Elevation Change Detection for Quantification of Extensive Permafrost Thaw Subsidence in East Siberian Coastal Lowlands

Permanently frozen ground in the Arctic is being destabilized by continuing permafrost degradation, an indicator of climate change in the northern high latitudes. Accelerated coastal erosion due to sea ice reduction and an increased intensity of ground settlement through ground ice melt caused by rising summer air temperatures result in widespread geomorphological activity. The objective of our study is to analyze time series of repeat terrestrial laser scanning (rLiDAR) for quantification of extensive land surface lowering through thaw subsidence, which is the main unknown in terms of recent landscape development in the vast but neglected coastal lowlands of the East Siberian Arctic. These in-situ data provide the basis for calibration and validation of large scale surface change assessments using very high resolution space-borne elevation data with high precision. Complementing our surveys, we conducted botanical mapping. This allows us to relate elevation differences to specific surface conditions and enhances our capabilities to extrapolate our local observations to larger areas through land-cover classifications of multispectral remote sensing data such as Sentinel-2. Additionally, highly detailed digital elevation models (DEMs) with sub-metre accuracy have been photogrammetrically derived from satellite stereo data. These DEMs contain valuable terrain height information for 3D change detection, in case of DEMs representing the state of a study area at different points in time. The results show that elevation differences are almost always negative. When calculated as rates over time, land surface lowering in the ground-ice-rich Siberian coastal lowlands permafrost amounts to 3-10 cm per year

Paleo-Ecology of the Yedoma Ice Complex on Sobo-Sise Island (Eastern Lena Delta, Siberian Arctic)

Late Pleistocene permafrost of the Yedoma type constitutes a valuable paleo-environmental archive due to the presence of numerous and well-preserved floral and faunal fossils. The study of the fossil Yedoma inventory allows for qualitative and quantitative reconstructions of past ecosystem and climate conditions and variations over time. Here, we present the results of combined paleo-proxy studies including pollen, chironomid, diatom and mammal fossil analyses from a prominent Yedoma cliff on Sobo-Sise Island in the eastern Lena Delta, NE Siberia to complement previous and ongoing paleo-ecological research in western Beringia. The Yedoma Ice Complex (IC) cliff on Sobo-Sise Island (up to 28 m high, 1.7 km long) was continuously sampled at 0.5 m resolution. The entire sequence covers the last about 52 cal kyr BP, but is not continuous as it shows substantial hiatuses at 36–29 cal kyr BP, at 20–17 cal kyr BP and at 15–7 cal kyr BP. The Marine Isotope Stage (MIS) 3 Yedoma IC (52–28 cal kyr BP) pollen spectra show typical features of tundra–steppe vegetation. Green algae remains indicate freshwater conditions. The chironomid assemblages vary considerably in abundance and diversity. Chironomid-based TJuly reconstructions during MIS 3 reveal warmer-than-today TJuly at about 51 cal kyr BP, 46-44 and 41 cal kyr BP. The MIS 2 Yedoma IC (28–15 cal kyr BP) pollen spectra represent tundra-steppe vegetation as during MIS 3, but higher abundance of Artemisia and lower abundances of algae remains indicate drier summer conditions. The chironomid records are poor. The MIS 1 (7–0 cal kyr BP) pollen spectra indicate shrub-tundra vegetation. The chironomid fauna is sparse and not diverse. The chironomid-based TJuly reconstruction supports similar-as-today temperatures at 6.4–4.4 cal kyr BP. Diatoms were recorded only after about 6.4 cal kyr BP. The Sobo-Sise Yedoma record preserves traces of the West Beringian tundra-steppe that maintained the Mammoth fauna including rare evidence for woolly rhinoceros’ presence. Chironomid-based TJuly reconstructions complement previous plant-macrofossil based TJuly of regional MIS 3 records. Our study from the eastern Lena Delta fits into and extends previous paleo-ecological Yedoma studies to characterize Beringian paleo-environments in the Laptev Sea coastal region

Космические снимки в новом Атласе «Российская Арктика»

