scholarly journals Transient thermal effects in Alpine permafrost

2009 ◽  
Vol 3 (1) ◽  
pp. 85-99 ◽  
Author(s):  
J. Noetzli ◽  
S. Gruber
Keyword(s):  
Climatic Conditions ◽  
Balance Model ◽  
High Mountain ◽  
Transient Effects ◽  
Mountain Areas ◽  
Past Climate ◽  
Climate Conditions ◽  
The Past ◽  
Numerical Experimentation ◽  
Time Periods

Abstract. In high mountain areas, permafrost is important because it influences the occurrence of natural hazards, because it has to be considered in construction practices, and because it is sensitive to climate change. The assessment of its distribution and evolution is challenging because of highly variable conditions at and below the surface, steep topography and varying climatic conditions. This paper presents a systematic investigation of effects of topography and climate variability that are important for subsurface temperatures in Alpine bedrock permafrost. We studied the effects of both, past and projected future ground surface temperature variations on the basis of numerical experimentation with simplified mountain topography in order to demonstrate the principal effects. The modeling approach applied combines a distributed surface energy balance model and a three-dimensional subsurface heat conduction scheme. Results show that the past climate variations that essentially influence present-day permafrost temperatures at depth of the idealized mountains are the last glacial period and the major fluctuations in the past millennium. Transient effects from projected future warming, however, are likely larger than those from past climate conditions because larger temperature changes at the surface occur in shorter time periods. We further demonstrate the accelerating influence of multi-lateral warming in steep and complex topography for a temperature signal entering the subsurface as compared to the situation in flat areas. The effects of varying and uncertain material properties (i.e., thermal properties, porosity, and freezing characteristics) on the subsurface temperature field were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over time periods of decades to centuries. At the end, the model was applied to the topographic setting of the Matterhorn (Switzerland). Results from idealized geometries are compared to this first example of real topography, and possibilities as well as limitations of the model application are discussed.

scholarly journals Transient thermal effects in Alpine permafrost

2008 ◽  
Vol 2 (2) ◽  
pp. 185-224 ◽  
Author(s):  
J. Noetzli ◽  
S. Gruber
Keyword(s):  
Thermal State ◽  
Ground Surface ◽  
Climatic Conditions ◽  
Balance Model ◽  
High Mountain ◽  
Complex Topography ◽  
Transient Effects ◽  
Mountain Areas ◽  
The Past ◽  
Numerical Experimentation

Abstract. In high mountain areas, permafrost is important because it influences natural hazards and construction practices, and because it is an indicator of climate change. The modeling of its distribution and evolution over time is complicated by steep and complex topography, highly variable conditions at and below the surface, and varying climatic conditions. This paper presents a systematic investigation of effects of climate variability and topography that are important for subsurface temperatures in Alpine permafrost areas. The effects of both past and projected future ground surface temperature variations on the thermal state of Alpine permafrost are studied based on numerical experimentation with simplified mountain topography. For this purpose, we use a surface energy balance model together with a subsurface heat conduction scheme. The past climate variations that essentially influence the present-day permafrost temperatures at depth are the last glacial period and the major fluctuations in the past millennium. The influence of projected future warming was assessed to cause even larger transient effects in the subsurface thermal field because warming occurs on shorter time scales. Results further demonstrate the accelerating influence of multi-lateral warming in Alpine topography for a temperature signal entering the subsurface. The effects of thermal properties, porosity, and freezing characteristics were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over shorter time periods (i.e., decades to centuries). Finally, as an example of a real and complex topography, the modeled transient three-dimensional temperature distribution in the Matterhorn (Switzerland) is given for today and in 200 years.

scholarly journals Chromosomal Q-Heterochromatin and Atherosclerosis

2017 ◽  
Vol 7 (1) ◽  
pp. 143
Author(s):  
A. I. Ibraimov
Keyword(s):  
Homo Sapiens ◽  
Single Species ◽  
Causative Factor ◽  
Mean Value ◽  
Biological Species ◽  
Climatic Conditions ◽  
Cold Climate ◽  
High Mountain ◽  
Mountain Areas ◽  
Blood Temperature

