Linking glacier extent and summer temperature in NE Russia - Implications for precipitation during the global Last Glacial Maximum

It is generally assumed that during the global Last Glacial Maximum (gLGM, i.e. 18–24 ka BP) dry climatic conditions in NE Russia inhibited the growth of large ice caps and restricted glaciers to mountain ranges. However, recent evidence has been found to suggest that glacial summers in NE Russia were as warm as at present while glaciers were more extensive than today. As a result, we hypothesize that precipitation must have been relatively high in order to compensate for the high summer temperatures and the resulting glacial ablation. We estimate precipitation abundance by mass balance calculations for the palaeo-glaciers on Kamchatka and in the Kankaren Range using a degree-day-modelling (DDM) approach, and find that precipitation during the gLGM was likely comparable to, or even exceeded, the modern average. We suggest that stronger than present southerly winds over the Northwest Pacific may have accounted for the abundant precipitation. The DDM-results imply that summer temperature, rather than aridity, limited glacier extent in the southern Pacific Sector of NE Russia during the gLGM

Glacial cirques as palaeoenvironmental indicators: Their potential and limitations

© 2015 Elsevier B.V. Glacial cirques are armchair-shaped erosional hollows, typified by steep headwalls and, often, overdeepened floors. They reflect former regions of glacier initiation, and their distribution is, therefore, linked to palaeoclimate. Because of this association, cirques can be analysed for the information they provide about past environments, an approach that has a strong heritage, and has seen resurgence over recent years. This paper provides a critical assessment of what cirques can tell us about past environments, and considers their reliability as palaeoenvironmental proxies. Specific focus is placed on information that can be obtained from consideration of cirque distribution, aspect, altitude, and morphometry. The paper highlights the fact that cirques potentially provide information about the style, duration and intensity of former glaciation, as well as information about past temperatures, precipitation gradients, cloud-cover and wind directions. In all, cirques are considered a valuable source of palaeoenvironmental information (if used judiciously), particularly as they are ubiquitous within formerly glaciated mountain ranges globally, thus making regional or even global scale studies possible. Furthermore, cirques often occupy remote and inaccessible regions where other palaeoenvironmental proxies may be limited or lacking

Distribution and pattern of moraines in far ne Russia reveal former glacial extent

Here we present a series of six maps illustrating the distribution of end moraines in Far NE Russia. The maps are the first to systematically document the distribution of moraines across this region from the Verkhoyansk Mountains at the westernmost limit of our study area to the Chukchi Peninsula in the NE and to Kamchatka in the south, covering almost 4 million km 2 . Moraines were identified and mapped from analysis of satellite images and digital elevation model data. A total of 2173 moraines are identified, and we highlight some 197 more speculative features (perhaps moraines) that require further investigation. The distribution of moraines indicates that much of the region, now largely ice-free, was formerly occupied by glaciers centred upon the region's uplands and that glacier outlets were typically < 200 km in length. The maps demonstrate the usefulness of remote sensing to derive an improved understanding of the glacial history of this vast and isolated region, and we present them to stimulate further work and act as a systematic framework for targeted geochronometric dating

Glacier Reconstruction

Glacier reconstruction typically aims to establish the former extent of ice masses at any given period. Such reconstructions are important because they provide crucial information about past (palaeo) glacier changes over much longer timescales than the observational record permits. Reconstructing the dimensions and dynamics of palaeo-ice masses enables equilibrium line altitudes, and temperature or precipitation to be calculated, making glaciers an important palaeo-climate proxy. Given this utility, geomorphologically-based glacier reconstructions have been generated for many regions globally, although the specific methods employed are rarely described formally. To address this shortcoming, this chapter describes some of the methods employed in generating geomorphologically-based reconstructions for ice sheets and mountain-scale glaciers (< ~1,000 km2)

Rapid glacial retreat on the Kamchatka Peninsula during the early 21st century

© Author(s) 2016. Monitoring glacier fluctuations provides insights into changing glacial environments and recent climate change. The availability of satellite imagery offers the opportunity to view these changes for remote and inaccessible regions. Gaining an understanding of the ongoing changes in such regions is vital if a complete picture of glacial fluctuations globally is to be established. Here, satellite imagery (Landsat 7, 8 and ASTER) is used to conduct a multi-annual remote sensing survey of glacier fluctuations on the Kamchatka Peninsula (eastern Russia) over the 2000-2014 period. Glacier margins were digitised manually and reveal that, in 2000, the peninsula was occupied by 673 glaciers, with a total glacier surface area of 775.7ĝ€±ĝ€27.9ĝ€km2. By 2014, the number of glaciers had increased to 738 (reflecting the fragmentation of larger glaciers), but their surface area had decreased to 592.9ĝ€±ĝ€20.4ĝ€km2. This represents a ĝ1/4 ĝ€24ĝ€% decline in total glacier surface area between 2000 and 2014 and a notable acceleration in the rate of area loss since the late 20th century. Analysis of possible controls indicates that these glacier fluctuations were likely governed by variations in climate (particularly rising summer temperatures), though the response of individual glaciers was modulated by other (non-climatic) factors, principally glacier size, local shading and debris cover