The increasing interest in the Arctic promotes appearance of new cartographic products to provide information for the primary tasks of this region development. So, several atlases of the Arctic have been already published. At the initiative and with the financial support from the oil and gas industry, a new Atlas «Russian Arctic» is being prepared for publication, in which considerable attention is given to the environmental aspects of the development of the North with account for conditions of changing climate. Unlike previous atlases, this Atlas contains thematic sets of satellite images reflecting changes in the natural environment, in particular, different types of natural ice under conditions of warming. The space part of the Atlas developed by the authors of this article covers a number of subjects. Thus, the decrease in the area of sea ice is illustrated by the materials of shooting from the space of the Northern polar cap for the period of the largest reduction in the area. Images made in different time fix retreating of the shores, composed of underground ice, being the result of the processes of thermal abrasion, thermal erosion and thermal denudation. Complicated ice conditions of navigation in the Ob Bay and characteristics of the Arctic rivers mouths are presented by pictures of tidal estuaries of the rivers Mezen and Kuloi. Images of ice jams at the mouth of the Northern Dvina River and materials of space monitoring of measures for liquidation of them are also given in the Atlas. Special attention is given to forms of permafrost relief, which are well displayed in high-resolution images. They show a polygonal micro-relief of different types and stages of development of them, as well as frost mounds, dales, and thermo-erosion forms. Formation of aufeises (naleds), thermokarst lakes, and craters of gas outbursts is also shown. The wildlife of the Arctic is represented in the Atlas as well. The pictures present a visual image of different types of tundra. The influence of warming on vegetation development is well reflected in the photo map of the dynamics of the vegetation index for 2000-2009, showing the growth of phytomass in the European North. The Atlas contains unique materials of satellite monitoring of Arctic mammals - walruses and seals. The impact of using mineral resources on the vulnerable nature of the Arctic is shown in the Khibiny region. Prominent examples of the vegetation degradation in the areas of Norilsk and Monchegorsk cities are given, where technogenic wastelands have been formed under the sulfuric acid fumes of the copper-nickel plants.Представлено космическое оснащение нового Атласа «Российская Арктика». Включённые в атлас космические снимки отражают изменения в районах криолитозоны, насыщенных разными видами природных льдов, остро реагирующих на потепление климата и освоение территории. Снимки группируются по темам: морские льды, берега северных морей, устьевые области арктических рек, многолетняя мерзлота, ландшафты, биота, недропользование, промышленное воздействие на экосистемы

Классификация криогенно-оползневых форм рельефа для целей картографирования и прогноза

A classification of cryogenic-landslide landforms is developed for mapping their distribution and dynamics. It is based on the previously suggested classification subdividing cryogenic landsliding into two main types: cryogenic translational landslides (or active-layer detachment slides), and cryogenic earth flows (or retrogressive thaw slumps). The increased proportion of retrogressive thaw slumps compared to active layer detachments in the North of West Siberia in the last decade creates the need for an expanded classification of cryogenic earth flows. One of the important issues is separating the process of landsliding and resulting landforms, which in English are covered by one term ‘retrogressive thaw slump’. In dealing with the landforms, we distinguish (1) open and (2) closed ones. Open cryogenic-landslide landforms are those formed by the retreating of the coast bluff due to the thaw of ice or ice-rich deposits with an additional impact from wave or stream action. Closed cryogenic-landslide landforms are those initiated on a slope landward, and thawed material is delivered to the coast or stream through an erosional channel. Morphologically we distinguish thermocirques and thermoterraces depending on the shape of the retreating headwall, crescent or linear, respectively. An important issue is the type of ground ice subjected to thaw: tabular, ice-wedge or constitutional ground ice are distinguished. Landforms can be active, stabilized or ancient. One can find both single landforms and their combination. The classification is based on a significant amount of field studies and interpretation of remote sensing data. Mapping of the cryogenic-landslide landforms is suggested using the proposed classification and indication features. The classification is based on the experience obtained mainly in the north of West Siberia. Applying it to other regions may require additional studies.Разработана классификация криогенно-оползневых форм рельефа, сформированных криогенными оползнями течения (КОТФР), для картографирования их распространения и динамики. В основе лежит значительный объем полевых исследований и интерпретации данных дистанционного зондирования Земли. Классификация включает генетические, морфологические и криолитологические особенности пород, определяющие морфологию и динамику КОТФР, их положение в рельефе, степень их активности, сочетание и комплексирование единичных КОТФР. Предложенная классификация и индикационные признаки используются для картографирования КОТФР на севере Западной Сибири

Химический, изотопный и газовый состав однолетнего морского льда по данным кернов дрейфующих станций БАРНЕО за 2013-2015 гг.

