cover) data are available. The Landsat 1, 2, and 3 satellites acquired approximately 10 000 multispectral scanner (MSS) (80 m resolution) and return-beam vidicon (RBV) (30 m resolution) photographic and digital images of Antarctica between 1972 and 1983. The quality of these images has been evaluated by USGS to determine the feasibility of using them for glaciological, climatological, and geological research. Results have been plotted on a base map of Antarctica and show about 45% of the nominal scene centers, or about 70% of the geographic area of the continent, to be covered by good-quality imagery. Landsat 4 started acquiring data in 1982 and Landsat 5 in 1984. Together the two satellites acquired more than 4 500 thematic mapper (TM) (30 m resolution) and MSS images of Antarctica through the 1988–89 austral summer season, which may be the last season of Landsat 4 and 5 acquisition. The majority of the scenes have been acquired by two major projects: the West German Institut für Angewandte Geodäsie project to acquire data from the Ronne Ice Shelf area to the Greenwich meridian, and the USGS project to acquire data of coastal Antarctica and the inland boundary of the ice shelves, for use by the Scientific Committee on Antarctic Research (SCAR) community. Landsat 4 and 5 have different orbital parameters from Landsat 1, 2, and 3. As a result Landsat 4 and 5 imagery have different areal coverage. The data also have been archived differently. While the Landsat 1, 2, and 3 data exist in film format, many Landsat 4 and 5 TM images exist only as high-density digital tapes, and, as a result, the scenes cannot be examined and evaluated before purchase. Computer evaluation of the Landsat 4 and 5 data indicate that about 1350 or about 30% of the images have 10% cloud cover or less. However, it is difficult for automatic systems or those unfamiliar with the area to discriminate between clouds and snow. Based on a sampling of the data, it is more likely that 10–15%, or about 500 scenes, are of good quality. Those scenes which have been examined and evaluated as part of the SCAR cooperative acquisition project and are known to be of good quality are plotted and compared with the earlier Landsat data. The combined plot gives accurate and reliable information on the location of good quality Landsat 1–5 data of Antarctica. More than 7 000 Sojuzkarta scenes have been collected over Antarctica since 1976. The most useful data consist of photography from the KATE-200 system (20 m resolution) and the KFA-1000 system (6 m resolution). The data have been plotted by the U.S. Geological Survey and will soon be available as an open-file report. Those scenes which have been evaluated as having 10% cloud cover or less are plotted separately and overlaid on the Landsat plots. Scenes which have been examined are excellent, but an insufficient number of scenes have been inspected to evaluate the accuracy of the cloud cover estimation. The Systeme Probatoire d'Observation de la Terre (SPOT) was launched in 1986 and has acquired more than 1200 scenes of Antarctica. SPOT data consist of multi-spectral (20 m resolution) and panchromatic (10 m resolution) photographic or digital imagery. SPOT also possesses a mechanical plane mirror which permits off-nadir imaging and the generation of stereoscopic images. The locations of these scenes are now being plotted by the U.S. Geological Survey. Scenes with 10% cloud cover or less will be combined with Landsat and Sojuzkarta data to provide an accurate summary of the availability and coverage of high-quality satellite data of Antarctica.
13
G. Ferrigno, Jane, and Bruce F. Molnia. "Evaluation Of Landsat, Spot, and Sojuzkarta Data Of Antarctica For Ice and Climate Research." Annals of Glaciology 14 (1990): 333–34. http://dx.doi.org/10.3189/s0260305500008946.
Full textAbstract:
Satellite data have proved suitable and cost-effective for ice and climate research in Antarctica. They have been used in numerous research efforts, including: monitoring coastal change, determining velocities of outlet glaciers, defining blue ice areas, tracking the movement of icebergs, and as a base for overlaying radar and other data. This paper reviews the data acquired since 1972 by the Landsat, SPOT and Sojuzkarta space systems and illustrates where good-quality (±10% cloud cover) data are available.The Landsat 1, 2, and 3 satellites acquired approximately 10 000 multispectral scanner (MSS) (80 m resolution) and return-beam vidicon (RBV) (30 m resolution) photographic and digital images of Antarctica between 1972 and 1983. The quality of these images has been evaluated by USGS to determine the feasibility of using them for glaciological, climatological, and geological research. Results have been plotted on a base map of Antarctica and show about 45% of the nominal scene centers, or about 70% of the geographic area of the continent, to be covered by good-quality imagery. Landsat 4 started acquiring data in 1982 and Landsat 5 in 1984. Together the two satellites acquired more than 4 500 thematic mapper (TM) (30 m resolution) and MSS images of Antarctica through the 1988–89 austral summer season, which may be the last season of Landsat 4 and 5 acquisition. The majority of the scenes have been acquired by two major projects: the West German Institut für Angewandte Geodäsie project to acquire data from the Ronne Ice Shelf area to the Greenwich meridian, and the USGS project to acquire data of coastal Antarctica and the inland boundary of the ice shelves, for use by the Scientific Committee on Antarctic Research (SCAR) community. Landsat 4 and 5 have different orbital parameters from Landsat 1, 2, and 3. As a result Landsat 4 and 5 imagery have different areal coverage. The data also have been archived differently. While the Landsat 1, 2, and 3 data exist in film format, many Landsat 4 and 5 TM images exist only as high-density digital tapes, and, as a result, the scenes cannot be examined and evaluated before purchase. Computer evaluation of the Landsat 4 and 5 data indicate that about 1350 or about 30% of the images have 10% cloud cover or less. However, it is difficult for automatic systems or those unfamiliar with the area to discriminate between clouds and snow. Based on a sampling of the data, it is more likely that 10–15%, or about 500 scenes, are of good quality. Those scenes which have been examined and evaluated as part of the SCAR cooperative acquisition project and are known to be of good quality are plotted and compared with the earlier Landsat data. The combined plot gives accurate and reliable information on the location of good quality Landsat 1–5 data of Antarctica.More than 7 000 Sojuzkarta scenes have been collected over Antarctica since 1976. The most useful data consist of photography from the KATE-200 system (20 m resolution) and the KFA-1000 system (6 m resolution). The data have been plotted by the U.S. Geological Survey and will soon be available as an open-file report. Those scenes which have been evaluated as having 10% cloud cover or less are plotted separately and overlaid on the Landsat plots. Scenes which have been examined are excellent, but an insufficient number of scenes have been inspected to evaluate the accuracy of the cloud cover estimation.The Systeme Probatoire d'Observation de la Terre (SPOT) was launched in 1986 and has acquired more than 1200 scenes of Antarctica. SPOT data consist of multi-spectral (20 m resolution) and panchromatic (10 m resolution) photographic or digital imagery. SPOT also possesses a mechanical plane mirror which permits off-nadir imaging and the generation of stereoscopic images. The locations of these scenes are now being plotted by the U.S. Geological Survey. Scenes with 10% cloud cover or less will be combined with Landsat and Sojuzkarta data to provide an accurate summary of the availability and coverage of high-quality satellite data of Antarctica.
14
Kristensen, M., and N. F. McIntyre. "Spectral Response Patterns of Snow and Ice Surfaces for the Landsat Multispectral Scanner (Abstract)." Annals of Glaciology 9 (1987): 249. http://dx.doi.org/10.1017/s0260305500000902.
Full textAbstract:
The high-resolution imagery recorded by systems such as the multi-spectral scanners (MSSs) of the Landsat satellites has revolutionized the study of all types of surface in the polar regions. Visible and near-infra-red imagery has found a wide range of glaciological uses. There is, however, a lack of comparability within and between MSS data which may be a contributary factor to some current problems in interpretation of remotely sensed glaciological data. With the expected continuity of MSS coverage for the forseeable future, it is highly desirable to extend use of the data beyond the basic mapping and feature identification which has made it such a valuable resource. One of the most obvious developments is to investigate characteristics of the reflecting surfaces and to achieve absolute identification of snow and ice surfaces. Although conversion of digital MSS grey tones to radiances enables direct comparison with other sources, automatic identification requires detailed and extensive knowledge of the spectral and reflecting characteristics of surfaces which are to be monitored. This is often best achieved through ground-based observation. In order to provide a base line against which corrected radiances from Landsat MSS data can be compared, a spectrally gated photometer has been used to measure albedo at MSS wave bands in a wide range of conditions. The surfaces monitored in several parts of Norway include sea ice, lake ice, snow, firn and glacier ice, permafrost, and reference surfaces. A range of supporting measurements (including grain-size, surface irregularity, density, level, and free-water content) allows accurate characterization of each surface. This enables identification of spectral-response patterns for each surface category and hence the classification of their reflectances as recorded by the MSS. Examples are given of the application of such classifications to imagery of the polar regions.
