scholarly journals Drone Surveying of Volumetric Ice Growth in a Steep River

2021 ◽  
Vol 2 ◽  
Author(s):  
Einar Rødtang ◽  
Knut Alfredsen ◽  
Ana Juárez
Keyword(s):  
Structure From Motion ◽  
Complex Geometry ◽  
Low Cost ◽  
Single Point ◽  
Ice Cover ◽  
River Ice ◽  
Ice Thickness ◽  
Surface Geometry ◽  
Ice Volume ◽  
Anchor Ice

Representative ice thickness data is essential for accurate hydraulic modelling, assessing the potential for ice induced floods, understanding environmental conditions during winter and estimation of ice-run forces. Steep rivers exhibit complex freeze-up behaviour combining formation of columnar ice with successions of anchor ice dams to build a complete ice cover, resulting in an ice cover with complex geometry. For such ice covers traditional single point measurements are unrepresentative. Gathering sufficiently distributed measurements for representativeness is labour intensive and at times impossible with hard to access ice. Structure from Motion (SfM) software and low-cost drones have enabled river ice mapping without the need to directly access the ice, thereby reducing both the workload and the potential danger in accessing the ice. In this paper we show how drone-based photography can be used to efficiently survey river ice and how these photographic surveys can be processed into digital elevation models (DEMs) using Structure from Motion. We also show how DEMs of the riverbed, riverbanks and ice conditions can be used to deduce ice volume and ice thickness distributions. A QGIS plugin has been implemented to automate these tasks. These techniques are demonstrated with a survey of a stretch of the river Sokna in Trøndelag, Norway. The survey was carried out during the winter 2020–2021 at various stages of freeze-up using a simple quadcopter with camera. The 500 m stretch of river studied was estimated to have an ice volume of up to 8.6 × 103 m3 (This corresponds to an average ice thickness of ∼67 cm) during the full ice cover condition of which up to 7.2 × 103 m3 (This corresponds to an average ice thickness of ∼57 cm) could be anchor ice. Ground Control Points were measured with an RTK-GPS and used to determine that the accuracy of these ice surface geometry measurements lie between 0.03 and 0.09 m. The ice thicknesses estimated through the SfM methods are on average 18 cm thicker than the manual measurements. Primarily due to the SfM methods inability to detect suspended ice covers. This paper highlights the need to develop better ways of estimating the volume of air beneath suspended ice covers.

scholarly journals Brief Communication: Mapping river ice using drones and structure from motion

2018 ◽  
Vol 12 (2) ◽  
pp. 627-633 ◽  
Author(s):  
Knut Alfredsen ◽  
Christian Haas ◽  
Jeffrey A. Tuhtan ◽  
Peggy Zinke
Keyword(s):  
Structure From Motion ◽  
Low Cost ◽  
Cold Climate ◽  
River Ice ◽  
River Morphology ◽  
Ice Thickness ◽  
Surface Model ◽  
Engineering Data ◽  
Site Access ◽  
Remote Sensing Methods

Abstract. In cold climate regions, the formation and break-up of river ice is important for river morphology, winter water supply, and riparian and instream ecology as well as for hydraulic engineering. Data on river ice is therefore significant, both to understand river ice processes directly and to assess ice effects on other systems. Ice measurement is complicated due to difficult site access, the inherent complexity of ice formations, and the potential danger involved in carrying out on-ice measurements. Remote sensing methods are therefore highly useful, and data from satellite-based sensors and, increasingly, aerial and terrestrial imagery are currently applied. Access to low cost drone systems with quality cameras and structure from motion software opens up a new possibility for mapping complex ice formations. Through this method, a georeferenced surface model can be built and data on ice thickness, spatial distribution, and volume can be extracted without accessing the ice, and with considerably fewer measurement efforts compared to traditional surveying methods. A methodology applied to ice mapping is outlined here, and examples are shown of how to successfully derive quantitative data on ice processes.

scholarly journals Brief communication: Mapping river ice using drones and structure from motion

2017 ◽  
Author(s):  
Knut Alfredsen ◽  
Christian Haas ◽  
Jeffrey A. Tuhtan ◽  
Peggy Zinke
Keyword(s):  
Structure From Motion ◽  
Low Cost ◽  
Cold Climate ◽  
River Ice ◽  
River Morphology ◽  
Ice Thickness ◽  
Potential Danger ◽  
Engineering Data ◽  
Site Access ◽  
Remote Sensing Methods

