scholarly journals Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers

2021 ◽  
Vol 15 (6) ◽  
pp. 2569-2574
Author(s):  
Joseph A. MacGregor ◽  
Michael Studinger ◽  
Emily Arnold ◽  
Carlton J. Leuschen ◽  
Fernando Rodríguez-Morales ◽  
...  
Keyword(s):  
Survey Design ◽  
Empirical Relation ◽  
Surface Scattering ◽  
Center Frequency ◽  
Airborne Radar ◽  
Volume Scattering ◽  
High Attenuation ◽  
Maximum Thickness ◽  
Radar Sounder ◽  
Thickness Measurements

Abstract. Radar sounding of the thickness of temperate glaciers is challenged by substantial volume scattering, surface scattering and high attenuation rates. Lower-frequency radar sounders are often deployed to mitigate these effects, but the lack of a global synthesis of their success limits progress in system and survey design. Here we extend a recent global compilation of glacier thickness measurements (GlaThiDa) with the center frequency for radar-sounding surveys. From a maximum reported thickness of ∼ 1500 m near 1 MHz, the maximum thickness sounded decreases by ∼ 500 m per frequency decade. Between 25–100 MHz, newer airborne radar sounders generally outperform older, ground-based ones. Based on globally modeled glacier thicknesses, we conclude that a multi-element, ≤30 MHz airborne radar sounder could survey most temperate glaciers more efficiently.

scholarly journals Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers

2021 ◽  
Author(s):  
Joseph A. MacGregor ◽  
Michael Studinger ◽  
Emily Arnold ◽  
Carlton J. Leuschen ◽  
Fernando Rodríguez-Morales
Keyword(s):  
Survey Design ◽  
Empirical Relation ◽  
Surface Scattering ◽  
Center Frequency ◽  
Airborne Radar ◽  
Polar Ice ◽  
Maximum Thickness ◽  
Attenuation Rate ◽  
Polar Ice Sheets ◽  
Radar Sounder

Abstract. Radar sounding of the thickness of temperate glaciers is more challenging than for polar ice sheets, due to the former's greater volume scattering (englacial water), surface scattering (crevasses and debris) and dielectric attenuation rate (warmer ice). Lower frequency (~1–100 MHz) radar sounders are commonly deployed to mitigate these effects, but the lack of a synthesis of existing radar-sounding surveys of temperate glaciers limits progress in system and survey design. Here we use a recent global synthesis of measured glacier thickness to evaluate the relation between the radar center frequency and maximum thickness. From a maximum reported thickness of ~1500 m near 1 MHz, the maximum thickness sounded decreases with increasing frequency by ~500 m per frequency decade. Newer airborne radar sounders generally outperform older, ground-based ones at comparable frequencies, so radar-sounder success is also influenced by system design and processing methods. Based on globally modeled glacier thicknesses, we conclude that a multi-element airborne radar sounder with a center frequency of ≤ 30 MHz could survey most temperate glaciers more efficiently than presently available systems.

scholarly journals Low-frequency radar sounding of ice in East Antarctica and southern Greenland

2014 ◽  
Vol 55 (67) ◽  
pp. 138-146 ◽  
Author(s):  
J. Mouginot ◽  
E. Rignot ◽  
Y. Gim ◽  
D. Kirchner ◽  
E. Le Meur
Keyword(s):  
Low Frequency ◽  
Radar Data ◽  
East Antarctica ◽  
Radar Signal ◽  
Airborne Radar ◽  
Ice Thickness ◽  
Decameter Wavelength ◽  
Radar Sounder ◽  
Thickness Measurements ◽  
Southwest Greenland

