scholarly journals Response of Soil Moisture Change to Hydrological Processes in a Continuous Permafrost Environment

1990 ◽  
Vol 21 (4-5) ◽  
pp. 235-252 ◽  
Author(s):  
Ming-ko Woo ◽  
Philip Marsh
Keyword(s):  
Active Layer ◽  
Hydrological Processes ◽  
Moisture Loss ◽  
Moisture Regime ◽  
Permafrost Environment ◽  
Wetland Site ◽  
Gamma Density ◽  
Lateral Inflow ◽  
Continuous Permafrost ◽  
Moisture Storage

The moisture content of the active layer at three sites in a continuous permafrost area was measured using a twin-probe gamma density meter. The moisture storage status at these sites were related to various hydrological processes. Moisture was gained by meltwater and rainfall infiltration, but lost to evaporation in summer. Lateral inflow maintained a thick saturated zone at the fen (wetland) site. At the gravel site, there was a net moisture loss due to evaporation and lateral outflow. Moisture changes in the active layer during the summer were examined in terms of the water balance at the three sites. This established quantitative relationships between the moisture regime and the major hydrological processes in the permafrost environment.

scholarly journals Recent changes to the hydrological cycle of an Arctic basin at the tundra–taiga transition

2018 ◽  
Vol 22 (7) ◽  
pp. 3993-4014 ◽  
Author(s):  
Sebastian A. Krogh ◽  
John W. Pomeroy
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Snow Water Equivalent ◽  
Hydrological Cycle ◽  
Arctic Basin ◽  
Hydrological Processes ◽  
Active Layer Thickness ◽  
Blowing Snow ◽  
Hydrological Changes ◽  
The Impact

Abstract. The impact of transient changes in climate and vegetation on the hydrology of small Arctic headwater basins has not been investigated before, particularly in the tundra–taiga transition region. This study uses weather and land cover observations and a hydrological model suitable for cold regions to investigate historical changes in modelled hydrological processes driving the streamflow response of a small Arctic basin at the treeline. The physical processes found in this environment and explicit changes in vegetation extent and density were simulated and validated against observations of streamflow discharge, snow water equivalent and active layer thickness. Mean air temperature and all-wave irradiance have increased by 3.7 ∘C and 8.4 W m−2, respectively, while precipitation has decreased 48 mm (10 %) since 1960. Two modelling scenarios were created to separate the effects of changing climate and vegetation on hydrological processes. Results show that over 1960–2016 most hydrological changes were driven by climate changes, such as decreasing snowfall, evapotranspiration, deepening active layer thickness, earlier snow cover depletion and diminishing annual sublimation and soil moisture. However, changing vegetation has a significant impact on decreasing blowing snow redistribution and sublimation, counteracting the impact of decreasing precipitation on streamflow, demonstrating the importance of including transient changes in vegetation in long-term hydrological studies. Streamflow dropped by 38 mm as a response to the 48 mm decrease in precipitation, suggesting a small degree of hydrological resiliency. These results represent the first detailed estimate of hydrological changes occurring in small Arctic basins, and can be used as a reference to inform other studies of Arctic climate change impacts.

Active layer slope movement in a continuous permafrost environment, Garry Island, Northwest Territories, Canada

1981 ◽  
Vol 18 (11) ◽  
pp. 1666-1680 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Velocity Profile ◽  
Active Layer ◽  
Vertical Velocity ◽  
Late Summer ◽  
Organic Layer ◽  
Field Investigations ◽  
Permafrost Environment ◽  
Vertical Velocity Profile ◽  
Ice Wedge ◽  
Ice Content

Field investigations have been carried out at Garry Island, N.W.T. for the 1964–1980 period in order to study downslope active layer movement at sites with two-sided (downward and upward) freezing and active ice-wedge growth. Movements have been determined with reference to semi-flexible plastic tubes inserted vertically into the ground and by deformation of lines of stakes. The results show that the vertical velocity profile on the hillslopes with clayey hummocks is convex downslope; the movement is plug-like and occurs in late summer; the plug-like movement progressively buries the interhummock peat to form a buried organic layer; and most of the plug-like movement can be attributed to frost creep by thaw of an ice-rich layer at the bottom of the active layer. The ice-rich layer forms by upfreezing in winter and the ice content may be augmented by ice lensing in the summer thaw period. In a sedgy drainage swale, the vertical velocity profile is concave downslope. The active layer of ice-wedge polygons shows a net movement outwards from the centres to the troughs. These studies show that active layer movement at sites with two-sided freezing and active ice-wedge polygons may differ substantially from sites with only one-sided freezing and without active ice-wedge polygons.

