scholarly journals Year-round simulated methane emissions from a permafrost ecosystem in Northeast Siberia

2017 ◽  
Author(s):  
Karel Castro-Morales ◽  
Thomas Kleinen ◽  
Sonja Kaiser ◽  
Sönke Zaehle ◽  
Fanny Kittler ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Russian Far East ◽  
Far East ◽  
Methane Emissions ◽  
The Arctic ◽  
Ch4 Emissions ◽  
Permafrost Thaw

Abstract. Methane emissions to the atmosphere from natural wetlands are estimated to be about 25 % of the total global CH4 emissions. In the Arctic, these areas are highly vulnerable to the effects of global warming due to atmospheric warming amplification, leading to soil hydrologic changes involving permafrost thaw, formation of deeper active layers, and rising topsoil temperatures. As a result, projected increase in the degradation of permafrost carbon will likely lead to higher CO2 and CH4 emissions from these areas. Here we evaluate year-round model-simulated CH4 emissions to the atmosphere (for 2014 and 2015) from a region of northeastern Siberia in the Russian Far East. Four CH4 transport pathways are modeled with a revisit-ed version of the process-based JSBACH-methane model: plant-mediated transport, ebullition and molecular diffusion in the presence or absence of snow. This model also simulates the extent of wetlands as the fraction of inundated area in a model grid cell using a TOP-MODEL approach, and these are evaluated against a highly resolved wetland product from remote sensing data. The model CH4 emissions are compared against ground-based CH4 flux measurements using the eddy covariance technique and flux chambers in the same area of study. The magnitude of the summertime modeled CH4 emissions is comparable to those from eddy covariance and flux chamber measurements. However, wintertime modeled CH4 emissions are underestimated by one order of magnitude. The annual CH4 emissions are dominated by plant-mediated transport (61 %), followed by ebullition (~ 35 %). Molecular diffusion of CH4 from the soil into the atmosphere during summer is negligible (0.02 %) compared to the diffusion through the snow during the non-growing season (~ 4 %). We investigate the relationship between temporal changes in the CH4 fluxes, soil temperature, and soil moisture content. Our results highlight the heterogeneity in CH4 emissions at a landscape scale and suggest that further improvements to the representation of large-scale hydrological conditions in the model, especially at regional scales in Arctic ecosystems influenced by permafrost thaw, will allow us to arrive at a more process-oriented land surface scheme and better simulate CH4 emissions under climate change.

scholarly journals Year-round simulated methane emissions from a permafrost ecosystem in Northeast Siberia

2018 ◽  
Vol 15 (9) ◽  
pp. 2691-2722 ◽  
Author(s):  
Karel Castro-Morales ◽  
Thomas Kleinen ◽  
Sonja Kaiser ◽  
Sönke Zaehle ◽  
Fanny Kittler ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Surface ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Russian Far East ◽  
Far East ◽  
Arctic Ecosystems ◽  
Transport Pathways ◽  
Ch4 Emissions ◽  
Permafrost Thaw

Abstract. Wetlands of northern high latitudes are ecosystems highly vulnerable to climate change. Some degradation effects include soil hydrologic changes due to permafrost thaw, formation of deeper active layers, and rising topsoil temperatures that accelerate the degradation of permafrost carbon and increase in CO2 and CH4 emissions. In this work we present 2 years of modeled year-round CH4 emissions into the atmosphere from a Northeast Siberian region in the Russian Far East. We use a revisited version of the process-based JSBACH-methane model that includes four CH4 transport pathways: plant-mediated transport, ebullition and molecular diffusion in the presence or absence of snow. The gas is emitted through wetlands represented by grid cell inundated areas simulated with a TOPMODEL approach. The magnitude of the summertime modeled CH4 emissions is comparable to ground-based CH4 fluxes measured with the eddy covariance technique and flux chambers in the same area of study, whereas wintertime modeled values are underestimated by 1 order of magnitude. In an annual balance, the most important mechanism for transport of methane into the atmosphere is through plants (61 %). This is followed by ebullition ( ∼  35 %), while summertime molecular diffusion is negligible (0.02 %) compared to the diffusion through the snow during winter ( ∼  4 %). We investigate the relationship between temporal changes in the CH4 fluxes, soil temperature, and soil moisture content. Our results highlight the heterogeneity in CH4 emissions at landscape scale and suggest that further improvements to the representation of large-scale hydrological conditions in the model will facilitate a more process-oriented land surface scheme and better simulate CH4 emissions under climate change. This is especially necessary at regional scales in Arctic ecosystems influenced by permafrost thaw.

