scholarly journals Geochemical characterization of supraglacial debris via in situ and optical remote sensing methods: a case study in Khumbu Himalaya, Nepal

2012 ◽  
Vol 6 (1) ◽  
pp. 85-100 ◽  
Author(s):  
K. A. Casey ◽  
A. Kääb ◽  
D. I. Benn
Keyword(s):  
Remote Sensing ◽  
Mass Flux ◽  
Surface Composition ◽  
Ground Truth ◽  
Thermal Infrared ◽  
Optical Remote Sensing ◽  
Glacier Surface ◽  
X Ray ◽  
Glacier Velocity ◽  
Remote Sensing Methods

Abstract. Surface glacier debris samples and field spectra were collected from the ablation zones of Nepal Himalaya Ngozumpa and Khumbu glaciers in November and December 2009. Geochemical and mineral compositions of supraglacial debris were determined by X-ray diffraction and X-ray fluorescence spectroscopy. This composition data was used as ground truth in evaluating field spectra and satellite supraglacial debris composition and mapping methods. Satellite remote sensing methods for characterizing glacial surface debris include visible to thermal infrared hyper- and multispectral reflectance and emission signature identification, semi-quantitative mineral abundance indicies and spectral image composites. Satellite derived supraglacial debris mineral maps displayed the predominance of layered silicates, hydroxyl-bearing and calcite minerals on Khumbu Himalayan glaciers. Supraglacial mineral maps compared with satellite thermal data revealed correlations between glacier surface composition and glacier surface temperature. Glacier velocity displacement fields and shortwave, thermal infrared false color composites indicated the magnitude of mass flux at glacier confluences. The supraglacial debris mapping methods presented in this study can be used on a broader scale to improve, supplement and potentially reduce errors associated with glacier debris radiative property, composition, areal extent and mass flux quantifications.

scholarly journals Characterization of glacier debris cover via in situ and optical remote sensing methods: a case study in the Khumbu Himalaya, Nepal

2011 ◽  
Vol 5 (1) ◽  
pp. 499-564 ◽  
Author(s):  
K. A. Casey ◽  
A. Kääb ◽  
D. I. Benn
Keyword(s):  
Remote Sensing ◽  
Mass Flux ◽  
Remote Sensing Data ◽  
Ground Truth ◽  
Radiative Properties ◽  
Optical Remote Sensing ◽  
Displacement Fields ◽  
Debris Cover ◽  
Glacier Velocity ◽  
Remote Sensing Methods

Abstract. Field spectrometry and physical samples of debris, snow and ice were collected from the ablation zones of Ngozumpa and Khumbu glaciers of the Khumbu Himalaya, Nepal in November and December 2009. Field acquired spectral reflectances and mineral and chemical composition of samples were used as ground truth for comparison with satellite optical remote sensing data. Supraglacial debris was characterized by several optical remote sensing methods, including hyperspectral reflectance analysis, multispectral band composites and indices, spectral angle relationships, thermal band temperature and emissivity analysis, as well as repeat image derived glacier velocity and theoretical supraglacial particle transport. Supraglacial mineral components were identified and mineral abundances were estimated on Khumbu Himalayan glaciers. Mass flux was estimated by false color composites and glacier velocity displacement fields. Supraglacial temperatures were compared with mineral abundances, implying potential parameters to estimate differential melt. Overall, glaciologic implications of debris cover characterizations are applicable to (1) glacier energy balance, (2) glacial kinematics and (3) mapping glacial extent. The methods presented can be used in synergy to improve supraglacial debris quantification and reduce errors associated with debris covered ice extent mapping, surface radiative properties, as well as debris covered ice mass flux and loss estimations.

scholarly journals Evaluation of Geospatial Tools for Generating Accurate Glacier Velocity Maps from Optical Remote Sensing Data

