scholarly journals Sediment-mass exchange between turbid meltwater streams and proglacial deposits of storglaciären, northern Sweden

1996 ◽  
Vol 22 ◽  
pp. 63-67 ◽  
Author(s):  
Per Holmlund ◽  
Helene Burman ◽  
Torbjörn Rost
Keyword(s):  
High Resolution ◽  
Marginal Zone ◽  
Morphological Changes ◽  
Aerial Photographs ◽  
Similar Amount ◽  
Northern Sweden ◽  
Cold Surface ◽  
Braided Streams ◽  
The Difference ◽  
Silt Load

Detailed changes in surface elevation of a recently deglaciated area have been mapped using a high-resolution photogrammetric method, with a view to estimating the contribution of debris from the proglacial area to the meltwater streams draining Storglaciären, northern Sweden, over the period 1980-90. The net contribution of sediments originating from the deglaciated area immediately in front of the glacier was of the order of 50% of the suspended silt load transported by meltwater at the flume Rännan downstream from the glacier, but at the same time, a similar amount of sediment accumulated along the streams. Though there is a significant exchange of mass, the net change is close to zero. Moreover, the survey provides detailed information about morphological changes in the landscape. Different processes, such as melting of permafrost, fluvial erosion and sedimentation, have been active.Erosion and sedimentation rates were calculated from the difference between digital terrain models based on aerial photographs taken in 1980 and 1990. The result shows erosion in the central part of the proglacial area and accumulation of coarser sediments along the braided streams. In places, the ground is sinking, possibly due to melting of permafrost.Where the ice is thinner, in the marginal zone, the thermal regime of ice in the tongue of Storglaciären corresponds well with the proglacial geomorphology. At present, the glacier has a 30-40 m thick cold surface layer which at the thinner marginal zone corresponds to a 100-200 m wide frozen rim. The temperature distribution within the ice was mapped using high-resolution radar.

scholarly journals Sediment-mass exchange between turbid meltwater streams and proglacial deposits of storglaciären, northern Sweden

1996 ◽  
Vol 22 ◽  
pp. 63-67 ◽  
Author(s):  
Per Holmlund ◽  
Helene Burman ◽  
Torbjörn Rost
Keyword(s):  
High Resolution ◽  
Marginal Zone ◽  
Morphological Changes ◽  
Aerial Photographs ◽  
Similar Amount ◽  
Northern Sweden ◽  
Cold Surface ◽  
Braided Streams ◽  
The Difference ◽  
Silt Load

Detailed changes in surface elevation of a recently deglaciated area have been mapped using a high-resolution photogrammetric method, with a view to estimating the contribution of debris from the proglacial area to the meltwater streams draining Storglaciären, northern Sweden, over the period 1980-90. The net contribution of sediments originating from the deglaciated area immediately in front of the glacier was of the order of 50% of the suspended silt load transported by meltwater at the flume Rännan downstream from the glacier, but at the same time, a similar amount of sediment accumulated along the streams. Though there is a significant exchange of mass, the net change is close to zero. Moreover, the survey provides detailed information about morphological changes in the landscape. Different processes, such as melting of permafrost, fluvial erosion and sedimentation, have been active.Erosion and sedimentation rates were calculated from the difference between digital terrain models based on aerial photographs taken in 1980 and 1990. The result shows erosion in the central part of the proglacial area and accumulation of coarser sediments along the braided streams. In places, the ground is sinking, possibly due to melting of permafrost.Where the ice is thinner, in the marginal zone, the thermal regime of ice in the tongue of Storglaciären corresponds well with the proglacial geomorphology. At present, the glacier has a 30-40 m thick cold surface layer which at the thinner marginal zone corresponds to a 100-200 m wide frozen rim. The temperature distribution within the ice was mapped using high-resolution radar.