15
Kristensen, M., and N. F. McIntyre. "Spectral Response Patterns of Snow and Ice Surfaces for the Landsat Multispectral Scanner (Abstract)." Annals of Glaciology 9 (1987): 249. http://dx.doi.org/10.3189/s0260305500000902.
Full textAbstract:
The high-resolution imagery recorded by systems such as the multi-spectral scanners (MSSs) of the Landsat satellites has revolutionized the study of all types of surface in the polar regions. Visible and near-infra-red imagery has found a wide range of glaciological uses. There is, however, a lack of comparability within and between MSS data which may be a contributary factor to some current problems in interpretation of remotely sensed glaciological data.With the expected continuity of MSS coverage for the forseeable future, it is highly desirable to extend use of the data beyond the basic mapping and feature identification which has made it such a valuable resource. One of the most obvious developments is to investigate characteristics of the reflecting surfaces and to achieve absolute identification of snow and ice surfaces. Although conversion of digital MSS grey tones to radiances enables direct comparison with other sources, automatic identification requires detailed and extensive knowledge of the spectral and reflecting characteristics of surfaces which are to be monitored. This is often best achieved through ground-based observation.In order to provide a base line against which corrected radiances from Landsat MSS data can be compared, a spectrally gated photometer has been used to measure albedo at MSS wave bands in a wide range of conditions. The surfaces monitored in several parts of Norway include sea ice, lake ice, snow, firn and glacier ice, permafrost, and reference surfaces. A range of supporting measurements (including grain-size, surface irregularity, density, level, and free-water content) allows accurate characterization of each surface. This enables identification of spectral-response patterns for each surface category and hence the classification of their reflectances as recorded by the MSS. Examples are given of the application of such classifications to imagery of the polar regions.
16
Carignan, M., D. Morin, R. Brochu, and A. Royer. "Évaluation du potentiel de la télédétection spatiale pour l'étude du milieu urbain : le cas de Montréal." Canadian Journal of Civil Engineering 14, no. 1 (February 1, 1987): 111–17. http://dx.doi.org/10.1139/l87-014.
Full textAbstract:
Satellite imagery in multispectral mode actually available is provided by MSS (multispectral scanner) and TM (thematic mapper) sensors aboard the American satellite LANDSAT-5. Potential use of this type of data for study of the urban environment is quite relevant, as it associates speed of analysis with competitive cost.Using as an example the study of the Montréal, Quebec region, enhanced color composite image production demonstrates the possibilities of TM data in the photo-interpretation of urban characteristics owing to better spatial resolution. On the other hand, the thematic analysis of land units using automatic classification techniques for cartographic purposes gives five land-use classes. These correspond quite well to the classification used by urbanists for major urban functions. The mean accuracy in terms of area is in the order of 97% for the total of urban areas and 75% for each class.
17
Dowdeswell, J. A. "Comparison of Landsat Multispectral Scanner and Thematic Mapper Radiometric and Spatial Characteristics Over Glaciers (Abstract)." Annals of Glaciology 9 (1987): 245. http://dx.doi.org/10.1017/s0260305500000835.
Full textAbstract:
For more than 10 years, images obtained from the four Landsat Multispectral Scanner (MSS) bands have provided important data for mapping and glaciological studies in the inaccessible polar regions. During this period, the specifications of the MSS have remained little altered, to allow data comparability. More recently, satellites 4 and 5 of the Landsat series have been equipped additionally with Thematic Mapper (TM) sensors. The TM has 7 bands in the visible, near infra-red, mid infra-red, and thermal infra-red, together with a larger dynamic range and improved spatial resolution relative to the MSS. The aim of this paper is to compare MSS and TM computer-compatible tapes (CCTs) from a glacierized area in order to demonstrate the advantages of using TM data in glaciological applications. The digital MSS and TM scenes compared were imaged simultaneously from Landsat 5 on 5 May 1984 over the north-west part of Spitsbergen, Svalbard (path 218, row 3). This location was selected because of the range of glaciological features present: numerous valley glaciers, the ice field of Holtedahlfonna, fast ice, and ice floes. Partially cloud-covered imagery was preferred, to allow comparison of the two sensors in terms of their ability to distinguish between clouds and snow. The time of year is also advantageous, in that Sun elevation (27°) is high enough for detector saturation to occur in MSS band 2 (Dowdeswell and McIntyre 1986). Surface-elevation data from airborne radio echo-sounding, and other ancilliary glaciological information, are also available for this part of Svalbard. Differences in the dynamic range and the wavelengths over which TM and MSS data are collected have two main implications for glaciological studies. First, snow and snow-covered ice masses can be distinguished easily from cloud cover in TM band 5 (1.57 to 1.78 μm). Snow appears dark whereas clouds are light at this wavelength. For example, thin clouds over part of Oscar II Land in Spitsbergen became apparent. In many MSS scenes of the Antarctic, the cloud-free ice-sheet surface has been misidentified as cloud-covered during quality-control analysis. Secondly, the wider dynamic range of the TM sensors means that saturation occurs less frequently over snow than was the case with MSS imagery. Digital analysis of MSS and TM scene radiance over Spitsbergen demonstrates this fact and implies that ice-surface topographic information will only rarely be degraded in TM imagery, although TM band 1 (0.45 to 0.52 μm) is most often saturated. The nominal spatial resolution of TM sensors is 30 m, except for the thermal infra-red band. This is a significant improvement over the 79 m by 56 m resolution of the MSS. A major advantage of this is that ice margins and ice-surface features can be more precisely identified. More accurate glacier maps can be made, and smaller variations in termini positions of outlet glaciers can be monitored. Ice-surface features, such as crevasses, are more likely to be recorded on TM imagery, and examples are shown from Spitsbergen glaciers. The identification of such features is of major importance in studies of ice-surface velocities from Landsat imagery. For sea-ice applications, the ability to identify smaller floes is also important; for example, in the analysis of floe-size distributions. The only significant drawbacks to the use of Landsat TM data in glaciological studies are the expense, particularly in the more useful digital format, and the small amount of coverage yet available for the polar regions.
18
Dowdeswell, J. A. "Comparison of Landsat Multispectral Scanner and Thematic Mapper Radiometric and Spatial Characteristics Over Glaciers (Abstract)." Annals of Glaciology 9 (1987): 245. http://dx.doi.org/10.3189/s0260305500000835.
Full textAbstract:
For more than 10 years, images obtained from the four Landsat Multispectral Scanner (MSS) bands have provided important data for mapping and glaciological studies in the inaccessible polar regions. During this period, the specifications of the MSS have remained little altered, to allow data comparability. More recently, satellites 4 and 5 of the Landsat series have been equipped additionally with Thematic Mapper (TM) sensors. The TM has 7 bands in the visible, near infra-red, mid infra-red, and thermal infra-red, together with a larger dynamic range and improved spatial resolution relative to the MSS. The aim of this paper is to compare MSS and TM computer-compatible tapes (CCTs) from a glacierized area in order to demonstrate the advantages of using TM data in glaciological applications.The digital MSS and TM scenes compared were imaged simultaneously from Landsat 5 on 5 May 1984 over the north-west part of Spitsbergen, Svalbard (path 218, row 3). This location was selected because of the range of glaciological features present: numerous valley glaciers, the ice field of Holtedahlfonna, fast ice, and ice floes. Partially cloud-covered imagery was preferred, to allow comparison of the two sensors in terms of their ability to distinguish between clouds and snow. The time of year is also advantageous, in that Sun elevation (27°) is high enough for detector saturation to occur in MSS band 2 (Dowdeswell and McIntyre 1986). Surface-elevation data from airborne radio echo-sounding, and other ancilliary glaciological information, are also available for this part of Svalbard.Differences in the dynamic range and the wavelengths over which TM and MSS data are collected have two main implications for glaciological studies. First, snow and snow-covered ice masses can be distinguished easily from cloud cover in TM band 5 (1.57 to 1.78 μm). Snow appears dark whereas clouds are light at this wavelength. For example, thin clouds over part of Oscar II Land in Spitsbergen became apparent. In many MSS scenes of the Antarctic, the cloud-free ice-sheet surface has been misidentified as cloud-covered during quality-control analysis. Secondly, the wider dynamic range of the TM sensors means that saturation occurs less frequently over snow than was the case with MSS imagery. Digital analysis of MSS and TM scene radiance over Spitsbergen demonstrates this fact and implies that ice-surface topographic information will only rarely be degraded in TM imagery, although TM band 1 (0.45 to 0.52 μm) is most often saturated.The nominal spatial resolution of TM sensors is 30 m, except for the thermal infra-red band. This is a significant improvement over the 79 m by 56 m resolution of the MSS. A major advantage of this is that ice margins and ice-surface features can be more precisely identified. More accurate glacier maps can be made, and smaller variations in termini positions of outlet glaciers can be monitored. Ice-surface features, such as crevasses, are more likely to be recorded on TM imagery, and examples are shown from Spitsbergen glaciers. The identification of such features is of major importance in studies of ice-surface velocities from Landsat imagery. For sea-ice applications, the ability to identify smaller floes is also important; for example, in the analysis of floe-size distributions.The only significant drawbacks to the use of Landsat TM data in glaciological studies are the expense, particularly in the more useful digital format, and the small amount of coverage yet available for the polar regions.