Proceedings ◽  
2018 ◽  
Vol 2 (7) ◽  
pp. 341 ◽  
Author(s):  
Shridhar D. Jawak ◽  
Shubhang Kumar ◽  
Alvarinho J. Luis ◽  
Mustansir Bartanwala ◽  
Shravan Tummala ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Remote Sensing Data ◽  
Optical Remote Sensing ◽  
Sensing Data ◽  
Geospatial Tools ◽  
Glacier Velocity

Remote sensing flow velocity of debris-covered glaciers using Landsat 8 data

2015 ◽  
Vol 40 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Lydia Sam ◽  
Anshuman Bhardwaj ◽  
Shaktiman Singh ◽  
Rajesh Kumar
Keyword(s):  
Remote Sensing ◽  
Flow Velocity ◽  
Accuracy Assessment ◽  
Geographical Area ◽  
Surface Flow ◽  
Velocity Estimation ◽  
Surface Velocity ◽  
Landsat 8 ◽  
Glacier Surface ◽  
Glacier Velocity

Changes in ice velocity of a glacier regulate its mass balance and dynamics. The estimation of glacier flow velocity is therefore an important aspect of temporal glacier monitoring. The utilisation of conventional ground-based techniques for detecting glacier surface flow velocity in the rugged and alpine Himalayan terrain is extremely difficult. Remote sensing-based techniques can provide such observations on a regular basis for a large geographical area. Obtaining freely available high quality remote sensing data for the Himalayan regions is challenging. In the present work, we adopted a differential band composite approach, for the first time, in order to estimate glacier surface velocity for non-debris and supraglacial debris covered areas of a glacier, separately. We employed various bandwidths of the Landsat 8 data for velocity estimation using the COSI-Corr (co-registration of optically sensed images and correlation) tool. We performed the accuracy assessment with respect to field measurements for two glaciers in the Indian Himalaya. The panchromatic band worked best for non-debris parts of the glaciers while band 6 (SWIR – short wave infrared) performed best in case of debris cover. We correlated six temporal Landsat 8 scenes in order to ensure the performance of the proposed algorithm on monthly as well as yearly timescales. We identified sources of error and generated a final velocity map along with the flow lines. Over- and underestimates of the yearly glacier velocity were found to be more in the case of slow moving areas with annual displacements less than 5 m. Landsat 8 has great capabilities for such velocity estimation work for a large geographic extent because of its global coverage, improved spectral and radiometric resolutions, free availability and considerable revisit time.

EFFICACITE DES IMAGES RADAR ET INFRAROUGE THERMIQUE, ET DE LA PHOTO COULEUR INFRAROUGE POUR L’INVENTAIRE DES CULTURES

1980 ◽  
Vol 60 (4) ◽  
pp. 1077-1085
Author(s):  
ROGER PAQUIN ◽  
GILLES LADOUCEUR
Keyword(s):  
Remote Sensing ◽  
Ground Truth ◽  
Thermal Infrared ◽  
Infrared Imagery ◽  
Ground Truth Data ◽  
Infrared Photography ◽  
Remote Sensing Technique ◽  
Field Crops ◽  
Radar Imagery ◽  
Thermal Infrared Imagery

Crops from 888 fields in a 300-km2 area between Rougemont and St-Hyacinthe were surveyed to compare the efficiency of radar (3–80 cm) and thermal infrared (8–14 μm) imagery with color infrared photography for crop identification. The color infrared photography and the thermal infrared imagery were taken by the Canadian Centre for Remote Sensing on 11 Aug. 1978, and the radar imagery by Intera on 19 Aug. The analysis of the thermal infrared imagery showed some correlations with the ground truth data, but the image could not be used in crop identification. Accordingly, observations from radar imagery could not serve in crop identification. However, similarities were observed between the radar and the thermal infrared imageries. The results showed once more that the color infrared photography as a remote sensing technique is the most useful to survey field crops.

scholarly journals EU-Net: An Efficient Fully Convolutional Network for Building Extraction from Optical Remote Sensing Images

