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  • 11
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    New results of the very high-resolution UAV surveys of the Yukon coast: Border to King Point (2018)
    In:  EPIC3Arctic Net, Ottawa, 2018-12-10-2018-12-14
    Details
    Publication Date: 2020-11-23
    Description: Climate models indicate the highest warming rates for the high latitudes, especially for the Arctic. Recent estimates indicate that the release of previously frozen organic carbon and its transformation into greenhouse gases may push global climate warming above the 1.5 °C targeted in the COP21 Paris Agreement (Schuur et al., 2015). Despite efforts to include carbon fluxes from permafrost degradation in climate models, the lateral fluxes of organic matter from land to sea are still not accounted for (Vonk and Gustafsson, 2013). Arctic permafrost coasts are major carbon (Schuur et al., 2015) and mercury pools (Schuster et al 2018) and represent about 34% of Earth’s coastline, with large sectors affected by significant erosion rates (Fritz et al, 2017). Year-round reduction in Arctic sea ice is forecasted and by the end of the 21st century, models indicate a decrease in sea ice area ranging from 43 to 94% in September and from 8 to 34% in February (IPCC, 2014). An increase of the sea-ice free season duration will expose coasts to wave action, extending the erosion into the shoulder seasons. Changing climate will also modify the contribution of terrestrial erosion, e.g. thermokarst, gully erosion and retrogressive thaw slumps (Fritz et al., 2015, Ramage et al 2017, 2018, Irrgang et al 2018). Understanding the current processes and both inter- and intra-annual dynamics of coastal erosion in the Arctic is essential to better predict future coastal erosion rates and hence to improve carbon and contaminant flux estimates. Following previous research by the Geological Research of Canada and the Alfred Wegener Institute, in July-August 2018, we resurveyed several long-term monitoring sites from the Canada-US border to King Point: Border, Clarence, Nunaluk, Herschel’s slumps A, B, C, D and Tina’s, Stokes West, Kay Point and King Point. Traditionally the repeat surveys were conducted using a DGPS survey along fixed transects that cross-cutted each site. In 2018, we have partially repeated the DGPS surveying and surveyed all sites with a SenseFly RTK ebee UAV with a S.O.D.A. camera and a Trimble R4 base station, allowing for preliminary model accuracies of ci. 10 cm. The poster shows the results of the 2018 surveys and first comparisons with data from previous seasons, including a discussion of the main results and methodological adjustments that may be needed for the 2019 surveys. This research is integrated in the H2020 European Union project Nunataryuk - Permafrost thaw and the changing Arctic coast, science for socioeconomic adaptation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev , info:eu-repo/semantics/conferenceObject
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  • 12
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    Monitoring Inter- and Intra-Seasonal Dynamics of Rapidly Degrading Ice-Rich Permafrost Riverbanks in the Lena Delta with TerraSAR-X Time Series (2017)
    Multidisciplinary Digital Publishing Institute
    In:  EPIC3Remote Sensing, Multidisciplinary Digital Publishing Institute, 10(1), ISSN: 2072-4292
    Details
    Publication Date: 2020-06-14
    Description: Arctic warming is leading to substantial changes to permafrost including rapid degradation of ice and ice-rich coasts and riverbanks. In this study, we present and evaluate a high spatiotemporal resolution three-year time series of X-Band microwave satellite data from the TerraSAR-X (TSX) satellite to quantify cliff-top erosion (CTE) of an ice-rich permafrost riverbank in the central Lena Delta. We apply a threshold on TSX backscatter images and automatically extract cliff-top lines to derive intra- and inter-annual CTE. In order to examine the drivers of erosion we statistically compare CTE with climatic baseline data using linear mixed models and analysis of variance (ANOVA). Our evaluation of TSX-derived CTE against annual optical-derived CTE and seasonal in situ measurements showed good agreement between all three datasets. We observed continuous erosion from June to September in 2014 and 2015 with no significant seasonality across the thawing season. We found the highest net annual cliff-top erosion of 6.9 m in 2014, in accordance with above-average mean temperatures and thawing degree days as well as low precipitation. We found high net annual erosion and erosion variability in 2015 associated with moderate mean temperatures but above average precipitation. According to linear mixed models, climate parameters alone could not explain intra-seasonal erosional patterns and additional factors such as ground ice content likely drive the observed erosion. Finally, mean backscatter intensity on the cliff surface decreased from −5.29 to −6.69 dB from 2013 to 2015, respectively, likely resulting from changes in surface geometry and properties that could be connected to partial slope stabilization. Overall, we conclude that X-Band backscatter time series can successfully be used to complement optical remote sensing and in situ monitoring of rapid tundra permafrost erosion at riverbanks and coasts by reliably providing information about intra-seasonal dynamics.