Origin of the alternate bright/dark contrast in HREM images of hexagonal crystals, particularly 6H-SiC

1993 ◽  
Vol 51 ◽  
pp. 914-915
Author(s):  
J.S. Bow ◽  
R.W. Carpenter ◽  
M.J. Kim
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Hexagonal Crystal ◽  
Detailed Explanation ◽  
Similar Character ◽  
High Resolution Images ◽  
The Difference ◽  
Zigzag Shape ◽  
Hexagonal Crystals ◽  
Dark Contrast

A prominent characteristic of high-resolution images of 6H-SiC viewed from [110] is a zigzag shape with a period of 6 layers as shown in Fig.1. Sometimes the contrast is same through the 6 layers of (0006) planes (Fig.1a), but in most cases it appears as in Fig.1b -- alternate bright/dark contrast among every three (0006) planes. Alternate bright/dark contrast is most common for the thicker specimens. The SAD patterns of these two types of image are almost same, and there is no indication that the difference results from compositional ordering. O’Keefe et al. concluded this type of alternate contrast was due to crystal tilt in thick parts of the specimen. However, no detailed explanation was given. Images of similar character from Ti3Al, which is also a hexagonal crystal, were reported by Howe et al. Howe attributed the bright/dark contrast among alternate (0002) Ti3Al planes to phase shifts produced by incident beam tilt.

Estimations for Percentage of Impervious Area by the Use of Satellite Remote Sensing Imagery

1994 ◽  
Vol 29 (1-2) ◽  
pp. 135-144 ◽  
Author(s):  
C. Deguchi ◽  
S. Sugio
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Satellite Imagery ◽  
Satellite Remote Sensing ◽  
Aerial Photographs ◽  
Estimation Errors ◽  
Remote Sensing Imagery ◽  
Impervious Area ◽  
Urbanized Areas

This study aims to evaluate the applicability of satellite imagery in estimating the percentage of impervious area in urbanized areas. Two methods of estimation are proposed and applied to a small urbanized watershed in Japan. The area is considered under two different cases of subdivision; i.e., 14 zones and 17 zones. The satellite imageries of LANDSAT-MSS (Multi-Spectral Scanner) in 1984, MOS-MESSR(Multi-spectral Electronic Self-Scanning Radiometer) in 1988 and SPOT-HRV(High Resolution Visible) in 1988 are classified. The percentage of imperviousness in 17 zones is estimated by using these classification results. These values are compared with the ones obtained from the aerial photographs. The percent imperviousness derived from the imagery agrees well with those derived from aerial photographs. The estimation errors evaluated are less than 10%, the same as those obtained from aerial photographs.

Array design

1968 ◽  
Vol 58 (3) ◽  
pp. 977-991
Author(s):  
Richard A. Haubrich
Keyword(s):  
High Resolution ◽  
Data Processing ◽  
Least Square ◽  
Wave Number ◽  
Array Design ◽  
Least Square Fit ◽  
The Difference ◽  
Set Of Points ◽  
Array Output

abstract Arrays of detectors placed at discrete points are often used in problems requiring high resolution in wave number for a limited number of detectors. The resolution performance of an array depends on the positions of detectors as well as the data processing of the array output. The performance can be expressed in terms of the “spectrum window”. Spectrum windows may be designed by a general least-square fit procedure. An alternate approach is to design the array to obtain the largest uniformly spaced coarray, the set of points which includes all the difference spacings of the array. Some designs obtained from the two methods are given and compared.

Volcanoes geological mapping and structural geology with UAS High Resolution Digital Terrain Model : the Kuei-Shan Tao case example (Eastern Taiwan).

2021 ◽  
Author(s):  
Benoit Deffontaines ◽  
Kuo-Jen Chang ◽  
Samuel Magalhaes ◽  
Gérardo Fortunato
Keyword(s):  
High Resolution ◽  
Okinawa Trough ◽  
Volcanic Rocks ◽  
Digital Terrain Model ◽  
Structural Features ◽  
Point Of View ◽  
Geological Mapping ◽  
Lava Flows ◽  
Aerial Photographs ◽  
Structural Scheme

<p>Volcanic areas in the World are often difficult to map especially in a structural point of view as (1) fault planes are generally covered and filled by more recent lava flows and (2) volcanic rocks have very few tectonic striations. Kuei-Shan Tao (11km from Ilan Plain – NE Taiwan) is a volcanic island, located at the soutwestern tip of the South Okinawa trough (SWOT). Two incompatible geological maps had been already published both lacking faults and structural features (Hsu, 1963 and Chiu et al., 2010). We propose herein not only to up-date the Kuei-Shan Tao geological map with our high resolution dataset, but also to create the Kuei-Shan Tao structural scheme in order to better understand its geological and tectonic history.</p><p>Consequently, we first acquired aerial photographs from our UAS survey and get our new UAS high resolution DTM (HR UAS-DTM hereafter) with a ground resolution <10cm processed through classical photogrammetric methods. Taking into account common sense geomorphic and structural interpretation and reasoning deduced form our HR UAS-DTM, and the outcropping lithologies situated all along the shoreline, we have up-dated the Kuei-Shan Tao geological mapping and its major structures. To conclude, the lithologies (andesitic lava flows and pyroclastic falls) and the new structural scheme lead us to propose a scenario for both the construction as well as the dismantling of Kuei-Shan Tao which are keys for both geology and geodynamics of the SWOT.</p>

scholarly journals Improvement in Surface Solar Irradiance Estimation Using HRV/MSG Data

