Papers by Sergey Sokratov

E3S Web of Conferences
The paper considers the problem of monitoring seasonal variations of ground temperature in northe... more The paper considers the problem of monitoring seasonal variations of ground temperature in northern and mountainous areas in the light of ongoing climate changes. To study seasonal variations of ground temperature, a model site of the Moscow State University Meteorological Observatory was used with the ability to monitor air temperature, snow cover thickness, and ground freezing temperature and depth, which was a prototype of a system for monitoring the state of permafrost soils used in the Arctic and mountain territories. The paper presents the results of monitoring seasonal variations of ground temperature based on the results of numerical modelling of the propagation of seasonal fluctuations of ground temperature in 2014-2017 in MATLAB environment which are in good agreement with the thermometry data and, therefore, the developed calculation scheme shows fairly good simulation results. This makes it possible to use the calculation scheme to assess the thermal state of frozen grou...

Avalanche Activity in Russia in the Changing Climate
Vestnik RFFI
The requirements for the calculation of indicators of avalanche activity determined by climatic c... more The requirements for the calculation of indicators of avalanche activity determined by climatic conditions in the territories under developing, as well as prognosis of their changes in the future are enshrined in Russian Federation legislation. However, the data required for this do not exist for all the regions of the country, especially those, that are only now included in the industrial exploration. The dependences between the climatic and the geomorpho- logical indicators and parameters of avalanches and avalanche activity are developed earlier on the basis of data from direct observations. The indicators are based on the average annual maximum ten-day snow cover height, the number of days with snow cover, the duration of the avalanche period and the average long-term frequency of avalanches. The climatic parameters presented by model MRI-CGCM3 (RCP 8.5) were incorporated into these dependences system. This made possible to estimate the indicators of avalanche activity for the m...
Change in snow avalanche and debris flow hazards in the region of Krasnaya Polyana as the result of anthropogenic activity
EGUGA, Apr 1, 2012
Impact of permafrost factor in ecological disasters due to spills of fuel and lubricants in the cryolithozone (with Norilsk region as an example)
AGU Fall Meeting Abstracts, Dec 1, 2020
Snow cover classification as representation of snow cover in large-scale climate models

European geosciences union general assembly, 2017
This research is focused on study of spatial and temporal variability of structure and characteri... more This research is focused on study of spatial and temporal variability of structure and characteristics of snowpack, quick identification of layers based on hardness and dispersion values received from snow micro penetrometer (SMP). We also discuss the detection of weak layers and definition of their parameters in non-alpine terrain. As long as it is the first SMP tool available in Russia, our intent is to test it in different climate and weather conditions. During two separate snowpack studies in plain and mountain landscapes, we derived density and grain size profiles by comparing snow density and grain size from snowpits and SMP measurements. The first case study was MSU meteorological observatory test site in Moscow. SMP data was obtained by 6 consecutive measurements along 10 m transects with a horizontal resolution of approximately 50 cm. The detailed description of snowpack structure, density, grain size, air and snow temperature was also performed. By comparing this information, the detailed scheme of snowpack evolution was created. The second case study was in Khibiny mountains. One 10-meter-long transect was made. SMP, density, grain size and snow temperature data was obtained with horizontal resolution of approximately 50 cm. The high-definition profile of snowpack density variation was acquired using received data. The analysis of data reveals high spatial and temporal variability in snow density and layer structure in both horizontal and vertical dimensions. It indicates that the spatial variability is exhibiting similar spatial patterns as surface topology. This suggests a strong influence from such factors as wind and liquid water pressure on the temporal and spatial evolution of snow structure. It was also defined, that spatial variation of snowpack characteristics is substantial even within homogeneous plain landscape, while in high-latitude mountain regions it grows significantly.
STRACT: The paper presents results of analysis of experimental data on activity of snow AS talliz... more STRACT: The paper presents results of analysis of experimental data on activity of snow AS tallization under temperature gradient conditions. In addition to temperature and temperature recds nt effects, recently accepted as the main factors influencing the snow recrystallization process, the g~ I~ of the water vapor flux and the volumetric mass production, related to the formed in snow heate ~cmass-fluxes, were estimated. The results suggest that the reported discrepancies between the an ults of observation and the modeled by presently used empirical construction recrystallization rates :~ be related to neglected before parameters of the water vapor in the pore space of snow.
The changing climate and economical potential of the Russian Arctic
European geosciences union general assembly, 2016
Methodology for assessment the avalanche nourishment of glaciers
2008 IACS International Classification for Seasonal Snow on the Ground
European geosciences union general assembly, 2017

Advances in Climate Change Research, 2021
Climate warming leads to vast changes in the land cover types and plant biomass in the northern h... more Climate warming leads to vast changes in the land cover types and plant biomass in the northern high-latitude regions. The overall trend is of shrubland and tree lines moving northwards, while changes in different land cover types and vegetation growth in response to climate change are largely unknown. Here, we selected land areas with latitudes higher than 50 N as the study area. We compared the land cover type changes and explored relationships between the normalized difference vegetation index (NDVI) values of different land cover types, air temperature, and precipitation during 1982e2015 based on dynamic grid. The results indicated that forest and shrubland areas increased as a large area of grassland shifted to forest and shrubland. The snow/ice, tundra and grassland largely have decreased from 1982 to 2015. Although approximately 277.3 Â 10 3 km 2 of barren land (6.2% of the total barren land area in 1982) changed to tundra, the tundra area still decreased because some tundra shifted to forest and grassland. The NDVI values of tundra significantly increased, but the shrubland showed a decreasing trend. Temperature in the growing season (June to September) showed the largest positive correlation coefficients with the NDVI values of forest, tundra, grassland, and cropland. However, due to shrubification processes and plant mortality in shrubland areas, the shrubland NDVI showed negative relationship with annual temperature but positively correlated with monthly t. Taken together, although there is large room for improvement of the land cover type data accuracy, our results suggested that the land cover types in high-latitude regions changed significantly, while the NDVI values of the different land cover types showed different responses to climate change.

