Download or read book Dielectric Properties of Ice Snow and Water at Microwave Frequencies and the Measurement of the Thickgrass of Ice and Snow Layers with Radar written by Communications Research Centre (Canada) and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dielectric Properties of Ice Snow and Water At Microwave Frequencies and the Measurement of the Thickness of Ice and Snow Layers With Radar written by Communications Research Centre (Canada) and published by . This book was released on 1973 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Dielectric Properties of Ice Snow and Water at Microwave Frequencies and the Measurement of the Thicknesses of Ice and Snow Layers with Radar written by Communications Research Centre (Canada) and published by . This book was released on 1973 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of the Dielectric Properties of Wet Snow Using a Microwave Technique written by Bruce D. Sweeny and published by . This book was released on 1974 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: An accurate method of measuring liquid water in snow covers is required to determine the properties of wet snow. The dielectric properties of wet snow must be utilized to adequately measure its liquid water content. In this study the effect of liquid water on the complex dielectric constant of natural snow is determined in the microwave frequency range. Deloor's method for calculating the dielectric constant for mixtures and the results of waveguide experiments on samples of wet snow and glass beads are used to construct a calibration curve relating the measured dielectric loss factor directly to the water content of wet snow. The results are independent of porosity, past history and chemical impurities. A relation between the effective dielectric constant and the porosity and water content is proposed and tested experimentally. The general nature of this relation is described and suggestions are made for the development of a more precise relation. It is concluded that the dielectric constant is a function of porosity and water content only.
Download or read book Determination of the Water Content of Snow by Dielectric Measurements written by Paul R. Camp and published by . This book was released on 1992 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advancing Microwave Radar Retrievals of Snow Depth on Sea Ice written by Arttu Jutila and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Snow is a key factor in the sea-ice and Earth's climate systems that modifies the physical, climatic, and biogeochemical processes taking place. One of its most important impacts is in regulating sea-ice growth and melt. Despite its importance, little is known about the spatial and temporal distribution of snow depth on sea ice on the regional to global scales. Snow is tightly coupled to the highly dynamic sea-ice and atmospheric conditions and it is, therefore, very heterogeneous and constantly evolving both in space and in time. As a spatially and temporally representative, global, year-round product of snow depth observations on sea ice does not exist to this date, applications often have to rely on climatological values that do not necessarily hold true in the rapidly warming global climate. The unknown properties directly translate into the uncertainty of the result. This dissertation takes on the ambitious goal of working toward full characterisation of the snow and sea-ice layers. To achieve that, the focus is on advancing microwave radar retrievals of snow depth on sea ice. Enhanced snow depth observations will enable improving other measurements of sea-ice related parameters, most importantly sea-ice thickness, and in joint analysis of coincident sea-ice measurements estimating sea-ice bulk density becomes possible. In the first step, field experiments with ground-based C and K band pulse radars are carried out to investigate microwave penetration into the snow cover. The results show the K band microwaves expectedly reflect from the snow surface while the C band microwaves penetrate closer to the snow-sea-ice interface potentially enabling dual-frequency snow depth retrieval in less than half of the studied cases and only on first-year ice. In the second step, radar measurements of snow depth on sea ice are upscaled by using an airborne radar in the western Arctic Ocean in 2017-2019. A high-sensitivity, ultra-wideband, frequency-modulated continuous-wave (FMCW) radar is integrated to the instrument configuration of the Alfred Wegener Institute's (AWI) IceBird sea-ice campaigns. Snow depth retrievals with a custom algorithm based on signal peakiness from the radar measurements at a low altitude of 200 ft show good consistency against high altitude measurements at 1500 ft, which are comparable to previous acquisitions. At the nominal low altitude of the IceBird surveys, the small, two-metre radar footprint increases the spatial resolution and reduces the effect of off-nadir targets. Validation against ground measurements reveal a sub-centimetre mean bias, which is below the sensor resolution. As the main result of this step, the AWI IceBird surveys are now capable of discriminating between the snow and sea-ice layers. In the third step, the full AWI IceBird sensor configuration, including airborne laser, radar, and electromagnetic induction sounding instruments, is exploited by collocating the coincident thickness and freeboard measurements and tracking the locations of air-snow, snow-sea-ice, and sea-ice-water interfaces for more than 3000 km along survey paths over different sea-ice types. Assuming values for snow and sea-water densities and that the sea-ice cover is in isostatic equilibrium, it is possible to derive sea-ice bulk density. The results show that the ice-type averaged densities for first-year and multi-year ice are higher than and do not differ as much as widely used values from previous studies. This highlights the demand of algorithms to adapt to changing sea-ice density in satellite altimetry retrievals of sea-ice thickness. Finally, a negative-exponential parametrisation of sea-ice bulk density is derived using sea-ice freeboard as the predictor variable for future applications. In conclusion, this dissertation takes important advancing steps in characterising the snow and sea-ice layers. Previously, the airborne AWI IceBird surveys carried out in late-winter were only able to measure the combined thickness of the snow and sea-ice layers but now, after successful integration of the FMCW radar and in combination with the airborne laser scanner measurements, it is possible to track the locations of all three interfaces bounding the snow-sea-ice system. Such airborne multi-instrument measurements of snow depth, sea-ice thickness, and freeboard are important data sets in their own right to complement the scarce observations of sea-ice related parameters in remote areas of the polar regions, but a joint analysis allows deriving further key parameters like sea-ice density. The results of this dissertation can be applied to improve retrievals of geophysical sea-ice parameters from the soon 30-year long satellite altimetry data record, which in turn will contribute to enhance monitoring the climate-sensitive sea-ice cover and modelling future projections of the changing global climate.
