UAV and GPR Data Integration in Glacier Geometry Reconstruction: A Case Study from Irenebreen, Svalbard

Although measurements of thickness and internal structure of glaciers are substantial for the understanding of their evolution and response to climate change, detailed data about polythermal glaciers, are scarce. Here, we present the first ground-penetrating radar (GPR) measurement data of Irenebreen, and high-resolution DEM and orthomosaic, obtained from unmanned aerial vehicle (UAV) photogrammetry. A combination of GPR and UAV data allowed for the reconstruction of the glacier geometry including thermal structure. We compare different methods of GPR signal propagation speed determination and argue that a common midpoint method (CMP) should be used if possible. Our observations reveal that…

APPLICATION OF UNMANNED AERIAL VEHICLES FOR GLACIER RESEARCH IN THE ARCTIC AND ANTARCTIC

Unmanned aerial vehicles or drones are nowadays widely used in a broad field of scientific and commercial applications. Despite this, it is quite a new method for glacier mapping in polar regions and has a lot of advantages, as well as disadvantages over more classical remote sensing instruments. Here we examine the main issues associated with the application of drones for glacier research from our experience in Iceland, Greenland and the Antarctic. We use DJI Phantom series drones for the obtaining of aerial photographs and produce digital surface models (resolution of 8 – 16 cm) and orthomosaics (resolution of 2 – 4 cm) for glacier mapping. Several issues related to the ground control poi…

New luminescence ages reveal Early to Middle Weichselian deposits in central Latvia

New optically stimulated luminescence (OSL) ages show that sandy deposits overlain by Late Weichselian subglacial till in central Latvia are of Early to Middle Weichselian age. The finer chronological resolution of unconsolidated sediment deposition in the Central Latvian Lowland (CLL) remains relatively unstudied, and here we provide a first characterisation of the deposits with respect to their age. Three OSL ages ranging between 84 ± 9 ka and 112 ± 11 ka suggest that the deposits studied in the CLL are of Early Weichselian age (MIS 5). We found no Middle Weichselian deposits in the CLL, and assume that any such younger sediments might have been eroded during the advance of the Zemgale Lo…

Multiple deformed layers in Weichselian lacustrine sediments at Baltmuiža, western Latvia

Fenoskandijas ledus vairoga Zemgales loba subglaciālās reljefa sistēmas un dinamika

Pētījums ir veikts par Fenoskandijas ledus vairoga Zemgales loba subglaciālajām reljefa formām un ledāja dinamiku Viduslatvijas zemienē un Ziemeļlietuvas līdzenumos, akcentējot drumlinu, lielizmēra glaciālo lineamentu, rievoto morēnu un ledājūdeņu straumju lineāro veidojumu morfoloģiju, telpisko sakārtojumu, iekšējo uzbūvi un veidošanās apstākļu kopsakarību ar ledāja–gultnes mijiedarbības zonas termālo apstākļu laiktelpiskajām izmaiņām. Balstoties uz lielmēroga topogrāfisko karšu un augstas izšķirtspējas reljefa modeļu analīzi, kartētas subglaciālās reljefa formas un iegūti to morfometriskie parametri. Lauka pētījumos ir iegūti oriģināli, ģeotelpiski precīzi piesaistīti dati par subglaciālo…

Subglacial topography and thickness of ice caps on the Argentine Islands

AbstractThis study presents the first subglacial topography and ice thickness models of the largest ice caps of the Argentine Islands, Wilhelm Archipelago, West Antarctica. During this study, ground-penetrating radar was used to map the thickness and inner structure of the ice caps. Digital surface models of all studied islands were created from aerial images obtained with a small-sized unmanned aerial vehicle and used for the construction of subglacial topography models. Ice caps of the Argentine Islands cover ~50% of the land surface of the islands on average. The maximum thickness of only two islands (Galindez and Skua) exceeds 30 m, while the average thickness of all islands is only ~5 …

STOP 14: Morphology and internal structure of the Lāči drumlin at Tērvete village, Zemgale Drumlin Field

Does glacial environment produce glacial mineral grains? Pro- and supra-glacial Icelandic sediments in microtextural study

Abstract Mineral grains from proglacial and supraglacial sedimentary settings in central south-eastern Iceland are considered in this study and analysed with the use of scanning electron microscope (SEM) techniques. By applying this, it is attempted to answer the key research question of whether quartz grains that come from a glacial-related sedimentary environment are indeed of glacial origin. The study also attempts to provide a linkage between microtextures produced on coarser and finer grains and to verify whether mineral grains from adjacent cryconite holes are similar or different. The preliminary assumption was that the more intense glacial grain record was based on several glacial a…

STOP 15: Morphology and internal structure of a ribbed moraine and drumlin remnant in the environs of Baldone, Central Latvian Lowland

Drumlins and related glaciogenic landforms of the Madliena Tilted plain, Central Latvian Lowland

