Report on Session 2b

1991 ◽  
Vol 7 (1) ◽  
pp. 409-414 ◽  
Author(s):  
D. J. Petley
Keyword(s):  
Ice Sheets ◽  
Weather Conditions ◽  
Land Area ◽  
Geological Time ◽  
Quaternary Period ◽  
Sea Levels ◽  
Stability Of Slopes ◽  
Profound Influence ◽  
Almost All ◽  
Glacial Periods

IntroductionNo part of geological time has had a more profound influence on the engineering characteristics of soils and rocks than the Quaternary period. Large areas of the earth’s surface are covered by superficial deposits of Quaternary age, and almost all surface soils and rocks affected by the changeds in climate which occurred in the Quaternary retain characteristics which have implications for engineering works at the present time.During the Quaternary period, at least five major glaciations occurred. During each glaciation, as the climate became colder, ice sheets spread from the poles and mountainous areas, to be followed by a retreat as warmer weather conditions prevailed during the inter-glacial periods. At the present time, in the Northern hemisphere, ice sheets cover approximately 10% of the total land area, but during the time of maximum glaciation in the Pleistocene, over 30% of the total land area was covered by ice.The volume of water taken up by the ice sheets caused significant variation in sea-levels. It has been estimated that the maximum and minimum sea-levels during the Quaternary were +200 m and -150 m 0D respectively. Indeed, following the main postglacial transgression at the end of the Devensian, the sea has been within 3 m of its present level for only the last 4000 or 5000 years. These large variation in sea-level significantly influenced the development and stability of slopes in coastal areas and inland.

Resistance of cherry varieties to spring return frozes in the conditions of Astrakhan region

2020 ◽  
Author(s):  
A.A. Dronic A.A. ◽  
Keyword(s):  
Weather Conditions ◽  
Damage Score ◽  
The Stability ◽  
Almost All ◽  
Total Damage ◽  
Continental Climate ◽  
Unfavorable Weather

The article presents an assessment of the stability of introduced cherry varieties to spring return frosts in 2020 in the conditions of the sharply continental climate of the Astrakhan region. As a result of unfavorable weather conditions, the total damage score of all varieties was 2-5 points. Almost all the studied varieties showed an insufficient level of resistance to recurrent frosts.

Revising key parameters for long-term carbon cycle models

2021 ◽  
Author(s):  
Chloé M. Marcilly ◽  
Trond H. Torsvik ◽  
Mathew Domeier ◽  
Dana L. Royer
Keyword(s):  
Sea Level ◽  
Age Distribution ◽  
Silicate Weathering ◽  
Geological Time ◽  
Sea Levels ◽  
Climate Fluctuations ◽  
Climate Gradients ◽  
Sea Level Fluctuations ◽  
Temperature And Precipitation

<p>CO<sub>2</sub> is the most important greenhouse gas in the Earth’s atmosphere and has fluctuated considerably over geological time. However, proxies for past CO<sub>2 </sub>concentrations have large uncertainties and are mostly limited to Devonian and younger times. Consequently, CO<sub>2</sub> modelling plays a key role in reconstructing past climate fluctuations. Facing the limitations with the current CO<sub>2</sub> models, we aim to refine two important forcings for CO<sub>2</sub> levels over the Phanerozoic, namely carbon degassing and silicate weathering.</p><p>Silicate weathering and carbonate deposition is widely recognized as a primary sink of carbon on geological timescales and is largely influenced by changes in climate, which in turn is linked to changes in paleogeography. The role of paleogeography on silicate weathering fluxes has been the focus of several studies in recent years. Their aims were mostly to constrain climatic parameters such as temperature and precipitation affecting weathering rates through time. However, constraining the availability of exposed land is crucial in assessing the theoretical amount of weathering on geological time scales. Associated with changes in climatic zones, the fluctuation of sea-level is critical for defining the amount of land exposed to weathering. The current reconstructions used in<sub></sub>models tend to overestimate the amount of exposed land to weathering at periods with high sea levels. Through the construction of continental flooding maps, we constrain the effective land area undergoing silicate weathering for the past 520 million years. Our maps not only reflect sea-level fluctuations but also contain climate-sensitive indicators such as coal (since the Early Devonian) and evaporites to evaluate climate gradients and potential weatherablity through time. This is particularly important after the Pangea supercontinent formed but also for some time after its break-up.</p><p>Whilst silicate weathering is an important CO<sub>2</sub> sink, volcanic carbon degassing is a major source but one of the least constrained climate forcing parameters. There is no clear consensus on the history of degassing through geological time as there are no direct proxies for reconstructing carbon degassing, but various proxy methods have been postulated. We propose new estimates of plate tectonic degassing for the Phanerozoic using both subduction flux from full-plate models and zircon age distribution from arcs (arc-activity) as proxies.</p><p>The effect of revised modelling parameters for weathering and degassing was tested in the well-known long-term models GEOCARBSULF and COPSE. They revealed the high influence of degassing on CO<sub>2</sub> levels using those models, highlighting the need for enhanced research in this direction. The use of arc-activity as a proxy for carbon degassing leads to interesting responses in the Mesozoic and brings model estimates closer to CO<sub>2 </sub> proxy values. However, from simulations using simultaneously the revised input parameters (i.e weathering and degassing) large model-proxy discrepancies remain and notably for the Triassic and Jurassic.</p><p> </p>

