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result(s) for
"Round, Vanessa"
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Surge dynamics and lake outbursts of Kyagar Glacier, Karakoram
2017
The recent surge cycle of Kyagar Glacier, in the Chinese Karakoram, caused formation of an ice-dammed lake and subsequent glacial lake outburst floods (GLOFs) exceeding 40 million m3 in 2015 and 2016. GLOFs from Kyagar Glacier reached double this size in 2002 and earlier, but the role of glacier surging in GLOF formation was previously unrecognised. We present an integrative analysis of the glacier surge dynamics from 2011 to 2016, assessing surge mechanisms and evaluating the surge cycle impact on GLOFs. Over 80 glacier surface velocity fields were created from TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement), Sentinel-1A, and Landsat satellite data. Changes in ice thickness distribution were revealed by a time series of TanDEM-X elevation models. The analysis shows that, during a quiescence phase lasting at least 14 years, ice mass built up in a reservoir area at the top of the glacier tongue, and the terminus thinned by up to 100 m, but in the 2 years preceding the surge onset this pattern reversed. The surge initiated with the onset of the 2014 melt season, and in the following 15 months velocity evolved in a manner consistent with a hydrologically controlled surge mechanism. Dramatic accelerations coincided with melt seasons, winter deceleration was accompanied by subglacial drainage, and rapid surge termination occurred following the 2015 GLOF. Rapid basal motion during the surge is seemingly controlled by high water pressure, caused by input of surface water into either an inefficient subglacial drainage system or unstable subglacial till. The potential lake volume increased to more than 70 million m3 by late 2016, as a result of over 60 m of thickening at the terminus. Lake formation and the evolution of the ice dam height should be carefully monitored through remote sensing to anticipate large GLOFs in the near future.
Journal Article
Large hydropower and water-storage potential in future glacier-free basins
by
Zekollari, Harry
,
Farinotti, Daniel
,
Round, Vanessa
in
704/106/125
,
704/106/694/2786
,
704/172/4081
2019
Climate change is causing widespread glacier retreat
1
, and much attention is devoted to negative impacts such as diminishing water resources
2
, shifts in runoff seasonality
3
, and increases in cryosphere-related hazards
4
. Here we focus on a different aspect, and explore the water-storage and hydropower potential of areas that are expected to become ice-free during the course of this century. For roughly 185,000 sites that are glacierized at present, we predict the potentially emerging reservoir storage volume and hydropower potential. Using a climate-driven glacier-evolution model
5
and topographical analysis
6
, we estimate a theoretical maximal total storage and hydropower potential of 875 ± 260 cubic kilometres and 1,355 ± 515 terawatt-hours per year, respectively (95% confidence intervals). A first-order suitability assessment that takes into account environmental, technical and economic factors identifies roughly 40 per cent of this potential (355 ± 105 cubic kilometres and 533 ± 200 terawatt-hours per year) as possibly being suitable for realization. Three quarters of the potential storage volume is expected to become ice-free by 2050, and the storage volume would be enough to retain about half of the annual runoff leaving the investigated sites. Although local impacts would need to be assessed on a case-by-case basis, the results indicate that deglacierizing basins could make important contributions to national energy supplies in several countries, particularly in High Mountain Asia.
Glacierized regions that are projected to become ice-free in this century could provide substantial water storage and hydroelectric power, according to this worldwide theoretical assessment.
Journal Article
Farming on the edge: assessing the impact of historical and future climate change on the mediterranean cropping margins of Australia
2025
The boundary between land suitable for low rainfall grain cropping and the arid interior suitable for extensive grazing has a history in South Australia dating back to Goyder in the 1860s and in Western Australia to Brookman in the 1900s. Historical and future shifts in climatically determined edges of cropping regions focus discussion on how farmers might adapt to a changing climate. We integrate the outputs of climate analysis and crop simulation modelling to explore the limits to crop production at the low rainfall margin of cropping in Western Australia and South Australia. Across 40 locations, growing season (April to October) rainfall over the past two decades was 2–27% drier than the long-term record which corresponded to declines in simulated wheat yields. Increasing CO
2
levels, from 296ppm in 1900 to 412ppm in 2020, reduced but didn’t eliminate the decline in simulated yield. Climate models indicate that even stronger rainfall declines could be experienced in the future, particularly over the Western Australian cropping regions. We ran APSIM simulations with projected climate data from 8 global climate models GCMs for a subset of 8 representative low rainfall sites across the Western Australian and South Australian cropping region. The 8 GCMs provide a range in projected water limited wheat yields consistent with the range of projected changes in rainfall from different GCMs. We discussed the results with low rainfall farmers and advisers in the regions and provide an overview of their responses to aid our interpretation. Farmers maintained that they were continually adapting to season-to-season variation and to the changing climate. Most farmers felt that their current business model was working, and that climate change hadn’t forced them to make drastic changes. There was a belief that improved technologies (e.g., new varieties) and agronomy had served them well in the past and would be able to keep pace with the effects of any climate change. Most of the changes over the last 30 years had been within cropping and grazing enterprises rather than changing enterprises to alternative land uses. The uptake of no-till farming was ranked as the largest change which enabled farmers to make better use of rainfall. Farmers had also changed varieties and adopted new crops. Participants accepted the importance of climate in the success of their cropping enterprises and that the climate was changing. However, there was a strong sense of technical optimism and a refusal to have their future defined by climate alone. Some farmers were concerned that transformation may be driven not directly by climate change, but rather by the policies associated with climate change.