ACME, a GIS tool for Automated Cirque Metric Extraction

Regional scale studies of glacial cirque metrics provide key insights on the (palaeo) environment related to the formation of these erosional landforms. The growing availability of high resolution terrain models means that more glacial cirques can be identified and mapped in the future. However, the extraction of their metrics still largely relies on time consuming manual techniques or the combination of, more or less obsolete, GIS tools. In this paper, a newly coded toolbox is provided for the automated, and comparatively quick, extraction of 16 key glacial cirque metrics; including length, width, circularity, planar and 3D area, elevation, slope, aspect, plan closure and hypsometry. The set of tools, named ACME (Automated Cirque Metric Extraction), is coded in Python, runs in one of the most commonly used GIS packages (ArcGIS) and has a user friendly interface. A polygon layer of mapped cirques is required for all metrics, while a Digital Terrain Model and a point layer of cirque threshold midpoints are needed to run some of the tools. Results from ACME are comparable to those from other techniques and can be obtained rapidly, allowing large cirque datasets to be analysed and potentially important regional trends highlighted

Examining the viability of the world’s busiest winter road to climate change using a process-based lake model

Winter roads play a vital role in linking communities and building economies in the northern high latitudes. With these regions warming two to three times faster than the global average, climate change threatens the long-term viability of these important seasonal transport routes. We examine how climate change will impact the world’s busiest heavy-haul winter road – the Tibbitt to Contwoyto Winter Road (TCWR) in northern Canada. The FLake freshwater lake model is used to project ice thickness for a lake at the start of the TCWR – first using observational climate data, and second using modelled future climate scenarios corresponding to varying rates of warming ranging from 1.5°C to 4°C above preindustrial temperatures. Our results suggest that 2°C warming could be a tipping point for the viability of the TCWR, requiring at best costly adaptation and at worst alternative forms of transportation. Containing warming to the more ambitious temperature target of 1.5°C pledged at the 2016 Paris Agreement may be the only way to keep the TCWR viable – albeit with a shortened annual operational season relative to present. More widely, we show that higher regional winter warming across much of the rest of Arctic North America threatens the long-term viability of winter roads at a continental scale. This underlines the importance of continued global efforts to curb greenhouse gas emissions to avoid many long-term and irreversible impacts of climate change

Idempotent convexity and algebras for the capacity monad and its submonads

Idempotent analogues of convexity are introduced. It is proved that the category of algebras for the capacity monad in the category of compacta is isomorphic to the category of $(\max,\min)$-idempotent biconvex compacta and their biaffine maps. It is also shown that the category of algebras for the monad of sup-measures ($(\max,\min)$-idempotent measures) is isomorphic to the category of $(\max,\min)$-idempotent convex compacta and their affine maps

Chronic non-specific low back pain - sub-groups or a single mechanism?

Copyright 2008 Wand and O'Connell; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain is a substantial health problem and has subsequently attracted a considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions for chronic non-specific low back pain indicate limited effectiveness for most commonly applied interventions and approaches. Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of effectiveness is at odds with their clinical experience of managing patients with back pain. A common explanation for this discrepancy is the perceived heterogeneity of patients with chronic non-specific low back pain. It is felt that the effects of treatment may be diluted by the application of a single intervention to a complex, heterogeneous group with diverse treatment needs. This argument presupposes that current treatment is effective when applied to the correct patient. An alternative perspective is that the clinical trials are correct and current treatments have limited efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important that the sub-grouping paradigm is closely examined. This paper argues that there are numerous problems with the sub-grouping approach and that it may not be an important reason for the disappointing results of clinical trials. We propose instead that current treatment may be ineffective because it has been misdirected. Recent evidence that demonstrates changes within the brain in chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of cortical reorganisation and degeneration. This perspective offers interesting insights into the chronic low back pain experience and suggests alternative models of intervention. Summary: The disappointing results of clinical research are commonly explained by the failure of researchers to adequately attend to sub-grouping of the chronic non-specific low back pain population. Alternatively, current approaches may be ineffective and clinicians and researchers may need to radically rethink the nature of the problem and how it should best be managed