scholarly journals Addressing Biases in Arctic-Boreal Carbon Cycling in the Community Land Model Version 5

2020 ◽  
Author(s):  
Leah Birch ◽  
Christopher R. Schwalm ◽  
Sue Natali ◽  
Danica Lombardozzi ◽  
Gretchen Keppel-Aleks ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Eddy Covariance ◽  
Land Surface ◽  
Large Scale ◽  
Carbon Allocation ◽  
Ecosystem Respiration ◽  
Terrestrial Ecosystem ◽  
The Arctic ◽  
Community Land Model ◽  
Warming World

Abstract. The Arctic-boreal zone (ABZ) is experiencing amplified warming, actively changing biogeochemical cycling of vegetation and soils. The land-to-atmosphere fluxes of CO2 in the ABZ have the potential to increase in magnitude and feedback to the climate causing additional large scale warming. The ability to model and predict this vulnerability is critical to preparation for a warming world, but Earth system models have biases that may hinder understanding the rapidly changing ABZ carbon fluxes. Here we investigate circumpolar carbon cycling represented by the Community Land Model 5 (CLM5.0) with a focus on seasonal gross primary productivity (GPP) in plant functional types (PFTs). We benchmark model results using data from satellite remote sensing products and eddy covariance towers. We find consistent biases in CLM5.0 relative to observational constraints: (1) the onset of deciduous plant productivity to be late, (2) the offset of productivity to lag and remain abnormally high for all PFTs in fall, (3) a high bias of grass, shrub, and needleleaf evergreen tree productivity, and (4) an underestimation of productivity of deciduous trees. Based on these biases, we focus model development of alternate phenology, photosynthesis schemes, and carbon allocation parameters at eddy covariance tower sites. Although our improvements are focused on productivity, our final Model Recommendation results in other component CO2 fluxes, e.g. Net Ecosystem Exchange (NEE) and Terrestrial Ecosystem Respiration (TER), that are more consistent with observations. Results suggest that algorithms developed for lower latitudes and more temperate environments can be inaccurate when extrapolated to the ABZ, and that many land surface models may not accurately represent carbon cycling and its recent rapid changes in high latitude ecosystems, especially when analyzed by individual PFTs.

Learning Soil Freeze Characteristic Curves with Universal Differential Equations

2021 ◽  
Author(s):  
Brian Groenke ◽  
Moritz Langer ◽  
Guillermo Gallego ◽  
Julia Boike
Keyword(s):  
Differential Equations ◽  
Phase Change ◽  
Land Surface ◽  
Large Scale ◽  
Characteristic Curve ◽  
Soil Freezing ◽  
Climate Feedback ◽  
The Arctic ◽  
Permafrost Thaw

<p>Permafrost thaw is considered one of the major climate feedback processes and is currently a significant source of uncertainty in predicting future climate states. Coverage of in-situ meteorological and land-surface observations is sparse throughout the Arctic, making it difficult to track the large-scale evolution of the Arctic surface and subsurface energy balance. Furthermore, permafrost thaw is a highly non-linear process with its own feedback mechanisms such as thermokarst and thermo-erosion. Land surface models, therefore, play an important role in our ability to understand how permafrost responds to the changing climate. There is also a need to quantify freeze-thaw cycling and the incomplete freezing of soil at depth (talik formation). One of the key difficulties in modeling the Arctic subsurface is the complexity of the thermal regime during phase change under freezing or thawing conditions. Modeling heat conduction with phase change accurately requires estimation of the soil freeze characteristic curve (SFCC) which governs the change in soil liquid water content with respect to temperature and depends on the soil physical characteristics (texture). In this work, we propose a method for replacing existing brute-force approximations of the SFCC in the CryoGrid 3 permafrost model with universal differential equations, i.e. differential equations that include one or more terms represented by a universal approximator (e.g. a neural network). The approximator is thus tasked with inferring a suitable SFCC from available soil temperature, moisture, and texture data. We also explore how remote sensing data might be used with universal approximators to extrapolate soil freezing characteristics where in-situ observations are not available.</p>