United Front: Partisans of the Leningrad Region and their connections with the Central Asian Soviet Republics

2021 ◽  
Vol 2021 (02) ◽  
pp. 214-225
Author(s):  
Sergey Kulik ◽  
Аnatoliy Kashevarov ◽  
Zamira Ishankhodjaeva
Keyword(s):  
World War Ii ◽  
Weather Conditions ◽  
Leningrad Region ◽  
World War ◽  
North West ◽  
The North ◽  
Occupied Territory ◽  
Central Asian ◽  
The Difference ◽  
Almost All

During World War II, representatives of almost all the Soviet Republics fought in partisan detachments in the occupied territory of the Leningrad Region. Among them were many representatives of the Central Asian republics: Kazakhstan, Kyrgyzstan and Uzbekistan. Many Leningrad citizens, including relatives of partisans, had been evacuated to Central Asia by that time. However, representatives of Asian workers’ collectives came to meet with the partisans. The huge distance, the difference in cultures and even completely different weather conditions did not become an obstacle to those patriots-Turkestanis who joined the resistance forces in the North-West of Russia.

scholarly journals Quaternary deposits between the Sukkertoppen ice cap and Nordre Strømfjord

1970 ◽  
Vol 28 ◽  
pp. 23-25
Author(s):  
A Weidick ◽  
N.W Ten Brink
Keyword(s):  
Land Area ◽  
The West ◽  
Quaternary Deposits ◽  
Sea Levels ◽  
West Greenland ◽  
Marine Deposits ◽  
Ice Cap

The area investigated during 1969 is located approximate1y between 66° 10' and 67° 30' N, and 50° and 52° W, the eastem half of the West Greenland ice-free land area transected by Søndre Strømfjord. The principal objectives of the work were to map and describe the glacial and emerged marine deposits for a Quatemary map at 1:500 000 scale, and to collect material for establishing a radiometric chronology of former ice-margin positions and sea levels. In order to study as large an area as possible, the investigations north of Søndre Strømfjord and Sondrestrom Airbase were conducted by A. Weidick, the area south of this by N. W. Ten Brink.

scholarly journals Financial Stability and Climate Change

2020 ◽  
Vol 9 (3) ◽  
pp. 27-43
Author(s):  
Nikola Fabris
Keyword(s):  
Climate Change ◽  
Financial Institutions ◽  
Financial Stability ◽  
Financial Risk ◽  
Negative Impact ◽  
Weather Conditions ◽  
Extreme Weather ◽  
Financial Risks ◽  
Balance Sheets ◽  
Sea Levels

AbstractFighting climate change is one of the biggest challenges in the 21st century. Climate change that leads to global warming has been increasingly visible in our environment. Extreme weather conditions such as hurricanes, floods, and droughts have been escalating and their acceleration can be expected in the future. They cause changes in sea levels, epidemics, large fires, etc. Increasingly, we are witnessing minor or major damage caused by these extreme weather conditions. Numerous studies have proven that climate change has negative impact on economic growth and prosperity. However, this paper starts from the premise that in addition to unequivocally identified threats, climate change also creates opportunities.The paper reaches a conclusion that climate change can adversely affect balance sheets of financial institutions. Therefore, climate change is a source of financial risk and thus a part of the mandate of central banks and supervisors in preserving financial stability. This type of risk has not been given enough attention by either supervisors or financial institutions over the past period. This paper develops a model for managing financial risks as a result of climate change.