Abstract. In cold climate regions, the formation and break-up of river ice is important for river morphology, winter water supply, riparian and instream ecology as well as for hydraulic engineering. Data on river ice is therefore significant, both to understand river ice processes directly and to assess ice effects on other systems. Ice measurement is complicated due to difficult site access, the inherent complexity of ice formations and the potential danger involved in carrying out on-ice measurements. Remote sensing methods are therefore highly useful, and satellite imagery, data from satellite-based radars as increasingly aerial and terrestrial imagery are currently applied. Access to low cost drone systems with quality cameras and Structure from Motion software opens up a new possibility for mapping complex ice formations. Through this method, a georeferenced DEM can be built and data on ice thickness, spatial distribution and volume can be extracted without accessing the ice and with considerable less measurement efforts compared to traditional surveying methods. The methodology applied to ice mapping is outlined here, and examples are shown on how to successfully apply the method to derive data on ice processes.

scholarly journals Evaluation of ice volume in the Okhotsk Sea by the ice age characteristics for the period of 2001–2019

2020 ◽  
Vol 200 (2) ◽  
pp. 427-444
Author(s):  
V. M. Pishchalnik ◽  
I. G. Minervin ◽  
P. A. Truskov
Keyword(s):  
Satellite Data ◽  
Ice Cover ◽  
Total Loss ◽  
Ice Age ◽  
Weighted Averaging ◽  
Ice Thickness ◽  
Okhotsk Sea ◽  
Age Composition ◽  
Ice Volume ◽  
Ice Concentration

Age of ice in the Okhotsk Sea in 2001–2019 is determined by analysis of satellite data from passive and active microwave spectroradiometers. The areas with certain age composition are contoured with monthly discreteness. Mean thickness of ice in these areas is calculated by weighted averaging of thickness for three main forms, neglecting the ice deformation. The ice volume is calculated by these areas, taking into account the ice concentration. The total mean winter ice volume in the Okhotsk Sea decreased in two decades with the rate of 32.2 km3/decade, on average, while the ice cover decreased by 3.2 %/decade and the average ice thickness decreased by 3.4 cm/decade. Total loss of the ice volume in the Okhotsk Sea in 2001–2019 is estimated as 34.5 %. The ice volume decreasing was caused by both ice thickness lowering (60 %) and ice cover reduction (40 %).

scholarly journals Quantification of Warming Climate-Induced Changes in Terrestrial Arctic River Ice Thickness and Phenology

2016 ◽  
Vol 29 (5) ◽  
pp. 1733-1754 ◽  
Author(s):  
Hotaek Park ◽  
Yasuhiro Yoshikawa ◽  
Kazuhiro Oshima ◽  
Youngwook Kim ◽  
Thanh Ngo-Duc ◽  
...  
Keyword(s):  
Process Model ◽  
Surface Air Temperature ◽  
The Arctic ◽  
River Ice ◽  
Ice Thickness ◽  
Biogeochemical Model ◽  
Climate Data ◽  
Ice Volume ◽  
Arctic Rivers ◽  
Phenological Dates

Abstract A land process model [the coupled hydrological and biogeochemical model (CHANGE)] is used to quantitatively assess changes in the ice phenology, thickness, and volume of terrestrial Arctic rivers from 1979 to 2009. The CHANGE model was coupled with a river routing and discharge model enabling explicit representation of river ice and water temperature dynamics. Model-simulated river ice phenological dates and thickness were generally consistent with in situ river ice data and landscape freeze–thaw (FT) satellite observations. Climate data indicated an increasing trend in winter surface air temperature (SAT) over the pan-Arctic during the study period. Nevertheless, the river ice thickness simulations exhibited a thickening regional trend independent of SAT warming, and associated with less insulation and cooling of underlying river ice by thinning snow cover. Deeper snow depth (SND) combined with SAT warming decreased simulated ice thickness, especially for Siberian rivers, where ice thickness is more strongly correlated with SND than SAT. Overall, the Arctic river ice simulations indicated regional trends toward later fall freezeup, earlier spring breakup, and consequently a longer annual ice-free period. The simulated ice phenological dates were significantly correlated with seasonal SAT warming. It is found that SND is an important factor for winter river ice growth, while ice phenological timing is dominated by seasonal SAT. The mean total Arctic river ice volume simulated from CHANGE was 54.1 km3 based on the annual maximum ice thickness in individual grid cells, while river ice volume for the pan-Arctic rivers decreased by 2.82 km3 (0.5%) over the 1979–2009 record. Arctic river ice is shrinking as a consequence of regional climate warming and coincident with other cryospheric components, including permafrost, glaciers, and sea ice.

scholarly journals Analyses of Peace River Shallow Water Ice Profiling Sonar data and their implications for the roles played by frazil ice and in situ anchor ice growth in a freezing river

