Coherent backscatter enhancement in bistatic Ku-/X-band radar observations of dry snow

Abstract. The coherent backscatter opposition effect (CBOE) enhances the backscatter intensity of electromagnetic waves by up to a factor of two in a very narrow cone around the direct return direction when multiple scattering occurs in a weakly absorbing, disordered medium. So far, this effect has not been investigated in terrestrial snow in the microwave spectrum. It has also received little attention in scattering models. We present the first characterization of the CBOE in dry snow using ground-based and space-borne bistatic radar systems. For a seasonal snow pack in Ku-band (17.2 GHz), we found backscatter enhancement of 50–60 % (+1.8–2.0 dB) at zero bistatic angle and a peak half-width-at-half-maximum (HWHM) of 0.25°. In X-band (9.65 GHz), we found backscatter enhancement of at least 35 % (+1.3 dB) and an estimated HWHM of 0.12° in the accumulation areas of glaciers in the Jungfrau-Aletsch region, Switzerland. Sampling of the peak shape at different bistatic angles allows estimating the scattering and absorption mean free paths, ΛT and ΛA. In the VV polarization, we obtained ΛT = 0.4 ± 0.1 m and ΛA = 19 ± 12 m at Ku-band, and ΛT = 2.1 ± 0.4 m, ΛA = 21.8 ± 2.7 m at X-band. The HH polarization yielded similar results. The observed backscatter enhancement is thus significant enough to require consideration in backscatter models describing monostatic and bistatic radar experiments. Enhanced backscattering beyond the Earth, on the surface of solar system bodies, has been interpreted as being caused by the presence of water ice. In agreement with this interpretation, our results confirm the presence of the CBOE at X- and Ku-band frequencies in terrestrial snow.

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Bistatic radar observations of the coherent backscatter opposition effect in dry snow

10.5194/egusphere-egu21-4563 ◽

2021 ◽

Author(s):

Marcel Stefko ◽

Silvan Leinss ◽

Irena Hajnsek

Keyword(s):

Mean Free Path ◽

Radar System ◽

Bistatic Radar ◽

Snow Layer ◽

Radar Observations ◽

Opposition Effect ◽

Snow Properties ◽

X Band ◽

Coherent Backscatter ◽

Ku Band

In this submission we report on observations of the coherent backscatter opposition effect (CBOE) in seasonal snow layers using bistatic radar, and the possible pathways towards estimation of snow properties from these radar observations.Bistatic radar refers to a configuration where the transmitter and the receiver are not in the same location. From the point of view of the observed target, there thus exists a non-zero angular separation between &#160;directions towards the transmitter and towards the receiver, referred to as the bistatic angle. The coherent backscatter opposition effect (CBOE) is a phenomenon that causes increased backscatter of coherent radiation at small bistatic angles (less than 1 degree) in refractive but non-absorbing disordered media (e.g. snow). It has been previously investigated to characterize surfaces of various water-ice covered Solar System bodies [1], however it has received comparatively little attention in Earth-focused observations, despite the well-known occurrence of significant volume scattering within snow and ice.Scattering models of CBOE relate the shape of the intensity peak (width, height) to specific parameters of the random medium (grain size, mean free path, reflectivity) [2]. Measurements of the CBOE peak profile are thus a possible pathway towards improving the accuracy of estimates of these parameters, and those closely connected to them, such as the snow water equivalent (SWE).We report on two separate observations of the CBOE-intensity peak in snow. We carried out ground-based observations using an experimental bistatic Ku-band radar system KAPRI [3], to observe the effect in a winter snow layer on top of the peak Rinerhorn in Davos, Switzerland. We also report on observations of backscatter enhancement in the accumulation zone of Aletsch glacier, using the spaceborne bistatic X-band synthetic aperture radar system TanDEM-X. Applying the aforementioned scattering models to the observations, we can estimate the mean free path of the scattered signal within the snow layer to be 10 cm at Ku-band, and 17 cm at X-band.We believe that further study of CBOE in the context of Earth-focused observations of snow and ice opens new opportunities for development of quantitative models aiming to derive snow properties from bistatic radar observations.REFERENCES[1] Black et al. 2001: Icy Galilean Satellites: Modeling Radar Reflectivities as a Coherent Backscatter Effect. Icarus, 151(2), 167&#8211;180. [2] Hapke et al. 1998: The Opposition Effect of the Moon: Coherent Backscatter and Shadow Hiding. Icarus, 133(1), 89&#8211;97. [3] Baffelli et al. 2017: Polarimetric Calibration of the Ku-Band Advanced Polarimetric Radar Interferometer. IEEE Transactions on Geoscience and Remote Sensing, 56(4), 2295&#8211;2311.

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Electromagnetic characterization of microwave sintered Sr1-xCaxMnO3 (0.0 ≤ x ≤ 0.4) thick films

Processing and Application of Ceramics ◽

10.2298/pac1301001p ◽

2013 ◽

Vol 7 (1) ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Rani Pawar ◽

Ninad Velhal ◽

Vijaya Puri

Keyword(s):

Impedance Matching ◽

Calcium Content ◽

Frequency Range ◽

Absorption Loss ◽

X Ray Diffraction ◽

X Ray ◽

X Band ◽

Electromagnetic Characteristics ◽

Ku Band

Electromagnetic characteristics of microwave sintered strontium calcium manganites thick film with variation in calcium content have been investigated. The X-ray diffraction analysis reveals tetragonal perovskite structure for all the compositions. The grain size increases with the increase in calcium content. The microwave absorption, complex permittivity, permeability and conductivity are reported in the frequency range of 8.2-18 GHz. The absorption loss is larger in Ku band while insertion loss is larger in X band. The permittivity, permeability and microwave conductivity decreases from X-band to Ku-band. The almost identical values of real part of permittivity and permeability indicate possible application as materials for impedance matching.

