scholarly journals The importance of a surface organic layer in simulating permafrost thermal and carbon dynamics

2016 ◽  
Vol 10 (1) ◽  
pp. 465-475 ◽  
Author(s):  
Elchin Jafarov ◽  
Kevin Schaefer
Keyword(s):  
Soil Carbon ◽  
Carbon Dynamics ◽  
Frozen Soil ◽  
Organic Layer ◽  
Active Layer Thickness ◽  
Frozen Ground ◽  
Initial Amount ◽  
Dynamic Surface ◽  
Carbon Redistribution ◽  
Significant Release

Abstract. Permafrost-affected soils contain twice as much carbon as currently exists in the atmosphere. Studies show that warming of the perennially frozen ground could initiate significant release of the frozen soil carbon into the atmosphere. Initializing the frozen permafrost carbon with the observed soil carbon distribution from the Northern Circumpolar Soil Carbon Database reduces the uncertainty associated with the modeling of the permafrost carbon feedback. To improve permafrost thermal and carbon dynamics we implemented a dynamic surface organic layer with vertical carbon redistribution, and introduced dynamic root growth controlled by active layer thickness, which improved soil carbon exchange between frozen and thawed pools. These changes increased the initial amount of simulated frozen carbon from 313 to 560 Gt C, consistent with observed frozen carbon stocks, and increased the spatial correlation of the simulated and observed distribution of frozen carbon from 0.12 to 0.63.

scholarly journals The importance of a surface organic layer in simulating permafrost thermal and carbon dynamics

2015 ◽  
Vol 9 (3) ◽  
pp. 3137-3163 ◽  
Author(s):  
E. Jafarov ◽  
K. Schaefer
Keyword(s):  
Soil Carbon ◽  
Layer Thickness ◽  
Active Layer ◽  
Carbon Dynamics ◽  
Frozen Soil ◽  
Organic Layer ◽  
Active Layer Thickness ◽  
Frozen Ground ◽  
Dynamic Surface ◽  
Thermal Dynamics

Abstract. Permafrost-affected soils contain twice as much carbon as currently exists in the atmosphere. Studies show that warming of the perennially frozen ground could initiate significant release of the frozen soil carbon into the atmosphere. To reduce the uncertainty associated with the modeling of the permafrost carbon feedback it is important to start with the observed soil carbon distribution and to better address permafrost thermal and carbon dynamics. We used the recent Northern Circumpolar Soil Carbon Dataset to simulate present soil organic carbon (SOC) distribution in permafrost-affected soils under the steady state climate forcing. We implemented a dynamic surface organic layer with vertical carbon redistribution and dynamic root growth controlled by active layer thickness to improve modeling of the permafrost thermodynamics. Our results indicate that a dynamic surface organic layer improved permafrost thermal dynamics and simulated active layer thickness, allowing better simulation of the observed SOC densities and their spatial distribution.

Soil carbon dynamics in Brazilian atlantic forest converted into pasture‐based dairy production systems

2020 ◽  
Author(s):  
Patricia Perondi Anchão Oliveira ◽  
Paulo Henrique Mazza Rodrigues ◽  
Maria Fernanda Ferreira Menegucci Praes ◽  
André Faria Pedroso ◽  
Bia Anchão Oliveira ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Atlantic Forest ◽  
Production Systems ◽  
Carbon Dynamics ◽  
Dairy Production ◽  
Brazilian Atlantic Forest ◽  
Soil Carbon Dynamics

scholarly journals Effects of preferential flow on snowmelt partitioning and groundwater recharge in frozen soils

2019 ◽  
Vol 23 (12) ◽  
pp. 5017-5031 ◽  
Author(s):  
Aaron A. Mohammed ◽  
Igor Pavlovskii ◽  
Edwin E. Cey ◽  
Masaki Hayashi
Keyword(s):  
Soil Moisture ◽  
Groundwater Recharge ◽  
Preferential Flow ◽  
Frozen Soil ◽  
Time Lags ◽  
Runoff Generation ◽  
Frozen Ground ◽  
Soil Matrix ◽  
Frozen Soils ◽  
Flow Through