    Repository Name: EPIC Alfred Wegener Institut
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  • 13
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    Thermo‐erosional valleys in Siberian ice‐rich permafrost (2021)
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    Publication Date: 2021-07-04
    Description: Thermal erosion is a major mechanism of permafrost degradation, resulting in characteristic landforms. We inventory thermo‐erosional valleys in ice‐rich coastal lowlands adjacent to the Siberian Laptev Sea based on remote sensing, Geographic Information System (GIS), and field investigations for a first regional assessment of their spatial distribution and characteristics. Three study areas with similar geological (Yedoma Ice Complex) but diverse geomorphological conditions vary in valley areal extent, incision depth, and branching geometry. The most extensive valley networks are incised deeply (up to 35 m) into the broad inclined lowland around Mamontov Klyk. The flat, low‐lying plain forming the Buor Khaya Peninsula is more degraded by thermokarst and characterized by long valleys of lower depth with short tributaries. Small, isolated Yedoma Ice Complex remnants in the Lena River Delta predominantly exhibit shorter but deep valleys. Based on these hydrographical network and topography assessments, we discuss geomorphological and hydrological connections to erosion processes. Relative catchment size along with regional slope interact with other Holocene relief‐forming processes such as thermokarst and neotectonics. Our findings suggest that thermo‐erosional valleys are prominent, hitherto overlooked permafrost degradation landforms that add to impacts on biogeochemical cycling, sediment transport, and hydrology in the degrading Siberian Yedoma Ice Complex.
    Description: Christiane Nüsslein‐Volhard Foundation
    Description: European Research Council http://dx.doi.org/10.13039/501100000781
    Description: German Academic Exchange Service DAAD P.R.I.M.E.
    Description: Helmholtz‐Gemeinschaft http://dx.doi.org/10.13039/501100001656
    Description: Polar Geospatial Center, NSF‐OPP awards
    Description: RapidEye Science Archive (RESA)
    Description: Russian Foundation for Basic Research http://dx.doi.org/10.13039/501100002261
    Description: Studienstiftung des Deutschen Volkes http://dx.doi.org/10.13039/501100004350
    Description: Universität Potsdam http://dx.doi.org/10.13039/501100004238
    Description: BMBF KoPf
    Keywords: 551.3 ; geomorphology ; periglacial landscapes ; permafrost degradation ; thermal erosion ; valley distribution ; Yedoma Ice Complex
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  • 14
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    Degradation of Ice Complex deposits in the Laptev Sea region - Geomorphological investigations combining remote sensing, GIS, and field data (2015)
    V.B. Sochava Institute of Geography SB RAS Publishers
    In:  EPIC3IX All-Russian Conference on Quaternary Research, Irkutsk, Russia, 2015-09-15-2015-09-20Irkutsk, Russia, V.B. Sochava Institute of Geography SB RAS Publishers
    Details
    Publication Date: 2015-12-09
    Description: Возросший научный интерес к деградации ледового комплекса в последнее время вызван актуальностью вопросов климатических изменений. Высокая уязвимость многолетнемерзлых отложений ледового комплекса связана с высоким содержанием в нем льда и лабильных органических веществ, что при потеплении климата, может привести к высвобождению парниковых газов в атмосферу. Термокарст и термоэрозия – два основных типа деградации многолетнемерзлых пород арктических равнин, и в частности регионов распространения ледового комплекса. Эти процессы и формирующиеся в результате формы рельефа способствуют высвобождению органических веществ в атмосферу и в гидросферу, а также могут оказать существенное влияние на водные и энергетические балансы подверженных их влиянию ландшафтов. В то время как термокарстовые процессы широко изучены, процессы термоэрозии исследованы недостаточно, несмотря на то, что соответствующие им формы рельефа, такие как термоэрозионные овраги, долины и долинные сети, широко распространены в регионе ледового комплекса. Нами было исследовано 1) воздействие термоэрозионных процессов на трансформацию рельефа в регионе моря Лаптевых с начала голоцена и 2) интенсивность современных термоэрозионных процессов и развитие