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Studies of permafrost agradation within peat mires leading to palsa growth and palsa dynamics during the Holocene are important for predicting the future of permafrost in a changing climate. The radiocarbon age of peat cover and stable isotope composition of the ice cores of palsas near Eletsky settlement, north‐east of the European part of Russia, were studied. Palsa growth was the most active between 8 and 5 cal ka BP. The main sources for ice core formation were precipitation‐fed surface and suprapermafrost waters. It is assumed that the isotope composition of the initial water was isotopically depleted compared with modern surface waters, which may be explained by general climate cooling during earlier stages of palsa growth (response to the 8.2 ka cooling event). The ice cores of the studied palsas were formed during the freezing of water in semi‐closed conditions, mainly by the segregation mechanism during permafrost agradation, thickness of the ice lenses and ice volume could depend on freezing rates and water supply. The upper part of the palsa ice core experienced deep thawing and could be saturated with meteoric water; repeated freezing of this part of the ice core likely occurred in closed system conditions. [ABSTRACT FROM AUTHOR]

Pingos are indicators of modern and past conditions of permafrost. In total, 1,620 pingos have been identified on the Yamal and Gydan peninsulas in western Siberia. The main purpose of this study is to consider the distribution of stable isotopes in pingo ice cores formed under conditions of open and closed systems. Two pingos from ice cores of different origin in the continuous permafrost zone of northwest Siberia have been considered: the Messoyaha‐1 pingo (10.5 m in height) and the Pestsovoe pingo (17 m in height). Drilling of the ice core was performed with continuous sampling of an undisturbed frozen core. Ice formation was estimated according to the Rayleigh fractionation in a closed‐system versus an open‐system framework. For the Pestsovoe pingo, a pronounced decrease in δ18O values with corresponding increase in dexc with depth indicates a closed system upon freezing of the lake talik from the top down. For the Messoyakha‐1 pingo, the values of δ18O and δ2Н showed a weak tendency to decrease with depth, with values of dexc varying randomly. Ice that was segregated in the overlying and underlying sediments had similar values of δ18O and δ2Н and a low slope. Isotopically nonequilibrium ice formation was established for ice which had been segregated in a closed system and for ice cores formed in an open to semiclosed system. The vacuum mechanism of water suction from the surrounding lake or lake talik may have played a significant role during the formation of the upper ice core of the Messoyakha‐1 pingo and its additional growth. [ABSTRACT FROM AUTHOR]

Early Holocene winter air temperatures have been reconstructed for the north‐eastern part of the East European Plain using stable isotope (δ18O and δ2H) records of syngenetic ice wedges. We show that ice wedges here actively grew synchronously with accumulation of peatlands in bogged and forested depressions between 10 and 8 cal ka BP, corresponding to the early Holocene Thermal Maximum. The slope of the δ2H–δ18O regression line is close to the global meteoric water line. This suggests the preservation of winter precipitation signal in the ice wedge with minor isotope transformation. The low range of stable isotope values in the ice wedge indicates quite stable winter climate conditions, favorable to ice wedge growth. Reconstructed mean winter air temperature was close to modern, but it is assumed that air temperature of the coldest winter month was lower and more stable than at present. [ABSTRACT FROM AUTHOR]

This study presents a dataset on long-term multidisciplinary glaciological, hydrological, and meteorological observations and isotope sampling in a sparsely monitored alpine zone of the North Caucasus in the Djankuat research basin. The Djankuat glacier, which is the largest in the basin, was chosen as representative of the central North Caucasus during the International Hydrological Decade and is one of 30 "reference" glaciers in the world that have annual mass balance series longer than 50 years (Zemp et al., 2009). The dataset features a comprehensive set of observations from 2007 to 2017 and contains yearly measurements of snow depth and density; measurements of dynamics of snow and ice melting; measurements of water runoff, conductivity, turbidity, temperature, δ18O , δ D at the main gauging station (844 samples in total) with an hourly or sub-daily time step depending on the parameter; data on δ18O and δ2H sampling of liquid precipitation, snow, ice, firn, and groundwater in different parts of the watershed taken regularly during melting season (485 samples in total); measurements of precipitation amount, air temperature, relative humidity, shortwave incoming and reflected radiation, longwave downward and upward radiation, atmospheric pressure, and wind speed and direction – measured at several automatic weather stations within the basin with 15 min to 1 h time steps; gradient meteorological measurements to estimate turbulent fluxes of heat and moisture, measuring three components of wind speed at a frequency of 10 Hz to estimate the impulse of turbulent fluxes of sensible and latent heat over the glacier surface by the eddy covariance method. Data were collected during the ablation period (June–September). The observations were halted in winter. The dataset is available from PANGAEA (10.1594/PANGAEA.894807, Rets et al., 2018a) and will be further updated. The dataset can be useful for developing and verifying hydrological, glaciological, and meteorological models for alpine areas, to study the impact of climate change on hydrology of mountain regions using isotopic and hydrochemical approaches in hydrology. As the dataset includes the measurements of hydrometeorological and glaciological variables during the catastrophic proglacial lake outburst in the neighboring Bashkara valley in September 2017, it is a valuable contribution to study lake outbursts. [ABSTRACT FROM AUTHOR]