We suppose that at study of the pathogenesis of atherosclerosis, it is possible that some evolutionary aspects of the problem are missed. This aspect is related to the peculiarity of human adaptation to climatic geographic conditions of Eurasia, which differ significantly from the climate of East Africa, where Homo sapiens was formed as a tropical biological species and so it has remained to this day. A hypothesis has been put forward that the pathogenesis of atherosclerosis is associated with some previously unknown features of the genome and the physical properties of the human body that arose in the process of its adaptation to a mild and cold climate. These adaptive genetic changes that have contributed to the development (settling) by Homo sapiens of non-tropical, including cold and high mountain areas of the Earth, resulted to the fact that a man became the single species vulnerable (predisposed) to atherosclerosis.Atherosclerosis is apparently a purely human disease that appeared after adaptation of man to climatic conditions of temperate and northern latitudes of the northern hemisphere. The type of vessels (arteries or veins) and the site of their lumen have no role in the development of atherosclerotic changes. The primary and main causative factor in the development of atherosclerosis is blood temperature. The degree of blood cooling in the lungs depends on geographical latitudes and altitude above sea-level of the site of permanent residence of man. The preclinical stage of atherosclerosis may develop into a pathological form predominantly in individuals in the genome of which the amount of chromosomal Q-heterochromatin material is higher than its mean value per individual in the population.

scholarly journals Modelling the evolution of Djankuat Glacier, North Caucasus, from 1752 until 2100 CE

2020 ◽  
Vol 14 (11) ◽  
pp. 4039-4061
Author(s):  
Yoni Verhaegen ◽  
Philippe Huybrechts ◽  
Oleg Rybak ◽  
Victor V. Popovnin
Keyword(s):  
Surface Area ◽  
Flow Line ◽  
Calibration Procedure ◽  
Climatic Conditions ◽  
Balance Model ◽  
North Caucasus ◽  
Initial State ◽  
Climate Conditions ◽  
The North ◽  
Debris Cover

Abstract. We use a numerical flow line model to simulate the behaviour of the Djankuat Glacier, a World Glacier Monitoring Service reference glacier situated in the North Caucasus (Republic of Kabardino-Balkaria, Russian Federation), in response to past, present and future climate conditions (1752–2100 CE). The model consists of a coupled ice flow–mass balance model that also takes into account the evolution of a supraglacial debris cover. After simulation of the past retreat by applying a dynamic calibration procedure, the model was forced with data for the future period under different scenarios regarding temperature, precipitation and debris input. The main results show that the glacier length and surface area have decreased by ca. 1.4 km (ca. −29.5 %) and ca. 1.6 km2 (−35.2 %) respectively between the initial state in 1752 CE and present-day conditions. Some minor stabilization and/or readvancements of the glacier have occurred, but the general trend shows an almost continuous retreat since the 1850s. Future projections using CMIP5 temperature and precipitation data exhibit a further decline of the glacier. Under constant present-day climate conditions, its length and surface area will further shrink by ca. 30 % by 2100 CE. However, even under the most extreme RCP 8.5 scenario, the glacier will not have disappeared completely by the end of the modelling period. The presence of an increasingly widespread supraglacial debris cover is shown to significantly delay glacier retreat, depending on the interaction between the prevailing climatic conditions, the debris input location, the debris mass flux magnitude and the time of release of debris sources from the surrounding topography.

scholarly journals Recent Climatic Mass Balance of the Schiaparelli Glacier at the Monte Sarmiento Massif and Reconstruction of Little Ice Age Climate by Simulating Steady-State Glacier Conditions

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 272
Author(s):  
Stephanie Suzanne Weidemann ◽  
Jorge Arigony-Neto ◽  
Ricardo Jaña ◽  
Guilherme Netto ◽  
Inti Gonzalez ◽  
...  
Keyword(s):  
Steady State ◽  
Mass Balance ◽  
Air Temperature ◽  
Little Ice Age ◽  
Similar Rate ◽  
Climatic Conditions ◽  
Ice Age ◽  
Balance Model ◽  
Climate Conditions ◽  
Recent Climate