форм рельефа в дельте р. Лены. Исследование и описание термоэрозионных форм рельефа на региональном уровне с использованием ГИС-анализа данных дистанционного зондирования, цифровых моделей рельефа и полевых исследований показали, что в Голоцене в некоторых частях дельты термоэрозия оказывала сильное влияние на деградацию ледового комплекса и гораздо более значительное, чем термокарст. Значительные различия в морфологии и пространственном распределении водотоков и термоэрозионных оврагов наблюдались между различными районами ледового комплекса, что связано с разницей размеров исследуемых районов, их рельефом и преобладающими криолитологическими свойствами, а также со степенью предыдущей деградации ледового комплекса термокарстом. Сравнение спутниковых снимков, полученных в период с 1964 по 2011 год показывает увеличение длины термоэрозионных водотоков и долин в пределах ледового комплекса дельты р. Лены на 1,6 %. При этом интенсивность современных термоэрозионных процессов сильно отличается в различных частях дельты, а также в течение различных промежутков времени.
    Repository Name: EPIC Alfred Wegener Institut
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  • 15
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    Characterizing thermo-erosional landforms in Siberian ice-rich permafrost. Morphometric investigations in the Lena Delta using high-resolution satellite imagery and digital elevation models (2015)
    In:  EPIC378 p.
    Details
    Publication Date: 2015-03-12
    Description: Rapid warming of the Arctic promotes widespread degradation of permafrost and affects the stability of arctic ecosystems. Thermokarst and thermal erosion are two major processes of permafrost degradation. The spatial extent of thermo-erosional processes and related landforms (e.g. gullies and valleys) and their impact on the widespread degradation of permafrost remains not well quantified. Addressing this research gap, this study is using a combination of field data, high-resolution satellite data and photogrammetically derived digital elevation models (DEMs) to conduct a detailed inventory and spatial analysis of thermo-erosional landforms in order to understand their dynamics as well as their relevance for permafrost degradation. The study area in the central Lena Delta is mainly composed of ice- and organic-rich and syngenetically frozen deposits of Late Pleistocene age called Ice Complex. Besides polygonal tundra, thermokarst lakes, wide thermokarst depressions and undisturbed Ice Complex surfaces the study area features a broad variety of thermo-erosional valleys. During an expedition in summer 2013 RTK GPS measurements of 11 ground control points and 28 transversal and 4 longitudinal profiles were conducted in three key sites. Geometric data fusion of GeoEye-1, RapidEye and ALOS PRISM datasets was performed and several high-resolution DEMs were generated. The DEMs were evaluated for absolute height and slope against the field dataset and the thermo-erosional stream network was mapped and morphometric analysis of the identified features was performed. The highest DEM accuracy was achieved when using a combination of six stereopairs from the years 2006 and 2009. The DEM derived transversal and longitudinal profiles reflect the actual shape and morphometry of the valleys. The identified stream network shows levels of high organization within thermokarst depressions and is poorly developed on the Ice Complex surface. The stream orientation tends to follow the height gradient of the study area towards north¬west, while streams outside of thermokarst depression show two main directions that could reflect the polygonal network in the ground. Accompanying permafrost warming thermokarst and thermo-erosional activity will further promote permafrost degradation. In this context thermo-erosional stream networks will expand within the Ice Complex and act as a major agent for the transport of remobilized fossil organic carbon to the Laptev Sea system.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Thesis , notRev
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  • 16
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    Characterizing thermo-erosional landforms in Siberian ice-rich permafrost - Morphometric investigations using high resolution satellite imagery and digital elevation models (2014)
    In:  EPIC3EUCOP4 - 4th European Conference on Permafrost, Évora, Portugal, 2014-06-18-2014-06-21