This paper presents new results on the morphometry and spatial distribution of the glaciogenic landforms and ice flow directions in the Madliena Tilted Plain that occupies the eastern part of the Central Latvian Lowland. Landforms were investigated by using topographic maps at scales of 1:25 000 and 1:10 000. There were identified and mapped 1461 glaciogenic landforms such as drumlins, end moraine ridges, eskers, ribbed moraines, marginal ridges, lateral shear margin moraines and recessional formations. Particular attention is given to the morphometry, spatial distribution, and the internal structure of drumlins. Glacial landscape of the study area was formed by the Zemgale ice lobe in cour…

Detailed subglacial topography and drumlins at the marginal zone of Múlajökull outlet glacier, central Iceland: Evidence from low frequency GPR data

Abstract New ground penetrating radar (GPR) observations on the Mulajokull surge-type outlet glacier, central Iceland, are presented. Overall 10.5 km of GPR profile lines were recorded parallel to the glacier margin in August, 2015. Detailed GPR investigations combined with high-accuracy GPS measurements allowed to build a high-resolution model of the subglacial topography. We provide new evidence of streamlined ridges beneath Mulajokull’s marginal zone interpreted as drumlins and show the location of the upper edge of the drumlin field. This discovery improves understanding of the location, morphology and development of drumlins as other geophysical observations of subglacial bedforms bene…

Subglacial bedforms of the Zemgale Ice Lobe, south-eastern Baltic

Abstract Presented in this paper are the results of the mapping of ∼6600 subglacial bedforms of the Zemgale Ice Lobe (ZIL), their composition and internal structure in the south-eastern Baltic region. Topographic maps at scale 1:10,000 were mainly used to map bedforms in Latvia, while a digital elevation model with cell size of 5 m was used for North Central Lithuania. The ZIL operated during the deglaciation of the Late Weichselian Scandinavian Ice Sheet (SIS), at least in the Middle Lithuanian and North Lithuanian glacial phases, and created a subglacial landform assemblage consisting of glacial lineations such as drumlins, mega-flutings, Mega Scale Glacial Lineations (MSGLs) and transver…

High-resolution orthophoto map and digital surface models of the largest Argentine Islands (the Antarctic) from unmanned aerial vehicle photogrammetry

This study presents the first high-resolution orthophoto maps and digital surface models (DSMs) of the largest Argentine Islands, West Antarctica. Aerial surveys with small unmanned aerial vehicle (UAV) were performed in Austral summer, 2018, taking 10,041 aerial photographs. Accuracy requirements were ensured using ground control points (GCPs). A resolution of 3.4 and 6.8 cm/px of orthomosaics and DSMs is reached on average, and the RMS reprojection error is 0.22 m on average. We report the morphometric parameters of surveyed islands and discuss issues related to accuracy and the usage of UAVs in polar conditions. This study demonstrates that small and low cost UAVs can be successfully use…

Mapping of large-scale diapir structures at the paleo-ice tongue bed in western Latvia from geophysical investigations and borehole data

Abstract This study comprises the investigation of the complex and deformed Late Pleistocene sedimentary sequence in western Latvia composed of sandy sediments that are protruded by large-scale clayey silt diapirs and covered by glaciotectonically disturbed discontinuous patches of the Late Weichselian till. We use detailed measurements by ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) combined with borehole data and sedimentological investigations at the Baltic Sea cliffs to map and characterize the large-scale deformation structures and discontinuous till patches. We distinguish the intriguing and previously not detected characteristics of the spatial distribut…

The thermal structure, subglacial topography and surface structures of the NE outlet of Eyjabakkajökull, east Iceland

Abstract This study presents the detailed surveys of the NE outlet of Eyjabakkajokull glacier, East Iceland, from the combination of low-frequency ground penetrating radar (GPR), unmanned aerial vehicle (UAV) and GNSS measurements. Data analyses reveal the complex subglacial topography with a prominent, up to 45-m-deep longitudinal trough in the central part of the outlet that serves as the main trunk for the fast ice flow during the glacier surges. During the last decade (2010–2018), the studied part of the glacier has thinned by 4.37 m/yr on average and the ice margin has retreated ~750 m. We detect a boundary between scatter-free zone and zone of intense scattering near the ice margin an…

Mūsdienu ledāji

Monogrāfijas mērķis ir iepazīstināt Zemes zinātņu un citu dabaszinātņu studentus un plašāku sabiedrību ar jautājumiem par mūsdienu ledāju un ledus vairogu attīstību, klasifikāciju, plūsmas mehānismiem, deformāciju, hidroloģiju, termālo struktūru, izplatību, izmaiņām un aktuālākajiem zinātniskajiem pētījumiem, kā arī ar Latvijas Universitātes zinātnieku polāro ekspedīciju organizāciju, norisi un rezultātiem. Galvenā uzmanība grāmatā pievērsta mūsdienu ledāju, galvenokārt Arktikas un Antarktikas reģionu ledus vairogu, raksturojumam, jo šie ledāji ietver lielāko daļu pasaules ledāju ledus masas. Papildus aplūkota arī ledus un ledājiem līdzīgu formu izplatība Saules sistēmas debess ķermeņos. Vi…