19
Goodwin, A. H., and D. G. Vaughan. "A topographic origin for double-ridge features in visible imagery of ice divides in Antarctica." Journal of Glaciology 41, no. 139 (1995): 483–89. http://dx.doi.org/10.1017/s0022143000034821.
Full textAbstract:
AbstractThe appearance of double-ridge features on visible imagery of the ice divides of Antarctic ice rises has often been noted but, largely due to a lack of adequate ground truth, their origins have remained enigmatic. We present several examples of ice rises and other isolated ice-flow centres that apparently show double ridges. We investigate one of these in particular: Fletcher Promontory, Antarctica. A digtal-elevation model (DEM) of the summit region is derived from surface profiles obtained using the Global Positioning System (GPS) and this is correlated with Landsat MSS satellite imagery. Precise registration is achieved by correlating image-brightness values with surface slope calculated along the direction of the Sun azimuth in the image. Using a simple bi-directional relation, the DEM data are used to model the Landsat image. We therefore demonstrate that the double ridge is a product of a subtle concavity parallel to the ridge and is unlikely to be dependent on other factors. This concavity is not predicted by steady-state models of ice divides and so we suggest that the ridge may not be in a steady-state but responding to changes in the glaciological boundary conditions. We speculate that this may be an indication of ongoing migration of the ice divide.
20
Goodwin, A. H., and D. G. Vaughan. "A topographic origin for double-ridge features in visible imagery of ice divides in Antarctica." Journal of Glaciology 41, no. 139 (1995): 483–89. http://dx.doi.org/10.3189/s0022143000034821.
Full textAbstract:
AbstractThe appearance of double-ridge features on visible imagery of the ice divides of Antarctic ice rises has often been noted but, largely due to a lack of adequate ground truth, their origins have remained enigmatic. We present several examples of ice rises and other isolated ice-flow centres that apparently show double ridges. We investigate one of these in particular: Fletcher Promontory, Antarctica. A digtal-elevation model (DEM) of the summit region is derived from surface profiles obtained using the Global Positioning System (GPS) and this is correlated with Landsat MSS satellite imagery. Precise registration is achieved by correlating image-brightness values with surface slope calculated along the direction of the Sun azimuth in the image. Using a simple bi-directional relation, the DEM data are used to model the Landsat image. We therefore demonstrate that the double ridge is a product of a subtle concavity parallel to the ridge and is unlikely to be dependent on other factors. This concavity is not predicted by steady-state models of ice divides and so we suggest that the ridge may not be in a steady-state but responding to changes in the glaciological boundary conditions. We speculate that this may be an indication of ongoing migration of the ice divide.
21
Hashim, Bassim Mohammed, Maitham Abdullah Sultan, Mazin Najem Attyia, Ali A. Al Maliki, and Nadhir Al-Ansari. "Change Detection and Impact of Climate Changes to Iraqi Southern Marshes Using Landsat 2 MSS, Landsat 8 OLI and Sentinel 2 MSI Data and GIS Applications." Applied Sciences 9, no. 10 (May 16, 2019): 2016. http://dx.doi.org/10.3390/app9102016.
Full textAbstract:
Marshes represent a unique ecosystem covering a large area of southern Iraq. In a major environmental disaster, the marshes of Iraq were drained, especially during the 1990s. Since then, droughts and the decrease in water imports from the Tigris and Euphrates rivers from Turkey and Iran have prevented them from regaining their former extent. The aim of this research is to extract the values of the normalized difference vegetation index (NDVI) for the period 1977–2017 from Landsat 2 MSS (multispectral scanner), Landsat 8 OLI (operational land imager) and Sentinel 2 MSI (multi-spectral imaging mission) satellite images and use supervised classification to quantify land and water cover change. The results from the two satellites (Landsat 2 and Landsat 8) are compared with Sentinel 2 to determine the best tool for detecting changes in land and water cover. We also assess the potential impacts of climate change through the study of the annual average maximum temperature and precipitation in different areas in the marshes for the period 1981–2016. The NDVI analysis and image classification showed the degradation of vegetation and water bodies in the marshes, as vast areas of natural vegetation and agricultural lands disappeared and were replaced with barren areas. The marshes were influenced by climatic change, including rising temperature and the diminishing amount of precipitation during 1981–2016.
22
Bindschadler, Robert A. "History of lower Pine Island Glacier, West Antarctica, from Landsat imagery." Journal of Glaciology 48, no. 163 (2002): 536–44. http://dx.doi.org/10.3189/172756502781831052.
Full textAbstract:
AbstractA 28 year record of lower Pine Island Glacier, West Antarctica, constructed from 15 Landsat images, shows changes at the terminus, grounding zone and both margins. The north margin has expanded 5 km into the adjacent ice shelf in a sustained event that was underway in 1973 and may have begun in 1957. Between 1991 and 1997, this expansion ceased and a new region of rifting was created associated with an ice rise on the glacier’s floating tongue. Changes in the topography of a nearby ice rise are used to deduce an upper-bound estimate of a 134 m thinning of the adjacent ice shelf. On the south margin, widening was limited to 1 km over the observation period and is seen propagating downstream in an intermediate-dated image. New areas of crevassing are also evident in the grounding zone of the glacier. Ice loss by the calving of large tabular bergs vastly exceeds mass loss by calving of many small bergs. These observations are consistent with reported changes of the 1990s and indicate that changes in the flow of Pine Island Glacier have occurred over the full period of satellite observations.
23
Sachs, Donald L., Phillip Sollins, and Warren B. Cohen. "Detecting landscape changes in the interior of British Columbia from 1975 to 1992 using satellite imagery." Canadian Journal of Forest Research 28, no. 1 (January 1, 1998): 23–36. http://dx.doi.org/10.1139/x97-186.
Full textAbstract:
To consider the regional scale effects of forest management requires complete and consistent data over large areas. We used Landsat Thematic Mapper and Multispectral Scanner (TM and MSS) imagery to map forest cover and detect major disturbances between 1975 and 1992 for a 4.2 x 106 ha area of interior British Columbia. Forested pixels were mapped into closed conifer, semiopen conifer, deciduous, and mixed forest classes, with further subdivision of the closed conifer type into three age-classes. The image-based estimate of harvested area was similar to an independent estimate from forest inventory data. Changes in landscape pattern from 1975 to 1992 were examined by calculating indices that describe overall landscape pattern and that of conifer and harvested patches in each biogeoclimatic zone. Harvesting affected 8.4% of the forest area outside provincial parks during the 17-year period. Harvested areas were consistently much smaller than conifer patches in all biogeoclimatic zones and had a lower percentage of interior area and perimeter/area ratio. Conifer patch-shape complexity varied between zones; harvested patches had simpler shapes and were similar in all zones. Results indicate that this landscape is only in the early stages of fragmentation, but a similar harvest pattern has been imposed on differing ecological zones.
24
Merrill, Evelyn, and Ron Marrs. "Remote Sensing of Vegetation Recovery in Grasslands after the 1988 Fires." UW National Parks Service Research Station Annual Reports 15 (January 1, 1991): 227–30. http://dx.doi.org/10.13001/uwnpsrc.1991.3031.
Full textAbstract:
Traditional methods for measurement of vegetative biomass can be time-consuming and laborÂintensive, especially across large areas. Yet such estimates are necessary to investigate the effects of large scale disturbances on ecosystem components and processes. One alternative to traditional methods for monitoring rangeland vegetation is to use satellite imagery. Because foliage of plants differentially absorbs and reflects energy within the electromagnetic spectrum, remote sensing of spectral data can be used to quantify the amount of vegetative biomass present in an area (Tucker and Sellers 1986). In 1987 we found that Landsat Multispectral Scanner (MSS) imagery could be used to quantify green herbaceous phytomass (GHP) on ungulate summer range in the northeastern portion of Yellowstone National Park. Estimates of GHP in the study area were well within values reported for the habitat types sampled (Mueggler and Steward 1980). Annual variation in GHP was related to winter snow accumulation probably due to the timing of snow melt (Merrill et al. 1988). Additionally, we found that GHP explained a significant amount of the variation in the per capita growth rate of elk and bison populations from 1972 to 1987 (Merrill and Boyce 1991). The extensive fires that occurred in the Park in the summer of 1988 provided an opportunity to determine whether remote sensing could be used to monitor grassland vegetation recovery in the Park and to explore the effects of the 1988 fires on ungulate populations using models we developed in 1987. Previous studies have used Landsat imagery to monitor succession of seral stages after fire in pine (Jakubauska et al. 1990), but no studies to our knowledge have used this approach to quantify herbaceous recovery in grasslands.