As a result of the work performed at the BARNEO drifting stations (2013-2015 in the polar region of the Arctic ocean), a comprehensive testing was carried out and new data were obtained on the structure of one-year sea ice, its salinity, the distribution of ions of water-soluble salts, and the content of isotopes δ2H and δ18O within the ice thickness and snow falling on the ice surface. The composition of gas inclusions in the ice was also determined. The distribution of electrical conductivity across the ice thickness, determined by analysis of the cores with a length of 175-178 cm, is typical for such ice - it decreases from top to bottom with two maxima on the lower and upper boundaries of the ice. This is typical characteristic of the first-year sea-ice. Snow cover is characterized by a significant increase in electrical conductivity at the contact with the underlying ice. The chemical composition of the investigated ice-cores and the ratio between its components are similar to the composition of the sea water, although the concentrations of all components are lower than in the initial solution. The composition of gas inclusions in the ice does closely correspond to the atmospheric air, and it practically does not change in depth. The isotopic composition in the cores becomes heavier towards the bottom of the ice. This allows conclusion of a gradual decrease in the contribution of water with a light isotopic composition. The change in the isotopic composition along the ice depth, with the separation of zones with more light isotopes, reflects the changing temperature conditions of ice accumulation (with low isotopic fractionation at rapid freezing under the large temperature gradient) and regional features of the isotopic composition of sea waters in which the ice drift takes place. Salinization of the snow horizon lying on the ice surface provides a possibility of the sea salt transportation not only from surface of open water, but also from the surface of sea ice. This may be used for paleogeographic reconstructions in the Arctic using the analysis of the composition of massive vein ice.На дрейфующих станциях БАРНЕО-2013-2015 гг. в районе Северного полюса исследованы керны морских льдов, а также образцы льда, снежного покрова, подлёдной морской воды, определён состав газовых включений во льду. Получены новые данные о строении морского льда, его солёности, распределении ионов водно-растворимых солей и содержании изотопов δ2Н и δ18O в толще льда и снега, выпадающего на поверхность льда

Paleo-Ecology of the Yedoma Ice Complex on Sobo-Sise Island (EasternLena Delta, Siberian Arctic)

Late Pleistocene permafrost of the Yedoma type constitutes a valuable paleo-environmental archive due to the presence of numerous and well-preserved floral and faunal fossils. The study of the fossil Yedoma inventory allows for qualitative and quantitative reconstructions of past ecosystem and climate conditions and variations over time. Here, we present the results of combined paleo-proxy studies including pollen, chironomid, diatom and mammal fossil analyses from a prominent Yedoma cliff on Sobo-Sise Island in the eastern Lena Delta, NE Siberia to complement previous and ongoing paleo-ecological research in western Beringia. The Yedoma Ice Complex (IC) cliff on Sobo-Sise Island (up to 28 m high, 1.7 km long) was continuously sampled at 0.5 m resolution. The entire sequence covers the last about 52 cal kyr BP, but is not continuous as it shows substantial hiatuses at 36–29 cal kyr BP, at 20–17 cal kyr BP and at 15–7 cal kyr BP. The Marine Isotope Stage (MIS) 3 Yedoma IC (52–28 cal kyr BP) pollen spectra show typical features of tundra–steppe vegetation. Green algae remains indicate freshwater conditions. The chironomid assemblages vary considerably in abundance and diversity. Chironomid-based TJuly reconstructions during MIS 3 reveal warmer-than-today TJuly at about 51 cal kyr BP, 46-44 and 41 cal kyr BP. The MIS 2 Yedoma IC (28–15 cal kyr BP) pollen spectra represent tundra-steppe vegetation as during MIS 3, but higher abundance of Artemisia and lower abundances of algae remains indicate drier summer conditions. The chironomid records are poor. The MIS 1 (7–0 cal kyr BP) pollen spectra indicate shrub-tundra vegetation. The chironomid fauna is sparse and not diverse. The chironomid-based TJuly reconstruction supports similar-as-today temperatures at 6.4–4.4 cal kyr BP. Diatoms were recorded only after about 6.4 cal kyr BP. The Sobo-Sise Yedoma record preserves traces of the West Beringian tundra-steppe that maintained the Mammoth fauna including rare evidence for woolly rhinoceros’ presence. Chironomid-based TJuly reconstructions complement previous plant-macrofossil based TJuly of regional MIS 3 records. Our study from the eastern Lena Delta fits into and extends previous paleo-ecological Yedoma studies to characterize Beringian paleo-environments in the Laptev Sea coastal region

Satellite images in the new Atlas «Russian Arctic»

