scholarly journals Dropstones in Lacustrine Sediments as a Record of Snow Avalanches—A Validation of the Proxy by Combining Satellite Imagery and Varve Chronology at Kenai Lake (South-Central Alaska)

Quaternary ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 11 ◽  
Author(s):  
Sien Thys ◽  
Maarten Van Daele ◽  
Nore Praet ◽  
Britta Jensen ◽  
Thomas Van Dyck ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Satellite Imagery ◽  
Variable Temperature ◽  
Sediment Cores ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Climate Data ◽  
Varve Chronology ◽  
South Central

Snow avalanches cause many fatalities every year and damage local economies worldwide. The present-day climate change affects the snowpack and, thus, the properties and frequency of snow avalanches. Reconstructing snow avalanche records can help us understand past variations in avalanche frequency and their relationship to climate change. Previous avalanche records have primarily been reconstructed using dendrochronology. Here, we investigate the potential of lake sediments to record snow avalanches by studying 27 < 30-cm-long sediment cores from Kenai Lake, south-central Alaska. We use X-ray computed tomography (CT) to image post-1964 varves and to identify dropstones. We use two newly identified cryptotephras to update the existing varve chronology. Satellite imagery is used to understand the redistribution of sediments by ice floes over the lake, which helps to explain why some avalanches are not recorded. Finally, we compare the dropstone record with climate data to show that snow avalanche activity is related to high amounts of snowfall in periods of relatively warm or variable temperature conditions. We show, for the first time, a direct link between historical snow avalanches and dropstones preserved in lake sediments. Although the lacustrine varve record does not allow for the development of a complete annual reconstruction of the snow avalanche history in the Kenai Lake valley, our results suggest that it can be used for long-term decadal reconstructions of the snow-avalanche history, ideally in combination with similar records from lakes elsewhere in the region.

scholarly journals A new methodology exploring the record of snow avalanches in lake sediments

2016 ◽  
Author(s):  
Laurent Fouinat ◽  
Pierre Sabatier ◽  
Jérôme Poulenard ◽  
Jean-Louis Reyss ◽  
Xavier Montet ◽  
...  
Keyword(s):  
Organic Matter ◽  
Global Change ◽  
Lake Sediments ◽  
Sediment Cores ◽  
Ct Scanning ◽  
Ct Scans ◽  
Snow Avalanches ◽  
X Ray ◽  
Steep Slopes ◽  
Non Destructive

Abstract. In recent years, wet avalanche deposits have become a subject of increasing concern in a context of both global change and winter mountain tourism activities. This study focuses on the use of a new methodology based on CT scans to identify snow avalanche deposits in lake sediment. Here, we study the mid-elevation Lake Lauvitel system (western French Alps), which features steep slopes and avalanche corridors. CT scanning is a fast, non-destructive method based on X-ray technology and allows the identification of elements with different densities. We applied this method to sediment cores, leading to the 3D identification of the dense rocks and organic matter macroremains that characterize wet avalanches. A total of eight periods of higher avalanche activity are identified since AD 1880 at the site. This new methodology is suitable for avalanche deposit reconstruction and may be applicable more widely in paleolimnological studies.

scholarly journals Projected impacts of climate change on hydropower potential in China

2016 ◽  
Author(s):  
Xingcai Liu ◽  
Qiuhong Tang ◽  
Nathalie Voisin ◽  
Huijuan Cui
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
River Flow ◽  
Southern China ◽  
Eastern China ◽  
General Circulation Models ◽  
Central China ◽  
Climate Data ◽  
South Central ◽  
Hydropower Potential

Abstract. Hydropower is an important renewable energy source in China, but it is sensitive to climate change, because the changing climate may alter hydrological conditions (e.g., river flow and reservoir storage). Future changes and associated uncertainties in China's gross hydropower potential (GHP) and developed hydropower potential (DHP) are projected using simulations from eight global hydrological models (GHMs) forced by five general circulation models (GCMs) with climate data under two representative concentration pathways (RCP2.6 and RCP8.5). Results show that the estimation of the present GHP of China is comparable to other studies; overall, the annual GHP is projected to change by −1.7 to 2% in the near future (2020–2050) and increase by 3 to 6 % in the late 21st century (2070–2099). The annual DHP is projected to change by −2.2 to −5.4 % (0.7–1.7 % of the total installed hydropower capacity [IHC]) and −1.3 to −4% (0.4–1.3 % of total IHC) for 2020–2050 and 2070–2099, respectively. Regional variations emerge: GHP will increase in northern China, but decrease in southern China – mostly in South-Central China and Eastern China – where numerous reservoirs and large IHCs currently are located. The area with the highest GHP in Southwest China will have more GHP, while DHP will reduce in the regions with high IHC (e.g., Sichuan and Hubei) in the future. The largest decrease in DHP (in %) will occur in autumn or winter, when streamflow is relatively low and water use is competitive. Large ranges in hydropower estimates across GHMs and GCMs highlight the necessity of using multi-model assessments under climate change conditions. This study prompts the consideration of climate change in planning for hydropower development and operations in China.

scholarly journals Informal Cooperative State-Federal Avalanche-Warning System and Public Education Program for South-Central Alaska, U.S.A.

