Hemispheric-scale climate response to Northern Eurasia land surface characteristics and snow anomalies   总被引：3，自引：0，他引：3  

Gavin Gong  Judah Cohen  Dara Entekhabi  Yan Ge   《Global and Planetary Change》2007,56(3-4):359

This paper presents a synopsis of recently published studies by the co-authors, which show that several land surface characteristics unique to Northern Eurasia are responsible for facilitating a causal relationship between autumn snow anomalies in this region and subsequent hemispheric winter climate patterns. The large size and extratropical location of the contiguous Eurasian land mass results in broad, continental-scale interannual snow cover extent and depth variations throughout autumn and winter, and corresponding diabatic heating anomalies. These surface anomalies occur in the presence of a large region of stationary wave activity, produced in part by the orographic barriers that separate northern/central Eurasia from southern/eastern Eurasia. This co-location of snow-forced anomalies and ambient wave energy is unique to Northern Eurasia, and initiates a teleconnection pathway involving stationary wave–mean flow interaction throughout the troposphere and stratosphere, ultimately resulting in a modulation of the winter Arctic Oscillation (AO). Complementary new results are also presented which show that partial snow cover extent or snow depth only anomalies in Northern Eurasia are insufficient to initiate the teleconnection pathway and produce a winter AO signal. This synopsis provides a useful interpretation of the earlier studies in the specific context of Northern Eurasia regional climate and environmental change.  相似文献   

Is being in work good for wellbeing? Work Integration Social Enterprises in regional Australia     

Katharine McKinnon  Melissa Kennedy  Jo Barraket  Tracy DeCotta 《The Australian geographer》2020,51(3):361-375

ABSTRACT

Work Integration Social Enterprises (WISE) offer supported work environments for people experiencing disadvantage, including people with disability. This paper reflects on a research project that is mapping the ways in which social enterprises in regional Australian cities produce wellbeing for their employees. Through supported employment programs, these organisations are transforming individual lives, helping to build a sense of self-worth and purpose, and increase individuals’ social skills and capacities. Many of the perceived benefits are associated with a belief in the innate good of paid work. Based upon interviews with employees in the social enterprises, it is apparent that the hopes attached to providing ‘meaningful work’ are considerable. At the same time social enterprises are taking on social responsibilities that were once provided by the state, while also selling their services as employers of disabled and disadvantaged members of society and maintaining commercial viability of the enterprise. Using feminist political economy alongside discussion of the distributive economy, this paper explores how contemporary policy conditions, productivist biases and normative discourses about the value of wage work inflect the forms of wellbeing that can be experienced by WISE workers.  相似文献   

Identifying oceanographic conditions conducive to coastal impacts on temperate open coastal beaches     

Leach  Chloe  Hague  Ben S.  Kennedy  David M.  Carvalho  Rafael C.  Ierodiaconou  Daniel 《Natural Hazards》2021,109(1):499-521

Natural Hazards - Warnings issued by meteorological or oceanographic agencies are a common means of allowing people to prepare for likely impactful events. Quantifying the relationships between...  相似文献   

The linkage between fault throw and footwall scarp erosion patterns: an example from the Bremstein Fault Complex,offshore Mid‐Norway     

Gavin M. Elliott  Paul Wilson  Christopher A.‐L. Jackson  Robert L. Gawthorpe  Lisa Michelsen  Ian R. Sharp 《Basin Research》2012,24(2):180-197

Studies of normal fault systems in modern extensional regimes (e.g. Basin and Range), and in exhumed, ancient rift basins (e.g. Gulf of Suez Rift) have shown a link between the evolution of fault‐related footwall topography and associated erosional drainage systems. In this study, we use 3D seismic reflection data to image the footwall crest of a gravity‐driven fault system developed during late Middle Jurassic to Early Cretaceous rifting on the Halten Terrace, offshore Mid‐Norway. This 22‐km‐long fault system lacks significant footwall uplift, with hangingwall subsidence accommodating throw accumulation on the fault system. Significant erosion has occurred along the length of the footwall crest and is defined by 96 catchments characterized by erosional channels. These erosional channels consist of small, linear systems up to 750 m long located along the front of the fault footwall. Larger, dendritic channel systems extend further back (up to 3 km normal to fault strike) into the footwall. These channels are up to 7 km long, up to 50 m deep and up to 1 km wide. Fault throw varies along strike, with greatest throw in the centre of the fault decreasing towards the fault tips; localized throw minima are interpreted to represent segment linkage points, which were breached as the fault grew. Comparison of the catchment location to the throw distribution shows that the largest catchments are in the centre of the fault and decrease in size to the fault tips. There is no link between the location of the breached segment linkage points and the location and size of the footwall catchments, suggesting that the first‐order control on footwall erosion patterns is the overall fault‐throw distribution.  相似文献   

2XMMi J225036.9+573154 – a new eclipsing AM Her binary discovered using XMM–Newton     

Gavin Ramsay  Simon Rosen  Pasi Hakala  Thomas Barclay 《Monthly notices of the Royal Astronomical Society》2009,395(1):416-421