Download or read book Dielectric Properties of Fresh water Ice at Microwave Frequencies written by Christian Mätzler and published by . This book was released on 1987 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical Characteristics of Snow and Ice written by Francis D. Horigan and published by . This book was released on 1953 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sea Ice Physics written by Michael Patrick Madden (M.S.) and published by . This book was released on 1994 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of the Dielectric Properties of Snow in the 4 18 GHz Frequency Range written by M. Hallikainen and published by . This book was released on 1982 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Dielectric Properties and Normalized Radar Cross section of Crude Oil contaminated Sea Ice written by Thomas David Neusitzer and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explores the effects of crude oil spilled beneath young sea ice on the dielectric properties and normalized radar cross-section of the ice at microwave (C-band) frequencies. The dielectric profile, also referred to as the complex permittivity profile, of sea ice is a governing factor in how the ice scatters incident electromagnetic waves, thus affecting its associated normalized radar cross-section. The dielectric profile of sea ice is dependent on both the geophysical and thermal properties of the ice. Crude oil contained beneath, within, or on the surface of young sea ice was expected to change these properties, thus impacting both the dielectric profile and normalized radar cross-section of the ice. Differences between the dielectric profile and normalized radar cross-section of uncontaminated and oil-contaminated sea ice is expected to facilitate detection of oil-contaminated sea ice through active microwave remote sensing technologies. As such, a discussion of the geophysical, thermodynamic, and electromagnetic properties of sea ice is presented, as well as an overview of the behaviour of oil in ice infested environments and the efforts undertaken to detect crude oil-contaminated sea ice. Following this, the details of a preliminary laboratory experiment conducted to explore the differences in the dielectric profiles of uncontaminated and contaminated sea ice are presented. Next, a comprehensive description of the meso-scale crude oil-in-sea ice experiment and the results, including the modelled dielectric profiles and measured normalized radar cross-sections of uncontaminated and oil-contaminated sea ice, is provided. Finally, a simulation study comparing the normalized radar cross-section for the uncontaminated and oil-contaminated cases is presented. Based on the experimental and simulation work conducted, the observed differences in the temperature profiles and normalized radar cross-sections of uncontaminated and oil-contaminated sea ice suggest that differentiation between uncontaminated and oil-contaminated young sea ice using microwave remote sensing technologies may be possible.
Download or read book Volume Scattering from Sea Ice and Glacier Snow written by Albert W. Biggs and published by . This book was released on 1970 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: This presentation considers volume scattering from Arctic sea ice and Cascade Mountain snow fields. Physical properties of sea ice and dielectric properties of glacier snow are described in terms of dielectric mixtures and the relaxation spectra of water at microwave frequencies. The VLF spectrum is included to illustrate analogous relaxation for ice. Scattering models are brine pockets in sea ice and ice spheroids in snow fields. Radar backscatter measurements of sea ice and SLAR images of snow fields are interpreted with these models. Simulation of sea ice in an acoustic tank demonstrates volume and surface scattering with good qualitative results. The dielectric relaxation phenomena in water at microwave frequencies is also interpreted as a mechanism for anomalous behavior.
Download or read book Dielectric Properties of Sea Ice at Microwave Frequencies written by Martti Hallikainen and published by . This book was released on 1977 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Use of Microwave Radiation for Great Lakes Ice Surveillance written by Brenda Blanton Hagman and published by . This book was released on 1976 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of the Interaction of Microwaves with the Natural Snow Cover written by Christian Mätzler and published by Routledge. This book was released on 1987 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Use of Microwave Radar Data to Interpret Physical Properties of Ice and Snow on the Greenland Ice Sheet written by Christopher M. Gero and published by . This book was released on 1995 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dielectric Properties of Snow written by and published by . This book was released on 1980 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper is a review of the dielectric properties of snow in the radio frequency range from 100 kHz to 35 GHz. Applicable dielectric mixing formulas are discussed and compared to available experimental data. Below 1 GHz, the dielectric behavior of snow is well understood and has led to development of sensors to measure the liquid water content of snow, while above 1 GHz, the scarcity of experimental data and the discrepancies between the few available measurements, particularly when liquid water is present, are responsible for the rather sketchy understanding of the dielectric behavior of snow in the microwave region.