2019 ◽  
Vol 11 (23) ◽  
pp. 2813 ◽  
Author(s):  
Wenchao Kang ◽  
Yuming Xiang ◽  
Feng Wang ◽  
Hongjian You
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Ground Truth ◽  
Aerial Image ◽  
Optical Remote Sensing ◽  
Building Extraction ◽  
Remote Sensing Images ◽  
Convolutional Network ◽  
Practical Applications ◽  
The Impact

Automatic building extraction from high-resolution remote sensing images has many practical applications, such as urban planning and supervision. However, fine details and various scales of building structures in high-resolution images bring new challenges to building extraction. An increasing number of neural network-based models have been proposed to handle these issues, while they are not efficient enough, and still suffer from the error ground truth labels. To this end, we propose an efficient end-to-end model, EU-Net, in this paper. We first design the dense spatial pyramid pooling (DSPP) to extract dense and multi-scale features simultaneously, which facilitate the extraction of buildings at all scales. Then, the focal loss is used in reverse to suppress the impact of the error labels in ground truth, making the training stage more stable. To assess the universality of the proposed model, we tested it on three public aerial remote sensing datasets: WHU aerial imagery dataset, Massachusetts buildings dataset, and Inria aerial image labeling dataset. Experimental results show that the proposed EU-Net is superior to the state-of-the-art models of all three datasets and increases the prediction efficiency by two to four times.

scholarly journals The Lavic Lake Fault: A Long-Term Cumulative Slip Analysis via Combined Field Work and Thermal Infrared Hyperspectral Airborne Remote Sensing

2020 ◽  
Vol 12 (21) ◽  
pp. 3586
Author(s):  
Rebecca A. Witkosky ◽  
Joann M. Stock ◽  
David M. Tratt ◽  
Kerry N. Buckland ◽  
Paul M. Adams ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Auxiliary Information ◽  
Slip Rate ◽  
Ground Truth ◽  
Thermal Infrared ◽  
Field Work ◽  
Tectonic Activity ◽  
Geologic Mapping ◽  
Eastern California Shear Zone

The 1999 Hector Mine earthquake ruptured to the surface in eastern California, with >5 m peak right-lateral slip on the Lavic Lake fault. The cumulative offset and geologic slip rate of this fault are not well defined, which inhibits tectonic reconstructions and risk assessment of the Eastern California Shear Zone (ECSZ). With thermal infrared hyperspectral airborne imagery, field data, and auxiliary information from legacy geologic maps, we created lithologic maps of the area using supervised and unsupervised classifications of the remote sensing imagery. We optimized a data processing sequence for supervised classifications, resulting in lithologic maps over a test area with an overall accuracy of 71 ± 1% with respect to ground-truth geologic mapping. Using all of the data and maps, we identified offset bedrock features that yield piercing points along the main Lavic Lake fault and indicate a 1036 +27/−26 m net slip, with 1008 +14/−17 m horizontal and 241 +51/−47 m vertical components. For the contribution from distributed shear, modern off-fault deformation values from another study imply a larger horizontal slip component of 1276 +18/−22 m. Within the constraints, we estimate a geologic slip rate of <4 mm/yr, which does not increase the sum geologic Mojave ECSZ rate to current geodetic values. Our result supports previous suggestions that transient tectonic activity in this area may be responsible for the discrepancy between long-term geologic and present-day geodetic rates.

What you see and what you get: combining near-infrared spectroscopy with powder diffraction

2017 ◽  
Vol 32 (S2) ◽  
pp. S3-S8
Author(s):  
Helen E. Maynard-Casely ◽  
Norman Booth ◽  
Leo Anderberg ◽  
Helen E.A. Brand ◽  
Daniel V. Cotton
Keyword(s):  
Remote Sensing ◽  
Infrared Spectroscopy ◽  
Near Infrared ◽  
Surface Composition ◽  
Planetary Surfaces ◽  
X Ray Diffraction ◽  
X Ray ◽  
Near Ir ◽  
Infra Red ◽  
Terrestrial Environments