scholarly journals Addressing biases in Arctic–boreal carbon cycling in the Community Land Model Version 5

2021 ◽  
Vol 14 (6) ◽  
pp. 3361-3382
Author(s):  
Leah Birch ◽  
Christopher R. Schwalm ◽  
Sue Natali ◽  
Danica Lombardozzi ◽  
Gretchen Keppel-Aleks ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Eddy Covariance ◽  
Land Surface ◽  
Large Scale ◽  
Carbon Allocation ◽  
Ecosystem Respiration ◽  
Terrestrial Ecosystem ◽  
The Arctic ◽  
Community Land Model ◽  
Warming World

Abstract. The Arctic–boreal zone (ABZ) is experiencing amplified warming, actively changing biogeochemical cycling of vegetation and soils. The land-to-atmosphere fluxes of CO2 in the ABZ have the potential to increase in magnitude and feedback to the climate causing additional large-scale warming. The ability to model and predict this vulnerability is critical to preparation for a warming world, but Earth system models have biases that may hinder understanding of the rapidly changing ABZ carbon fluxes. Here we investigate circumpolar carbon cycling represented by the Community Land Model 5 (CLM5.0) with a focus on seasonal gross primary productivity (GPP) in plant functional types (PFTs). We benchmark model results using data from satellite remote sensing products and eddy covariance towers. We find consistent biases in CLM5.0 relative to observational constraints: (1) the onset of deciduous plant productivity to be late; (2) the offset of productivity to lag and remain abnormally high for all PFTs in fall; (3) a high bias of grass, shrub, and needleleaf evergreen tree productivity; and (4) an underestimation of productivity of deciduous trees. Based on these biases, we focus on model development of alternate phenology, photosynthesis schemes, and carbon allocation parameters at eddy covariance tower sites. Although our improvements are focused on productivity, our final model recommendation results in other component CO2 fluxes, e.g., net ecosystem exchange (NEE) and terrestrial ecosystem respiration (TER), that are more consistent with observations. Results suggest that algorithms developed for lower latitudes and more temperate environments can be inaccurate when extrapolated to the ABZ, and that many land surface models may not accurately represent carbon cycling and its recent rapid changes in high-latitude ecosystems, especially when analyzed by individual PFTs.

State youth policy and its role in social development

2020 ◽  
Vol 22 (5) ◽  
pp. 12-18
Author(s):  
YURI V. BEREZUTSKIY ◽  
◽  
NIKOLAY M. BAYKOV ◽  
Keyword(s):  
Social Development ◽  
Large Scale ◽  
Russian Far East ◽  
Social Activity ◽  
Far East ◽  
The State ◽  
Youth Policy ◽  
Employment Conditions ◽  
Sociological Studies ◽  
Migratory Movements

The article presents the analysis of the state youth policy as an instrument of influence on the state and social development of youth, its social activity. The contradictions that exist between the performance indicators declared by the state policy and the real problems of youth, determined by the living conditions, are indicated. Based on the results of all-Russian and regional sociological studies and statistics, the motives of migratory movements of youth from their territories of residence to the centers of gravity of the country and foreign countries that have more attractive living and employment conditions for youth are justified. Using the example of the Russian Far East, the dysfunctional consequences of the clerical-bureaucratic approach laid down in the state youth policy to quantify the state of youth ignoring its large-scale migration outflow from the territories of residence are substantiated. Scientific and practical recommendations on improvement of indicators of the state youth policy promoting strengthening of its role in providing the basic needs of youth in various spheres of activity, especially in development of youth business are offered.

