Discrimination of Arctic multi-year ice from first-year ice using SCATSAT-1 data

The distinctive dielectric properties of multi-year ice that make it stand out from the first-year ice has been exploited in this study to discriminate the Arctic multi-year ice from the first-year ice. We have used the backscattering coefficient, the brightness temperature and the gamma-naught data from the ISRO's miniature satellite SCATSAT-1 for this study. Principal component analysis in conjunction with the ISODATA unsupervised classification technique has been used to achieve the goal of this study. The classification results so obtained have been compared with a well-established sea ice type data product from the EUMETSAT's Ocean & Sea Ice Satellite Application Facility. Moreover, we have employed a change detection technique to ascertain the changes in the Arctic multi-year ice for the SCATSAT-1 period 2016 through 2018 (autumn and spring changes)

Discrimination of Arctic multi-year ice from first-year ice using SCATSAT-1 data

98-104The distinctive dielectric properties of multi-year ice that make it stand out from the first-year ice has been exploited in this study to discriminate the Arctic multi-year ice from the first-year ice. We have used the backscattering coefficient, the brightness temperature and the gamma-naught data from the ISRO's miniature satellite SCATSAT-1 for this study. Principal component analysis in conjunction with the ISODATA unsupervised classification technique has been used to achieve the goal of this study. The classification results so obtained have been compared with a well-established sea ice type data product from the EUMETSAT's Ocean & Sea Ice Satellite Application Facility. Moreover, we have employed a change detection technique to ascertain the changes in the Arctic multi-year ice for the SCATSAT-1 period 2016 through 2018 (autumn and spring changes)

Satellite radar altimetry of sea ice

The thesis concerns the analysis and interpretation of data from satellite borne radar altimeters over ice covered ocean surfaces. The applications of radar altimetry are described in detail and consider monitoring global climate change, the role that sea ice plays in the climate system, operational applications and the extension of high precision surface elevation measurements into areas of sea ice. The general nature of sea ice cover is discussed and a list of requirements for sea ice monitoring is provided and the capability of different satellite sensors to satisfy needs is examined. The operation of satellite borne altimeter over non-ocean surfaces is discussed in detail. Theories of radar backscatter over sea ice are described and are used to predict the radar altimeter response to different types of sea ice cover. Methods employed for analysis of altimeter data over sea ice are also described. Data from the Seasat altimeter is examined on a regional and global scale and compared with sea ice climatology. Data from the Geosat altimeter is compared with co-incident imagery from the Advanced Very High Resolution Radiometer and also from airborne Synthetic Aperture Radar. Correlations are observed between the altimeter data and imagery for the ice edge position, zones within the ice cover, new ice and leads, vast floes and the fast ice boundary. An analysis of data collected by the Geosat altimeter over a period of more than two years is used to derive seasonal and inter-annual variations in the total Antarctic sea ice extent. In addition the retrieval of high accuracy elevation measurements over sea ice areas is carried out. These data are used to produce improved maps of sea surface topography over ice- covered ocean and provide evidence of the ability of the altimeter to determine sea ice freeboard directly. In addition the changing freeboard of two giant Antarctic tabular icebergs, as measured by the Geosat altimeter, is presented. As a summary the achievements are reviewed and suggestions are made towards directions for further work on present data sets and for future data from the ERS-1 satellite

Earth Resources: A continuing bibliography with indexes (Issue 37)

This bibliography lists 512 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1 and March 31, 1983. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Investigation of Sea Ice Using Multiple Synthetic Aperture Radar Acquisitions

The papers of this thesis are not available in Munin. Paper I: Yitayew, T. G., Ferro-Famil, L., Eltoft, T. & Tebaldini, S. (2017). Tomographic imaging of fjord ice using a very high resolution ground-based SAR system. Available in IEEE Transactions on Geoscience and Remote Sensing, 55 (2):698-714. Paper II: Yitayew, T. G., Ferro-Famil, L., Eltoft, T. & Tebaldini, S. (2017). Lake and fjord ice imaging using a multifrequency ground-based tomographic SAR system. Available in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 10(10):4457-4468. Paper III: Yitayew, T. G., Divine, D. V., Dierking, W., Eltoft, T., Ferro-Famil, L., Rosel, A. & Negrel, J. Validation of Sea ice Topographic Heights Derived from TanDEMX Interferometric SAR Data with Results from Laser Profiler and Photogrammetry. (Manuscript).The thesis investigates imaging in the vertical direction of different types of ice in the arctic using synthetic aperture radar (SAR) tomography and SAR interferometry. In the first part, the magnitude and the positions of the dominant scattering contributions within snow covered fjord and lake ice layers are effectively identified by using a very high resolution ground-based tomographic SAR system. Datasets collected at multiple frequencies and polarizations over two test sites in Tromsø area, northern Norway, are used for characterizing the three-dimensional response of snow and ice. The presented experimental results helped to improve our understanding of the interaction between radar waves and snow and ice layers. The reconstructed radar responses are also used for estimating the refractive indices and the vertical positions of the different sub-layers of snow and ice. The second part of the thesis deals with the retrieval of the surface topography of multi-year sea ice using SAR interferometry. Satellite acquisitions from TanDEM-X over the Svalbard area are used for analysis. The retrieved surface height is validated by using overlapping helicopter-based stereo camera and laser profiler measurements, and a very good agreement has been found. The work contributes to an improved understanding regarding the potential of SAR tomography for imaging the vertical scattering distribution of snow and ice layers, and for studying the influence of both sensor parameters such as its frequency and polarization and scene properties such as layer stratification, air bubbles and small-scale roughness of the interfaces on snow and ice backscattered signal. Moreover, the presented results reveal the potential of SAR interferometry for retrieving the surface topography of sea ice