AbstractWe discuss a decameter-wavelength airborne radar sounder, the Warm Ice Sounding Explorer (WISE), that provides ice thickness in areas where radar signal penetration at higher frequencies is expected to be limited. Here we report results for three campaigns conducted in Greenland (2008, 2009, 2010) and two in Antarctica (2009, 2010). Comparisons with higher-frequency radar data indicate an accuracy of ±55 m for ice-thickness measurements in Greenland and ±25 m in Antarctica. We also estimate ice thickness of the Qassimiut lobe in southwest Greenland, where few ice-thickness measurements have been made, demonstrating that WISE penetrates in strongly scattering environments.

scholarly journals Pemantauan Fase Pertumbuhan Tanaman Padi Menggunakan Citra Radarsat-2 Quad Polarimetrik

2021 ◽  
Vol 5 (1) ◽  
pp. 1-14
Author(s):  
Rian Nurtyawan ◽  
Gerryn Maulannisaa
Keyword(s):  
Rice Plant ◽  
Alpha Angle ◽  
Surface Scattering ◽  
Growth Phases ◽  
Phase Zone ◽  
Volume Scattering ◽  
Initiation Phase ◽  
Remote Sensing Technology ◽  
Sensing Technology

ABSTRAKIndramayu merupakan salah satu lumbung padi Indonesia yang ada di wilayah Jawa Barat dimana Badan Pusat Statistik mencatat pada tahun 2014, Indramayu menghasilkan padi sebesar 1.361.374 ton. Untuk memantau produksi padi, sangat diperlukan pemantauan fase pertumbuhan tanaman padi, salah satu metodenya dengan teknologi penginderaan jauh sistem RADAR menggunakan citra RADARSAT-2 quad polarimetrik. Penelitian ini bertujuan untuk mengklasifikasi daerah fase pertumbuhan tanaman padi menggunakan metode Cloude Pottier H/A/α (entropi/anisotropi/sudut alfa) dan mengevaluasi metode tersebut dalam klasifikasi fase pertumbuhan tanaman padi. Hasil dari penelitian ini yaitu peta klasifikasi fase pertumbuhan tanaman padi dimana dari keseluruhan akuisisi citra, luas lahan tertinggi adalah fase germination/laut yang berjumlah 2.368.242 m2 (22 September 2014). Hasil klasifikasi ini disesuaikan dengan bidang H-α classification plane untuk mengetahui pada zona mana yang memiliki hamburan paling dominan. Hasil pada 18 Juni 2014 dan 5 Agustus 2014 menunjukkan zona 7 (fase panicle initiation/inisiasi malai), zona 8 (fase milk stage/gabah matang susu), dan zona 9 (fase germination/perkecambahan benih atau fase seeding/pertunasan) menjadi zona yang dominan dimana ketiga mekanisme memiliki arti double-bounce scattering (Z7), volume scattering (Z8), dan surface scattering (Z9) sedangkan pada 22 September 2014 dan 16 Oktober 2014 hamburan yang paling dominan terdapat pada Z8 (fase milk stage/gabah matang susu) dengan mekanisme volume scattering dan Z9 (fase germination/perkecambahan benih atau fase seeding/pertunasan) dengan mekanisme surface scattering.Kata kunci: Pertumbuhan Padi, Klasifikasi, RADARSAT-2, H/A/α ABSTRACTIndramayu is one of Indonesia's granary in West Java where Statistic Data Center noted that in 2014 Indramayu produced 1.361.374 tons of rice. It’s necessary to monitor growth phase of rice plant for monitoring rice production, one of the method is remote sensing technology is the RADAR system with RADARSAT-2 image quad-polarimetric. This study aims to classify the phase of growth of rice plants using the Cloude Pottier H / A / α method (entropy / anisotropy / alpha angle) and evaluate these methods in classification of rice plant growth phases. The results of this study are the classification map of the rice plant phase where from the overall image acquisition, the highest land area is the germination / sea phase, which amounts to 2,368,242 m2 (22 September 2014). The classification results are adjusted with the H-α classification plane to find out which zone has the most dominant scattering. The result on 18 June 2014 and 5 August 2014 showed zone 7 (panicle initiation phase), zone 8 (milk stage phase), and zone 9 (germination/seeding) to be the dominant zone where the three mechanisms mean double-bounce scattering (Z7), volume scattering (Z8), and surface scattering (Z9) while on 22 September 2014 and 16 October 2014 the most dominant scattering is in Z8 (milk stage phase) with volume scattering mechanism and Z9 (germination/seeding phase) with surface scattering mechanismKeywords: Rice Growth , Classification, RADARSAT-2, H/A/α.

