Topic
Talik
About: Talik is a research topic. Over the lifetime, 226 publications have been published within this topic receiving 6084 citations.
Papers published on a yearly basis
Papers
TL;DR: In this article, the authors used synthetic aperture radar (SAR) data for classification of terrain units and surface water properties, while historical aerial photographs and satellite images (IKONOS) were used for assessment of pond shrinking and recent thermokarst progression.
Abstract: The purpose of this study was to characterize the geomorphological processes controlling the dynamics of ponds and to identify and characterize groundwater infiltration and surface water dynamics for a tundra terrain located in discontinuous permafrost near Council, Alaska. Thermokarst processes and permafrost degradation were studied, focusing upon the interaction between surface and groundwater systems via an open talik. Synthetic aperture radar (SAR) data were used for classification of terrain units and surface water properties, while historical aerial photographs and satellite images (IKONOS) were used for assessment of pond shrinking and recent thermokarst progression. Geophysical surveys (ground penetrating radar and DC resistivity) were conducted to detect permafrost thickness and talik formations. Temperature boreholes and hydrological observation wells were monitored throughout the year and provided ground truth for validation of remotely-sensed data and geophysical surveys. Field and laboratory analyses enabled quantitative determination of subsurface hydrologic and thermal properties. We found many areas where alluvium deposits and ice-wedge polygonal terrain had developed thermokarst features within the last 20 years. Thermokarst ponds located over ice-wedge terrain have decreased in surface area since at least the early 20th Century. Small thermokarst features initially developed into tundra ponds perched over permafrost in response to some local disturbance to the surface. These thermokarst ponds grew larger and initiated large taliks that completely penetrated the permafrost. These taliks allowed internal drainage throughout the year causing the ponds to shrink under recent climatic conditions. Shrinking pond surface areas may become a common feature in the discontinuous permafrost regions as a consequence of warming climate and thawing permafrost. Copyright © 2003 John Wiley & Sons, Ltd.
547 citations
TL;DR: A review of the literature that has contributed to our understanding of patterns, processes and feedbacks, and the environmental consequences of thermokarst, focusing on hillslope, thaw lake and wetland processes is provided in this article.
Abstract: The term thermokarst describes the processes and landforms that involve collapse of the land surface as a result of the melting of ground ice. We review the literature that has contributed to our understanding of patterns, processes and feedbacks, and the environmental consequences of thermokarst, focusing on hillslope, thaw lake and wetland processes. Advances in remote sensing techniques, and their application in a broad suite of change detection studies, indicate recent increases in the rates and magnitude of thermokarst including retrogressive thaw slumping, lake expansion and the transformation of frozen peatlands to collapsed wetlands. Field-based studies and modelling have enhanced the knowledge of processes and feedbacks associated with warming permafrost, changes in talik geometry and accelerated thaw slump activity, and thaw lake expansion. Hydrological processes can strongly influence the rates of thaw lake and gully development, and the degradation of frozen peatlands. Field studies and calibrated modelling efforts that investigate the drivers of thermokarst and test conceptual ideas of landscape evolution will be critical to further advance the prediction of landscape and ecosystem change. Thermokarst research provides an important context for studying the environmental implications of permafrost degradation. Hillslope thermokarst can alter the water quality of lakes and streams with implications for aquatic ecosystems. Investigation of the interactions between thermokarst and hydrologic and ecological processes has improved knowledge of the feedbacks that accelerate change or lead to stabilisation in terrestrial and thaw lake environments. Finally, the influence of permafrost thaw on soil carbon dynamics will be an important focus of thermokarst research because of feedbacks with the global climate system. Copyright © Her Majesty the Queen in Right of Canada 2013.
499 citations
TL;DR: In this article, the impact of wildfire on permafrost during and after 11 boreal forest fire sites including two controlled burns was studied using 11 Boreal Forest fire sites, and the authors found that the thermal impact of fire on ground thermal conductivity may increase 10-fold and surface albedo can decrease by 50% depending on the extent of burning.