2018 ◽  
Vol 10 (8) ◽  
pp. 1288 ◽  
Author(s):  
Filomena Romano ◽  
Domenico Cimini ◽  
Angela Cersosimo ◽  
Francesco Di Paola ◽  
Donatello Gallucci ◽  
...  
Keyword(s):  
High Resolution ◽  
Solar Irradiance ◽  
Research Council ◽  
National Research Council ◽  
The Other ◽  
Data Channel ◽  
The Difference ◽  
Photovoltaic Plants ◽  
Sky Conditions ◽  
Advanced Model

The Advanced Model for the Estimation of Surface Solar Irradiance (AMESIS) was developed at the Institute of Methodologies for Environmental Analysis of the National Research Council of Italy (IMAA-CNR) to derive surface solar irradiance from SEVIRI radiometer on board the MSG geostationary satellite. The operational version of AMESIS has been running continuously at IMAA-CNR over all of Italy since 2017 in support to the monitoring of photovoltaic plants. The AMESIS operative model provides two different estimations of the surface solar irradiance: one is obtained considering only the low-resolution channels (SSI_VIS), while the other also takes into account the high-resolution HRV channel (SSI_HRV). This paper shows the difference between these two products against simultaneous ground-based observations from a network of 63 pyranometers for different sky conditions (clear, overcast and partially cloudy). Comparable statistical scores have been obtained for both AMESIS products in clear and cloud situation. In terms of bias and correlation coefficient over partially cloudy sky, better performances are found for SSI_HRV (0.34 W/m2 and 0.995, respectively) than SSI_VIS (−33.69 W/m2 and 0.862) at the expense of the greater run-time necessary to process HRV data channel.

scholarly journals Reading the bed morphology of a mountain stream: a geomorphometric study on high-resolution topographic data

2010 ◽  
Vol 14 (2) ◽  
pp. 393-405 ◽  
Author(s):  
S. Trevisani ◽  
M. Cavalli ◽  
L. Marchi
Keyword(s):  
High Resolution ◽  
Ad Hoc ◽  
Flow Direction ◽  
Spatial Scales ◽  
Mountain Stream ◽  
Topographic Data ◽  
The Difference ◽  
Morphological Differences ◽  
High Level ◽  
Local Anomalies

Abstract. High-resolution topographic data expand the potential of quantitative analysis of the earth surface, improving the interpretation of geomorphic processes. In particular, the morphologies of the channel beds of mountain streams, which are characterised by strong spatial variability, can be analysed much more effectively with this type of data. In this study, we analysed the aerial LiDAR topographic data of a headwater stream, the Rio Cordon (watershed area: 5 km2), located in the Dolomites (north-eastern Italy). The morphology of the channel bed of Rio Cordon is characterised by alternating step pools, cascades, and rapids with steps. We analysed the streambed morphology by means of ad hoc developed morphometric indices, capable of highlighting morphological features at a high level of spatial resolution. To perform the analysis and the data interpolation, we carried out a channel-oriented coordinate transformation. In the new coordinate system, the calculation of morphometric indices in directions along and transverse to the flow direction is straightforward. Three geomorphometric indices were developed and applied as follows: a slope index computed on the whole width of the channel bed, directional variograms computed along the flow direction and perpendicular to it, and local anomalies, calculated as the difference between directional variograms at different spatial scales. Directional variograms in the flow direction and local anomalies have proven to be effective at recognising morphologic units, such as steps, pools and clusters of large boulders. At the spatial scale of channel reaches, these indices have demonstrated a satisfactory capability to outline patterns associated with boulder cascades and rapids with steps, whereas they did not clearly differentiate between morphologies with less marked morphological differences, such as step pools and cascades.

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