Knowledge of the surface composition of planetary bodies comes from a number of sources; such as landers, remote sensing and meteorites. However, the bulk mapping of the composition of planetary surfaces has been undertaken by analysis of reflected sunlight and these data—principally collected in the near-infra-red (IR) region—are notoriously broad and ambiguous. Hence, if laboratory spectra could be tied to physical properties measurements, such as diffraction, this would substantially aid our understanding of processes occurring in these extra-terrestrial environments. This contribution presents the capability of collecting near-IR data at the same time as neutron and synchrotron X-ray diffraction in a range of conditions (low temperature, vacuum, and humidity variations) and highlights two examples where this capability could enhance our understanding of planetary surfaces.

scholarly journals Spatio-temporal changes in glacier-wide mass balance quantified by optical remote sensing on 30 glaciers in the French Alps for the period 1983–2014

2016 ◽  
Vol 62 (236) ◽  
pp. 1153-1166 ◽  
Author(s):  
ANTOINE RABATEL ◽  
JEAN PIERRE DEDIEU ◽  
CHRISTIAN VINCENT
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Satellite Images ◽  
Optical Remote Sensing ◽  
European Alps ◽  
Mass Balances ◽  
Glacier Surface ◽  
Uncertainty Range ◽  
French Alps ◽  
Optical Satellite Images

AbstractRemote sensing is a powerful method to reconstruct annual mass-balance series over past decades by exploiting archives of available images, as well as to study glaciers in inaccessible regions. We present the application of a methodological framework based only on optical satellite images to retrieve glacier-wide annual mass balances for 30 glaciers in the French Alps. The glacier-wide annual mass balance for the period 1983–2014 was reconstructed by combining changes in glacier volumes computed from remote-sensing derived DEMs with annual measurements of the snow line altitude on satellite images. Data from direct observations on two of the glaciers confirmed the accuracy of the annual mass balances quantified by remote sensing with an average difference of ~0.3 m w.e., within the uncertainty range of the methods. Our results confirm the significant increase in mass loss since the early 2000s, with a difference >1 m w.e. a−1 between the periods 1983–2002 and 2003–14. The region-wide mass balance for the French Alps over the period 1979–2011 was −0.66 ± 0.27 m w.e. a−1, close to that of the European Alps. We also show that changes in glacier surface area or length are not representative of changes in mass balance at the scale of a few decades.

scholarly journals Impact of varying debris cover thickness on catchment scale ablation: a case study for Koxkar glacier in the Tien Shan

2013 ◽  
Vol 7 (6) ◽  
pp. 5307-5332 ◽  
Author(s):  
M. Juen ◽  
C. Mayer ◽  
A. Lambrecht ◽  
H. Haidong ◽  
L. Shiyin
Keyword(s):  
Remote Sensing ◽  
Field Measurements ◽  
Ground Truth ◽  
Tien Shan ◽  
Shielding Effect ◽  
Catchment Scale ◽  
Glacier Surface ◽  
Glacier Terminus ◽  
Covered Area ◽  
Debris Cover

Abstract. To quantify the ablation processes on a debris covered glacier, a simple distributed ablation model has been developed and applied to a selected glacier. For this purpose, a bundle of field measurements was carried out to collect empirical data. A morphometric analysis of the glacier surface enables us to statistically capture the areal distribution of topographic features that influence debris thickness and consequently ablation. Remote sensing techniques, using high resolution satellite imagery, were used to extrapolate the ground truth results to the whole ablation area and to map and classify melt-relevant surface types. As a result, a practically applicable method is presented, that allows the estimation of ablation on a debris covered glacier by combining field data and remote sensing information. The sub-debris ice ablation accounts for about 19% of the entire ice ablation, while the percentage of the moraine covered area accounts for approximately 32% of the entire glacerized area. Although the ice cliffs occupy only 1.7% of the debris covered area the melt amount accounts for approximately 15% of the total sub-debris ablation and 2.7% of the total ablation respectively. Our study highlights the influence of debris cover on the response of the glacier terminus to climate warming. Due to the fact that melt rates beyond 0.1m of moraine cover are highly restricted the shielding effect of the debris cover dominates over the temperature- and elevation dependence of the ablation in the bare ice case.

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