Introduction

2004 ◽  
Author(s):  
Robert A. Berner
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Global Climate ◽  
Geological Time ◽  
Short Term ◽  
Quaternary Period ◽  
Geological Time Scale ◽  
The Earth

The cycle of carbon is essential to the maintenance of life, to climate, and to the composition of the atmosphere and oceans. What is normally thought of as the “carbon cycle” is the transfer of carbon between the atmosphere, the oceans, and life. This is not the subject of interest of this book. To understand this apparently confusing statement, it is necessary to separate the carbon cycle into two cycles: the short-term cycle and the long-term cycle. The “carbon cycle,” as most people understand it, is represented in figure 1.1. Carbon dioxide is taken up via photosynthesis by green plants on the continents or phytoplankton in the ocean. On land carbon is transferred to soils by the dropping of leaves, root growth, and respiration, the death of plants, and the development of soil biota. Land herbivores eat the plants, and carnivores eat the herbivores. In the oceans the phytoplankton are eaten by zooplankton that are in turn eaten by larger and larger organisms. The plants, plankton, and animals respire CO2. Upon death the plants and animals are decomposed by microorganisms with the ultimate production of CO2. Carbon dioxide is exchanged between the oceans and atmosphere, and dissolved organic matter is carried in solution by rivers from soils to the sea. This all constitutes the shortterm carbon cycle. The word “short-term” is used because the characteristic times for transferring carbon between reservoirs range from days to tens of thousands of years. Because the earth is more than four billion years old, this is short on a geological time scale. As the short-term cycle proceeds, concentrations of the two principal atmospheric gases, CO2 and CH4, can change as a result of perturbations of the cycle. Because these two are both greenhouse gases—in other words, they adsorb outgoing infrared radiation from the earth surface—changes in their concentrations can involve global warming and cooling over centuries and many millennia. Such changes have accompanied global climate change over the Quaternary period (past 2 million years), although other factors, such as variations in the receipt of solar radiation due to changes in characteristics of the earth’s orbit, have also contributed to climate change.

scholarly journals City-Scale Distance Sensing via Bispectral Light Extinction in Bad Weather

2020 ◽  
Vol 12 (9) ◽  
pp. 1401
Author(s):  
Dong Zhao ◽  
Yuta Asano ◽  
Lin Gu ◽  
Imari Sato ◽  
Huixin Zhou
Keyword(s):  
Extinction Coefficient ◽  
Near Infrared ◽  
Imaging System ◽  
Weather Conditions ◽  
Light Extinction ◽  
Selection Strategy ◽  
Infrared Wavelengths ◽  
The Difference ◽  
Bad Weather ◽  
Almost All

In this paper, we propose a novel city-scale distance sensing algorithm based on atmosphere optics. The suspended particles, especially in bad weather, would attenuate the light at almost all wavelengths. Observing this fact and starting from the light scattering mechanism, we derive a bispectral distance sensing algorithm by leveraging the difference of extinction coefficient between two specifically selected near infrared wavelengths. The extinction coefficient of the atmosphere is related to both wavelength and meteorological conditions, also known as visibility, such as the fog and haze day. To account for different bad weather conditions, we explicitly introduce visibility into our algorithm by incorporating it into the calculation of extinction coefficient, making our algorithm simple yet effective. To capture the data, we build a bispectral imaging system that is able to take a pair of images with a monochrome camera and two narrow band-pass filters. We also present a wavelength selection strategy that allows us to accurately sense distance regardless of material reflectance and texture. Specifically, this strategy determines two distinct near infrared wavelengths by maximising the extinction coefficient difference while minimizing the influence of building’s reflectance variance. The experiments empirically validate our model and its practical performance on the distance sensing for the city-scale buildings.

