Download or read book Glacial Movements in Greenland from Doppler Satellite Observations written by Alice Jean Remington Drew and published by . This book was released on 1982 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial Movements in Greenland from Doppler Satellite Observations written by Alice Jean Remington Drew and published by . This book was released on 1983 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Topography of the Greenland Ice Sheet from Satellite Radar Altimetry written by and published by . This book was released on 1989 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document describes the process of production of maps of the surface of the Greenland ice sheet from data from remote sensing by a Seasat satellite, and defines ice flow directions, together with maps of the Jakobshavn Glacier drainage and the ice divide near Crete Station.
Download or read book A Mini surge on the Ryder Glacier Greenland observed by satellite radar interferometry written by Ian Joughin and published by . This book was released on 1996 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Satellite Geodesy written by Günter Seeber and published by Walter de Gruyter. This book was released on 2008-08-22 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the entire field of satellite geodesy and is intended to serve as a textbook for advanced undergraduate and graduate students, as well as a reference for professionals and scientists in the fields of engineering and geosciences such as geodesy, surveying engineering, geomatics, geography, navigation, geophysics and oceanography. The text provides a systematic overview of fundamentals including reference systems, time, signal propagation and satellite orbits, together with observation methods such as satellite laser ranging, satellite altimetry, gravity field missions, very long baseline interferometry, Doppler techniques, and Global Navigation Satellite Systems (GNSS). Particular emphasis is given to positioning techniques, such as the NAVSTAR Global Positioning System (GPS), and to applications. Numerous examples are included which refer to recent results in the fields of global and regional control networks; gravity field modeling; Earth rotation and global reference frames; crustal motion monitoring; cadastral and engineering surveying; geoinformation systems; land, air, and marine navigation; marine and glacial geodesy; and photogrammetry and remote sensing. This book will be an indispensable source of information for all concerned with satellite geodesy and its applications, in particular for spatial referencing, geoinformation, navigation, geodynamics, and operational positioning.
Download or read book Satellite Image Atlas of Glaciers of the World Asia U S Geological Survey Professional Paper 1386 F written by U.S. Geological Survey and published by . This book was released on 2012-11-01 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Greenland Ice Core written by Chester C. Langway and published by American Geophysical Union. This book was released on 1985 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Correlation based Approach to Modeling Interferometric Radar Observations of the Greenland Ice Sheet written by E. Weber Hoen and published by . This book was released on 2001 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Interferometric synthetic aperture radar (InSAR) phase observations have greatly increased our understanding of the topography and motion of ice sheets, but yield little information on the sub-surface structure, a needed description for mass-balance estimates. Inversion of a diffuse volume scatter model shows that InSAR correlation values, p, can be related to radiowave penetration depths, d, which depend on characteristics of the snow/ice volume. Application to European Research Satellite (ERS) images (VV, 5.6 cm, 23 ̊incidence angle) of the Greenland ice sheet imply C-band d of 0 m along the rocky coast, 10-20 m in the bare ice zone, and 20-35 m in the percolation zone and dry snow zone, consistent with in situ results. Moreover, volume scattering reduces the ERS critical baseline from about 1100 m to 300 m. Correlation and backscatter power (ơ0) observations can be combined for further understanding of the snow/ice volume. In particular, p and ơ0 data of 15 km-long, 50 m-high topographic undulations in the dry snow zone arc minimum on the windward side and maximum on the lee side, with 1 to 3 dB variation typical. These spatial variations in the scattering medium appear to follow from differences in snow accumulation due to prevailing winds. Assuming that snow-grains are the dominant source of backscatter, the classical independent-scatterer model is physically implausible at firn densities; a second-order dense-medium radiative transfer model also is unable to explain both the observed d and ơ0. A modified Born approach provides a better match to ơ0 and p separately, but leads to different grain size solutions for each measurement type. A buried layer model based on the incoherent addition of echoes from hoar layer interfaces, in which scattering from a single layer is derived from small-perturbation methods, reconciles the ERS ơ0 and p data, with variations in hoar layer spacing of 12-17 cm providing the needed structural fluctuations for the observed range of ơ0 and p. Translation of layer spacing into accumulation rates predicts a 40% variability in accumulation rate from the windward to lee side and, more importantly, addresses high-resolution mapping of continental accumulation rates"--Leaves iv-v.