A comprehensive in situ and remote sensing data set from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign

The Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign was carried out north-west of Svalbard (Norway) between 23 May and 6 June 2017. The objective of ACLOUD was to study Arctic boundary layer and mid-level clouds and their role in Arctic amplification. Two research aircraft (Polar 5 and 6) jointly performed 22 research flights over the transition zone between open ocean and closed sea ice. Both aircraft were equipped with identical instrumentation for measurements of basic meteorological parameters, as well as for turbulent and radiative energy fluxes. In addition, on Polar 5 active and passive remote sensing instruments were installed, while Polar 6 operated in situ instruments to characterize cloud and aerosol particles as well as trace gases. A detailed overview of the specifications, data processing, and data quality is provided here. It is shown that the scientific analysis of the ACLOUD data benefits from the coordinated operation of both aircraft. By combining the cloud remote sensing techniques operated on Polar 5, the synergy of multi-instrument cloud retrieval is illustrated. The remote sensing methods were validated using truly collocated in situ and remote sensing observations. The data of identical instruments operated on both aircraft were merged to extend the spatial coverage of mean atmospheric quantities and turbulent and radiative flux measurement. Therefore, the data set of the ACLOUD campaign provides comprehensive in situ and remote sensing observations characterizing the cloudy Arctic atmosphere. All processed, calibrated, and validated data are published in the World Data Center PANGAEA as instrument-separated data subsets (Ehrlich et al., 2019b, https://doi.org/10.1594/PANGAEA.902603)

Gazing at the Solar System: Capturing the Evolution of Dunes, Faults, Volcanoes, and Ice from Space

Gazing imaging holds promise for improved understanding of surface characteristics and processes of Earth and solar system bodies. Evolution of earthquake fault zones, migration of sand dunes, and retreat of ice masses can be understood by observing changing features over time. To gaze or stare means to look steadily, intently, and with fixed attention, offering the ability to probe the characteristics of a target deeply, allowing retrieval of 3D structure and changes on fine and coarse scales. Observing surface reflectance and 3D structure from multiple perspectives allows for a more complete view of a surface than conventional remote imaging. A gaze from low Earth orbit (LEO) could last several minutes allowing for video capture of dynamic processes. Repeat passes enable monitoring time scales of days to years. Numerous vantage points are available during a gaze (Figure 1). Features in the scene are projected into each image frame enabling the recovery of dense 3D structure. The recovery is robust to errors in the spacecraft position and attitude knowledge, because features are from different perspectives. The combination of a varying look angle and the solar illumination allows recovering texture and reflectance properties and permits the separation of atmospheric effects. Applications are numerous and diverse, including, for example, glacier and ice sheet flux, sand dune migration, geohazards from earthquakes, volcanoes, landslides, rivers and floods, animal migrations, ecosystem changes, geysers on Enceladus, or ice structure on Europa. The Keck Institute for Space Studies (KISS) hosted a workshop in June of 2014 to explore opportunities and challenges of gazing imaging. The goals of the workshop were to develop and discuss the broad scientific questions that can be addressed using spaceborne gazing, specific types of targets and applications, the resolution and spectral bands needed to achieve the science objectives, and possible instrument configurations for future missions. The workshop participants found that gazing imaging offers the ability to measure morphology, composition, and reflectance simultaneously and to measure their variability over time. Gazing imaging can be applied to better understand the consequences of climate change and natural hazards processes, through the study of continuous and episodic processes in both domains

Scientific and Technical Publishing at Goddard Space Flight Center in Fiscal Year 1994

This publication is a compilation of scientific and technical material that was researched, written, prepared, and disseminated by the Center's scientists and engineers during FY94. It is presented in numerical order of the GSFC author's sponsoring technical directorate; i.e., Code 300 is the Office of Flight Assurance, Code 400 is the Flight Projects Directorate, Code 500 is the Mission Operations and Data Systems Directorate, Code 600 is the Space Sciences Directorate, Code 700 is the Engineering Directorate, Code 800 is the Suborbital Projects and Operations Directorate, and Code 900 is the Earth Sciences Directorate. The publication database contains publication or presentation title, author(s), document type, sponsor, and organizational code. This is the second annual compilation for the Center

Earth Resources, A Continuing Bibliography with Indexes

This bibliography lists 460 reports, articles and other documents introduced into the NASA scientific and technical information system between July 1 and September 30, 1984. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economical analysis