Kangaru osu morfoloģija, iekšējā uzbūve un veidošanās apstākļi

Lamsters K., 2009. Kangaru osu morfoloģija, uzbūve un veidošanās apstākļi. Bakalaura darbs. Latvijas Universitāte, Rīga. 57 lpp. Bakalaura darbā ir apkopots pētījums par Kangaru osu morfoloģiju, uzbūvi un veidošanās apstākļiem. Kā Kangaru osi tiek identificēti Ogres Kangari, Lielie jeb Suntažu Kangari, Mazie jeb Allažu Kangari un Sidgundas Kangari, kas atrodas Viduslatvijas zemienes Ropažu līdzenumā un Madlienas nolaidenumā. Osu morfoloģija, uzbūve un telpiskā orientācija ļauj spriest par zemledāja noteces īpatnībām, paleostraumju virzieniem, ledāja gultnes ietekmi uz osu veidošanos un ledāja dinamiku pētāmajā teritorijā. Bakalaura darbā veiktie pētījumi liecina par to, ka osu veidošanās da…

Liquefaction and re-liquefaction of sediments induced by uneven loading and glacigenic earthquakes: Implications of results from the Latvian Baltic Sea coast

Abstract Seven internally-deformed layers were recognised in the shallow marine bay sediments deposited during mid Marine Isotope Stage 2 along the Latvian Baltic Sea coast bluff at Baltmuiža. Detailed sedimentological analyses of these deformed layers indicate that liquefaction was responsible for the development of soft-sediment deformation structures (SSDS) including injection structures, load casts, flame structures and pseudonodules. Traces of both initial liquefaction and re-liquefaction were recognised within at least four of the seven layers with SSDS (two different generations of pseudonodules and injection structures, clastic injection pipes, disrupted load casts). This is a uniqu…

HIGH-RESOLUTION SURFACE AND BED TOPOGRAPHY MAPPING OF RUSSELL GLACIER (SW GREENLAND) USING UAV AND GPR

Abstract. This study presents the detailed survey of the northern marginal part of Russell Glacier, SW Greenland using the combination of unmanned aerial vehicle (UAV) photogrammetry and low-frequency ground penetrating radar (GPR) measurements. Obtained digital elevation model (DEM) and ice thickness data from GPR data allowed the generation of high precision subglacial topography model. We report uncertainties arising from GPR, GPS, and DEM suggesting sufficient accuracy for the reconstruction of glacier bed topography. GPR data and generated subglacial topography model does not reveal any possible Nye channel that could be incised into the bedrock, however, we were able to detect englaci…

A Brief Review of Ground Penetrating Radar Investigation Results of Ice Caps on Galindez, Winter and Skua Islands (Wilhelm Archipelago, Antarctica) for the Period April 2017 – January 2019

This paper represents results of GPR surveying of the ice caps on Galindez (–64.24716W; –65.24992S), Winter (–64.25954W; –65.24944S) and Skua (–64.26530W; –65.25309S) islands (Wilhelm Archipelago, Antarctica) for the period April 2017 — January 2019. The main objectives were identification of the ice layering, monitoring of interglacial heterogeneities (crevasses, interglacial channels and voids) and measurements of the ice thickness. Methods: Surveying on the glaciers has been done with ground coupled shielded bowtie antenna VIY3-300 (300 MHz) GPR and with air coupled dipole Zond 12-e (75 MHz) antenna system. Monitoring investigation of glacier’s interior has been done with VIY3-300. Zond …

Madlienas nolaidenuma glaciālās reljefa formas un to veidošanās apstākļi

Lamsters, K. Madlienas nolaidenuma glaciālās reljefa formas un to veidošanās apstākļi. Maģistra darbs. Rīga, Latvijas Universitāte, Ģeogrāfijas un Zemes zinātņu fakultāte, 2011. Maģistra darbā ir veikts pētījums par Madlienas nolaidenuma glaciālajām reljefa formām un to veidošanās apstākļiem. Lielākā uzmanība ir pievērsta drumlinu morfoloģijai, telpiskajam sakārtojumam un iekšējai uzbūvei, kas detāli pētīta Brencēnu kalna drumlinā. Darba rezultātā ir izveidota ģeomorfoloģiskā kartoshēma, kurā attēloti drumlini, gala morēnas, bīdes sānu morēnas, marginālās grēdas un osi. Ir noteikti drumlinu morfoloģisko parametri, veikta to ģeotelpiskā un statiskā analīze. Lauka pētījumos apsekoti atsegumi …

High-resolution orthophoto map and digital surface models of the largest Argentine Islands (the Antarctic) from unmanned aerial vehicle photogrammetry

This study presents the first high-resolution orthophoto maps and digital surface models (DSMs) of the largest Argentine Islands, West Antarctica. Aerial surveys with small unmanned aerial vehicle (UAV) were performed in Austral summer, 2018, taking 10,041 aerial photographs. Accuracy requirements were ensured using ground control points (GCPs). A resolution of 3.4 and 6.8 cm/px of orthomosaics and DSMs is reached on average, and the RMS reprojection error is 0.22 m on average. We report the morphometric parameters of surveyed islands and discuss issues related to accuracy and the usage of UAVs in polar conditions. This study demonstrates that small and low cost UAVs can be successfully use…