We report the discovery of an eclipsing polar, 2XMMi J225036.9+573154, using XMM–Newton . It was discovered by searching the light curves in the 2XMMi catalogue for objects showing X-ray variability. Its X-ray light curve shows a total eclipse of the white dwarf by the secondary star every 174 min. An extended pre-eclipse absorption dip is observed in soft X-rays at  φ= 0.8–0.9  , with evidence for a further dip in the soft X-ray light curve at  φ∼ 0.4  . Further, X-rays are seen from all orbital phases (apart from the eclipse) which make it unusual amongst eclipsing polars. We have identified the optical counterpart, which is faint  ( r = 21)  , and shows a deep eclipse (>3.5 mag in white light). Its X-ray spectrum does not show a distinct soft X-ray component which is seen in many, but not all, polars. Its optical spectrum shows Hα in emission for a fraction of the orbital period.  相似文献   

Stable Fe isotope fractionations produced by aqueous Fe(II)-hematite surface interactions   总被引：1，自引：0，他引：1  

Lingling Wu  Brian L. Beard  Eric E. Roden  Christopher B. Kennedy 《Geochimica et cosmochimica acta》2010,74(15):4249-8833

Stable Fe isotope fractionations were investigated during exposure of hematite to aqueous Fe(II) under conditions of variable Fe(II)/hematite ratios, the presence/absence of dissolved Si, and neutral versus alkaline pH. When Fe(II) undergoes electron transfer to hematite, Fe(II) is initially oxidized to Fe(III), and structural Fe(III) on the hematite surface is reduced to Fe(II). During this redox reaction, the newly formed reactive Fe(III) layer becomes enriched in heavy Fe isotopes and light Fe isotopes partition into aqueous and sorbed Fe(II). Our results indicate that in most cases the reactive Fe(III) that undergoes isotopic exchange accounts for less than one octahedral layer on the hematite surface. With higher Fe(II)/hematite molar ratios, and the presence of dissolved Si at alkaline pH, stable Fe isotope fractionations move away from those expected for equilibrium between aqueous Fe(II) and hematite, towards those expected for aqueous Fe(II) and goethite. These results point to formation of new phases on the hematite surface as a result of distortion of Fe-O bonds and Si polymerization at high pH. Our findings demonstrate how stable Fe isotope fractionations can be used to investigate changes in surface Fe phases during exposure of Fe(III) oxides to aqueous Fe(II) under different environmental conditions. These results confirm the coupled electron and atom exchange mechanism proposed to explain Fe isotope fractionation during dissimilatory iron reduction (DIR). Although abiologic Fe(II)_aq - oxide interaction will produce low δ⁵⁶Fe values for Fe(II)_aq, similar to that produced by Fe(II) oxidation, only small quantities of low-δ⁵⁶Fe Fe(II)_aq are formed by these processes. In contrast, DIR, which continually exposes new surface Fe(III) atoms during reduction, as well as production of Fe(II), remains the most efficient mechanism for generating large quantities of low-δ⁵⁶Fe aqueous Fe(II) in many natural systems.  相似文献   

The Australian physical environment – By Howard Bridgman, Deirdre Dragovich and John Dodson     

David Kennedy 《New Zealand geographer》2009,65(2):161-162

  相似文献   

ART: Inspired by science and nature     

Philip Kennedy 《Geology Today》1998,14(3):93-94

  相似文献   

Measurements of high-frequency shallow-water acoustic phasefluctuations     

Stanic  S.J. Goodman  R.R. Meredith  R.W. Kennedy  E. 《Oceanic Engineering, IEEE Journal of》2000,25(4):507-515

A shallow-water high-frequency (HF) acoustic propagation experiment was conducted just off shore in Panama City, FL. Several broad-band high-resolution sources and receivers were mounted on stable platforms and deployed in water depths of 8-10 m. Signals covering the frequency range from 20 to 200 kHz were transmitted from the sources to two spatially separated receivers. The data were analyzed to provide estimates of the signal phase variances as a function of frequency and source-to-receiver range. These phase variabilities are correlated with small-scale water column thermal variabilities and ocean swell conditions  相似文献   

A stochastic interpretation of the tailing effect in solute transport     

C. A. Kennedy  W. C. Lennox 《Stochastic Environmental Research and Risk Assessment (SERRA)》2001,15(4):325-340

 The advection-dispersion equation (ADE) is inadequate for describing tails in solute breakthrough curves. Re-examination of solute breakthrough curves from one-dimensional experiments in porous media and channel flow literature shows a consistent discrepancy compared with solutions to the ADE. The leading tail of breakthrough curves is sharper, and the trailing tail is longer and smoother, than best fitting, least-squares ADE solutions. A random particle simulation exercise shows that the ADE may firstly be erroneous because of the assumption of time steps over which random solute movements are considered independent. Definition of such time steps hinges upon the slowest random movements, such as those predominantly by molecular diffusion. A second potential source of error is the highly skewed nature of the inverse distribution of underlying, micro-scale velocities, which causes slow convergence to normality under the central limit theorem.  相似文献