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Permittivity and Permeability Characterization of SiC and Ferro Metals for Structural Health Monitoring Utilization

MATEC Web of Conferences ◽

10.1051/matecconf/201822505007 ◽

2018 ◽

Vol 225 ◽

pp. 05007

Author(s):

Alaa Raad Hussein ◽

Thar M. Badri Albarody ◽

Puteri Sri Melor Bt M. Yousf ◽

Monis Abdulmanan Abdullah ◽

Husam Kareem Mohsin Al-Jothery

Keyword(s):

Electromagnetic Waves ◽

Nano Particles ◽

Electromagnetic Properties ◽

Filler Materials ◽

Operation Conditions ◽

Sensing Technology ◽

X Band ◽

Permittivity And Permeability ◽

Source Of Information

The need for wireless sensing technology has rapidly increased recently, specifically the usage of electromagnetic waves which becoming more required as a source of information. Silicon carbide (SiC) Nano particles has been used in this study, the material under test (MUT) was exposed directly to a microwave field to examine the electromagnetic behavior. The permittivity and permeability were investigated with different filler materials to approach best and optimal electromagnetic absorbing characteristics to assist engineers to monitor structure-based composite for defects evaluation that may occur during operation conditions or through manufacturing process. XRD, FESEM and both complex permittivity and permeability were measured for the pure materials that candidate for this study. The results showed that all the selected nanostructure material exhibit a good purity with proper electromagnetic properties in the X- band, this can lead to absorbing and transmission properties that can be used in monitoring structures or manufactured part during fabrication process.

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Characterization of the PAZ X band SAR Using the HITCHHIKER Ground Receiver

10.36227/techrxiv.14453721 ◽

2021 ◽

Author(s):

Florian Behner ◽

Simon Reuter ◽

Holger Nies ◽

Juan Manuel Cuerda Munoz ◽

Marcos Garcia Rodriguez ◽

...

Keyword(s):

Scientific Community ◽

Earth Observation ◽

Radar Signal ◽

Bistatic Radar ◽

System Calibration ◽

Radar Images ◽

X Band ◽

Instrument Measuring ◽

Earth Observation Satellite

<div>With the start of the Spanish PAZ system, another earth observation satellite has become available to the scientific community. Following the launch of the PAZ science phase, we performed a number of ground experiments using different modes of the satellites SAR instrument, measuring the transmitted radar signal as well as its ground reflections using the HITCHHIKER receiver. The data acquired in these experiments is analyzed and used in collaboration with the PAZ calibration team at INTA to characterize the PAZ instrument and thus verify the system calibration. Further we obtained bistatic radar images from the data of the HITCHHIKER ground receiver.</div>

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Characterization of the PAZ X band SAR Using the HITCHHIKER Ground Receiver

10.36227/techrxiv.14453721.v1 ◽

2021 ◽

Author(s):

Florian Behner ◽

Simon Reuter ◽

Holger Nies ◽

Juan Manuel Cuerda Munoz ◽

Marcos Garcia Rodriguez ◽

...

Keyword(s):

Scientific Community ◽

Earth Observation ◽

Radar Signal ◽

Bistatic Radar ◽

System Calibration ◽

Radar Images ◽

X Band ◽

Instrument Measuring ◽

Earth Observation Satellite

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Determination of Nearshore Wave Conditions and Bathymetry from X-Band Radar Systems

10.21236/ada613880 ◽

2004 ◽

Author(s):

Okey G. Nwogu ◽

Paul S. Bell

Keyword(s):

Radar Systems ◽

X Band ◽

Wave Conditions

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Organic matter and water from asteroid Itokawa

Scientific Reports ◽

10.1038/s41598-021-84517-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Q. H. S. Chan ◽

A. Stephant ◽

I. A. Franchi ◽

X. Zhao ◽

R. Brunetto ◽

...

Keyword(s):

Organic Matter ◽

Solar System ◽

Parent Body ◽

Asteroid Belt ◽

True Nature ◽

Water Ice ◽

Nanocrystalline Graphite ◽

Terrestrial Water ◽

Solar System Bodies ◽

Small Dust

AbstractUnderstanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. In this study, we have studied both the water and organic contents from a dust particle recovered from the surface of near-Earth asteroid 25143 Itokawa by the Hayabusa mission, which was the first mission that brought pristine asteroidal materials to Earth’s astromaterial collection. The organic matter is presented as both nanocrystalline graphite and disordered polyaromatic carbon with high D/H and 15N/14N ratios (δD = + 4868 ± 2288‰; δ15N = + 344 ± 20‰) signifying an explicit extra-terrestrial origin. The contrasting organic feature (graphitic and disordered) substantiates the rubble-pile asteroid model of Itokawa, and offers support for material mixing in the asteroid belt that occurred in scales from small dust infall to catastrophic impacts of large asteroidal parent bodies. Our analysis of Itokawa water indicates that the asteroid has incorporated D-poor water ice at the abundance on par with inner solar system bodies. The asteroid was metamorphosed and dehydrated on the formerly large asteroid, and was subsequently evolved via late-stage hydration, modified by D-enriched exogenous organics and water derived from a carbonaceous parent body.

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