1980 ◽  
Vol 26 (94) ◽  
pp. 497-500 ◽  
Author(s):  
Steve W. Hackett ◽  
Douglas Fesler
Keyword(s):  
Public Education ◽  
Warning System ◽  
Federal Agencies ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Mountainous Areas ◽  
The Past ◽  
South Central ◽  
Avalanche Warning ◽  
Outdoor Educators

Abstract The sagas of Alaskan winter outdoor activities contain increasing accounts of sudden deaths from snow avalanches. Over 100 documented fatalities have occurred within Alaska since 1898 ; 22 people died in south-central Alaska in the past 8 years. With increases in population, development, and use of the mountainous areas, avalanche warning and public education have acquired a new and very important function in Alaska. Some efforts towards establishing an avalanche warning system for south-central Alaska have been initiated by state and federal agencies. Snow-avalanche education programs presented by Alaska Division of Parks, local rescue groups, and outdoor educators have helped to increase the overall avalanche awareness in the Anchorage community. Formalization and expansion of current efforts are aimed to reduce future snow-avalanche accidents and fatalities.

scholarly journals Informal Cooperative State-Federal Avalanche-Warning System and Public Education Program for South-Central Alaska, U.S.A.

1980 ◽  
Vol 26 (94) ◽  
pp. 497-500
Author(s):  
Steve W. Hackett ◽  
Douglas Fesler
Keyword(s):  
Public Education ◽  
Warning System ◽  
Federal Agencies ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Mountainous Areas ◽  
The Past ◽  
South Central ◽  
Avalanche Warning ◽  
Outdoor Educators

AbstractThe sagas of Alaskan winter outdoor activities contain increasing accounts of sudden deaths from snow avalanches. Over 100 documented fatalities have occurred within Alaska since 1898 ; 22 people died in south-central Alaska in the past 8 years. With increases in population, development, and use of the mountainous areas, avalanche warning and public education have acquired a new and very important function in Alaska.Some efforts towards establishing an avalanche warning system for south-central Alaska have been initiated by state and federal agencies. Snow-avalanche education programs presented by Alaska Division of Parks, local rescue groups, and outdoor educators have helped to increase the overall avalanche awareness in the Anchorage community. Formalization and expansion of current efforts are aimed to reduce future snow-avalanche accidents and fatalities.

CHARACTERIZING SNOW AVALANCHES RECORDED IN LAKE SEDIMENTS IN CENTRAL COLORADO

2016 ◽  
Author(s):  
Zara K. Hickman ◽  
◽  
Christy E. Briles ◽  
Andrew Gray
Keyword(s):  
Lake Sediments ◽  
Snow Avalanches

Twelfth Century AD

2017 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Alan L. Kolata
Keyword(s):  
Climate Change ◽  
Southern Oscillation ◽  
Sediment Cores ◽  
Critical Role ◽  
Lake Titicaca ◽  
Independent Evidence ◽  
Tropical Regions ◽  
Ice Cap ◽  
Paleoclimate Records ◽  
Past Climate Change

Climate is a fundamental and independent variable of human existence. Given that 50 percent of the Earth’s surface and much of its population exist between 30oN and 30oS, paleoenvironmental research in the Earth’s tropical regions is vital to our understanding of the world’s current and past climate change. Most of the solar energy that drives the climate system is absorbed in these regions. Paleoclimate records reveal that tropical processes, such as variations in the El Niño-Southern Oscillation (ENSO), have affected the climate over much of the planet. Climatic variations, particularly in precipitation and temperature, play a critical role in the adaptations of agrarian cultures located in zones of environmental sensitivity, such as those of the coastal deserts, highlands, and altiplano of the Andean region. Paleoclimate records from the Quelccaya ice cap (5670 masl) in highland Peru that extend back ~1800 years show good correlation between precipitation and the rise and fall of pre-Hispanic civilizations in western Peru and Bolivia. Sediment cores extracted from Lake Titicaca provide independent evidence of this correspondence with particular reference to the history of the pre-Hispanic Tiwanaku state centered in the Andean altiplano. Here we explore, in particular, the impacts of climate change on the development and ultimate dissolution of this altiplano state.

scholarly journals Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part II: Climate Change Impact Assessment)