The Cordillera Darwin Icefield loses mass at a similar rate as the Northern and Southern Patagonian Icefields, showing contrasting individual glacier responses, particularly between the north-facing and south-facing glaciers, which are subject to changing climate conditions. Detailed investigations of climatic mass balance processes on recent glacier behavior are not available for glaciers of the Cordillera Darwin Icefield and surrounding icefields. We therefore applied the coupled snow and ice energy and mass balance model in Python (COSIPY) to assess recent surface energy and mass balance variability for the Schiaparelli Glacier at the Monte Sarmiento Massif. We further used COSIPY to simulate steady-state glacier conditions during the Little Ice Age using information of moraine systems and glacier areal extent. The model is driven by downscaled 6-hourly atmospheric data and high resolution precipitation fields, obtained by using an analytical orographic precipitation model. Precipitation and air temperature offsets to present-day climate were considered to reconstruct climatic conditions during the Little Ice Age. A glacier-wide mean annual climatic mass balance of −1.8 ± 0.36 m w.e. a − 1 was simulated between between April 2000 and March 2017. An air temperature decrease between −0.9 ° C and −1.7 ° C in combination with a precipitation offset of up to +60% to recent climate conditions is necessary to simulate steady-state conditions for Schiaparelli Glacier in 1870.

scholarly journals Landscape diversity and biodiversity of Fann Mountains (Tajikistan)

2013 ◽  
Vol 32 (4) ◽  
Author(s):  
Oimahmad Rahmonov ◽  
Leszek Majgier ◽  
Wiaczesław Andrejczuk ◽  
Jarosław Banaszek ◽  
Dominik Karkosz ◽  
...  
Keyword(s):  
Endemic Species ◽  
Deciduous Forest ◽  
Flood Plain ◽  
Geological Structure ◽  
Climatic Conditions ◽  
Landscape Diversity ◽  
High Mountain ◽  
Climate Conditions ◽  
Shrub Steppe ◽  
High Level

AbstractRahmonov O., Majgier L., Andrejczuk W., Banaszek J., Karkosz D., Parusel T., Szymczyk A.: Landscape diversity and biodiversity of Fann Mountains (Tajikistan). Ekologia (Bratislava), Vol. 32, No. 4, p. 388-395, 2013.The aim of study is a presentation of main vegetation landscape diversity and biodiversity in case of endemic species in the Fann Mountains area, in horizontal and vertical approach. In terms of biodiversity, the high-mountain ecosystems of Central Asia include the most valuable areas in the world called as hotspot, and also are exposed to intense human pressure causing the destruction of habitats. Vegetation landscapes of Fann Mountains are very diverse because of high-mountain character of this area, local climatic conditions, topography and habitats. That differentiation leads up to biodiversity and formation of unique plant landscapes and endemic species. The vegetation landscapes in altitude order are represented by forbs meadow steppe, thymes, swamp, broad-leaf forest, juniper forests, flood-plain small-leaved forest, tugai, light deciduous forest, pistachio, forbs wormwood, almond, rare vegetation with cushion-shaped species, wormwood eurotia, steppe, thorny grasses with shrub-steppe, rocks and taluses with rare vegetation alpine zones. High level of endemism in Fann Mountains is connected to natural conditions such as geological structure, relief, high-mountain ranges and climate conditions. This fact has an influence on forming mosaic biotops, often isolated by orographic barriers.

scholarly journals Reconstruction of Past Glacier Changes with an Ice-Flow Glacier Model: Proof of Concept and Validation

2021 ◽  
Vol 9 ◽  
Author(s):  
Julia Eis ◽  
Larissa van der Laan ◽  
Fabien Maussion ◽  
Ben Marzeion
Keyword(s):  
Mass Balance ◽  
Real World ◽  
Balance Model ◽  
Limited Information ◽  
Ice Flow ◽  
Past Climate ◽  
The Past ◽  
Glacier Changes ◽  
Climate Time Series ◽  
Good Agreement

Estimations of global glacier mass changes over the course of the 20th century require automated initialization methods, allowing the reconstruction of past glacier states from limited information. In a previous study, we developed a method to initialize the Open Global Glacier Model (OGGM) from past climate information and present-day geometry alone. Tested in an idealized framework, this method aimed to quantify how much information present-day glacier geometry carries about past glacier states. The method was not applied to real-world cases, and therefore, the results were not comparable with observations. This study closes the gap to real-world cases by introducing a glacier-specific calibration of the mass balance model. This procedure ensures that the modeled present-day geometry matches the observed area and that the past glacier evolution is consistent with bias-corrected past climate time series. We apply the method to 517 glaciers, spread globally, for which either mass balance observations or length records are available, and compare the observations to the modeled reconstructed glacier changes. For the validation of the initialization method, we use multiple measures of reconstruction skill (e.g., MBE, RMSE, and correlation). We find that the modeled mass balances and glacier lengths are in good agreement with the observations, especially for glaciers with many observation years. These results open the door to a future global application.