2021 ◽  
Vol 15 (5) ◽  
pp. 2473-2489
Author(s):  
John R. Marko ◽  
David R. Topham
Keyword(s):  
Shallow Water ◽  
Water Column ◽  
River Ice ◽  
Water Ice ◽  
Frazil Ice ◽  
Ice Volume ◽  
Peace River ◽  
Simple Physical Model ◽  
Anchor Ice

Abstract. Peace River SWIPS (Shallow Water Ice Profiling Sonar) data were analyzed to quantify the roles of frazil ice and riverbed anchor ice grown in situ during the initial buildup of a seasonal ice cover. Data were derived through quasi-continuous monitoring of frazil parameters throughout the water column, providing direct and indirect measures of anchor ice volume and mass growth rates. Analyses utilized water level and air and water temperature information in conjunction with acoustic volume backscattering coefficient data to track and interpret spatial and temporal changes in riverbed and water column ice. Interest focused on four frazil intervals characterized by anomalously low levels of frazil content (relative to simulations with an anchor-ice-free river ice model) as distinguished by two strikingly different types of time dependences. A simple physical model was proposed to quantitatively account for discrepancies between measured and simulated results in terms of the pronounced dominance of anchor ice as an initial source of river ice volume and mass. The distinctive differences in temporally variable water column frazil content are attributed, in this model, to corresponding differences in the stabilities of riverbed anchor ice layers against detachment and buoyancy-driven movement to the river surface. In accord with earlier observations, the stability of in situ grown riverbed ice layers appears to be inversely proportional to cooling rates. The strength of the coupling between the two studied ice species was shown to be strong enough to detect changes in the anchor ice constituent from variations in water column frazil content.

scholarly journals The Antarctic sea ice cover from ICESat-2 and CryoSat-2: freeboard, snow depth and ice thickness

2020 ◽  
Author(s):  
Sahra Kacimi ◽  
Ron Kwok
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Basal Layer ◽  
Ice Cover ◽  
Ice Thickness ◽  
Data Set ◽  
Amundsen Sea ◽  
Ice Volume ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract. We offer a view of the Antarctic sea ice cover from lidar (ICESat-2) and radar (CryoSat-2) altimetry, with retrievals of freeboards, snow depth, and ice volume that span an 8-month winter between April 2019 and November 2019. Snow depths are from freeboard differences. The multiyear ice in the West Weddell sector stands out with a mean sector thickness > 2 m. Thinnest ice is found near polynyas (Ross Sea and Ronne) where new ice areas are exported seaward and entrained in the surrounding ice cover. For all months, the results suggest that ~ 60–70 % of the total freeboard is comprised of snow. The remarkable response of the ice cover to mechanical convergence in the coastal Amundsen Sea, associated with onshore winds, was captured in the correlated increase in local freeboards and thickness. While the spatial patterns in the freeboard, snow depth, and thickness composites are as expected, the observed seasonality in these variables is surprisingly weak likely attributable to competing processes (snowfall, snow redistribution, snow-ice formation, ice deformation, basal growth/melt) that contribute to uncorrelated changes in the total and radar freeboards. Broadly, evidence points to biases in CryoSat-2 freeboards of at least a few centimeters from high salinity snow (> 10 psu) in the basal layer resulting in lower/higher snow depth/ice thickness retrievals although the extent of these areas cannot be established in the current data set. Adjusting CryoSat-2 freeboards by 3/6 cm gives a circumpolar ice volume of 14,700/12,400 km3 in October, for an average thickness of ~ 1.09/0.93 m. Validation of Antarctic sea ice parameters remains a challenge, there are no seasonally and regionally diverse data sets that could be used to assess these large-scale satellite retrievals.

scholarly journals Analyses of Peace River SWIPS data and its implications for the roles played by frazil ice and in situ anchor ice growth in a freezing river

2020 ◽  
Author(s):  
John R. Marko ◽  
David R. Topham
Keyword(s):  
Water Column ◽  
River Ice ◽  
Frazil Ice ◽  
Ice Volume ◽  
Peace River ◽  
Indirect Measures ◽  
Simple Physical Model ◽  
Anchor Ice ◽  
Initial Source