Abstract. Snowmelt is a major source of groundwater recharge in cold regions. Throughout many landscapes snowmelt occurs when the ground is still frozen; thus frozen soil processes play an important role in snowmelt routing, and, by extension, the timing and magnitude of recharge. This study investigated the vadose zone dynamics governing snowmelt infiltration and groundwater recharge at three grassland sites in the Canadian Prairies over the winter and spring of 2017. The region is characterized by numerous topographic depressions where the ponding of snowmelt runoff results in focused infiltration and recharge. Water balance estimates showed infiltration was the dominant sink (35 %–85 %) of snowmelt under uplands (i.e. areas outside of depressions), even when the ground was frozen, with soil moisture responses indicating flow through the frozen layer. The refreezing of infiltrated meltwater during winter melt events enhanced runoff generation in subsequent melt events. At one site, time lags of up to 3 d between snow cover depletion on uplands and ponding in depressions demonstrated the role of a shallow subsurface transmission pathway or interflow through frozen soil in routing snowmelt from uplands to depressions. At all sites, depression-focused infiltration and recharge began before complete ground thaw and a significant portion (45 %–100 %) occurred while the ground was partially frozen. Relatively rapid infiltration rates and non-sequential soil moisture and groundwater responses, observed prior to ground thaw, indicated preferential flow through frozen soils. The preferential flow dynamics are attributed to macropore networks within the grassland soils, which allow infiltrated meltwater to bypass portions of the frozen soil matrix and facilitate both the lateral transport of meltwater between topographic positions and groundwater recharge through frozen ground. Both of these flow paths may facilitate preferential mass transport to groundwater.

Accounting for space and time in soil carbon dynamics in timbered rangelands

2012 ◽  
Vol 38 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Christopher Dean ◽  
Stephen H. Roxburgh ◽  
Richard J. Harper ◽  
David J. Eldridge ◽  
Ian W. Watson ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Carbon Dynamics ◽  
Soil Carbon Dynamics ◽  
Space And Time

Geothermal modeling of soil or mine tailings with concurrent freezing and deposition

1998 ◽  
Vol 35 (2) ◽  
pp. 234-250 ◽  
Author(s):  
JF (Derick) Nixon ◽  
Nick Holl
Keyword(s):  
Snow Cover ◽  
Mine Tailings ◽  
Frozen Soil ◽  
Freezing And Thawing ◽  
Frozen Ground ◽  
Geothermal Model ◽  
Winter Time ◽  
Upper Boundary ◽  
Good Agreement

A geothermal model is described that simulates simultaneous deposition, freezing, and thawing of mine tailings or sequentially placed layers of embankment soil. When layers of soil or mine tailings are placed during winter subfreezing conditions, frozen layers are formed in the soil profile that may persist with time. The following summer, warmer soil placement may not be sufficient to thaw out layers from the preceding winter. Remnant frozen soil layers may persist for many years or decades. The analysis is unique, as it involves a moving upper boundary and different surface snow cover functions applied in winter time. The model is calibrated based on two uranium mines in northern Saskatchewan. The Rabbit Lake scenario involves tailings growth to a height of 120 m over a period of 24 years. At Key Lake, tailings increase in height at a rate of 1.3 m/year. Good agreement between the observed position of frozen layers and those predicted by the model is obtained. Long-term predictions indicate that from 80 to 200 years would be required to thaw out the frozen layers formed during placement, assuming 1992 placement conditions continue. Deposition rates of 1.5-3 m/year give the largest amounts of frozen ground. The amount of frozen ground is sensitive to the assumed snow cover function during winter.Key words: geothermal, model, tailings, freezing, deposition.

scholarly journals The changing global carbon cycle: linking plant-soil carbon dynamics to global consequences

2009 ◽  
Vol 97 (5) ◽  
pp. 840-850 ◽  
Author(s):  
F. Stuart Chapin III ◽  
Jack McFarland ◽  
A. David McGuire ◽  
Eugenie S. Euskirchen ◽  
Roger W. Ruess ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Soil Carbon ◽  
Carbon Dynamics ◽  
Global Carbon Cycle ◽  
Soil Carbon Dynamics ◽  
Plant Soil ◽  
Global Carbon

Soil carbon dynamics in Canadian Agricultural Ecoregions: Quantifying climatic influence on soil biological activity

2007 ◽  
Vol 122 (4) ◽  
pp. 461-470 ◽  
Author(s):  
M.A. Bolinder ◽  
O. Andrén ◽  
T. Kätterer ◽  
R. de Jong ◽  
A.J. VandenBygaart ◽  
...  
Keyword(s):  
Biological Activity ◽  
Soil Carbon ◽  
Carbon Dynamics ◽  
Soil Biological Activity ◽  
Climatic Influence ◽  
Soil Carbon Dynamics
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