scholarly journals DEVELOPMENT OF A SET-TYPE SPRINKLING MACHINE AND SUBSTANTIATION OF ITS PARAMETERS

2020 ◽  
Author(s):  
В.С. ТЕТЕРИН ◽  
Д.С. МЕЛЬНИЧУК
Keyword(s):  
Moisture Content ◽  
Active Layer ◽  
Water Regime ◽  
Crop Productivity ◽  
Living Environment ◽  
Moisture Regime ◽  
Climate Conditions ◽  
Natural Rainfall ◽  
Production Processes ◽  
Epicyclic Gear

Важным фактором, влияющим на урожайность сельскохозяйственных культур, является формирование оптимального водного режима в активном слое почвы. Изменение содержания воды в среде произрастания растений позволяет управлять протекающими в них продукционными процессами. Оптимизация водного режима в активном слое почвы достигается путем проведения плановых гидромелиоративных работ, связанных с увлажнением почвогрунта до глубины залегания основной массы корневой системы сельскохозяйственных культур. Одним из наиболее совершенных способов проведения таких работ является дождевание, так как данный способ наиболее приближен к процессу естественного выпадения осадков. Дождевальная техника с каждым годом находит все большее применение, даже в районах с благоприятным климатом. При этом существующие дождевальные машины не могут в полной мере производить качественный полив сельскохозяйственных угодий из-за конструктивных особенностей и специфики ландшафта, на котором они применяются, образуя в процессе полива зоны с избыточным и недостаточным увлажнением. В связи с этим была разработана дождевальная установка позиционного действия, обладающая возможностью полива по траектории, близкой к прямоугольной. Получение данной траектории достигается за счет использования принципа планетарной передачи. В статье представлена конструктивная схема разработанной дождевальной установки, рассмотрен принцип её работы, приведены результаты математического анализа и моделирования кинематических процессов, происходящих во время её работы. Приведённые результаты исследований показывают, что использование предлагаемой дождевальной установки позволит повысить качество полива за счет траектории орошения, наиболее близкой к прямоугольной. Использование подобной траектории обеспечит сокращение расхода водных ресурсов за счет оптимизации процесса орошения и снижения переувлажненных площадей и площадей с недостаточным уровнем увлажнения, тем самым способствуя равномерному и оптимальному развитию сельскохозяйственных культур. Forming the optimal water regime in the active layer of soil is an important factor that affects crop productivity. Changing moisture content in the living environment of plants allows to ensure control over their production processes. Optimization of moisture regime in the active layer of soil is achieved by carrying out systematic hydromeliorative practices, involving wetting of the soil to the depth of occurrence of crops root system. One of the optimal methods is sprinkling, since this method is the most similar to natural rainfall. Sprinkling machines are becoming more widely used every year, even in regions with favorable climate conditions. However, the existing sprinkling machines are not able to provide effective irrigation of arable lands due to certain design features and particular characteristics of the landscape of application area, that results in formation of zones of excessive and insufficient wetting in the process of irrigation. In this connection, we developed a set-type sprinkling machine, able to distribute water along the trajectory, which is close to rectangular. This trajectory is obtained through the application of epicyclic gear system. The paper introduces a design concept of the developed sprinkling machine, describes its operating principle, provides results of the mathematical analysis and modeling kinematic processes during operation. The presented results of the studies show, that using the proposed sprinkling machine contributes to the improvement of irrigation effectiveness due to water trajectory, which is the closest to rectangular. Such trajectory will ensure more efficient use of water resources through optimization of the irrigation process and reduction of areas of excessive and insufficient moisture content, that contributes to the balanced and proper development of crops.

Slope hydrology as influenced by thawing of the active layer, Resolute, N.W.T.