25
Merrill, Evelyn, and Ron Marrs. "Remote Sensing of Vegetation Recovery in Grasslands After th 1988 Fires." UW National Parks Service Research Station Annual Reports 16 (January 1, 1992): 188–90. http://dx.doi.org/10.13001/uwnpsrc.1992.3115.
Full textAbstract:
Traditional methods for measurement of vegetative biomass can be time-consuming and laborÂintensive, especially across large areas. Yet such estimates are necessary to investigate the effects of large scale disturbances on ecosystem components and processes. One alternative to traditional methods for monitoring rangeland vegetation is to use satellite imagery. Because foliage of plants differentially absorbs and reflects energy within the electromagnetic spectrum, remote sensing of spectral data can be used to quantify the amount of vegetative biomass present in an area (Tucker and Sellers 1986). In 1987 we found that Landsat Multispectral Scanner (MSS) imagery could be used to quantify green herbaceous phytomass (GHP) on ungulate summer range in the northeastern portion of Yellowstone National Park. Estimates of GHP in the study area were well within values reported for the habitat types sampled (Mueggler and Steward 1980). Annual variation in GHP was related to winter snow accumulation probably due to the timing of snow melt (Merrill et al. 1988). Additionally, we found that GHP explained a significant amount of the variation in the per capita growth rate of elk population from 1972 to 1987 (Merrill and Boyce 1991). The extensive fires that occurred in the Park in the summer of 1988 provided an opportunity to determine whether remote sensing could be used to monitor grassland vegetation recovery in the Park and to explore the effects of the 1988 fires on ungulate populations using models we developed in 1987. Previous studies have used Landsat imagery to monitor succession of seral stages after fire in pine (Jakubauskas et al. 1990), but no studies to our knowledge have used this approach to quantify herbaceous recovery in grasslands. The objectives during this study period were: (1) to develop and validate a model for predicting GHP in sagebrush-grassland communities using 1989-91 Landsat TM spectral information and field data on GHP; and (2) to describe broad-scale vegetation recovery in burned areas and physiographic and soil features which influence the recovery.
26
Nasanbat, Elbegjargal, Erdenetogtokh Erdenebat, Bolorchuluun Chogsom, Ochirkhuyag Lkhamjav, and Lkhagvadorj Nanzad. "IKH TURGEN MOUNTAIN GLACIER CHANGE AND 3D SURFACE EXTENTS PREDICTION USING LONG TERM LANDSAT IMAGE AND CLIMATE DATA." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-3 (April 23, 2018): 173–76. http://dx.doi.org/10.5194/isprs-annals-iv-3-173-2018.
Full textAbstract:
The glacier is most important the freshwater resources and indicator of the climate change. The researchers noted that during last decades the glacier is melting due to global warming. The study calculates a spatial distribution of protentional change of glacier coverage in the Ikh Turgen mountain of Western Mongolia, and it integrates long-term climate data and satellite datasets. Therefore, in this experiment has tried to estimation three-dimensional surface area of the glacier. For this purpose, Normalized difference snow index (NDSI) was applied to decision tree approach, using Landsat MSS, TM, ETM+ and LC8 imagery for 1975–2016, a surface and slope for digital elevation model, precipitation and air temperature historical data of meteorological station. The potential volume area significantly changed glacier cover of the Ikh Turgen Mountain, and the area affected by highly variable precipitation and air temperature regimes. Between 1972 and 2016, a potential area of glacier area has been decreased in Ikh Turgen mountain region.
27
Cheng, Daniel, Wayne Hayes, Eric Larour, Yara Mohajerani, Michael Wood, Isabella Velicogna, and Eric Rignot. "Calving Front Machine (CALFIN): glacial termini dataset and automated deep learning extraction method for Greenland, 1972–2019." Cryosphere 15, no. 3 (April 1, 2021): 1663–75. http://dx.doi.org/10.5194/tc-15-1663-2021.
Full textAbstract:
Abstract. Sea level contributions from the Greenland Ice Sheet are influenced by the rapid changes in glacial terminus positions. The documentation of these evolving calving front positions, for which satellite imagery forms the basis, is therefore important. However, the manual delineation of these calving fronts is time consuming, which limits the availability of these data across a wide spatial and temporal range. Automated methods face challenges that include the handling of clouds, illumination differences, sea ice mélange, and Landsat 7 scan line corrector errors. To address these needs, we develop the Calving Front Machine (CALFIN), an automated method for extracting calving fronts from satellite images of marine-terminating glaciers, using neural networks. The results are often indistinguishable from manually curated fronts, deviating by on average 86.76 ± 1.43 m from the measured front. Landsat imagery from 1972 to 2019 is used to generate 22 678 calving front lines across 66 Greenlandic glaciers. This improves on the state of the art in terms of the spatiotemporal coverage and accuracy of its outputs and is validated through a comprehensive intercomparison with existing studies. The current implementation offers a new opportunity to explore subseasonal and regional trends on the extent of Greenland's margins and supplies new constraints for simulations of the evolution of the mass balance of the Greenland Ice Sheet and its contributions to future sea level rise.
28
Rankl, M., C. Kienholz, and M. Braun. "Glacier changes in the Karakoram region mapped by multimission satellite imagery." Cryosphere 8, no. 3 (May 23, 2014): 977–89. http://dx.doi.org/10.5194/tc-8-977-2014.
Full textAbstract:
Abstract. Positive glacier-mass balances in the Karakoram region during the last decade have fostered stable and advancing glacier termini positions, while glaciers in the adjacent mountain ranges have been affected by glacier recession and thinning. In addition to fluctuations induced solely by climate, the Karakoram is known for a large number of surge-type glaciers. The present study provides an updated and extended inventory on advancing, stable, retreating, and surge-type glaciers using Landsat imagery from 1976 to 2012. Out of 1219 glaciers the vast majority showed a stable terminus (969) during the observation period. Sixty-five glaciers advanced, 93 glaciers retreated, and 101 surge-type glaciers were identified, of which 10 are new observations. The dimensional and topographic characteristics of each glacier class were calculated and analyzed. Ninety percent of nonsurge-type glaciers are shorter than 10 km, whereas surge-type glaciers are, in general, longer. We report short response times of glaciers in the Karakoram and suggest a shift from negative to balanced/positive mass budgets in the 1980s or 1990s. Additionally, we present glacier surface velocities derived from different SAR (synthetic aperture radar) sensors and different years for a Karakoram-wide coverage. High-resolution SAR data enables the investigation of small and relatively fast-flowing glaciers (e.g., up to 1.8 m day−1 during an active phase of a surge). The combination of multitemporal optical imagery and SAR-based surface velocities enables an improved, Karakoram-wide glacier inventory and hence, provides relevant new observational information on the current state of glaciers in the Karakoram.
29
DEWIDAR, KH M. "Monitoring temporal changes of the surface water area of the Burullus and Manzala lagoons using automatic techniques applied to a Landsat satellite data series of the Nile Delta coast." Mediterranean Marine Science 12, no. 2 (November 21, 2011): 462. http://dx.doi.org/10.12681/mms.45.
Full textAbstract:
This study introduces the automated shoreline techniques used to monitor the temporal change of surface water area of the Burullus and Manzala lagoons. In this study, a series of Landsat image data are acquired at intermittent intervals between 1972 and 2006 for the Burullus lagoon and between 1972 and 2007 for the Manzala lagoon. All Landsat images were radiometrically calibrated and converted to reflectance values. The reflectance values of each date were atmospherically corrected using the 6S model. The automated shoreline technique was checked against field observations by using GPS over the four seasons for each lagoon during reconnaissance for the shoreline boundary. The accuracy of the extracted shoreline boundary for each lagoon was validated by calculating the area of a big aquaculture farm in the study area from satellite imagery and the available topographic maps. The resulting accuracy of this technique used was approximately 97.5%. From the spatial temporal analysis of the satellite data, the results indicate that the rate change of aquatic surface area of the Manzala lagoon is –7.3 km2/yr and for the Burullus lagoon -2.7 km2/yr during the approximately 35 year period of study. The changes which were detected in this study indicate that the surface water area of Manzala lagoon and Burullus lagoon have decreased to 62.6% and 61.9 respectively of their original size during this time.
30
Adams, Matthew, Peter L. Smith, and Xihua Yang. "Assessing the effects of groundwater extraction on coastal groundwater-dependent ecosystems using satellite imagery." Marine and Freshwater Research 66, no. 3 (2015): 226. http://dx.doi.org/10.1071/mf14010.