scholarly journals Vegetation responses to interglacial warming in the Arctic: examples from Lake El'gygytgyn, Far East Russian Arctic

2013 ◽  
Vol 9 (3) ◽  
pp. 1211-1219 ◽  
Author(s):  
A. V. Lozhkin ◽  
P. M. Anderson
Keyword(s):  
Deciduous Forest ◽  
Russian Far East ◽  
Coniferous Forest ◽  
Far East ◽  
The Arctic ◽  
Dark Coniferous Forest ◽  
Vegetation Responses ◽  
Wide Range ◽  
Lake El’Gygytgyn ◽  
Shrub Tundra

Abstract. Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea–Larix–Betula–Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial–interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula–Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios.

scholarly journals Soil moisture control over autumn season methane flux, Arctic Coastal Plain of Alaska

2012 ◽  
Vol 9 (4) ◽  
pp. 1423-1440 ◽  
Author(s):  
C. S. Sturtevant ◽  
W. C. Oechel ◽  
D. Zona ◽  
Y. Kim ◽  
C. E. Emerson
Keyword(s):  
Large Scale ◽  
Winter Season ◽  
Methane Flux ◽  
Soil Freezing ◽  
The Arctic ◽  
Freezing Process ◽  
Unfrozen Water ◽  
Ch4 Emission ◽  
Ch4 Emissions ◽  
Autumn Season

Abstract. Accurate estimates of annual budgets of methane (CH4) efflux in arctic regions are severely constrained by the paucity of non-summer measurements. Moreover, the incomplete understanding of the ecosystem-level sensitivity of CH4 emissions to changes in tundra moisture makes prediction of future CH4 release from the Arctic extremely difficult. This study addresses some of these research gaps by presenting an analysis of eddy covariance and chamber measurements of CH4 efflux and supporting environmental variables during the autumn season and associated beginning of soil freeze-up at our large-scale water manipulation site near Barrow, Alaska (the Biocomplexity Experiment). We found that the autumn season CH4 emission is significant (accounting for 21–25% of the average growing season emission), and that this emission is mostly controlled by the fraction of inundated landscape, atmospheric turbulence, and the decline in unfrozen water during the period of soil freezing. Drainage decreased autumn CH4 emission by a factor of 2.4 compared to our flooded treatment. Flooding slowed the soil freezing process which has implications for extending elevated CH4 emissions longer into the winter season.

MECHANISMS FOR THE DEVELOPMENT OF TRANSPORT INFRASTRUCTURE IN COMPLEX CLIMATE AND GEOGRAPHIC CONDITIONS

2020 ◽  
pp. 03-07
Author(s):  
Vladimir Victorovich Tsyganov
Keyword(s):  
Strategic Management ◽  
Large Scale ◽  
Far East ◽  
Transport Infrastructure ◽  
The Arctic ◽  
Arctic Zone ◽  
The Far East

Mechanisms and procedures for strategic management of the development of transport infrastructure in a large-scale region located in difficult climatic and geographical conditions are proposed. These mechanisms and procedures are illustrated by the example of managing the development of transport infrastructure in Siberia, the Far East and the Arctic zone of Russia.

Microplastic in the Arctic and Russian Far East Coastal Ground

2020 ◽  
Vol 24 (4) ◽  
pp. 16-19 ◽  
Author(s):  
Ya.Yu. Blinovskaya ◽  
O.A. Kulikova ◽  
E.A. Mazlova ◽  
M.V. Gavrilo
Keyword(s):  
Russian Far East ◽  
Far East ◽  
Average Concentration ◽  
The Arctic ◽  
Arctic Seas ◽  
The Far East ◽  
The World

The first steps have been taken to study microplastics in the beach areas of the Arctic seas and the southern part of the Far East. Researches have shown that the average concentration in the areas studied is about 1 particle per kilogram of beach ground which is significantly lower than in other regions of the world. However due to the difficult access and irregular nature of the work an objective situation cannot be presented yet.

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