scholarly journals Geodetic reanalysis of annual glaciological mass balances (2001–2011) of Hintereisferner, Austria

2018 ◽  
Vol 12 (3) ◽  
pp. 833-849 ◽  
Author(s):  
Christoph Klug ◽  
Erik Bollmann ◽  
Stephan Peter Galos ◽  
Lindsey Nicholson ◽  
Rainer Prinz ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Balance ◽  
Laser Scanning ◽  
Meteorological Conditions ◽  
Mass Balances ◽  
Statistical Comparison ◽  
Airborne Laser ◽  
Significant Difference ◽  
Cumulative Mass ◽  
Grid Based

Abstract. This study presents a reanalysis of the glaciologically obtained annual glacier mass balances at Hintereisferner, Ötztal Alps, Austria, for the period 2001–2011. The reanalysis is accomplished through a comparison with geodetically derived mass changes, using annual high-resolution airborne laser scanning (ALS). The grid-based adjustments for the method-inherent differences are discussed along with associated uncertainties and discrepancies of the two methods of mass balance measurements. A statistical comparison of the two datasets shows no significant difference for seven annual, as well as the cumulative, mass changes over the 10-year record. Yet, the statistical view hides significant differences in the mass balance years 2002/03 (glaciological minus geodetic records  = +0.92 m w.e.), 2005/06 (+0.60 m w.e.), and 2006/07 (−0.45 m w.e.). We conclude that exceptional meteorological conditions can render the usual glaciological observational network inadequate. Furthermore, we consider that ALS data reliably reproduce the annual mass balance and can be seen as validation or calibration tools for the glaciological method.

scholarly journals A reanalysis of one decade of the mass balance series on Hintereisferner, Ötztal Alps, Austria: a detailed view into annual geodetic and glaciological observations

2017 ◽  
Author(s):  
Christoph Klug ◽  
Erik Bollmann ◽  
Stephan P. Galos ◽  
Lindsey Nicholson ◽  
Rainer Prinz ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Balance ◽  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
Mass Balances ◽  
Statistical Comparison ◽  
Airborne Laser ◽  
Significant Difference ◽  
Cumulative Mass ◽  
Grid Based

Abstract. This study presents a reanalysis of the glaciologically obtained 2001–11 annual glacier mass balances record at Hintereisferner, Ötztal Alps, Austria. The reanalysis is accomplished through a comparison with geodetically derived mass changes, using annual high-resolution airborne laser scanning (ALS). The grid based adjustments for the method-inherent differences are discussed along with associated uncertainties and discrepancies of the two forms of mass balance measurements. A statistical comparison of the two datasets shows no significant difference for seven annual as well as the cumulative mass changes over the ten years record. Yet, the statistical view hides significant differences in the mass balance years 2002/03 (glaciological minus geodetic records = +0.92 m w.e.), 2005/06 (+0.60 m w.e.) and 2006/07 (−0.45 m w.e.). The validity of the results is critically assessed and concludes that exceptional atmospheric circumstances can render the usual glaciological observational network inadequate. Furthermore, we consider that ALS data reliably reproduce the annual mass balance and can be seen as calibration tools of or, under certain circumstances, even as a substitute for the glaciological method.

scholarly journals Comparison and Evaluation of Different Pit-Filling Methods for Generating High Resolution Canopy Height Model Using UAV Laser Scanning Data

2021 ◽  
Vol 13 (12) ◽  
pp. 2239
Author(s):  
Ying Quan ◽  
Mingze Li ◽  
Yuanshuo Hao ◽  
Bin Wang
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Evaluation Framework ◽  
Canopy Height ◽  
Filter Method ◽  
Individual Tree ◽  
Significant Difference ◽  
Point Interpolation ◽  
Canopy Height Model ◽  
Height Model

As a common form of light detection and ranging (LiDAR) in forestry applications, the canopy height model (CHM) provides the elevation distribution of aboveground vegetation. A CHM is traditionally generated by interpolating all the first LiDAR echoes. However, the first echo cannot accurately represent the canopy surface, and the resulting large amount of noise (data pits) also reduce the CHM quality. Although previous studies concentrate on many pit-filling methods, the applicability of these methods in high-resolution unmanned aerial vehicle laser scanning (UAVLS)-derived CHMs has not been revealed. This study selected eight widely used, recently developed, representative pit-filling methods, namely first-echo interpolation, smooth filtering (mean, medium and Gaussian), highest point interpolation, pit-free algorithm, spike-free algorithm and graph-based progressive morphological filtering (GPMF). A comprehensive evaluation framework was implemented, including a quantitative evaluation using simulation data and an additional application evaluation using UAVLS data. The results indicated that the spike-free algorithm and GPMF had excellent visual performances and were closest to the real canopy surface (root mean square error (RMSE) of simulated data were 0.1578 m and 0.1093 m, respectively; RMSE of UAVLS data were 0.3179 m and 0.4379 m, respectively). Compared with the first-echo method, the accuracies of the spike-free algorithm and GPMF improved by approximately 23% and 22%, respectively. The pit-free algorithm and highest point interpolation method also have advantages in high-resolution CHM generation. The global smooth filter method based on the first-echo CHM reduced the average canopy height by approximately 7.73%. Coniferous forests require more pit-filling than broad-leaved forests and mixed forests. Although the results of individual tree applications indicated that there was no significant difference between these methods except the median filter method, pit-filling is still of great significance for generating high-resolution CHMs. This study provides guidance for using high-resolution UAVLS in forestry applications.

