scholarly journals Syngenetic dynamic of permafrost of a polar desert solifluction lobe, Ward Hunt Island, Nunavut

2017 ◽  
Vol 3 (2) ◽  
pp. 301-319 ◽  
Author(s):  
Manuel Verpaelst ◽  
Daniel Fortier ◽  
Mikhail Kanevskiy ◽  
Michel Paquette ◽  
Yuri Shur
Keyword(s):  
Active Layer ◽  
Climate Warming ◽  
Mass Movements ◽  
Polar Desert ◽  
Freeze Thaw ◽  
Slowing Down ◽  
Central Depression ◽  
Ice Content ◽  
The Impact ◽  
Coarse Gravel

Repeated freeze–thaw cycles on slopes trigger sorting and solifluction mass movements, while subsequent displacement of material modifies the geomorphology of slopes as well as permafrost dynamics. This study focuses on the geomorphology and the cryostratigraphy of a polar desert stone-banked solifluction lobe with the objective to clarify the impact of slow mass movements on ground ice aggradation. The morphology of the solifluction lobe was characterized by peripheral ridges of coarse gravel, partially surrounding a depression filled with finer sediments saturated with water and covered by organics. Cryostratigraphic analysis demonstrated that the solifluction lobe’s formation led to the development of a syngenetic layer of permafrost with an ice content that varied according to the location in the lobe. The ice-rich cryofacies formed in the central depression of the lobe should act as a buffer to potential active layer deepening, slowing down its thawing, whereas the ice-poor cryofacies formed under the ridges is expected to thaw faster than the central depression under climate warming scenarios. Thawing of the ice-rich zone in the future will result in differential thaw subsidence between the ridges and the central depression of solifluction lobes, along with increased drainage through the ridges and subsequent changes in hydrology.

scholarly journals Sentinel-1 InSAR Measurements of Elevation Changes over Yedoma Uplands on Sobo-Sise Island, Lena Delta

2018 ◽  
Vol 10 (7) ◽  
pp. 1152 ◽  
Author(s):  
Jie Chen ◽  
Frank Günther ◽  
Guido Grosse ◽  
Lin Liu ◽  
Hui Lin
Keyword(s):  
Active Layer ◽  
Late Pleistocene ◽  
Air Temperature ◽  
Climate Warming ◽  
Temperature Fluctuations ◽  
Surface Elevation ◽  
Freeze Thaw ◽  
Elevation Changes ◽  
Mean Annual Air Temperature ◽  
Lena Delta

Yedoma—extremely ice-rich permafrost with massive ice wedges formed during the Late Pleistocene—is vulnerable to thawing and degradation under climate warming. Thawing of ice-rich Yedoma results in lowering of surface elevations. Quantitative knowledge about surface elevation changes helps us to understand the freeze-thaw processes of the active layer and the potential degradation of Yedoma deposits. In this study, we use C-band Sentinel-1 InSAR measurements to map the elevation changes over ice-rich Yedoma uplands on Sobo-Sise Island, Lena Delta with frequent revisit observations (as short as six or 12 days). We observe significant seasonal thaw subsidence during summer months and heterogeneous inter-annual elevation changes from 2016–17. We also observe interesting patterns of stronger seasonal thaw subsidence on elevated flat Yedoma uplands by comparing to the surrounding Yedoma slopes. Inter-annual analyses from 2016–17 suggest that our observed positive surface elevation changes are likely caused by the delayed progression of the thaw season in 2017, associated with mean annual air temperature fluctuations.

Weathering regime and geochemical conditions in a polar desert environment, Haughton impact structure region, Devon Island, Canada

2008 ◽  
Vol 45 (10) ◽  
pp. 1139-1157 ◽  
Author(s):  
Denis Lacelle ◽  
Véronique Juneau ◽  
André Pellerin ◽  
Bernard Lauriol ◽  
Ian D. Clark
Keyword(s):  
Active Layer ◽  
Chemical Weathering ◽  
Surface Sediments ◽  
Impact Structure ◽  
Desert Environment ◽  
Polar Desert ◽  
Devon Island ◽  
Mechanical Weathering ◽  
Thermal Dilation ◽  
The Impact