Abstract. Peace River SWIPS (Shallow Water Ice Profiling Sonar) data were analyzed to assess and quantify the roles of frazil ice suspensions and riverbed anchor ice grown in situ during the initial buildup of a seasonal ice cover. Data were derived from quasi-continuous monitoring of frazil parameters throughout the water column to provide direct and indirect measures of anchor ice volume and mass growth rates. Analyses utilized water level and air and water temperature information and directly measured acoustic volume backscattering coefficients to track and interpret spatial and temporal changes in riverbed and water column ice constituents. Interests were focused on 4 specific frazil intervals characterized by anomalously low levels of frazil content (relative to simulations with an anchor ice-free river ice model) distinguished by two strikingly different types of time dependences. A simple physical model was proposed to quantitatively account for discrepancies between measured and simulated results in terms of the pronounced dominance of anchor ice as an initial source of river ice volume and mass. The distinctive differences in temporally variable water column frazil content are attributed, in this model, to corresponding differences in the stabilities of riverbed anchor ice layers against detachment and buoyancy-driven movement to the river surface. In accord with earlier observations, the stability of in situ grown riverbed ice layers appears to be inversely proportional to cooling rates. The strength of the coupling between the two studied ice species was shown to be strong enough to detect changes in the anchor ice constituent from variations in water column frazil content.

Rapid mapping accuracy assessment using low-cost UAV and open-source Structure from Motion

2020 ◽  
Vol 52 ◽  
pp. 55-61
Author(s):  
Ettore Potente ◽  
Cosimo Cagnazzo ◽  
Alessandro Deodati ◽  
Giuseppe Mastronuzzi
Keyword(s):  
Open Source ◽  
Structure From Motion ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Mapping Accuracy ◽  
Rapid Mapping ◽  
Source Structure

scholarly journals Ice thickness distribution of all Swiss glaciers based on extended ground-penetrating radar data and glaciological modeling

2021 ◽  
pp. 1-19
Author(s):  
Melchior Grab ◽  
Enrico Mattea ◽  
Andreas Bauder ◽  
Matthias Huss ◽  
Lasse Rabenstein ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Thickness Distribution ◽  
Radar Data ◽  
Tourism Industry ◽  
Swiss Alps ◽  
Ice Thickness ◽  
Hazard Management ◽  
Bed Topography ◽  
Ice Volume ◽  
Ground Penetrating

Abstract Accurate knowledge of the ice thickness distribution and glacier bed topography is essential for predicting dynamic glacier changes and the future developments of downstream hydrology, which are impacting the energy sector, tourism industry and natural hazard management. Using AIR-ETH, a new helicopter-borne ground-penetrating radar (GPR) platform, we measured the ice thickness of all large and most medium-sized glaciers in the Swiss Alps during the years 2016–20. Most of these had either never or only partially been surveyed before. With this new dataset, 251 glaciers – making up 81% of the glacierized area – are now covered by GPR surveys. For obtaining a comprehensive estimate of the overall glacier ice volume, ice thickness distribution and glacier bed topography, we combined this large amount of data with two independent modeling algorithms. This resulted in new maps of the glacier bed topography with unprecedented accuracy. The total glacier volume in the Swiss Alps was determined to be 58.7 ± 2.5 km3 in the year 2016. By projecting these results based on mass-balance data, we estimated a total ice volume of 52.9 ± 2.7 km3 for the year 2020. Data and modeling results are accessible in the form of the SwissGlacierThickness-R2020 data package.

scholarly journals Measuring and inferring the ice thickness distribution of four glaciers in the Tien Shan, Kyrgyzstan

2020 ◽  
pp. 1-18
Author(s):  
Lander Van Tricht ◽  
Philippe Huybrechts ◽  
Jonas Van Breedam ◽  
Johannes J. Fürst ◽  
Oleg Rybak ◽  
...  
Keyword(s):  
Cross Validation ◽  
Thickness Distribution ◽  
Tien Shan ◽  
Ice Thickness ◽  
Ice Volume ◽  
In Situ Data ◽  
Radio Echo Sounding ◽  
Thickness Measurements ◽  
Tien Shan Mountains

Abstract Glaciers in the Tien Shan mountains contribute considerably to the fresh water used for irrigation, households and energy supply in the dry lowland areas of Kyrgyzstan and its neighbouring countries. To date, reconstructions of the current ice volume and ice thickness distribution remain scarce, and accurate data are largely lacking at the local scale. Here, we present a detailed ice thickness distribution of Ashu-Tor, Bordu, Golubin and Kara-Batkak glaciers derived from radio-echo sounding measurements and modelling. All the ice thickness measurements are used to calibrate three individual models to estimate the ice thickness in inaccessible areas. A cross-validation between modelled and measured ice thickness for a subset of the data is performed to attribute a weight to every model and to assemble a final composite ice thickness distribution for every glacier. Results reveal the thickest ice on Ashu-Tor glacier with values up to 201 ± 12 m. The ice thickness measurements and distributions are also compared with estimates composed without the use of in situ data. These estimates approach the total ice volume well, but local ice thicknesses vary substantially.

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