Abstract: [1] The impact to the permafrost during and after wildfire was studied using 11 boreal forest fire sites including two controlled burns. Heat transfer by conduction to the permafrost was not significant during fire. Immediately following fire, ground thermal conductivity may increase 10-fold and the surface albedo can decrease by 50% depending on the extent of burning of the surficial organic soil. The thickness of the remaining organic layer strongly affects permafrost degradation and aggradation. If the organic layer thickness was not reduced during the burn, then the active layer (the layer of soil above permafrost that annually freezes and thaws) did not change after the burn in spite of the surface albedo decrease. Any significant disturbance to the surface organic layer will increase heat flow through the active layer into the permafrost. Approximately 3–5 years after severe disturbance and depending on site conditions, the active layer will increase to a thickness that does not completely refreeze the following winter. This results in formation of a talik (an unfrozen layer below the seasonally frozen soil and above the permafrost). A thawed layer (4.15 m thick) was observed at the 1983 burned site. Model studies suggest that if an organic layer of more than 7–12 cm remains following a wildfire then the thermal impact to the permafrost will be minimal in the boreal forests of Interior Alaska.
342 citations
1 Jan 2003
TL;DR: In this article, the impact of wildfire on permafrost during and after 11 boreal forest fire sites including two controlled burns was studied using eleven borealforest fire sites, and the authors found that ground thermalconductivity may increase 10-fold and the surface albedo can decrease by 50% depending on the extent of burning of the surficial organic soil.
Abstract: The impact to the permafrost during and after wildfire was studied using 11 borealforest fire sites including two controlled burns. Heat transfer by conduction to thepermafrost was not significant during fire. Immediately following fire, ground thermalconductivity may increase 10-fold and the surface albedo can decrease by 50%depending on the extent of burning of the surficial organic soil. The thickness of theremaining organic layer strongly affects permafrost degradation and aggradation. If theorganic layer thickness was not reduced during the burn, then the active layer (the layerof soil above permafrost that annually freezes and thaws) did not change after the burn inspite of the surface albedo decrease. Any significant disturbance to the surface organiclayer will increase heat flow through the active layer into the permafrost. Approximately3–5 years after severe disturbance and depending on site conditions, the active layer willincrease to a thickness that does not completely refreeze the following winter. Thisresults in formation of a talik (an unfrozen layer below the seasonally frozen soil andabove the permafrost). A thawed layer (4.15 m thick) was observed at the 1983 burnedsite. Model studies suggest that if an organic layer of more than 7–12 cm remainsfollowing a wildfire then the thermal impact to the permafrost will be minimal in theboreal forests of Interior Alaska.
255 citations
TL;DR: In this article, the authors measured soil hydrologic and thermal dynamics and soil organic carbon (OC) dynamics across a collapse-scar bog chronosequence in interior Alaska and found that the accumulation of OC in near-surface bog peat continued for nearly 1,000 years following permafrost thaw, at which point accumulation rates slowed.
Abstract: Recent warming at high-latitudes has accelerated permafrost thaw in northern peatlands, and thaw can have profound effects on local hydrology and ecosystem carbon balance. To assess the impact of permafrost thaw on soil organic carbon (OC) dynamics, we measured soil hydrologic and thermal dynamics and soil OC stocks across a collapse-scar bog chronosequence in interior Alaska. We observed dramatic changes in the distribution of soil water associated with thawing of ice-rich frozen peat. The impoundment of warm water in collapse-scar bogs initiated talik formation and the lateral expansion of bogs over time. On average, Permafrost Plateaus stored 137 ± 37 kg C m -2 , whereas OC storage in Young Bogs and Old Bogs averaged 84 ± 13 kg C m -2 . Based on our reconstructions, the accumulation of OC in near-surface bog peat continued for nearly 1,000 years following permafrost thaw, at which point accumulation rates slowed. Rapid decomposition of thawed forest peat reduced deep OC stocks by nearly half during the first 100 years following thaw. Using a simple mass-balance model, we show that accumulation rates at the bog surface were not sufficient to balance deep OC losses, resulting in a net loss of OC from the entire peat column. An uncertainty analysis also revealed that the magnitude and timing of soil OC loss from thawed forest peat depends substantially on variation in OC input rates to bog peat and variation in decay constants for shallow and deep OC stocks. These findings suggest that permafrost thaw and the subsequent release of OC from thawed peat will likely reduce the strength of northern permafrost-affected peatlands as a carbon dioxide sink, and consequently, will likely accelerate rates of atmospheric warming.
206 citations
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Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 25 |
| 2020 | 21 |
| 2019 | 16 |
| 2018 | 12 |
| 2017 | 11 |
| 2016 | 17 |