This study examines the physical and geochemical properties of near-surface sediments, as well as the geochemical and stable O–H–C isotope composition of (ground)surface waters in and around the Haughton impact structure region (Devon Island, Nunavut) to determine the types of weathering (mechanical, (bio)chemical) and their relative contribution in this polar desert environment. The surface sediments collected from the Allen Bay and Thumb Mountain formations surrounding the impact crater are dominated by sand-sized particles; whereas the impact melt breccias inside the crater have a greater abundance of silt-sized particles. The subsurface sediments in the Allen Bay formation show a near equal amount of sand- and silt-sized particles. However, the micromorphologies of the sand-sized particles collected at the surface revealed that these grains, irrespective of the local geology, were heavily fractured. By contrast, fractures and rounded pits are observed on the surface of the sand grains located within the active layer; whereas those located just above the permafrost table have only rounded cavities on their surface. The (ground)waters also show variations in their solute concentration with depth; the highest concentrations being found in the groundwaters near the top of permafrost. Taken together, these observations suggest that there is a progressive evolution from a mechanically dominated weathering regime near the surface, to increasing chemical weathering with depth. The transition from mechanical weathering near the surface to increasing chemical weathering with depth can be attributed to the decreasing frequency and intensity of mechanical weathering processes (i.e., frost action, wetting–drying, thermal dilation) with depth, and to the presence of permafrost, which allows a greater availability of water for chemical aqueous reactions at the base of the active layer.

The Health of Refugees

2019 ◽  
Keyword(s):  
Age Groups ◽  
Refugee Health ◽  
Mass Movements ◽  
Ethical Challenges ◽  
Displaced Populations ◽  
Political Landscape ◽  
The Media ◽  
Multidisciplinary Perspective ◽  
The Impact

There have been significant changes in the numbers, patterns, and circumstances of refugees and in the political landscape to support humanitarianism since the publication of the first edition of this collection. Like the first edition, this volume provides a multidisciplinary perspective on refugee health, tracing the health repercussions on individuals and populations from the drivers of forced mass movements of populations from situations of conflict and other disasters through to the process of resettlement in countries other than their countries of origin. Drawing on the expertise of academics, practitioners, and UN frontline experts, the collection covers three main aspects of refugee health: the concepts, definitions, and context from a human rights, humanitarianism, and social determinants of health perspective; the intersection of vulnerabilities across age groups and settings; and the ethical challenges for practitioners and researchers working with forcibly displaced populations seeking to resettle. The collection concludes with an analysis of the role of the media in shaping our perceptions of refugees and the impact on policy and access to care.

scholarly journals Modeling the Impact of Atmospheric Warming on Staple Crop Growth in China in the 1960s and 2000s

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Qing Zhang ◽  
Wen Zhang ◽  
Yongqiang Yu ◽  
Tingting Li ◽  
Lijun Yu
Keyword(s):  
Winter Wheat ◽  
Climate Warming ◽  
Northeast China ◽  
Cropping Systems ◽  
Crop Growth ◽  
East China ◽  
Frequency Distributions ◽  
Before And After ◽  
The 1960S ◽  
The Impact

Responses of crop growth to climate warming are fundamental to future food security. The response of crops to climate change may be subtly different at their growing stages. Close insights into the differentiated stage-dependent responses of crops are significantly important in making adaptive adjustments of crops’ phenological optimization and cultivar improvement in diverse cropping systems. Using the Agro-C model, we studied the influence of past climate warming on crops in typical cropping systems in China. The results showed that while the temperature had increased distinctly from the 1960s to 2000s, the temperature frequency distributions in the growth season of crops moved to the high-temperature direction. The low temperature days during the crop growth periods that suppress crop growth decreased in the winter wheat area in North and East China, rice and maize areas in Northeast China, and the optimum temperature days increased significantly. As a result, the above ground biomass (AGB) of rice and maize in Northeast China and winter wheat in North and East China increased distinctly, while that of rice in South China had no significant change. A comparison of the key growth periods before and after heading (silking) showed that the warming before heading (silking) made a great contribution to the increase in the AGB, especially for winter wheat.

scholarly journals The impact of gross domestic product on the financing and investment efficiency of China’s commercial banks

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhen Shi ◽  
Shijiong Qin ◽  
Yung-ho Chiu ◽  
Xiaoying Tan ◽  
Xiaoli Miao
Keyword(s):  
Gross Domestic Product ◽  
Commercial Banks ◽  
Domestic Product ◽  
Investment Efficiency ◽  
Internal Factors ◽  
Slowing Down ◽  
Return On Capital ◽  
Overall Efficiency ◽  
Financing And Investment ◽  
The Impact