1983 ◽  
Vol 20 (6) ◽  
pp. 978-986 ◽  
Author(s):  
Ming-ko Woo ◽  
Peter Steer
Keyword(s):  
Surface Topography ◽  
Active Layer ◽  
Surface Runoff ◽  
Storage Capacity ◽  
Water Storage ◽  
High Arctic ◽  
Surface Flow ◽  
Water Storage Capacity ◽  
Continuous Permafrost ◽  
Generate Surface

High arctic slopes have a shallow active layer that thaws unevenly during summer. The result is often a lack of agreement between the configuration of the frost table and the surface topography, and this has effects on the slope hydrology. (1) Areas with a shallow frost table favour surface runoff but areas with a deeper frost table require a thick zone of saturation to generate surface flow. Uneven thaw depths then cause alternating seepage and re-emergence of water down a slope. (2) The configuration of the frost table is highly dynamic, causing day to day changes in water storage capacity in the active layer. (3) A frost table with local depressions can pond up groundwater, which may be rapidly released when part of the frozen sill is breached by continual thawing. (4) The topographical drainage divide may not correspond with the subsurface drainage divide as defined by the frost table, thus allowing groundwater to drain laterally across topographical boundaries. These findings show that a knowledge of the frost table behaviour, both spatially and temporally, is essential to the study of slope hydrology in continuous permafrost terrains.

Watershed Hydrology and Chemistry in the Alaskan Boreal Forest: The Central Role of Permafrost

2006 ◽  
Author(s):  
Larry D. Hinzman ◽  
Kevin C. Petrone
Keyword(s):  
Boreal Forest ◽  
Active Layer ◽  
Hydrological Processes ◽  
Organic Layer ◽  
Freezing And Thawing ◽  
Surface Soils ◽  
Near Surface ◽  
Organic Layers ◽  
Discontinuous Permafrost ◽  
Permafrost Soils

Hydrological processes exert strong control over biological and climatic processes in every ecosystem. They are particularly important in the boreal zone, where the average annual temperatures of the air and soil are relatively near the phase-change temperature of water (Chapter 4). Boreal hydrology is strongly controlled by processes related to freezing and thawing, particularly the presence or absence of permafrost. Flow in watersheds underlain by extensive permafrost is limited to the near-surface active layer and to small springs that connect the surface with the subpermafrost groundwater. Ice-rich permafrost, near the soil surface, impedes infiltration, resulting in soils that vary in moisture content from wet to saturated. Interior Alaska has a continental climate with relatively low precipitation (Chapter 4). Soils are typically aeolian or alluvial (Chapter 3). Consequently, in the absence of permafrost, infiltration is relatively high, yielding dry surface soils. In this way, discontinuous permafrost distribution magnifies the differences in soil moisture that might normally occur along topographic gradients. Hydrological processes in the boreal forest are unique due to highly organic soils with a porous organic mat on the surface, short thaw season, and warm summer and cold winter temperatures. The surface organic layer tends to be much thicker on north-facing slopes and in valley bottoms than on south-facing slopes and ridges, reflecting primarily the distribution of permafrost. Soils are cooler and wetter above permafrost, which retards decomposition, resulting in organic matter accumulation (Chapter 15). The markedly different material properties of the soil layers also influence hydrology. The highly porous near-surface soils allow rapid infiltration and, on hillsides, downslope drainage. The organic layer also has a relatively low thermal conductivity, resulting in slow thaw below thick organic layers. The thick organic layer limits the depth of thaw each summer to about 50–100 cm above permafrost (i.e., the active layer). As the active layer thaws, the hydraulic properties change. For example, the moisture-holding capacity increases, and additional subsurface layers become available for lateral flow. The mosaic of Alaskan vegetation depends not only on disturbance history (Chapter 7) but also on hydrology (Chapter 6).

scholarly journals Geocryological Zones Of Antarctica (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 345 ◽  
Author(s):  
B.I. Vtyurin
Keyword(s):  
Active Layer ◽  
Mean Annual Temperature ◽  
Freezing And Thawing ◽  
Ground Ice ◽  
Frost Action ◽  
Maximum Thickness ◽  
Continuous Permafrost ◽  
The Mean ◽  
Ice Content ◽  
The Antarctic