scholarly journals Measuring geophysical parameters of the Greenland ice sheet using airborne radar altimetry

1995 ◽  
Vol 41 (139) ◽  
pp. 607-618 ◽  
Author(s):  
Ellen J. Ferraro ◽  
Calvin T. Swift
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Surface Scattering ◽  
Altimeter Data ◽  
Radar Altimeter ◽  
Volume Scattering ◽  
Scattering Model ◽  
Time Period ◽  
Field Season ◽  
Satellite Radar

AbstractThis paper presents radar-altimeter scattering models for each of the diagenetic zones of the Greenland ice sheet. AAFE radar-altimeter waveforms obtained during the 1991 and 1993 NASA multi-sensor airborne altimetry experiments over Greenland reveal that the Ku-band return pulse changes significantly with the different diagenetic zones. These changes are due to varying amounts of surface and volume scattering in the return waveform.In the ablation and soaked zones, where surface scattering dominates the AAFE return, geophysical parameters such as rms surface height and rms surface slope are obtained by fitting the waveforms to a surface-scattering model. Waveforms from the percolation zone show that sub-sruface ice features have a much more significant effect on the return pulse than the surrounding snowpack. Model percolation waveforms, created using a combined surface- and volume-scattering model and an ice-feature distribution obtained during the 1993 field season, agree well with actual AAFE waveforms taken in the same time period. Using a combined surface- and volume-scattering model for the dry-snow-zone return waveforms, the rms surface height and slope and the attenuation coefficient of the snowpack are obtained. These scattering models not only allow geophysical parameters of the ice sheet to he measured but also help in the understanding of satellite radar-altimeter data.

Supplementary material to "Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers"

2021 ◽  
Author(s):  
Joseph A. MacGregor ◽  
Michael Studinger ◽  
Emily Arnold ◽  
Carlton J. Leuschen ◽  
Fernando Rodríguez-Morales
Keyword(s):  
Empirical Relation ◽  
Center Frequency ◽  
Supplementary Material

scholarly journals Layer optimized SAR processing and slope estimation in radar sounder data

2019 ◽  
Vol 65 (254) ◽  
pp. 983-988 ◽  
Author(s):  
Davide Castelletti ◽  
Dustin M. Schroeder ◽  
Elisa Mantelli ◽  
Andrew Hilger
Keyword(s):  
Signal To Noise Ratio ◽  
Reconstruction Algorithm ◽  
Airborne Radar ◽  
West Antarctica ◽  
Phase Interference ◽  
Slope Estimation ◽  
Using Data ◽  
Radar Sounder ◽  
Along Track ◽  
Sar Processing

AbstractEnglacial layers in Antarctica and Greenland are indicators of the dynamic, rheological and subglacial configuration of the ice sheets. Airborne radar sounder data is the primary remote sensing solution for directly observing englacial layers and structures at the glacier-catchment to ice-sheet scale. However, when traditional along-track synthetic aperture radar (SAR) processing is applied, steep layers can disappear, limiting the detectability and interpretability of englacial layer geometry. This study provides a reconstruction algorithm to address the problem of destructive phase interference during the radargram formation. We develop and apply a novel SAR processor optimized for layer detection that enhances the Signal-to-Noise ratio (SNR) of specular reflectors. The algorithm also enables the automatic estimation of layer slope. We demonstrate the algorithm using data acquired at the Institute Ice Stream, West Antarctica.

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