Full textAbstract:
Terrestrial vegetation that depends on the subsurface presence of water can be severely affected by groundwater extraction. We analysed Landsat imagery to assess the ecological risk posed by groundwater pumping to native vegetation on the Tomago Sandbeds, a coastal sand mass in northern New South Wales. The effect of extraction on each major vegetation community was assessed by comparing rates of evapotranspiration between extraction zones and matched areas outside the influence of extraction. We found a significant long-term change in evapotranspiration close to groundwater extraction points within most forest, woodland and scrub communities, including those not currently regarded as being wholly dependent on groundwater. We therefore suggest that management of groundwater-dependent ecosystems should not be based on degree of dependence but instead on their sensitivity to groundwater management regimes. Our approach can provide policy makers with information needed to evaluate and adjust groundwater management within groundwater-dependent ecosystems.
31
Islam, Hamza, Habibuulah Abbasi, Ahmed Karam, Ali Hassan Chughtai, and Mansoor Ahmed Jiskani. "Geospatial analysis of wetlands based on land use/land cover dynamics using remote sensing and GIS in Sindh, Pakistan." Science Progress 104, no. 2 (April 2021): 003685042110261. http://dx.doi.org/10.1177/00368504211026143.
Full textAbstract:
In this study, the Land Use/Land Cover (LULC) change has been observed in wetlands comprises of Manchar Lake, Keenjhar Lake, and Chotiari Reservoir in Pakistan over the last four decades from 1972 to 2020. Each wetland has been categorized into four LULC classes; water, natural vegetation, agriculture land, and dry land. Multitemporal Landsat satellite data including; Multi-Spectral Scanner (MSS), Thematic Mapper (TM), and Operational Land Imager (OLI) images were used for LULC changes evaluation. The Supervised Maximum-likelihood classifier method is used to acquire satellite imagery for detecting the LULC changes during the whole study period. Soil adjusted vegetation index technique (SAVI) was also used to reduce the effects of soil brightness values for estimating the actual vegetation cover of each study site. Results have shown the significant impact of human activities on freshwater resources by changing the natural ecosystem of wetlands. Change detection analysis showed that the impacts on the land cover affect the landscape of the study area by about 40% from 1972 to 2020. The vegetation cover of Manchar Lake and Keenjhar Lake has been decreased by 6,337.17 and 558.18 ha, respectively. SAVI analysis showed that soil profile is continuously degrading which vigorously affects vegetation cover within the study area. The overall classification accuracy and Kappa statistics showed an accuracy of >90% for all LULC mapping studies. This work demonstrates the LULC changes as a critical monitoring basis for ongoing analyses of changes in land management to enable decision-makers to establish strategies for effectively using land resources.
32
Ren, Shaoting, Evan S. Miles, Li Jia, Massimo Menenti, Marin Kneib, Pascal Buri, Michael J. McCarthy, Thomas E. Shaw, Wei Yang, and Francesca Pellicciotti. "Anisotropy Parameterization Development and Evaluation for Glacier Surface Albedo Retrieval from Satellite Observations." Remote Sensing 13, no. 9 (April 28, 2021): 1714. http://dx.doi.org/10.3390/rs13091714.
Full textAbstract:
Glacier albedo determines the net shortwave radiation absorbed at the glacier surface and plays a crucial role in glacier energy and mass balance. Remote sensing techniques are efficient means to retrieve glacier surface albedo over large and inaccessible areas and to study its variability. However, corrections of anisotropic reflectance of glacier surface have been established for specific shortwave bands only, such as Landsat 5 Thematic Mapper (L5/TM) band 2 and band 4, which is a major limitation of current retrievals of glacier broadband albedo. In this study, we calibrated and evaluated four anisotropy correction models for glacier snow and ice, applicable to visible, near-infrared and shortwave-infrared wavelengths using airborne datasets of Bidirectional Reflectance Distribution Function (BRDF). We then tested the ability of the best-performing anisotropy correction model, referred to from here on as the ‘updated model’, to retrieve albedo from L5/TM, Landsat 8 Operational Land Imager (L8/OLI) and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery, and evaluated these results with field measurements collected on eight glaciers around the world. Our results show that the updated model: (1) can accurately estimate anisotropic factors of reflectance for snow and ice surfaces; (2) generally performs better than prior approaches for L8/OLI albedo retrieval but is not appropriate for L5/TM; (3) generally retrieves MODIS albedo better than the MODIS standard albedo product (MCD43A3) in both absolute values and glacier albedo temporal evolution, i.e., exhibiting both fewer gaps and better agreement with field observations. As the updated model enables anisotropy correction of a maximum of 10 multispectral bands and is implemented in Google Earth Engine (GEE), it is promising for observing and analyzing glacier albedo at large spatial scales.
33
Gloriza Fernandes, Patrícia, José Antônio Baptista Neto, Khaue Silva Vieira, Marcelo Pompermayer de Almeida, Thulio Righeti Correa, Jessica de Freitas Delgado, and Estefan Monteiro da Fonseca. "Multitemporal analysis by remote sensing of the evolution of coastal line of Guanabara Bay, Rio de Janeiro, Brazil." Sistemas & Gestão 15, no. 1 (April 13, 2020): 59–69. http://dx.doi.org/10.20985/1980-5160.2020.v15n1.1619.
Full textAbstract:
Changes in coastlines are considered one of the most dynamic processes in coastal environments. Therefore, the mapping of such variations has become important in the survey of coastal impacts. In the past years, remote sensing has been used in mapping the coastline. In this research, the coastline of Guanabara Bay, in Rio de Janeiro, Brazil, was mapped in the years of 1938, 1974, 1984, 1997, and 2015, by using geo-referencing software and existing cartographic documents. To map the changes, the bay was divided into four sections, in which maps were produced in graphical format, using ArcGIS, in scales 1:175.000 and 1:250.000. The research used satellite images from Landsat 1 Multispectral Scanner System (MSS), Landsat 5 Thematic Mapper (TM), and Landsat 8 Operational Land Imager (OLI), integrated under geographic information system database, for a visual analysis (qualitative), and statistical observation (quantitative) of orbital images. The data indicate more intense transformations between the years 1938 and 1974, with a total landing area of 15.220.000m². This area corresponds to 69.23% of the amount suppressed during the interval 1938-2015.
34
Lei, Yang, Alex Gardner, and Piyush Agram. "Autonomous Repeat Image Feature Tracking (autoRIFT) and Its Application for Tracking Ice Displacement." Remote Sensing 13, no. 4 (February 18, 2021): 749. http://dx.doi.org/10.3390/rs13040749.
Full textAbstract:
In this paper, we build on past efforts with regard to the implementation of an efficient feature tracking algorithm for the mass processing of satellite images. This generic open-source feature tracking routine can be applied to any type of imagery to measure sub-pixel displacements between images. The routine consists of a feature tracking module (autoRIFT) that enhances computational efficiency and a geocoding module (Geogrid) that mitigates problems found in existing geocoding algorithms. When applied to satellite imagery, autoRIFT can run on a grid in the native image coordinates (such as radar or map) and, when used in conjunction with the Geogrid module, on a user-defined grid in geographic Cartesian coordinates such as Universal Transverse Mercator or Polar Stereographic. To validate the efficiency and accuracy of this approach, we demonstrate its use for tracking ice motion by using ESA’s Sentinel-1A/B radar data (seven pairs) and NASA’s Landsat-8 optical data (seven pairs) collected over Greenland’s Jakobshavn Isbræ glacier in 2017. Feature-tracked velocity errors are characterized over stable surfaces, where the best Sentinel-1A/B pair with a 6 day separation has errors in X/Y of 12 m/year or 39 m/year, compared to 22 m/year or 31 m/year for Landsat-8 with a 16-day separation. Different error sources for radar and optical image pairs are investigated, where the seasonal variation and the error dependence on the temporal baseline are analyzed. Estimated velocities were compared with reference velocities derived from DLR’s TanDEM-X SAR/InSAR data over the fast-moving glacier outlet, where Sentinel-1 results agree within 4% compared to 3–7% for Landsat-8. A comprehensive apples-to-apples comparison is made with regard to runtime and accuracy between multiple implementations of the proposed routine and the widely-used “dense ampcor" program from NASA/JPL’s ISCE software. autoRIFT is shown to provide two orders of magnitude of runtime improvement with a 20% improvement in accuracy.
35
Chand, Pritam, Milap Chand Sharma, Rakesh Bhambri, Chandrashekhar V. Sangewar, and Navin Juyal. "Reconstructing the pattern of the Bara Shigri Glacier fluctuation since the end of the Little Ice Age, Chandra valley, north-western Himalaya." Progress in Physical Geography: Earth and Environment 41, no. 5 (September 25, 2017): 643–75. http://dx.doi.org/10.1177/0309133317728017.
