Geomorphological impact and morphodynamic effects on flow conveyance of the 1999 jökulhlaup at sólheimajökull,Iceland          下载免费PDF全文

Kate E. H. Staines  Jonathan L. Carrivick 《地球表面变化过程与地形》2015,40(10):1401-1416

The 1999 jökulhlaup at Sólheimajökull was the first major flood to be routed through the proglacial system in over 600 years. This study reconstructed the flood using hydrodynamic, sediment transport and morphodynamic numerical modelling informed by field surveys, aerial photograph and digital elevation model analysis. Total modelled sediment transport was 469 800 m³ (+/‐ 20%). Maximum erosion of 8.2 m occurred along the ice margin. Modelled net landscape change was –86 400 m³ (+/‐ 40%) resulting from –275 400 m³ (+/‐ 20%) proglacial erosion and 194 400 m³ (+/‐ 20%) proglacial deposition. Peak erosion rate and peak deposition rate were 650 m³ s^‐1 (+/‐ 20%) and 595 m³ s^‐1 (+/‐ 20%), respectively, and coincided with peak discharge of water at 1.5 h after flood initiation. The pattern of bed elevation change during the rising limb suggested widespread activation of the bed, whereas more organisation, perhaps primitive bedform development, occurred during the falling limb. Contrary to simplistic conceptual models, deposition occurred on the rising stage and erosion occurred on the falling limb. Comparison of the morphodynamic results with a hydrodynamic simulation illustrated effects of sediment transport and bed elevation change on flow conveyance. The morphodynamic model advanced flood arrival and peak discharge timings by 100% and 19%, respectively. However, peak flow depth and peak flow velocity were not significantly affected. We suggest that morphodynamic processes not only increase flow mass and momentum but that they also introduce a feedback process whereby flood conveyance becomes more efficient via erosion of minor bed protrusions and deposition that infills or subdues minor bed hollows. A major implication of this study is that reconstructions of outburst floods that ignore sediment transport, such as those used in interpretation of long‐term hydrological record and flood risk assessments, may need considerable refinement. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Imaging vulnerability: the iconography of climate change     

Kate Manzo 《Area》2010,42(1):96-107

This paper explores the iconography of climate change in contemporary climate action campaigns in the UK. I aim to show how sample images are simultaneously scientific denotations of global warming and cultural connotations of danger and vulnerability. I further demonstrate that while similar images are associated with different agendas and geographical visions, they attach to a shared discourse of vulnerability that has Western (colonial) roots. The paper concludes with an overview of possible ways for climate action campaigns to effectively convey their political messages without recycling colonial visions of the world.  相似文献   

Framing the use of geo-information in government: a tale of two perspectives     

Yola Georgiadou  Gianluca Miscione  Kate Lance  Walter de Vries 《Earth Science Informatics》2009,2(4):271-282

While commercial virtual globes (e.g. Google Earth) and global scientific cyber-infrastructures (e.g. Digital Earth) are revolutionizing the way we use and produce geo-information, we still lack a rich conceptual understanding of how genuine human actors use geo-information and associated technologies in real work settings. In this paper, we conceptualize the use of geo-information as encompassing people’s actual use practices, the values to which people aspire through geo-information use, and the rules that either legally prescribe or just encourage optimal use. Values, practices and rules can be illuminated from two perspectives (or lenses), the market and the polis, resulting in radically different insights on the use of geo-information as a social phenomenon. We argue that with a polis lens we stand a chance to explain how authentic human actors, groups and communities with different values, interests and motivations use geo-information, and how societal benefits materialize or not as a result. Seen from a polis lens, values are not easily measurable standards of goodness, dominant public management ideas can be the source of technical-organizational change in government while policies can be fruitfully examined as persuasive arguments to target audiences. With a polis lens, we are more likely to understand the emergence of new practices, value contests and global rules underpinning commercial virtual globes and scientific cyber-infrastructures.  相似文献   

Probability density of the multipole vectors for a Gaussian cosmic microwave background     

Mark R. Dennis †  Kate Land 《Monthly notices of the Royal Astronomical Society》2008,383(2):424-434

  相似文献   

The slow violence of life without cash: borders,state restrictions,and exclusion in the U.K. and Australia     

Kate Coddington 《Geographical review》2019,109(4):527-543

In the U.K., refused asylum seekers who are considered destitute are provided with subsistence‐level financial support through the Azure card, a cashless technology similar to a debit card. In Australia, identical technology is used to quarantine fifty percent of the welfare benefits of mainly Aboriginal residents of the Northern Territory. In this paper, I explore the underlying state logics driving such punitive financial policies directed at these populations, arguing that cashless technologies represent a form of slow violence that employs financial tactics to undermine the provision of care for populations with precarious citizenship status. Financial tactics enact new forms of border securitization, slowly but permanently excluding people with precarious claims to citizenship from participation in the nation  相似文献   