Journal Article
Realised added value in dynamical downscaling of Australian climate change
by
Evans, Jason P
,
Di Virgilio Giovanni
,
Round, Vanessa
in
Adaptation
,
Atmospheric precipitations
,
Climate adaptation
2020
Coarse resolution global climate models (GCMs) cannot resolve fine-scale drivers of regional climate, which is the scale where climate adaptation decisions are made. Regional climate models (RCMs) generate high-resolution projections by dynamically downscaling GCM outputs. However, evidence of where and when downscaling provides new information about both the current climate (added value, AV) and projected climate change signals, relative to driving data, is lacking. Seasons and locations where CORDEX-Australasia ERA-Interim and GCM-driven RCMs show AV for mean and extreme precipitation and temperature are identified. A new concept is introduced, ‘realised added value’, that identifies where and when RCMs simultaneously add value in the present climate and project a different climate change signal, thus suggesting plausible improvements in future climate projections by RCMs. ERA-Interim-driven RCMs add value to the simulation of summer-time mean precipitation, especially over northern and eastern Australia. GCM-driven RCMs show AV for precipitation over complex orography in south-eastern Australia during winter and widespread AV for mean and extreme minimum temperature during both seasons, especially over coastal and high-altitude areas. RCM projections of decreased winter rainfall over the Australian Alps and decreased summer rainfall over northern Australia are collocated with notable realised added value. Realised added value averaged across models, variables, seasons and statistics is evident across the majority of Australia and shows where plausible improvements in future climate projections are conferred by RCMs. This assessment of varying RCM capabilities to provide realised added value to GCM projections can be applied globally to inform climate adaptation and model development.
Journal Article
Historical and future drought impacts in the Pacific islands and atolls
by
Heady, Craig
,
Tofaeono, Tile
,
Daphne, Arieta
in
Agricultural drought
,
Agriculture
,
Atmospheric Sciences
2021
Drought is known as a “creeping disaster” because drought impacts are usually noticed months or years after a drought begins. In the Pacific Island Countries and Territories (PICTs), there is almost no ability to tell when a drought will begin or end, especially for droughts other than meteorological droughts. Monitoring, forecasting and managing drought in the PICTs is complex due to the variety of different ways droughts occur, and the diverse direct and indirect causes and consequences of drought, across the PICT region. For example, the impacts of drought across the PICTs vary significantly depending on (i) the type of drought (e.g. meteorological drought or agricultural drought); (ii) the location (e.g. high islands versus atolls); (iii) socioeconomic conditions in the location affected by drought; and (iv) cultural attitudes towards the causes of drought (e.g. a punishment from God versus a natural process that is potentially predictable and something that can be managed). This paper summarises what is known and unknown about drought impacts in the PICTs and provides recommendations to guide future research and investment towards minimising the negative impacts of droughts when they inevitably occur in the PICTs.
Journal Article
Neurogenic Bowel in Acute Rehabilitation Following Spinal Cord Injury: Impact of Laxatives and Opioids
2021
Objective: To explore the association between bowel dysfunction and use of laxatives and opioids in an acute rehabilitation setting following spinal cord injury (SCI). Methods: Data was collected regarding individuals with acute traumatic/non-traumatic SCI over a two-year period (2012–2013) during both the week of admission and discharge of their inpatient stay. Results: An increase in frequency of bowel movement (BM) (p = 0.003) and a decrease in frequency of fecal incontinence (FI) per week (p < 0.001) between admission and discharge was found across all participants. There was a reduction in the number of individuals using laxatives (p = 0.004) as well as the number of unique laxatives taken (p < 0.001) between admission and discharge in our cohort. The number of individuals using opioids and the average dose of opioids in morphine milligram equivalents (MME) from admission to discharge were significantly reduced (p = 0.001 and p = 0.02, respectively). There was a positive correlation between the number of laxatives and frequency of FI at discharge (r = 0.194, p = 0.014), suggesting that an increase in laxative use results in an increased frequency of FI. Finally, there was a significant negative correlation between average dose of opioids (MME) and frequency of BM at discharge, confirming the constipating effect of opioids (r = −0.20, p = 0.009).
Journal Article