Full textAbstract:
The pattern of glacial records since the end of the Little Ice Age (LIA) are essential for evaluating glacier fluctuations and their link to post-LIA climate change. Although recession of the Himalayan glaciers is well-documented in this period, debate continues as to the magnitude and accuracy of estimated recession rates. This study presents a reconstruction of the pattern of fluctuations at the Bara Shigri Glacier in the Himachal Himalaya during the termination of the LIA (∼1850). A multi-data integrative analysis (MDIA) technique consisting of repeat terrestrial photographs, historical archives and reports, geomorphological evidence and maps, and high to medium spatial resolution satellite images (Corona, Hexagon, Landsat and WorldView-2) was used with supplemented by extensive field validation. The results indicate that during the early part of the 19th century the terminus of Bara Shigri Glacier was at ∼3900 m asl. Following this, there was a continuous recession with a total retreat of 2898 ± 50 m, which corresponds to a frontal areal loss of 4 ± 1 km2 in the last 151 years (1863–2014). Compared to this, during the last half century (1965–2014), the glacierised area was reduced by 1.1 ± 0.02 km2 with a concomitant terminus retreat of 1100 ± 32 m. The early 19th century advance is ascribed to a combination of cooling during this period, glacier topographical characteristics and contributions from steep-fronted avalanching tributaries. The late 19th century recession can be attributed to an overall increase in the temperature with a corresponding decrease in precipitation in the north-western Himalaya. Results are at variance with earlier, larger estimates of the frontal area loss for the Bara Shigri Glacier using either Survey of India (SoI) topographic maps or coarse spatial resolution satellite images (e.g. Landsat MSS) as historical datasets, and demonstrate the utility of mixed method approaches including higher-resolution satellite imagery for accurate estimation of glacier behaviour in this region.
36
Billah, Mohammad Maruf. "Mapping and Monitoring Erosion-Accretion in an Alluvial River Using Satellite Imagery – The River Bank Changes of the Padma River in Bangladesh." Quaestiones Geographicae 37, no. 3 (September 6, 2018): 87–95. http://dx.doi.org/10.2478/quageo-2018-0027.
Full textAbstract:
Abstract The Padma river is widely known for its dynamic and disastrous behaviour, and the river has been experiencing intense and frequent bank erosion and deposition leading to the changes and shifting of bank line. In this paper, a time series of Landsat satellite imagery MSS, TM and OLI and TIRS images and are used to detect river bank erosion-accretion and bank line shifting during the study period 1975–2015. This study exhibits a drastic increase of erosion and accretion of land along the Padma river. The results show that from 1975 to 2015, the total amount of river bank erosion is 49,951 ha of land, at a rate of 1,249 ha a−1 and the total amount of accretion is 83,333 ha of land, at a rate of 2,083 ha a−1. Throughout the monitoring period, erosion-accretion was more pronounced in the right part of the river and bank line had been shifting towards the southern direction. The paper also reveals that the total area of islands had been increased significantly, in 2015 there was about 50,967 ha of island area increased from 20,533 ha of island area in 1975, and the results evidence consistency of sedimentation in the river bed.
37
Jacobel, Robert W., Audrey E. Robinson, and Robert A. Bindschadler. "Studies of the grounding-line location on Ice Streams D and E, Antarctica." Annals of Glaciology 20 (1994): 39–42. http://dx.doi.org/10.3189/1994aog20-1-39-42.
Full textAbstract:
Landsat Thematic Mapper (TM) images were used prior to the 1991–92 field season to infer the position of the grounding line at the mouths of Ice Streams D and E, West Antarctica. Our field plan for mass-balance studies was based on this determination, and thus the imagery played a central role in both the scientific and logistics planning. A radar profile along the flow direction was made across the inferred grounding line at one location, and ice-thickness measurements together with surface surveying enable us to compare the hydrostatic surface and the actual topography to determine the point at which the ice becomes grounded. The profile transits from floating to grounded ice at the same location as the grounding line inferred from the imagery. Changes in the radar-echo strength also occur at this location, giving further support to this interpretation. Tilt studies of the ice flexure caused by tidal variations at locations on either side of this grounding point give additional evidence that grounding is occurring close by. The combination of these three measurements therefore confirms the grounding-line location derived from the satellite imagery and supports the use of this technique to determine grounding.
38
Jacobel, Robert W., Audrey E. Robinson, and Robert A. Bindschadler. "Studies of the grounding-line location on Ice Streams D and E, Antarctica." Annals of Glaciology 20 (1994): 39–42. http://dx.doi.org/10.1017/s0260305500016207.
Full textAbstract:
Landsat Thematic Mapper (TM) images were used prior to the 1991–92 field season to infer the position of the grounding line at the mouths of Ice Streams D and E, West Antarctica. Our field plan for mass-balance studies was based on this determination, and thus the imagery played a central role in both the scientific and logistics planning. A radar profile along the flow direction was made across the inferred grounding line at one location, and ice-thickness measurements together with surface surveying enable us to compare the hydrostatic surface and the actual topography to determine the point at which the ice becomes grounded. The profile transits from floating to grounded ice at the same location as the grounding line inferred from the imagery. Changes in the radar-echo strength also occur at this location, giving further support to this interpretation. Tilt studies of the ice flexure caused by tidal variations at locations on either side of this grounding point give additional evidence that grounding is occurring close by. The combination of these three measurements therefore confirms the grounding-line location derived from the satellite imagery and supports the use of this technique to determine grounding.
39
Hauser, Sarah, and Andreas Schmitt. "Glacier Retreat in Iceland Mapped from Space: Time Series Analysis of Geodata from 1941 to 2018." PFG – Journal of Photogrammetry, Remote Sensing and Geoinformation Science 89, no. 3 (April 28, 2021): 273–91. http://dx.doi.org/10.1007/s41064-021-00139-y.
Full textAbstract:
AbstractIn recent decades, glaciers outside Greenland and Antarctica have shown increasingly rapid rates of mass loss and retreat of the ice front, which is associated with climatic and oceanic warming. Due to their maritime location, Icelandic glaciers are sensitive to short-term climate fluctuations and have shown rapid rates of retreat and mass loss over the last decade. In this study, historical maps (1941–1949) of the US Army Map Service (AMS series C762) and optical satellite imagery (Landsat 1, Landsat 5, Landsat 7, Landsat 8, and Sentinel-2) are used to study the Langjökull, Hofsjökull and Vatnajökull ice caps. By the help of the Normalized Difference Snow Index (NDSI), the glacier terminus fluctuations of the ice caps from 1973 to 2018 and the Equilibrium Line Altitude (ELA) from 1973 to 2018 are analyzed. The results are compared with climate data, especially with mean summer temperatures and winter precipitation. Due to the negative temperature gradient with increasing altitude, bivariate histograms are generated, showing the glaciated area per altitude zone and time, and providing a prediction of the future development until 2050 and beyond. The results indicate that Langjökull, Hofsjökull and Vatnajökull are retreating and advancing over the study period in correlation with the mean summer temperature, with a steady decrease over time being the clearest and most significant trend. The lower parts of the glaciers, thus, will probably disappear during the next decades. This behaviour is also evident by an exceptional increase of the ELA observed on all three glaciers, which leads to a reduction of the accumulation zone.
40
Kouraev, Alexei V., Elena A. Zakharova, Andrey G. Kostianoy, Mikhail N. Shimaraev, Lev V. Desinov, Evgeny A. Petrov, Nicholas M. J. Hall, Frédérique Rémy, and Andrey Ya Suknev. "Giant ice rings in southern Baikal: multi-satellite data help to study ice cover dynamics and eddies under ice." Cryosphere 15, no. 9 (September 24, 2021): 4501–16. http://dx.doi.org/10.5194/tc-15-4501-2021.
Full textAbstract:
Abstract. Ice cover on lakes is subject to atmospheric forcing from above and the influence of water dynamics and heat flux from below. One characteristic example of these influences in some large lakes, such as Lake Baikal in Russia, are the giant ice rings and the associated eddies under the ice cover. In April 2020 a giant ice ring appeared in southern Baikal, and a lens-like eddy was detected below the ice. We analysed the temporal changes of ice cover using satellite images from multiple satellite missions – MODIS on Terra and Aqua, Sentinel-1 SAR, Sentinel 2 MSI, Landsat 8, PlanetScope, satellite photography from the International Space Station, and radar altimetry data from Jason-3. Satellite imagery and meteorological data show unusual temporal changes of ice colour in April 2020, which were explained by water infiltration into the ice followed by the competing influences of cold air from above and the warm eddy below the ice. Tracking of ice floe displacement also makes it possible to estimate eddy currents and their influence on the upper water layer. Multi-satellite data contribute to a better understanding of the development of ice cover in the presence of eddies, the role of eddies in horizontal and vertical heat and mass exchange, and their impact on the chemistry and biology of the lakes and on human activity.
41
Herreid, Sam, Francesca Pellicciotti, Alvaro Ayala, Anna Chesnokova, Christian Kienholz, Joseph Shea, and Arun Shrestha. "Satellite observations show no net change in the percentage of supraglacial debris-covered area in northern Pakistan from 1977 to 2014." Journal of Glaciology 61, no. 227 (2015): 524–36. http://dx.doi.org/10.3189/2015jog14j227.