Download or read book Glaciological Observations Using Phase sensitive Radar written by Ole Zeising and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The large ice sheets in Greenland and Antarctica are losing mass due to global warming. In particular, the acceleration of ice streams and thus the increased discharge into the ocean contributes significantly to global sea-level rise. The floating extensions of the ice streams counteract this, but intense basal melting can destabilise the ice shelves. In this thesis, a contribution is made to determine the melt rates of two ice shelves, which are crucial for the future mass losses of the respective ice sheets. In the north, the focus is on the Northeast Greenland Ice Stream (NEGIS) that feeds the Nioghalvfjerdsbrae (79°N Glacier). My analysis of phase-sensitive radar measurements indicates high melt rates near the onset of the ice stream and thus the presence of subglacial melt water, which is associated with the formation of the ice flow. An extensive study in my thesis reveals that the 79°N Glacier has been thinned out considerably in recent years due to extreme melt rates and that large channels have been formed. Melt rates of the Filchner Ice Shelf, Antarctica, which I also determined using phase-sensitive radar measurements, are comparatively low. I was able to attribute significant deviations from remote sensing-derived melt rates to inaccuracies in the used ice flow velocity field. Furthermore, I show that the use of newer velocity fields improves the determination of the melt rates from remote sensing. My analysis of melt rate time series in the vicinity of a channel indicates higher melt rates in the summer as well as several melt events spread over the entire measurement period. Another study combines measurements and numerical modelling and shows that higher melt rates must have occurred in the past than those that were measured. These would lead to the closure of the channel within 250 years. Thus, neither the channel itself nor the present day melt rates endanger the stability of one of the largest Antarctic ice shelves at present.
Download or read book Satellite Investigations of Ice Dynamics and Supraglacial Lake Development in Greenland written by Kate Hannah Briggs and published by . This book was released on 2012 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis aims to improve the current understanding of the processes which control the flow variability of Greenland Ice Sheet (GrIS) outlet glaciers. The most recent Intergovernmental Governmental Panel on Climate Change (IPCC) report (Meehl et al., 2007) identifies that a critical limitation to forecasts of sea-level rise are uncertainties in modelling the ice dynamics of the GrIS. Using Synthetic Aperture Radar (SAR) feature tracking, seasonal velocities of land- and marine- terminating glaciers in a region in the northeast of Greenland are measured. Records of air temperature in conjunction with seasonal observations of supraglacial lake development, sea ice conditions and ice front positions, derived from SAR imagery, are used to investigate the controls on the observed variations in ice velocity. A clear link between ice velocities and glacier hydrology is found. These findings are consistent with observations from other glaciers in Greenland and are suggestive of a universal hydrological forcing of ice velocity for the whole of the GrIS ablation zone. Lake drainage events have been identified as a key factor in linking atmospheric changes, glacier hydrology and ice velocities in Greenland. For modelling purposes, a means of parameterising the distribution and evolution of supraglacial lakes is therefore needed. Assuming that water will pond in surface depressions, this thesis assesses the ability of using Digital Elevation Models (DEMs) for this purpose. High resolution DEMs are created using Interferometric SAR (InSAR) for two, separate regions of the GrIS. The positions and areal extent of surface depressions are compared with those of lakes observed in optical satellite imagery. The level of correspondence between the two datasets is found to be poor as a result of the resolution of the DEMs and the physical differences between surface depressions and lakes (e.g. lakes may not fill the capacity of the depression). An alternative method for parameterising the seasonal distribution of supra-glacial lakes, by extrapolating trends observed in current lake distributions, is investigated. The locations and evolution of lakes in the west of Greenland during the summer of 2003 are mapped using 47 Moderate Resolution Imaging Spectroradiometer (MODIS) images. Clear trends are identified in the distributions of lakes with elevation and are linked to the seasonal melt-cycle and to changes in ice thickness and its influence on surface depressions, tensile stresses and hydrofracturing. It may be possible to extrapolate these trends to other regions and higher elevations on the ice sheet, thereby enabling the distribution of lakes to be parameterised in ice sheet models. The findings of this thesis help to contribute to the understanding of the interaction between climate and ice dynamics in the context of the GrIS.