    Details
    Publication Date: 2014-07-10
    Description: The spatial extent of thermoerosional processes and related landforms (e.g. gullies, valleys) and their impact on the widespread degradation of permafrost is still not well quantified. Remote sensing data and digital elevation models (DEMs) are widely used to derive and analyse geomorphometric relief characteristics in order to detect periglacial landscape dynamics such as thermal erosion. However, geometric correction of remote sensing data and generation of DEMs in polar lowlands is challenging due to the low relief of arctic tundra landscapes and often scarce reference data. Therefore, high-resolution DEMs of high quality are hardly available, especially for Siberian study regions. Addressing these difficulties, this study is using a multi-sensor and multi-temporal data approach for a detailed inventory and spatial analysis of thermo-erosional landforms on Kurungnakh Island in the central Lena Delta, which is composed of ice-rich permafrost. Two DEMs were generated from ALOS PRISM stereo-datasets acquired in 2006 and 2009 for detection of short-time volumetric change. Mapping of thermo-erosional landforms was then performed using a time-series of orthorectified GeoEye-1 and RapidEye datasets. We present a validation of the generated DEMs based on extensive ground measurements on Kurungnakh Island, performed during an expedition in July 2013. Longitudinal and transversal profiles of thermo-erosional valleys were measured at three key sites, each representing different valley types. Profiles were extracted from the DEMs and compared to profiles measured in the field in order to provide error ranges for DEM-based valley profile analyses. Our datasets provide a new level of accuracy and a basis for further studies on Kurungnakh Island.
    Repository Name: EPIC Alfred Wegener Institut
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  • 17
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    Past and recent thermal erosion degrades Siberian Yedoma (2014)
    In:  EPIC3EUCOP4 - 4th European Conference on Permafrost, Évora, Portugal, 2014-06-18-2014-06-21
    Details
    Publication Date: 2014-07-10
    Description: The high thaw vulnerability of Yedoma (Ice Complex) in combination with its high contents of labile organic matter makes these ice-rich permafrost deposits an object of research activities that investigate permafrost degradation and the permafrost-carbon feedback under a warming climate. Thermokarst and thermal erosion are two major types of permafrost degradation in Arctic lowlands, and in particular Yedoma landscapes. These processes and resulting landforms release fossil organic matter to the atmosphere and the hydrological system, and may also substantially alter the water and energy balances of the affected landscapes. While thermokarst has been widely investigated, data is sparse on thermal erosion, despite the fact that related landforms, such as thermo-erosional gullies, valleys and valley networks, cover vast parts of Yedoma landscapes. We investigate 1) the impact of past thermo-erosional processes on the transformation of the Late Pleistocene Yedoma relief in the Siberian Laptev Sea region to the recent relief situation and 2) the impact of recent thermo-erosional processes and landforms on the hydrological and biogeochemical regime of Yedoma landscapes. Our regional inventory of thermo-erosional landforms using GIS-based analysis of remote sensing data, digital elevation models, and field investigations demonstrates that thermal erosion severely affected Siberian Yedoma during the Holocene, in some regions much more than thermokarst. Strong variations in the morphology and spatial distribution of streams and valleys are observed and can be attributed to differences in the size and relief characteristics of the study areas as well as to their predominant cryolithological properties, which are also influenced by degradation of the Yedoma by thermokarst prior to thermal erosion. Investigations of recent thermo-erosional processes focused on a key area in the central Lena Delta, Kurungnakh Island. We compare and contrast discharge regimes and mass fluxes of different thermo-erosional landforms draining different surface and relief types of this Yedoma landscape on the basis of field measurements and water sample analyses.