Full textAbstract:
AbstractSpatial evolution of supraglacial debris cover on mountain glaciers is a largely unmonitored and poorly understood phenomenon that directly affects glacier melt. Supraglacial debris cover for 93 glaciers in the Karakoram, northern Pakistan, was mapped from Landsat imagery acquired in 1977, 1998, 2009 and 2014. Surge-type glaciers occupy 41% of the study area and were considered separately. The time series of debris-covered surface area change shows a mean value of zero or near-zero change for both surging and non-surging glaciers. An increase in debris-covered area is often associated with negative regional mass balances. We extend this logic to suggest that the stable regional mass balances in the Karakoram explain the zero or near-zero change in debris-covered area. This coupling of trends combined with our 37 year time series of data suggests the Karakoram anomaly extends further back in time than previously known.
42
Waqas, Muhammad, Majid Nazeer, Muhammad Shahzad, and Ibrahim Zia. "Spatial and Temporal Variability of Open-Ocean Barrier Islands along the Indus Delta Region." Remote Sensing 11, no. 4 (February 20, 2019): 437. http://dx.doi.org/10.3390/rs11040437.
Full textAbstract:
Barrier islands (BIs) have been designated as the first line of defense for coastal human assets against rising sea level. Global mean sea level may rise from 0.21 to 0.83 m by the end of 21st century as predicted by the Intergovernmental Panel on Climate Change (IPCC). Although the Indus Delta covers an area of 41,440 km² surrounded by a chain of BIs, this may result in an encroachment area of 3750 km2 in Indus Delta with each 1 m rise of sea level. This study has used a long-term (1976 to 2017) satellite data record to study the development, movement and dynamics of BIs located along the Indus Delta. For this purpose, imagery from Landsat Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Operational Land Imager (OLI) sensors was used. From all these sensors, the Near Infrared (NIR) band (0.7–0.9 µm) was used for the delineation and extraction of the boundaries of 18 BIs. It was found that the area and magnitude of these BIs is so dynamic, and their movement is so great that changes in their positions and land areas have continuously been changing. Among these BIs, 38% were found to be vulnerable to oceanic factors, 37% were found to be partially vulnerable, 17% remained partially sustainable, and only 8% of these BIs sustained against the ocean controlling factors. The dramatic gain and loss in area of BIs is due to variant sediment budget transportation through number of floods in the Indus Delta and sea-level rise. Coastal protection and management along the Indus Delta should be adopted to defend against the erosive action of the ocean.
43
Hopkinson, Chris, Brendon Fuoco, Travis Grant, Suzanne E. Bayley, Brian Brisco, and Ryan MacDonald. "Wetland Hydroperiod Change Along the Upper Columbia River Floodplain, Canada, 1984 to 2019." Remote Sensing 12, no. 24 (December 14, 2020): 4084. http://dx.doi.org/10.3390/rs12244084.
Full textAbstract:
Increasing air temperatures and changing hydrological conditions in the mountainous Kootenay Region of British Columbia, Canada are expected to affect floodplain wetland extent and function along the Columbia River. The objective of this study was to determine the seasonally inundated hydroperiod for a floodplain section (28.66 km2) of the Upper Columbia River wetlands complex using time series satellite image observations and binary open water mask extraction. A mid pixel resolution (30 m) optical satellite image time series of 61 clear sky scenes from the Landsat Thematic Mapper (TM) and Operational Land Imager (OLI) sensors were used to map temporal variations in floodplain open water wetland extent during the April to October hydrologically active season from 1984 to 2019 (35 years). The hydroperiod from the first 31 scenes (T1: 18 years) was compared to the second 30 (T2: 16 years) to identify changes in the permanent and seasonal open water bodies. The seasonal variation in open water extent and duration was similar across the two time periods but the permanent water body extent diminished by ~16% (or ~3.5% of the floodplain). A simple linear model (r2 = 0.87) was established to predict floodplain open water extent as a function of river discharge downstream of the case study area. Four years of Landsat Multi-Spectral Scanner (MSS) data from 1992 to 1995 (12 scenes) were examined to evaluate the feasibility of extending the hydroperiod record back to 1972 using lower resolution (60 m) archive data. While the MSS hydroperiod produced a similar pattern of open water area to duration to the TM/OLI hydroperiod, small open water features were omitted or expanded due to the lower resolution. While MSS could potentially extend the TM/OLI hydroperiod record, this was not performed as the loss of features like the river channel diminished its value for change detection purposes. Radarsat 2 scenes from 2015 to 2019 were examined to evaluate the feasibility of continued mountain valley hydroperiod monitoring using higher spatial and temporal resolution sensors like the Radarsat Constellation Mission (RCM). From the available horizontal transmit/receive (HH) single polarization sample set (8 scenes), the hydroperiod pattern of open water extent to duration was similar to the longer Landsat time series and possessed greater feature detail, but it was significantly reduced in seasonal inundation area due to the systematic omission of open water areas containing emergent vegetation. However, accepting that differences exist in sensor-based hydroperiod attributes, the higher temporal resolution of RCM will be suited to mountain floodplain inundation monitoring and open water hydroperiod analysis.
44
Salam, MA, and MAT Pramanik. "Forest Cover Change Analysis Using Remote Sensing Techniques in Madhupur Sal Forest of Bangladesh." Journal of Environmental Science and Natural Resources 10, no. 2 (November 29, 2018): 73–78. http://dx.doi.org/10.3329/jesnr.v10i2.39015.
Full textAbstract:
Deforestation, degradation, damages, transformation and over exploitation of forests are the common problem in different parts of the world. Timely monitoring and assessment of forest resources may help to address and identify the above mentioned problems and thus proper guidance may be given the forest resources manager for rational planning and management of forests. Apart from the conventional methods of forest monitoring, remote sensing with its unique capability of synoptic viewing, real time and repetitive nature offers a potential tool for monitoring and evaluation of forest resources and hence remote sensing technology has been successfully used in various studies like forest inventory, monitoring of forest cover changes and forest damage assessment. In the present research forest cover change analysis in ‘Madhupur Sal Forest’ located in central part of Bangladesh has been investigated using satellite remote sensing data and spatial analysis. Transformation of ‘Sal forest’ to other landuse has been studied using the Landsat MSS (Multi Spectral Scanner) data of 1973 and Landsat 8 OLI (Operational Land Imager) data of 2015. Driving forces behind the transformation of ‘Sal forest’ has also been investigated through GPS (Global Positioning System) based ground verification and interview with the people living in the locality.J. Environ. Sci. & Natural Resources, 10(2): 73-78 2017
45
Azzaoui, Mohamed, Benchohra Maamar, Leila Soudani, Belgacem Nouar, Mohamed Berreyah, and Mohamed Maatoug. "Spatial dynamics of land cover in the Sdamas region (Tiaret, Algeria)." Journal of Geology, Geography and Geoecology 27, no. 1 (July 10, 2018): 12–19. http://dx.doi.org/10.15421/111825.
Full textAbstract:
The Sdamas massif to which our contribution relates is located in West Algeria, it is an integral part of the Tiaret mountains. The aim of our study is to analyze the land cover of the Sdamas region over a 43-year interval grouped into 9 thematic classes: mineral surfaces (urban planning), wetland, vegetation, bare soils and fallow etc. The spatial and temporal dynamics of land use require regular monitoring of vegetation cover from remote sensing imagery. It is for this reason that we relied on field data to perform the diachronic analysis with three well-defined scenes 1972, 1998 and 2015, using Landsat satellite images (MSS, TM and ETM +). The analysis of these maps covering the same region shows the different changes that have taken place at ground level. We found that our natural plant space has undergone a strong degradation, disruption and regression because of different human activities, namely: overgrazing, clearing, fires, urbanization, (there has been a remarkable increase in the population of the communes of the study area). Inadequate and ineffective forestry interventionsand work, and lack of sustained protection are reasons of these processes. Factors affecting the forest ecosystem are bioclimate and human action. Indeed, the bioclimate, through atmospheric drought, is the main factor governing the diversity of these formations of the Sdamas mountains.
46
Gardiner, DB, GJ Tupper, and GS Dundeon. "A Quantitative Appraisal of Woody Shrub Encroachment in Western New South Wales." Rangeland Journal 20, no. 1 (1998): 26. http://dx.doi.org/10.1071/rj9980026.