Changes in net ecosystem exchange of CO2 in Arctic and their relationships with climate change during 2002–2017
Advances in Climate Change Research, 2021
Abstract Arctic warming leads to permafrost degradation, which can increase ecosystem respiration... more Abstract Arctic warming leads to permafrost degradation, which can increase ecosystem respiration and release more greenhouse gas into the atmosphere. Meanwhile, climate warming also promotes the plant growth and increases carbon assimilation. Presently, it is largely unknown about the carbon budget and their responses to climate change in the Arctic regions. In this study, to investigate the seasonal and annual net ecosystem carbon exchange (NEE), we collected 71 observation stations for net ecosystem exchange (NEE) of CO2 in the high latitude permafrost regions during 2002–2017. The results showed that the annual NEE was −8.2 ± 4.1 g CO2 m−2 d−1 for forest, −3.3 ± 2.6 g CO2 m−2 d−1 for shrub, −4.8 ± 4.1 g CO2 m−2 d−1 for grassland, −3.6 ± 3.0 g CO2 m−2 d−1 for wetland and 0.02 ± 0.62 g CO2 m−2 d−1 for tundra, respectively. From 2002 to 2017, the CO2 emissions of grassland (carbon source) showed a decreasing trend, and the CO2 assimilation of shrub and forest (carbon sink) has been increased. The wetland and tundra are shifting from carbon sources to sinks. There were great variations in temperature sensitivities (Q10) of NEE in different seasons, with larger values in winter and lower values in summer. These findings indicate that the Arctic terrestrial ecosystem presently acts as a carbon sink, while there is a possibility that future warming, especially the warming in winter, may decrease the carbon sink of the Arctic terrestrial ecosystem.

Export of nutrients and suspended solids from major Arctic rivers and their response to permafrost degradation
Advances in Climate Change Research, 2021
Abstract The rapid warming of the Arctic has led to permafrost degradation, accelerating the tran... more Abstract The rapid warming of the Arctic has led to permafrost degradation, accelerating the transport of terrestrial materials by rivers. The quantitative assessment of riverine nutrients and total suspended solids (TSS) flux is important to clarify the land–ocean connections in the Arctic. However, much is unknown about the estimates of these components from direct measurements in the Arctic rivers and the response of the components to permafrost degradation. Here, we report the results from the Arctic Great Rivers Observatory (Arctic-GRO) for the six major Arctic rivers (Yenisey, Lena, Ob’, Mackenzie, Yukon, and Kolyma) to investigate the riverine exports of TSS, total dissolved nitrogen (TDN), nitrate ( NO 3 − ), bicarbonate ( HCO 3 − ), total dissolved phosphorus (TDP), and phosphate ( PO 4 3 − ). The results showed that from 2004 to 2017, the annual TSS, TDN, and NO 3 − exports to the Arctic Ocean were approximately 106,026 Gg, 692 Gg, and 130 Gg, respectively, and the HCO 3 − , TDP, and PO 4 3 − exports were approximately 79,092 Gg, 32 Gg, and 18 Gg, respectively. There were remarkable variations in component concentrations and fluxes between seasons. More than 80% of the TDN, TDP, PO 4 3 − , and TSS exports mainly occurred in spring and summer, and a high HCO 3 − flux was recorded in summer, while a high NO 3 − flux in some rivers occurred in winter. The active layer thickness was significantly positively correlated with the annual TDN, NO 3 − , and HCO 3 − exports. In addition, the HCO 3 − flux of the six Arctic rivers increased by 247 Gg per year during 2004–2017. The positive relationship between the active layer thickness and river discharge indicates that permafrost degradation accelerated riverine carbonate, nitrogen, and phosphorus exports. This study demonstrates that riverine exports play an important role both in the Arctic terrestrial and marine ecosystems, and permafrost degradation will likely increase the riverine material exports to the ocean.

Ambio, Jan 17, 2016
Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover an... more Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for impact assessments and adaptation strategies. Although much progress has been made in understanding and predicting snow-cover changes and their multiple consequences, many uncertainties remain. In this paper, we review advances in snow monitoring and modelling, and the impact of snow changes on ecosystems and society in Arctic regions. Interdisciplinary activities are required to resolve the current limitations on measuring and modelling snow characteristics through the cold season and at different spatial scales to assure human well-being, economic stability, and improve the ability to predict manage and adapt to natural hazards in the Arctic region.
GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY, 2014
Change In Isotopic Content of Snow As A Result of Evaporation From The Snow Surface
ABSTRACT

The project focused on multi-scale and multi-disciplinary aspects of seasonal snow cover in the l... more The project focused on multi-scale and multi-disciplinary aspects of seasonal snow cover in the landscape. The snow physics parameterization takes into account snow structure for use in the Global Circulation Models (GCM). The geographic classification of snow classes is based on snow types, snow layers and crystal types. Numerical experiments with a GCM are performed. The outputs of the largescale models are linked to regional models and compared with measured data. The correlations between snow and hydrology are studied. The economic aspects of the snow, e.g. in tourism and transport, are analyzed. Three years of working together was not enough to answer all the questions that we originally posed. We could explore the potential of a longer lasting cooperation and, with some specific steps, contributed to the exploration of the interrelations of landscape and snow in different spatial scales. Research of this kind should continue in future.
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Papers by Sergey Sokratov