Download or read book Atlas of Satellite Observations Related to Global Change written by Robert J. Gurney and published by Cambridge University Press. This book was released on 1993-11-25 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global environmental change is one of the most pressing international issues of the next century. There is a need to monitor the Earth's vital signs, from atmospheric ozone to tropical deforestation to sea level change. Models used to predict global changes have not yet fully used global observational data sets. Satellite data sets will be vital in addressing global change issues, in determining natural variability and monitoring global and regional changes. This timely volume provides an illustration of the variety of satellite-derived global data sets now available, their uses, advantages and limitations, and the range of variation that has already been observed with these data. A team of distinguished contributors provide a highly illustrated and accessible account suitable for the general scientific reader.
Download or read book Movement observations on the Greenland ice cap written by George Wallerstein and published by . This book was released on 1957 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radioglaciology written by V.V. Bogorodsky and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antarctica, the sixth continent, was discovered more than 160 years ago. Since then this large, mysterious continent of ice and penguins has attracted world interest. Scientific expeditions from various countries have begun to study the geographical and natural conditions of the icy continent. Systematic and comprehensive inves tigations in the Antarctic started in the middle of our century. In 1956 the First Soviet Antarctic Expedition headed to the coast of Antarctica. Their program included studies of the atmosphere, hydrosphere and cryosphere. Thirty years have since passed. Scientists have unveiled many secrets of Antarctica: significant geophysical processes have been investigated, and a large body of new information on the Antarctic weather, Southern Ocean hydrology and Antarctic glaciers has been obtained. We can now claim that the horizons of polar geo physics, oceanology, and particularly glaciology, have expanded. Scientific inves tigators have obtained new information about all Antarctic regions and thus have created the opportunity to use the Antarctic in the interests of mankind.
Download or read book Encyclopedia of Snow Ice and Glaciers written by Vijay P. Singh and published by Springer Science & Business Media. This book was released on 2011-06-29 with total page 1301 pages. Available in PDF, EPUB and Kindle. Book excerpt: The earth’s cryosphere, which includes snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost, contains about 75% of the earth’s fresh water. It exists at almost all latitudes, from the tropics to the poles, and plays a vital role in controlling the global climate system. It also provides direct visible evidence of the effect of climate change, and, therefore, requires proper understanding of its complex dynamics. This encyclopedia mainly focuses on the various aspects of snow, ice and glaciers, but also covers other cryospheric branches, and provides up-to-date information and basic concepts on relevant topics. It includes alphabetically arranged and professionally written, comprehensive and authoritative academic articles by well-known international experts in individual fields. The encyclopedia contains a broad spectrum of topics, ranging from the atmospheric processes responsible for snow formation; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide distribution; glaciation and ice ages; glacier dynamics; glacier surface and subsurface characteristics; geomorphic processes and landscape formation; hydrology and sedimentary systems; permafrost degradation; hazards caused by cryospheric changes; and trends of glacier retreat on the global scale along with the impact of climate change. This book can serve as a source of reference at the undergraduate and graduate level and help to better understand snow, ice and glaciers. It will also be an indispensable tool containing specialized literature for geologists, geographers, climatologists, hydrologists, and water resources engineers; as well as for those who are engaged in the practice of agricultural and civil engineering, earth sciences, environmental sciences and engineering, ecosystem management, and other relevant subjects.
Download or read book NASA SP written by and published by . This book was released on 1989 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Eismitte in the Scientific Imagination written by J. Martin-Nielsen and published by Springer. This book was released on 2013-12-18 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the 18th century, Greenland's geometric center, Eismitte, has been one of the most forbidding but scientifically rich locations in the Arctic. Tracing its history from European contact through the Cold War, this study shows how Eismitte was the setting for scientific knowledge production as well as diplomatic maneuvering.
Download or read book Remote Sensing of Glaciers written by Petri Pellikka and published by CRC Press. This book was released on 2009-12-16 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glaciers and ice sheets have been melting significantly during recent decades, posing environmental threats at local, regional and global scales. Changes in glaciers are one of the clearest indicators of alterations in regional climate, since they are governed by changes in accumulation (from snowfall) and ablation (by melting of ice). Glacier chan