Full textAbstract:
Landsat Multispectral Scanner (MSS) digital imagery was used to estimate the distribution, density and change in woody shrub cover over time in western New South Wales. The purpose of the project was to derive maps of woody cover which can be used as a basis for regional planning and property planning. Assessment of woody vegetation cover using satellite imagery enables regions which are more susceptible to shrub encroachment to be targeted for control strategies. Dry season images which had minimal green vegetation were used, because the spectral signatures of scrubby ground cover interfered with the proper classification of woody vegetation. For each region, multidate imagery was classified using a pixel unmixing algorithm to derive data sets which showed woody canopy cover. These data were then rescaled to percentage values using aerial photography sampled throughout each region. A geographic information system (GIS) was used to derive changes in woody cover between both dates and to present the data in map form. Most current woody cover in the study area occurs at less than 20% cover, whilst higher levels (40 to 80%) occur in the eastern parts of the Louth and Barnato regions. At least 20,3 10 km2 of the 120,000 km2 study area is already affected by woody vegetation cover levels of greater than 40%, which significantly reduces carrying capacity and pastoral productivity. Changes in woody cover over a 10 to 20 year period were varied. Approximately 24% (26,041 km2) was relatively stable, whilst 20% of the Barnato region had moderate decreases (1 1 to 30%) due to wildfires, and increases of 11 to 30% cover occurred on 'hard red' soils in the east. Emerging woody vegetation of less than 10% cover occurred over 1816 km2 of Sandplains and Stony Lowlands in the Louth and Barnato regions, whilst woody vegetation levels of more than 40% cover occurred in the Barnato region. Considerable 'infilling' of previously unwooded areas was noted for regions which already had high levels of woody cover. A minimal amount of prescribed clearing was apparent from the change data, which suggests that effective control of shrubs is difficult to achieve and that future scenarios will see continued encroachment. The findings suggest that the southern Louth and Barnato regions are most at risk of further shrub encroachment, and that these areas need to be targeted for shrub control. The data provide a quantitative estimate of woody shrub cover which is useful for economic assessments, as well as providing an information base upon which woody shrub management strategies can be developed. Key words: Landsat Multispectral Scanner, remote sensing, geographic information system, change detection, rangeland, monitoring, land cover.
47
Mernild, Sebastian H., Mauri Pelto, Jeppe K. Malmros, Jacob C. Yde, Niels T. Knudsen, and Edward Hanna. "Identification of snow ablation rate, ELA, AAR and net mass balance using transient snowline variations on two Arctic glaciers." Journal of Glaciology 59, no. 216 (2013): 649–59. http://dx.doi.org/10.3189/2013jog12j221.
Full textAbstract:
AbstractIdentification of the transient snowline (TSL) from high spatial resolution Landsat imagery on Lemon Creek Glacier (LCG), southeast Alaska, USA, and Mittivakkat Gletscher (MG), southeast Greenland, is used to determine snow ablation rates, the equilibrium-line altitude (ELA) and the accumulation-area ratio (AAR). The rate of rise of the TSL during the ablation season on a glacier where the balance gradient is known provides a measure of the snow ablation rate. On both LCG and MG, snow pits were completed in regions that the TSL subsequently transects. This further provides a direct measure of the snow ablation rates for a particular year. TSL observations from multiple dates during the ablation season from 1998 to 2011 at LCG and 1999 to 2012 at MG were used to explore the consistency of the TSL rise and snow ablation rate. On LCG and MG the satellite-derived mean TSL migration rates were 3.8 ± 0.6 and 9.4 ± 9.1 m d−1, respectively. The snow ablation rates were 0.028 ± 0.004 m w.e. d−1 for LCG and 0.051 ± 0.018 m w.e. d−1 for MG estimated by applying a TSL–mass-balance-gradient method, and 0.031 ± 0.004 and 0.047 ± 0.019 m w.e. d−1 by applying a snow-pit–satellite method, illustrating significant agreement between the two different approaches for both field sites. Also, satellite-derived ELA and AAR, and estimated net mass-balance (Ba) conditions were in agreement with observed ELA, AAR and Ba conditions for LCG and MG.
48
Rastner, Philipp, Rainer Prinz, Claudia Notarnicola, Lindsey Nicholson, Rudolf Sailer, Gabriele Schwaizer, and Frank Paul. "On the Automated Mapping of Snow Cover on Glaciers and Calculation of Snow Line Altitudes from Multi-Temporal Landsat Data." Remote Sensing 11, no. 12 (June 14, 2019): 1410. http://dx.doi.org/10.3390/rs11121410.
Full textAbstract:
Mapping snow cover (SC) on glaciers at the end of the ablation period provides a possibility to rapidly obtain a proxy for their equilibrium line altitude (ELA) which in turn is a metric for the mass balance. Satellite determination of glacier snow cover, derived over large regions, can reveal its spatial variability and temporal trends. Accordingly, snow mapping on glaciers has been widely applied using several satellite sensors. However, as glacier ice originates from compressed snow, both have very similar spectral properties and standard methods to map snow struggle to distinguish snow on glaciers. Hence, most studies applied manual delineation of snow extent on glaciers. Here we present an automated tool, named ‘ASMAG’ (automated snow mapping on glaciers), to map SC on glaciers and derive the related snow line altitude (SLA) for individual glaciers using multi-temporal Landsat satellite imagery and a digital elevation model (DEM). The method has been developed using the example of the Ötztal Alps, where an evaluation of the method is possible using field-based observations of the annual equilibrium line altitude (ELA) and the accumulation area ratio (AAR) measured for three glaciers for more than 30 years. The tool automatically selects a threshold to map snow on glaciers and robustly calculates the SLA based on the frequency distribution of elevation bins with more than 50% SC. The accuracy of the SC mapping was about 90% and the SLA was determined successfully in 80% of all cases with a mean uncertainty of ±19 m. When cloud-free scenes close to the date of the highest snowline are available, a good to very good agreement of SC ratios (SCR)/SLA with field data of AAR/ELA are obtained, otherwise values are systematically higher/lower as useful images were often acquired too early in the summer season. However, glacier specific differences are still well captured. Snow mapping on glaciers is impeded by clouds and their shadows or when fresh snow is covering the glaciers, so that more frequent image acquisitions (as now provided by Sentinel-2) would improve results.
49
Evans, Eleri, Richard Essery, and Richard Lucas. "Changing snow cover and the net mass balance of Storglaciären, northern Sweden." Annals of Glaciology 49 (2008): 199–204. http://dx.doi.org/10.3189/172756408787814933.
Full textAbstract:
AbstractThe spatial and temporal variability of seasonal snow cover in glacierized catchments has important implications for the net mass balance of alpine glaciers. This study examines the relationship between changing snowpack volume, the resulting winter balance and the net mass balance of Storglaciären, northern Sweden. Using a conceptual model, the net seasonal snow input to the glacier is simulated daily for 16 years from 1990. From this the annual snow accumulation and winter balance are calculated. The model outputs are compared with snowlines delineated from classified aerial photographs, ASTER and Landsat 7 ETM+ satellite imagery, and with measured Storglaciären winter balances. The results of the model indicate variability in the winter balance over the study period, though there is a slightly negative trend overall. The highest winter balances and seasonal snow volumes occurred in the early 1990s and correspond with positive net mass balances. However, the slightly negative trend in winter balance and decreased net seasonal snow volumes suggested by the model, combined with the measured increasing trend in mass lost due to ablation, have resulted in decreasing glacier net mass balances and a corresponding rise in ELA over the study period.
50
Stokes, Chris R., Stephen D. Gurney, Maria Shahgedanova, and Victor Popovnin. "Late-20th-century changes in glacier extent in the Caucasus Mountains, Russia/Georgia." Journal of Glaciology 52, no. 176 (2006): 99–109. http://dx.doi.org/10.3189/172756506781828827.
Full textAbstract:
AbstractGlaciers occupy an area of ~1600km2 in the Caucasus Mountains. There is widespread evidence of retreat since the Little Ice Age, but an up-to-date regional assessment of glacier change is lacking. In this paper, satellite imagery (Landsat Thematic Mapper and Enhanced Thematic Mapper Plus) is used to obtain the terminus position of 113 glaciers in the central Caucasus in 1985 and 2000, using a manual delineation process based on a false-colour composite (bands 5, 4, 3). Measurements reveal that 94% of the glaciers have retreated, 4% exhibited no overall change and 2% advanced. The mean retreat rate equates to ~8ma–1, and maximum retreat rates approach ~38 m a–1. The largest (>10 km2) glaciers retreated twice as much (~12ma–1) as the smallest (<1 km2) glaciers (~6ma–1), and glaciers at lower elevations generally retreated greater distances. Supraglacial debris cover has increased in association with glacier retreat, and the surface area of bare ice has reduced by ~10% between 1985 and 2000. Results are compared to declassified Corona imagery from the 1960s and 1970s and detailed field measurements and mass-balance data for Djankuat glacier, central Caucasus. It is concluded that the decrease in glacier area appears to be primarily driven by increasing temperatures since the 1970s and especially since the mid-1990s. Continued retreat could lead to considerable changes in glacier runoff, with implications for regional water resources.