Criteria for the determination of geocryological zones are: (1) distribution of permafrost, (2) the mean annual temperature of permafrost, (3) thickness of the active layer, (4) types of ground ice and ice content of permafrost, (5) regularities of cryogenic structure, (6) cryogenic phenomena, and (7) types of cryogenic relief. Interpretation of the available data allows us to delineate the following geocryological zones in the Antarctic: (1) sub-Antarctic islands, (2) coastalcontinental, and (3) intercontinental. The brief general geocryological characteristic of these zones is given in the paper. The sub-Antarctic island zone features discontinuous and continuous permafrost. The mean annual temperature of the permafrost is near 0°C and the maximum thickness is several tens of metres. The seasonal thawed zone has a thickness of 0.4 to 1.2 m. There are visible ice inclusions and very small ice forms in the permafrost and seasonal frost. Frost action causes frost sorting, hill - slope forms, and thermokarst. Ice-wedges are not found in the sub-Antarctic zone. The coastal-continental zone has continuous permafrost. The mean annual temperature of the permafrost therejs -1°C in the Antarctic Peninsula and up to -5 to -7°C in East Antarctica. Maximum thickness of the permafrost is over 100 m and the active layer is 0.3 to 1 m. The ground ice is mainly pore ice but in some places there is buried glacier ice in moraine. Frost action, frost sorting, creep, nivation, and pre-glacial slope forms are developed in the coastalcontinental zone. The intercontinental zone consists of continuous permafrost only. The mean annual temperature of the permafrost there is -10°C or lower. Thickness of this permafrost is several hundreds of metres and of the active layer is 0.1 to 0.5 m. The ice content is low with only small ice forms. The cryogenic structure of the permafrost is the same as the coastal-continental zone. Because alternate freezing and thawing is infrequent in the intercontinental zone all cryogenic processes are less rapid than in the other zones. Thermokarst is not found there and 1n general the intercontinental zone is not as well studied as the two other zones.

scholarly journals Contrasting extreme runoff events in areas of continuous permafrost, Arctic Alaska

2008 ◽  
Vol 39 (4) ◽  
pp. 287-298 ◽  
Author(s):  
Douglas L. Kane ◽  
Larry D. Hinzman ◽  
Robert E. Gieck ◽  
James P. McNamara ◽  
Emily K. Youcha ◽  
...  
Keyword(s):  
Surface Water ◽  
Active Layer ◽  
Coastal Plain ◽  
The Arctic ◽  
Near Surface ◽  
Extreme Flows ◽  
Continuous Permafrost ◽  
Drought Conditions ◽  
Snowmelt Flood ◽  
Kuparuk River

Spring snowmelt floods in the Arctic are common and can be expected every year, mainly because of the extensive snow cover that ablates relatively quickly. However, documentation of extreme flows (both low and high) in the Arctic is lacking in part because extreme flows are relatively rare and gauging sites are very sparse, with most of short duration. In the nested Kuparuk River research watersheds on the North Slope of Alaska, two large summer floods have been observed (July 1999 and August 2002) in the headwaters; these high flows are contrasted to the low flows (drought conditions) observed in the summers of 2005 and 2007. It is clear that the continuous permafrost and the limited near-surface storage in the shallow active layer are responsible for both the high and low flow responses. Or, stated another way, the active layer is a poor buffer to both floods and droughts. When contrasting summer floods with snowmelt floods, it is clear from flood frequency analyses that the smaller, high-gradient headwater basins will be dominated by summer floods while those watersheds draining the low gradient coastal plain will be dominated by snowmelt floods. The two summer floods in the headwaters had flows that were three to four times greater than the largest measured snowmelt flood, while on the coastal plain the 2002 summer storm for the whole of the Kuparuk River only produced the maximum summer runoff of record that was about 1/4 of the maximum snowmelt flood. So, on the coastal plain and even for the Greater Kuparuk River that drains across the coastal plain, snowmelt floods dominate. Drought conditions prevail in summers when the limited surface water storage in the active layer and surface water bodies is depleted because evapotranspiration exceeds precipitation.

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