The Phase A study of the ESA M4 mission candidate ARIEL     

Ludovic Puig  Göran Pilbratt  Astrid Heske  Isabel Escudero  Pierre-Elie Crouzet  Bram de Vogeleer  Kate Symonds  Ralf Kohley  Pierre Drossart  Paul Eccleston  Paul Hartogh  Jeremy Leconte  Giusi Micela  Marc Ollivier  Giovanna Tinetti  Diego Turrini  Bart Vandenbussche  Paulina Wolkenberg 《Experimental Astronomy》2018,46(1):211-239

ARIEL, the Atmospheric Remote sensing Infrared Exoplanet Large survey, is one of the three M-class mission candidates competing for the M4 launch slot within the Cosmic Vision science programme of the European Space Agency (ESA). As such, ARIEL has been the subject of a Phase A study that involved European industry, research institutes and universities from ESA member states. This study is now completed and the M4 down-selection is expected to be concluded in November 2017. ARIEL is a concept for a dedicated mission to measure the chemical composition and structure of hundreds of exoplanet atmospheres using the technique of transit spectroscopy. ARIEL targets extend from gas giants (Jupiter or Neptune-like) to super-Earths in the very hot to warm zones of F to M-type host stars, opening up the way to large-scale, comparative planetology that would place our own Solar System in the context of other planetary systems in the Milky Way. A technical and programmatic review of the ARIEL mission was performed between February and May 2017, with the objective of assessing the readiness of the mission to progress to the Phase B1 study. No critical issues were identified and the mission was deemed technically feasible within the M4 programmatic boundary conditions. In this paper we give an overview of the final mission concept for ARIEL as of the end of the Phase A study, from scientific, technical and operational perspectives.  相似文献   

Outside country: histories of inland Australia     

Kate Darian-Smith 《The Australian geographer》2015,46(4):535-536

  相似文献   

Water use strategies of two co‐occurring tree species in a semi‐arid karst environment          下载免费PDF全文

Brooke A. Swaffer  Kate L. Holland  Tanya M. Doody  Chris Li  John Hutson 《水文研究》2014,28(4):2003-2017

The flow of precipitation from the surface through to groundwater in karst systems is a complex process involving storage in the unsaturated zone and diffuse and preferential recharge pathways. The processes associated with this behaviour are not well understood, despite the prevalence of karst aquifers being used as freshwater supplies. As a result, uncertainty regarding the ecohydrological processes in this geological setting remains large. In response to the need to better understand the impact of woody vegetation on groundwater recharge, annual evapotranspiration (ET) rates and tree water sources were measured for two years above a shallow, fresh karst aquifer. Water use strategies of the co‐occurring Eucalyptus diversifolia subsp. diversifolia Bonpl. and Allocasuarina verticillata (Lam.) L. Johnson were investigated using a monthly water balance approach, in conjunction with measurement of the stable isotopes of water, leaf water potentials and soil matric potentials. The results suggest that it is unlikely groundwater resources are required to sustain tree transpiration, despite its shallow proximity to the soil surface, and that similarities exist between ET losses and the estimated long‐term average rainfall for this area. Irrespective of stand and morphological differences, E. diversifolia and A. verticillata ET rates showed remarkable convergence, demonstrating the ability of these co‐occurring species to maximise their use of the available precipitation, which avoids the requirement to differentiate between these species when estimating ET at a landscape scale. We conclude that the water holding capacity of porous geological substrates, such as those associated with karst systems, will play an important role in equilibrating annual rainfall variability and should be considered when assessing ecohydrological links associated with karst systems. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

The multipole vectors of the Wilkinson Microwave Anisotropy Probe, and their frames and invariants     

Kate Land  João Magueijo 《Monthly notices of the Royal Astronomical Society》2005,362(3):838-846

  相似文献   

The effects of Martian near surface conditions on the photochemistry of amino acids     

Inge Loes ten Kate  James R.C. Garry  Bernard Foing 《Planetary and Space Science》2006,54(3):296-302

In order to understand the complex multi-parameter system of destruction of organic material on the surface of Mars, step-by-step laboratory simulations of processes occurring on the surface of Mars are necessary. This paper describes the measured effects of two parameters, a CO₂ atmosphere and low temperature, on the destruction rate of amino acids when irradiated with Mars-like ultraviolet light (UV). The results show that the presence of a 7 mbar CO₂ atmosphere does not affect the destruction rate of glycine, and that cooling the sample to 210 K (average Mars temperature) lowers the destruction rate by a factor of 7. The decrease in the destruction rate of glycine by cooling the sample is thought to be predominantly caused by the slower reaction kinetics. When these results are scaled to Martian lighting conditions, cold thin films of glycine are assumed to have half-lives of 250 h under noontime peak illumination. It has been hypothesised that the absence of detectable native organic material in the Martian regolith points to the presence of oxidising agents. Some of these agents might form via the interaction of UV with compounds in the atmosphere. Water, although a trace component of Mars’ atmosphere, is suggested to be a significant source of oxidising species. However, gaseous CO₂ or adsorbed H₂O layers do not influence the photodestruction of amino acids significantly in the absence of reactive soil. Other mechanisms such as chemical processes in the Martian regolith need to be effective for rapid organic destruction.  相似文献