The increasing interest in the Arctic promotes appearance of new cartographic products to provide information for the primary tasks of this region development. So, several atlases of the Arctic have been already published. At the initiative and with the financial support from the oil and gas industry, a new Atlas «Russian Arctic» is being prepared for publication, in which considerable attention is given to the environmental aspects of the development of the North with account for conditions of changing climate. Unlike previous atlases, this Atlas contains thematic sets of satellite images reflecting changes in the natural environment, in particular, different types of natural ice under conditions of warming. The space part of the Atlas developed by the authors of this article covers a number of subjects. Thus, the decrease in the area of sea ice is illustrated by the materials of shooting from the space of the Northern polar cap for the period of the largest reduction in the area. Images made in different time fix retreating of the shores, composed of underground ice, being the result of the processes of thermal abrasion, thermal erosion and thermal denudation. Complicated ice conditions of navigation in the Ob Bay and characteristics of the Arctic rivers mouths are presented by pictures of tidal estuaries of the rivers Mezen and Kuloi. Images of ice jams at the mouth of the Northern Dvina River and materials of space monitoring of measures for liquidation of them are also given in the Atlas. Special attention is given to forms of permafrost relief, which are well displayed in high-resolution images. They show a polygonal micro-relief of different types and stages of development of them, as well as frost mounds, dales, and thermo-erosion forms. Formation of aufeises (naleds), thermokarst lakes, and craters of gas outbursts is also shown. The wildlife of the Arctic is represented in the Atlas as well. The pictures present a visual image of different types of tundra. The influence of warming on vegetation development is well reflected in the photo map of the dynamics of the vegetation index for 2000-2009, showing the growth of phytomass in the European North. The Atlas contains unique materials of satellite monitoring of Arctic mammals - walruses and seals. The impact of using mineral resources on the vulnerable nature of the Arctic is shown in the Khibiny region. Prominent examples of the vegetation degradation in the areas of Norilsk and Monchegorsk cities are given, where technogenic wastelands have been formed under the sulfuric acid fumes of the copper-nickel plants

Analyzing tundra vegetation characteristics for enhancing terrestrial LiDAR surveys of permafrost thaw subsidence on yedoma uplands

Surface subsidence is a widespread phenomenon in Arctic lowlands characterized by permafrost deposits. Together with active layer thickness dynamics surface subsidence is an important indicator of permafrost degradation in climate warming conditions. Due to small changes of surface heights of several centimeters or less per year, high-resolution and high-accuracy data are necessary to detect thaw subsidence dynamics in tundra lowlands. An appropriate method to receive such data is repeat terrestrial laser scanning (LiDAR). However, for LiDAR data analysis, uncertainties connected with vegetation dynamics should be taken into account. The vegetation type and its succession reflect the microrelief features, resulting in an areal differentiation of surface heights changes. Depending on wetness, possible influences might result from moss-lichen cover and its thickness dynamics. In this study we present some results of the vegetation characteristics and dynamics in context of its impact on the terrestrial LiDAR investigations for thaw subsidence assessment on yedoma uplands. During expeditions to the Lena Delta and the Bykovsky Peninsula in Northern Yakutia in 2015-2016, repeat terrestrial laser scanning was conducted on yedoma uplands formed by very ice-rich Yedoma Ice Complex deposits. On the Bykovsky Peninsula, detailed vegetation descriptions of the main vegetation types were done including all species projective cover, cotton grass tussocks height and area sizes, moss-lichen thickness and ALT measurements. Subsidence was about 3.5 cm on average and is mostly observed on drained inclined sites with dwarf-shrub graminoid, cotton-grass, moss-lichen tundra, representing initial baydzherakhs (thermokarst mounds). Surface heave is observed mainly within bogged depressions with sedge, moss tundra. The average ALT was 39±4.1 cm and 32±5.6 cm in 2015 and 2016, respectively. However, the ALT significantly varies locally and depends on the vegetation type and species. Cotton grass leaves average length decreased from 14.4 in 2015 to 12.9 as well as tussock area size (0.32 m2 in 2015, and 0.13 m2 in 2016). This data can be used for the interpretation of LiDAR data for sites with cotton grass prevalence. Less deep ALT and cotton grass size in 2016 indicate that climate conditions were less favorable for seasonal subsidence development in 2016. The sum of positive daily air temperatures was almost in the same order of magnitude in 2016 as in 2015 for the period until end of August (636 degree days in 2015 and 628 degree days in 2016). However, interannual surface subsidence was progressing, indicating a decreased resistivity of yedoma uplands in terms of thaw subsidence under current, generally warmer conditions. The thickness of the moss-lichens layer in average is about 5 cm for the live part and 12 cm for both live and non-live parts. The lab drying in the 20°С conditions shows the decrease of moss-lichens layer samples thickness from 12,4 to 11,8 cm in average. The changes of moss-lichens thickness could be ignored as drying resulted in small changes it is very unlikely to have such drying in really tundra conditions Our results show the importance of considering vegetation and their dynamics for the interpretation of repeat terrestrial LiDAR data for thaw subsidence estimation