scholarly journals Modelled glacier equilibrium line altitudes during the mid-Holocene in the southern mid-latitudes

2015 ◽  
Vol 11 (11) ◽  
pp. 1575-1586 ◽  
Author(s):  
C. Bravo ◽  
M. Rojas ◽  
B. M. Anderson ◽  
A. N. Mackintosh ◽  
E. Sagredo ◽  
...  
Keyword(s):  
New Zealand ◽  
Mass Balance ◽  
Southern Hemisphere ◽  
Austral Summer ◽  
Climatic Conditions ◽  
Equilibrium Line ◽  
Balance Model ◽  
Glacier Mass Balance ◽  
Mass Balance Model ◽  
Climate Conditions

Abstract. Glacier behaviour during the mid-Holocene (MH, 6000 years BP) in the Southern Hemisphere provides observational data to constrain our understanding of the origin and propagation of palaeoclimate signals. In this study we examine the climatic forcing of glacier response in the MH by evaluating modelled glacier equilibrium line altitudes (ELAs) and climatic conditions during the MH compared with pre-industrial time (PI, year 1750). We focus on the middle latitudes of the Southern Hemisphere, specifically Patagonia and the South Island of New Zealand. Climate conditions for the MH were obtained from PMIP2 model simulations, which in turn were used to force a simple glacier mass balance model to simulate changes in ELA. In Patagonia, the models simulate colder conditions during the MH in austral summer (−0.2 °C), autumn (−0.5 °C), and winter (−0.4), and warmer temperatures (0.2 °C) during spring. In the Southern Alps the models show colder MH conditions in autumn (−0.7 °C) and winter (−0.4 °C), warmer conditions in spring (0.3 °C), and no significant change in summer temperature. Precipitation does not show significant changes but exhibits a seasonal shift, with less precipitation from April to September and more precipitation from October to April during the MH in both regions. The mass balance model simulates a climatic ELA that is 15–33 m lower during the MH compared with PI conditions. We suggest that the main causes of this difference are driven mainly by colder temperatures associated with the MH simulation. Differences in temperature have a dual effect on glacier mass balance: (i) less energy is available for ablation during summer and early autumn and (ii) lower temperatures cause more precipitation to fall as snow rather than rain in late autumn and winter, resulting in more accumulation and higher surface albedo. For these reasons, we postulate that the modelled ELA changes, although small, may help to explain larger glacier extents observed by 6000 years BP in South America and New Zealand.

scholarly journals The Transformation of Agro-Climatic Resources of the Altai Region under Changing Climate Conditions

Agriculture ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 68 ◽  
Author(s):  
Nina Maximova ◽  
Komali Kantamaneni ◽  
Gennady Morkovkin ◽  
Darya Arnaut ◽  
Louis Rice
Keyword(s):  
Growing Season ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Integrated Analysis ◽  
Published Data ◽  
Climate Conditions ◽  
Related Data ◽  
Growing Season Length ◽  
Altai Region ◽  
The Past

This research examines the transformation of the agro-climatic conditions of the Altai region as a result of climate change. The climate of the Altai region in Russia is sharply continental and characterized by dry air and significant weather variability, both in individual seasons and years. The current study is determined by the lack of detailed area-related analytical generalizations for the territory of the Altai region over the past 30 years. Most of the published data dealing with an integrated analysis of the agro-climatic conditions in the Altai region date back to the late 1960s and early 1970s; in most cases, this data is from climate reference-books based on the generalized data from the first half of the 20th century. To make accurate forecasts and to efficiently manage agricultural production in the Altai region, area-related data on the state and dynamics of agro-climatic changes have been analysed. The results reveal that in the period between 1964 and 2017, significant climatic changes occurred in the territory of the Altai region. These climatic changes affected the growing season length, which increased due to a shift in the dates of the air temperature transition above 10 °C, to earlier dates in spring and to later dates in autumn. Furthermore, the current study also revealed that the foothills of the Altai Mountains are the most moistened parts of the region and the Kulunda lowland is the most arid part. In the Altai region, the accumulated temperatures and amounts of precipitation during the growing season increased significantly, and the values of integrated coefficients and indices that reflect the moisture supply conditions for the territory also changed significantly. Based upon the results, a schematic map of the current precipitation distribution on the Altai region’s territory has been generated. These results and this map may be used to conduct more detailed studies in the field of agro-climatology and to update the current borders of agro-climatic areas and revision of the agro-climatic zonation scheme.