Ice‐wedge ice can provide a valuable record of past winter climate variability at high latitudes yet to date this proxy has been applied only sparsely across the Chukotka region of Siberia. Here we present data from eight ice‐wedges at four sites across a 600‐km transect in Eastern Chukotka which we use to reconstruct regional Holocene winter paleotemperature. The Holocene age of ice‐wedges was established by radiocarbon dating of peat surrounding individual ice‐wedges. Our suite of radiocarbon ages suggests that the studied ice‐wedges formed between 12.9–11.8 and 3–2.5 cal ka BP. δ18O and δ2H values from ice‐wedge ice indicate that in coastal areas of Eastern Chukotka mean January air temperatures in the first half of the Holocene were on average 2–3°С lower than modern values, a finding that corresponds well with winter climate reconstructions for the other areas of Beringia. The variability of reconstructed mean January air temperatures in the study area did not exceed 2–4°C during the early to mid‐Holocene. [ABSTRACT FROM AUTHOR]

The study presents a dataset on long-term complex glaciological, hydrological, meteorological observations and isotopes sampling in an extremely underreported alpine zone of the North Caucasus. The Djankuat research basin is of 9.1 km², situated on elevations between 2500-4000 m, by 30 % covered with glaciers. The biggest in the basin - the Djankuat glacier was chosen as representative of the central North Caucasus during the International Hydrological Decade and is one of 30 "reference" glaciers in the world that have annual mass balance series longer than 50 years (Zemp et al., 2009). The dataset covers 2007-2017 and contains the result of yearly measurements of snow thickness and density; dynamics of snow and ice melting; measurements of water runoff, conductivity, turbidity, temperature, δ18O, δ²H on the main gauging station (844 samples in sum) with a one-hour or several-hours step depending on the parameter; data on δ18O and δ²H sampling of liquid precipitation, snow, ice, firn, groundwater in different parts of the watershed regularly in time during melting season (485 samples in sum); precipitation amount, air temperature, relative humidity, shortwave incoming and reflected radiation, longwave downward and upward radiation, atmospheric pressure, wind speed and direction - measured on several automatic weather stations within the basin with 15 min - one-hour step; gradient meteorological measurements to estimate turbulent fluxes of heat and moisture, measuring three components of wind speed at a frequency of 10 hertz to estimate the turbulent impulse heat fluxes over the glacier surface by the eddy covariance method. All the observations were done during ablation period (June-September) and were interrupted in winter. The dataset was published on knb.ecoinformatics.org long-term repository doi: https://doi.org/10.5063/F1H1307Q and will be further updated. The dataset can be useful for developing and verifying hydrological, glaciological and meteorological models for high elevation territories, to study impact of climate change on hydrology of mountain regions, using isotopic and hydrochemical approaches to study mountain territories. As the dataset includes the measurements of hydrometeorological and glaciological parameters during the catastrophic proglacial lake outburst in the neighboring Bashkara valley in September 2017, it is a valuable contribution to the study of this dangerous hydrological phenomena. [ABSTRACT FROM AUTHOR]

Perennial frost mounds identified as lithalsas occur in the Sentsa River valley of the Eastern Sayan Mountains, Russia. We report the first detailed study of permafrost in this region, based on analysis of the cryostructure and distribution of stable isotopes of oxygen and hydrogen, and ion concentrations from the ice-rich cores of two lithalsas 3-7 m high. Their main cryostructures are reticulate and lenticular, with visible ice contents exceeding 50-60%. The vertical and lateral distribution of δ18О and δD values show a step-by-step mechanism of lithalsa growth: in the first stage a large lithalsa formed, and in the second stage a small lithalsa formed. The more negative isotope values of ice in the large lithalsa ice probably resulted from gradual release of isotopically depleted water from the central to peripheral part of the massif during ice segregation in water-saturated fine-grained lake sediments. Minor variations of isotope values suggest intensive recharge of lake-fen and meteoric water supply during freezing and lithalsa growth. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]