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1548
Author(s):  
Suresh Marahatta ◽  
Deepak Aryal ◽  
Laxmi Prasad Devkota ◽  
Utsav Bhattarai ◽  
Dibesh Shrestha
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Models ◽  
Assessment Tool ◽  
Swat Model ◽  
Global Climate Models ◽  
Climate Data ◽  
The Future ◽  
The Impact ◽  
Mountainous River

This study aims at analysing the impact of climate change (CC) on the river hydrology of a complex mountainous river basin—the Budhigandaki River Basin (BRB)—using the Soil and Water Assessment Tool (SWAT) hydrological model that was calibrated and validated in Part I of this research. A relatively new approach of selecting global climate models (GCMs) for each of the two selected RCPs, 4.5 (stabilization scenario) and 8.5 (high emission scenario), representing four extreme cases (warm-wet, cold-wet, warm-dry, and cold-dry conditions), was applied. Future climate data was bias corrected using a quantile mapping method. The bias-corrected GCM data were forced into the SWAT model one at a time to simulate the future flows of BRB for three 30-year time windows: Immediate Future (2021–2050), Mid Future (2046–2075), and Far Future (2070–2099). The projected flows were compared with the corresponding monthly, seasonal, annual, and fractional differences of extreme flows of the simulated baseline period (1983–2012). The results showed that future long-term average annual flows are expected to increase in all climatic conditions for both RCPs compared to the baseline. The range of predicted changes in future monthly, seasonal, and annual flows shows high uncertainty. The comparative frequency analysis of the annual one-day-maximum and -minimum flows shows increased high flows and decreased low flows in the future. These results imply the necessity for design modifications in hydraulic structures as well as the preference of storage over run-of-river water resources development projects in the study basin from the perspective of climate resilience.

scholarly journals Flood Risk and Adaptation Strategies for Soybean Production Systems on the Flood-Prone Pampas under Climate Change

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1187
Author(s):  
Wouter Julius Smolenaars ◽  
Spyridon Paparrizos ◽  
Saskia Werners ◽  
Fulco Ludwig
Keyword(s):  
Climate Change ◽  
Flood Risk ◽  
Risk Perceptions ◽  
Production Systems ◽  
Adaptation Strategies ◽  
Flood Events ◽  
Climate Data ◽  
Soybean Production ◽  
Drying Trend ◽  
Sowing Season

In recent decades, multiple flood events have had a devastating impact on soybean production in Argentina. Recent advances suggest that the frequency and intensity of destructive flood events on the Argentinian Pampas will increase under pressure from climate change. This paper provides bottom-up insight into the flood risk for soybean production systems under climate change and the suitability of adaptation strategies in two of the most flood-prone areas of the Pampas region. The flood risk perceptions of soybean producers were explored through interviews, translated into climatic indicators and then studied using a multi-model climate data analysis. Soybean producers perceived the present flood risk for rural accessibility to be of the highest concern, especially during the harvest and sowing seasons when heavy machinery needs to reach soybean lots. An analysis of climatic change projections found a rising trend in annual and harvest precipitation and a slight drying trend during the sowing season. This indicates that the flood risk for harvest accessibility may increase under climate change. Several adaptation strategies were identified that can systemically address flood risks, but these require collaborative action and cannot be undertaken by individual producers. The results suggest that if cooperative adaptation efforts are not made in the short term, the continued increase in flood risk may force soybean producers in the case study locations to shift away from soybean towards more robust land uses.

scholarly journals Vulnerability of the North Water ecosystem to climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sofia Ribeiro ◽  
Audrey Limoges ◽  
Guillaume Massé ◽  
Kasper L. Johansen ◽  
William Colgan ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Late Holocene ◽  
Sediment Cores ◽  
Arctic Ecosystems ◽  
Little Auk ◽  
The North ◽  
Water Ecosystem ◽  
North Water

AbstractHigh Arctic ecosystems and Indigenous livelihoods are tightly linked and exposed to climate change, yet assessing their sensitivity requires a long-term perspective. Here, we assess the vulnerability of the North Water polynya, a unique seaice ecosystem that sustains the world’s northernmost Inuit communities and several keystone Arctic species. We reconstruct mid-to-late Holocene changes in sea ice, marine primary production, and little auk colony dynamics through multi-proxy analysis of marine and lake sediment cores. Our results suggest a productive ecosystem by 4400–4200 cal yrs b2k coincident with the arrival of the first humans in Greenland. Climate forcing during the late Holocene, leading to periods of polynya instability and marine productivity decline, is strikingly coeval with the human abandonment of Greenland from c. 2200–1200 cal yrs b2k. Our long-term perspective highlights the future decline of the North Water ecosystem, due to climate warming and changing sea-ice conditions, as an important climate change risk.

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