scholarly journals Sensitivity of potential evaporation estimates to 100 years of climate variability

2015 ◽  
Vol 19 (2) ◽  
pp. 997-1014 ◽  
Author(s):  
R. P. Bartholomeus ◽  
J. H. Stagge ◽  
L. M. Tallaksen ◽  
J. P. M. Witte
Keyword(s):  
Hydrological Modeling ◽  
Historical Record ◽  
Climatic Conditions ◽  
Potential Evaporation ◽  
Step Potential ◽  
Climate Conditions ◽  
The Past ◽  
Stationary Signals ◽  
Global Dimming ◽  
Empirical Coefficients

Abstract. Hydrological modeling frameworks require an accurate representation of evaporation fluxes for appropriate quantification of, e.g., the water balance, soil moisture budget, recharge and groundwater processes. Many frameworks have used the concept of potential evaporation, often estimated for different vegetation classes by multiplying the evaporation from a reference surface ("reference evaporation") by crop-specific scaling factors ("crop factors"). Though this two-step potential evaporation approach undoubtedly has practical advantages, the empirical nature of both reference evaporation methods and crop factors limits its usability in extrapolations under non-stationary climatic conditions. In this paper, rather than simply warning about the dangers of extrapolation, we quantify the sensitivity of potential evaporation estimates for different vegetation classes using the two-step approach when calibrated using a non-stationary climate. We used the past century's time series of observed climate, containing non-stationary signals of multi-decadal atmospheric oscillations, global warming, and global dimming/brightening, to evaluate the sensitivity of potential evaporation estimates to the choice and length of the calibration period. We show that using empirical coefficients outside their calibration range may lead to systematic differences between process-based and empirical reference evaporation methods, and systematic errors in estimated potential evaporation components. Quantification of errors provides a possibility to correct potential evaporation calculations and to rate them for their suitability to model climate conditions that differ significantly from the historical record, so-called no-analog climate conditions.

scholarly journals Modelling the evolution of Djankuat Glacier, North Caucasus, from 1752 until 2100 AD

2020 ◽  
Author(s):  
Yoni Verhaegen ◽  
Philippe Huybrechts ◽  
Oleg Rybak ◽  
Victor V. Popovnin
Keyword(s):  
Surface Area ◽  
Calibration Procedure ◽  
Climatic Conditions ◽  
Balance Model ◽  
Climatic Data ◽  
North Caucasus ◽  
Initial State ◽  
Climate Conditions ◽  
The North ◽  
Debris Cover

Abstract. We use a numerical 1.5D model to simulate the behaviour of the Djankuat Glacier, a WGMS reference glacier situated in the North Caucasus (Republic of Kabardino-Balkaria, Russian Federation), in response to past, present and future climate conditions (1752–2100 AD). The model consists of a coupled ice flow−mass balance model that also takes into account the evolution of a supraglacial debris cover. After simulation of the past retreat by applying a dynamic calibration procedure, the model was forced with climatic data for the future period under different scenarios regarding temperature, precipitation and debris input. The main results show that the glacier length and surface area have decreased by 1.4 km and 1.6 km2 respectively between the initial state in 1752 AD and present-day conditions. Some minor stabilization and/or readvancements of the glacier have occurred, but the general trend shows an almost continuous retreat since the 1850s. Future projections exhibit a further decline of the glacier. Under constant present-day climate conditions, its length and surface area will further shrink by ca. 50 % by 2100 AD. However, even under the most extreme RCP 8.5 scenario, the glacier will not have disappeared completely. The presence of an increasingly widespread supraglacial debris cover is shown to significantly delay glacier retreat, depending on the interaction between the prevailing climatic conditions, the debris input location, the debris mass flux magnitude and the time of release of debris sources from the surrounding topography.

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