scholarly journals On the potential of very high-resolution repeat DEMs in glacial and periglacial environments

2010 ◽  
Vol 4 (1) ◽  
pp. 53-65 ◽  
Author(s):  
J. Abermann ◽  
A. Fischer ◽  
A. Lambrecht ◽  
T. Geist
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Airborne Lidar ◽  
Primary Data ◽  
Glacier Area ◽  
Airborne Laser ◽  
Multi Temporal ◽  
Rock Glaciers ◽  
Data Source ◽  
Very High

Abstract. The potential of high-resolution repeat DEMs was investigated for glaciological applications including periglacial features (e.g. rock glaciers). It was shown that glacier boundaries can be delineated using airborne LIDAR-DEMs as a primary data source and that information on debris cover extent could be extracted using multi-temporal DEMs. Problems and limitations are discussed, and accuracies quantified. Absolute deviations of airborne laser scanning (ALS) derived glacier boundaries from ground-truthed ones were below 4 m for 80% of the ground-truthed values. Overall, we estimated an accuracy of +/−1.5% of the glacier area for glaciers larger than 1 km2. The errors in the case of smaller glaciers did not exceed +/−5% of the glacier area. The use of repeat DEMs in order to obtain information on the extent, characteristics and activity of rock glaciers was investigated and discussed based on examples.

scholarly journals Investigations on intra-annual elevation changes using multi-temporal airborne laser scanning data: case study Engabreen, Norway

2005 ◽  
Vol 42 ◽  
pp. 195-201 ◽  
Author(s):  
Thomas Geist ◽  
Hallgeir Elvehøy ◽  
Miriam Jackson ◽  
Johann Stötter
Keyword(s):  
Mass Balance ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Remote Sensing Data ◽  
Control Area ◽  
Airborne Laser Scanning ◽  
Time Interval ◽  
Scanner Data ◽  
Glacier Surface ◽  
Airborne Laser

AbstractKey issues of glacier monitoring are changes in glacier geometry and glacier mass. As accurate direct measurements are costly and time-consuming, the use of various remote-sensing data for glacier monitoring is explored. One technology used and described here is airborne laser scanning. The method enables the derivation of high-quality digital elevation models (DEMs) with a vertical and horizontal accuracy in the sub-metre range. Between September 2001 and August 2002, three laser scanner data acquisition flights were carried out, covering the whole area of Engabreen, Norway, and corresponding well to the measurement dates for the mass-balance year 2001/02. The data quality of the DEMs is assessed (e.g. by comparing the values with a control area which has been surveyed independently or GPS ground profiles measured during the flights). For the whole glacier, surface elevation change and consequently volume change is calculated, quantified and compared with traditional mass-balance data for the same time interval. For the winter term, emergence/submergence velocity is determined from laser scanner data and snow-depth data and is compared with velocity measurements at stakes. The investigations reveal the high potential of airborne laser scanning for measuring the extent and the topography of glaciers as well as changes in geometry (Δarea, Δvolume).

scholarly journals Minor Imbalance of the Lowermost Italian Glacier from 2006 to 2019

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2503
Author(s):  
Jessica De Marco ◽  
Luca Carturan ◽  
Livia Piermattei ◽  
Sara Cucchiaro ◽  
Daniele Moro ◽  
...  
Keyword(s):  
Mass Balance ◽  
Laser Scanning ◽  
Climate Changes ◽  
Average Rate ◽  
European Alps ◽  
Surface Dynamics ◽  
Solid Precipitation ◽  
Airborne Laser ◽  
Geodetic Mass Balance ◽  
Annual Balance

The response of very small glaciers to climate changes is highly scattered and little known in comparison with larger ice bodies. In particular, small avalanche-fed and debris-covered glaciers lack mass balance series of sufficient length. In this paper we present 13 years of high-resolution observations over the Occidentale del Montasio Glacier, collected using Airborne Laser Scanning, Terrestrial Laser Scanning, and Structure from Motion Multi-View Stereo techniques for monitoring its geodetic mass balance and surface dynamics. The results have been analyzed jointly with meteorological variables, and compared to a sample of “reference” glaciers for the European Alps. From 2006 to 2019 the mass balance showed high interannual variability and an average rate much closer to zero than the average of the Alpine reference glaciers (−0.09 vs. −1.42 m water equivalent per year, respectively). This behavior can be explained by the high correlation between annual balance and solid precipitation, which displayed recent peaks. The air temperature is not significantly correlated with the mass balance, which is main controlled by avalanche activity, shadowing and debris cover. However, its rapid increase is progressively reducing the fraction of solid precipitation, and increasing the length of the ablation season.

scholarly journals Airborne laser scanning for high-resolution mapping of Antarctica

Eos ◽  
2005 ◽  
Vol 86 (25) ◽  
pp. 237 ◽  
Author(s):  
Bea Csatho ◽  
Toni Schenk ◽  
William Krabill ◽  
Terry Wilson ◽  
William Lyons ◽  
...  
Keyword(s):  
High Resolution ◽  
Laser Scanning ◽  
Airborne Laser Scanning ◽  
High Resolution Mapping ◽  
Airborne Laser ◽  
Resolution Mapping
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