Approaches to the study of hillslope development due to mass movement

1993 ◽  
Vol 17 (1) ◽  
pp. 32-49 ◽  
Author(s):  
S.M. Brooks ◽  
K.S. Richards ◽  
M.G. Anderson
Keyword(s):  
Internal Friction ◽  
Pore Water ◽  
Water Table ◽  
Soil Cover ◽  
Slip Surface ◽  
Mass Movement ◽  
Slope Angle ◽  
Geological Time ◽  
Stability Of Slopes ◽  
Pore Water Pressures

Slope-angle histograms have traditionally provided a data base for the evaluation of changing angles over geological time. Ideas relating to hillslope development due to mass movement have considered a lowering in regolith shear resistance due to weathering, producing slope-angle decline. Decreasing values for angles of internal friction, along with increasing pore water pressures, have been suggested to explain slope-angle decline through time. These ideas have considered simple changes in undifferentiated regolith. This article considers the role of progressive pedogenesis in determining the changing stability of slopes. For this it is necessary to evaluate the changes which occur within individual horizons to produce an increasingly differentiated soil cover. Angles of internal friction alter at different rates and in different ways depending on whether the horizon is losing or gaining weathered material through translocation. Furthermore, the increasing internal differentiation of the soil cover has complex effects on its hydrological response. Instead of the two scenarios previously envisaged, one involving the water table below the slip surface and the other involving the water table at the ground surface, slope stability needs to be evaluated in the light of continually changing negative or positive pore water pressures. Each storm produces a different response, and this response alters with soil development, complicating the assessment of failure timing and depth. The study of evolving soil profiles is of fundamental significance to a range of geomorphological processes, requiring closer evaluation in the future.

V.—The Thickness of the Ice-Cap in the various Glacial Periods

1906 ◽  
Vol 3 (3) ◽  
pp. 120-124 ◽  
Author(s):  
Ernst H. L. Schwarz
Keyword(s):  
South Africa ◽  
Ice Sheets ◽  
Maximum Load ◽  
Earth’S Crust ◽  
Ice Ages ◽  
Ice Cap ◽  
The Alps ◽  
Earth's Crust ◽  
Glacial Periods ◽  
The Antarctic

In estimating the maximum load which pressed upon the northern type of Glacial (Dwyka) Conglomerate in Prieska, Cape Colony, I assumed that the calculations of Sir Wyville Thomson and Bernacci were correct, and that the greatest column of ice that could exist on the earth's surface was from 1,400 to 1,600 feet high. This limit, however, is by no means accepted by European glacialists, who, though they do not go as far as Dr. Croll in assuming thicknesses of 120,000 feet, yet see no reason why there could not have been ice-sheets 5,000 feet thick. The publication of Captain Scott's narrative of the voyage of the “Discovery” has given us certain definite data from the Antarctic which enable the case for the 1,600 feet maximum to be put with more confidence, and I will endeavour in the present paper to state the main lines of the argument. The question is of importance not only to us in South Africa with our two Palæozoic ice-ages, but to all geologists, as it affects the problem of the earth's equilibrium. To give a recent example, Professor Penck, in describing the Bodensee, discusses whether the weight of ice pouring down from the Alps in a sheet 3,600 feet thick may not have had some effect in producing a sinking in the earth's crust.

Responses of Non-volant Mammals to Late Quaternary Climatic Changes in the Wet Tropics Region of North-eastern Australia

1997 ◽  
Vol 24 (5) ◽  
pp. 493 ◽  
Author(s):  
J. W. Winter
Keyword(s):  
Late Quaternary ◽  
Temperature Tolerance ◽  
Climatic Changes ◽  
Glacial Period ◽  
Profound Influence ◽  
Eastern Australia ◽  
North Eastern ◽  
Sclerophyll Forest ◽  
Wet Tropics ◽  
Glacial Periods

It is generally recognised that the distribution of vertebrates in rainforest and wet sclerophyll forest of the Wet Tropics region of north-eastern Australia is profoundly influenced by the formation of two rainforest refugia at the height of Pleistocene glacial periods. Anomalies in the distribution of non-volant mammals indicate that other events may be equally important. In this paper, past geographical occurrence of non-volant mammals is examined by equating the mammals’ known temperature tolerance with palaeoclimatic temperature zones. It is hypothesised that dispersal and vicariant phases taking place since the most recent glacial period have had a profound influence on current patterns of distribution. A major dispersal phase of cool-adapted species occurred after the glacial period, and continuous populations were subsequently fragmented into upland isolates by expansion of warm rainforest during the late post-glacial period. These upland isolates remain substantially unchanged to the present day. Species shared either with New Guinea or south-eastern Australia arrived in the region during the most recent post-glacial period. Clarification of periods of vicariance and dispersal provides a conceptual framework for testing relative divergences of populations within and between regions.

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