AbstractChina’s commercial banks have developed at a very rapid speed in recent decades. However, with global economic development slowing down, the impact of gross domestic product growth as an exogenous factor cannot be ignored. Most existing studies only consider the internal factors of banks, and neglect their external economic factors. This study thus adopts an undesirable dynamic slacks-based measure under an exogenous model in combination with the Kernel density curve to explore the efficiency of state-owned commercial banks (SOCBs), joint-stock commercial banks (JSCBs), and urban commercial banks (UCBs) in China from 2012 to 2018. The results show that SOCBs have the highest overall efficiency, followed by JSCBs, then UCBs. The efficiencies of SOCBs, JSCBs, and UCBs in the financing stage are greater than those in the investment stage, indicating that the latter stage brings down overall efficiency. Thus, all commercial banks need to focus on the efficiency of non-performing loans and return on capital. Finally, SOCBs need to strengthen internal controls, reduce non-performing loans and improve return on capital. JSCBs should actively expand its business while controlling costs, and UCBs should optimize its management.

A new approach to the stability analysis of thawing slopes

1980 ◽  
Vol 17 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Luis E. Vallejo
Keyword(s):  
Stability Analysis ◽  
Water Content ◽  
Pore Water ◽  
Active Layer ◽  
Necessary Conditions ◽  
Mass Movements ◽  
New Approach ◽  
Pore Water Pressures ◽  
The Stability ◽  
Excess Pore

A new approach to the stability analysis of thawing slopes at shallow depths, taking into consideration their structure (this being a mixture of hard crumbs of soil and a fluid matrix), is presented. The new approach explains shallow mass movements such as skin flows and tongues of bimodal flows, which usually take place on very low slope inclinations independently of excess pore water pressures or increased water content in the active layer, which are necessary conditions in the methods available to date to explain these movements.

Modeling the impact of climate warming on potato phenology

2022 ◽  
Vol 132 ◽  
pp. 126404
Author(s):  
Sahrish Naz ◽  
Shakeel Ahmad ◽  
Ghulam Abbas ◽  
Zartash Fatima ◽  
Sajjad Hussain ◽  
...  
Keyword(s):  
Climate Warming ◽  
The Impact

scholarly journals Volume change behaviour and microstructure of stabilized loess under cyclic freeze–thaw conditions

2016 ◽  
Vol 43 (10) ◽  
pp. 865-874 ◽  
Author(s):  
Sheng-lin Wang ◽  
Qing-feng Lv ◽  
Hassan Baaj ◽  
Xiao-yuan Li ◽  
Yan-xu Zhao
Keyword(s):  
Fly Ash ◽  
Volume Change ◽  
Cement Content ◽  
Frost Heave ◽  
Equivalent Diameter ◽  
Surface Porosity ◽  
Change Rate ◽  
Freeze Thaw ◽  
Significant Damage ◽  
The Impact

Freeze–thaw action is considered to be one of the most destructive actions that can induce significant damage in stabilized subgrades in seasonally frozen loess areas. Laboratory tests including frost heave – thaw shrinkage and microstructure change during freeze–thaw cycles were conducted to evaluate the volume change rate of loess stabilized with cement, lime, and fly ash under the impact of cyclic freeze–thaw conditions. The loess specimens collapsed after eight freeze–thaw cycles (192 h), but most stabilized loess specimens had no visible damage after all freeze–thaw cycles were completed. All of the stabilized loess samples underwent a much smaller volume change than the loess alone after the freeze–thaw cycles. Although surface porosity and equivalent diameter of stabilized loess samples increased, the stabilized loess can retain its microstructure during freeze–thaw cycles when the cement content was less than 6%. To ensure freeze–thaw resistance of stabilized loess subgrades, the mix proportions of the three additives was recommended to be 4 to 5% cement, 6% lime, and 10% fly ash.

The impact of recrystallisation on the freeze‐thaw cycles of red seabream ( Pagrus major ) fillets

2018 ◽  
Vol 54 (5) ◽  
pp. 1642-1650 ◽  
Author(s):  
Minjie Cao ◽  
Jing Wang ◽  
Ailing Cao ◽  
David Shiuan ◽  
Rongfa Guan ◽  
...  
Keyword(s):  
Pagrus Major ◽  
Red Seabream ◽  
Freeze Thaw ◽  
The Impact
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