    Repository Name: EPIC Alfred Wegener Institut
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  • 18
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    Upscaling Water Body Size Distributions (2014)
    In:  EPIC3DUE Permafrost 2014 workshop, Frascati, Italy, 2014-02-11-2014-02-13
    Details
    Publication Date: 2019-07-16
    Description: The millions of ponds and small lakes in Arctic lowlands have been identified as biogeochemical hotspots with high process rates. However, water bodies with surface areas smaller than 1 km² are not captured on a global scale. This study upscales local, high-resolution water body size distributions to the regional scale in the Lena Delta (Siberia) and the Mackenzie Delta (Canada). We investigate (i) the variability of water body size distributions within and between the two deltas, and (ii) relate differences to hydrological, geomorphological and permafrost processes. Water bodies are mapped from aerial, TerraSAR-X and Kompsat-2 imagery with resolutions of 4 m and better. The Lena Delta features about 40% more ponds than the Mackenzie Delta. Within-landscape variability is low in both deltas which allows the estimation of regional distributions. Statistical properties of such regional distributions can be used to incorporate ponds and small lakes into larger-scale climate and ecosystem models.
    Repository Name: EPIC Alfred Wegener Institut
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  • 19
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    Degradation of Siberian ice-rich permafrost by thermal erosion (2013)
    In:  EPIC3Arbeitskreis Permafrost, Salzburg, Austria, 2013-10-24-2013-10-26
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    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
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  • 20
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    Lake water balance of a thermokarst lake on Kurungnakh, Lena delta, northern Siberia (2014)
    In:  EPIC3EUCOP4 - 4th European Conference on Permafrost, Évora, Portugal, 2014-06-18-2014-06-21http://www.eucop4.org/
    Details
    Publication Date: 2021-08-16
    Description: Hydrological processes in permafrost regions are still hard to represent in models because of a lack of sufficient process understanding based on field observations in different permafrost settings. This work delivers an important contribution to the knowledge of hydrological processes, specifically the water balance of a thermokarst lake in ice -rich permafrost. The goal of this research is to quantify the water balance based on field measurements of hydraulic components as well as modeling. The study site is located on Kurungnakh, an island in the central part of the Lena river delta in northern Siberia underlain by continuous ice- rich permafrost. The investigated lake, Lucky Lake, covers an area of about 3 km² and has a volume of approximately 20 * 10^6 m³. Field measurements of the water balance components were conducted in a period from July 15th to August 26th. Precipitation was recorded by an automatic rain gauge, at a nearby site on Kurungnakh island. Open channel inflow from a neighboring thermokarst lake into Lucky Lake was identified. It was possible to estimate the amount of water input by using a measurement device based on electro magnetism (Flo-Mate). The outflow of Lucky Lake was determined every ten minutes by using the stage -discharge relationship of an installed weir and a radar sensor. The evaporation of the thermokarst lake was calculated using climate data from weather stations on Kurungnakh island and the neighboring island Samoylov. The lake water storage was measured using an automated water level sensor in 30 minutes intervals. Water levels in the shallow active layer were recorded at seven measurements sites within the catchment of Lucky Lake. Changes of the active layer, hydraulic conductivity in the thawed layer and the groundwater level on the permafrost table were measured at different locations during the mentioned period. This contribution shows the measured and estimated water balance components for the thermokarst lake. During the period of measurement the discharge decreased significantly, due to unusual small amount of precipitation in this summer. The evaporation measured during this time was as usual high compared to the rest of the year. These two main drivers for the water balance explain the development of water storage within the lake, as it also decreased. In consequence evaporation dominated the water balance of Lucky Lake during the measurement period by far
    Repository Name: EPIC Alfred Wegener Institut
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