Vulnerability of solar energy infrastructure and output to climate change     

Anthony Patt  Stefan Pfenninger  Johan Lilliestam 《Climatic change》2013,121(1):93-102

This paper reviews the potential vulnerability of solar energy systems to future extreme event risks as a consequence of climate change. We describe the three main technologies likely to be used to harness sunlight—thermal heating, photovoltaic (PV), and concentrating solar power (CSP)—and identify critical climate vulnerabilities for each one. We then compare these vulnerabilities with assessments of future changes in mean conditions and extreme event risk levels. We do not identify any vulnerabilities severe enough to halt development of any of the technologies mentioned, although we do find a potential value in exploring options for making PV cells more heat-resilient and for improving the design of cooling systems for CSP.  相似文献   

Warming permafrost in European mountains   总被引：3，自引：0，他引：3  

Charles Harris  Daniel Vonder Mühll  Ketil Isaksen  Wilfried Haeberli  Johan Ludvig Sollid  Lorenz King  Per Holmlund  Francesco Dramis  Mauro Guglielmin  David Palacios 《Global and Planetary Change》2003,39(3-4):215-225

Here we present the first systematic measurements of European mountain permafrost temperatures from a latitudinal transect of six boreholes extending from the Alps, through Scandinavia to Svalbard. Boreholes were drilled in bedrock to depths of at least 100 m between May 1998 and September 2000. Geothermal profiles provide evidence for regional-scale secular warming, since all are nonlinear, with near-surface warm-side temperature deviations from the deeper thermal gradient. Topographic effects lead to variability between Alpine sites. First approximation estimates, based on curvature within the borehole thermal profiles, indicate a maximum ground surface warming of +1 °C in Svalbard, considered to relate to thermal changes in the last 100 years. In addition, a 15-year time series of thermal data from the 58-m-deep Murtèl–Corvatsch permafrost borehole in Switzerland, drilled in creeping frozen ice-rich rock debris, shows an overall warming trend, but with high-amplitude interannual fluctuations that reflect early winter snow cover more strongly than air temperatures. Thus interpretation of the deeper borehole thermal histories must clearly take account of the potential effects of changing snow cover in addition to atmospheric temperatures.  相似文献   

Local galactic evolution     

Johan Holmberg  Birgitta NordstrÖm  Bjarne Rosenkilde Jørgensen  Johannes Andersen 《Astrophysics and Space Science》2003,284(2):685-688

The evolution of the Solar neighbourhood is followed using a unique, magnitude complete and kinematically unbiased sample of 14,000 F, G, and K dwarfs. Metallicity, age, space motion and galactic orbits have been determined for all stars. The result is a detailed view of the complex evolution of the local Milky Way, which must be matched by any model for the chemical and dynamical evolution of the Galactic disk. E.g., such models must explain the shape and large scatter in the age-metallity relation as well as the overall metallicity distribution; the evolution of stellar kinematics with age; the distribution of stars in velocity space; and the contributions from the thick and thin disks to all these relations. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

White dwarfs and Galactic dark matter     

Chris Flynn  Janne Holopainen  Johan Holmberg 《Monthly notices of the Royal Astronomical Society》2003,339(3):817-824

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Latitudinal Variations of Diurnal Meteor Rates     

Csilla Szasz  Johan Kero  Asta Pellinen-Wannberg  John D. Mathews  Nick J. Mitchell  Werner Singer 《Earth, Moon, and Planets》2004,95(1-4):101-107

The presence of a diurnal variation in meteor activity is well established. The sporadic meteor count rates are higher on the local dawn side and lower on the local dusk side. This phenomenon is caused by the Earth’s orbital motion and rotation. Meteor radar measurements have been compared from Esrange, Kiruna, Sweden, at 68° N, from Juliusruh, Germany, at 55° N, and from Ascension Island, at 8° S, to investigate how the diurnal variation depends on season at different latitudes. Data have been used from vernal and autumnal equinoxes and summer and winter solstices to locate the largest seasonal differences.  相似文献   

On the mass-to-light ratio of the local Galactic disc and the optical luminosity of the Galaxy     

Chris Flynn  Johan Holmberg  Laura Portinari  Burkhard Fuchs  Hartmut Jahreiß 《Monthly notices of the Royal Astronomical Society》2006,372(3):1149-1160

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Arsenic in shallow groundwater of Bangladesh: investigations from three different physiographic settings   总被引：1，自引：0，他引：1  

M. Aziz Hasan  K. Matin Ahmed  Ondra Sracek  Prosun Bhattacharya  Mattias von Brömssen  Sandra Broms  Johan Fogelström  M. Lutful Mazumder  Gunnar Jacks 《Hydrogeology Journal》2007,15(8):1507-1522

Occurrences of arsenic (As) in the Bengal Basin of Bangladesh show close relationships with depositional environments and sediment textures. Hydrochemical data from three sites with varying physiography and sedimentation history show marked variations in redox status and dissolved As concentrations. Arsenic concentration in groundwater of the Ganges Flood Plain (GFP) is characteristically low, where high Mn concentrations indicate redox buffering by reduction of Mn(IV)-oxyhydroxides. Low DOC, \( {\text{HCO}}^{ - }_{3} \), \( {\text{NH}}^{ + }_{4} \) and high \( {\text{NO}}^{ - }_{3} \) and \( {\text{SO}}^{{2 - }}_{4} \) concentrations reflect an elevated redox status in GFP aquifers. In contrast, As concentration in the Ganges Delta Plain (GDP) is very high along with high Fe and low Mn. In the Meghna Flood Plain (MFP), moderate to high As and Fe concentrations and low Mn are detected. Degradation of organic matter probably drives redox reactions in the aquifers, particularly in MFP and GDP, thereby mobilising dissolved As. Speciation calculations indicate supersaturation with respect to siderite and vivianite in the groundwater samples at MFP and GDP, but groundwater in the GFP wells is generally supersaturated with respect to rhodochrosite. Values of log P_CO2 at MFP and GDP sites are generally higher than at the GFP site. This is consistent with Mn(IV)-redox buffering suggested at the GFP site compared to Fe(III)-redox buffering at MFP and GDP sites.  相似文献   

Mobility and Transport of Nd Isotopes in the Vadose Zone During Weathering of Granitic Till in a Boreal Forest     

Björn Öhlander  Magnus Land  Johan Ingri  Anders Widerlund 《Aquatic Geochemistry》2014,20(1):1-17

There is a broad correlation between the ε_Nd values for rivers (including both the water and the particulate material it carries) and the age of the source terrain. This paper presents Nd isotope distribution data for soil, soil water, groundwater, and stream water samples gathered in a small catchment in northern Sweden. The results show that the release of Nd and Sm from boreal forests into streams and, eventually, into the oceans is more complicated than previously realized. The weathering of till causes changes in both the Nd isotopic composition and Sm/Nd ratios. Both the Sm/Nd ratio and ε_Nd were higher in strongly weathered soils horizons than in less weathered till, since minerals with high Sm/Nd ratios were, on average, more resistant to weathering than those with low Sm/Nd ratios. In contrast to the situation for the main minerals and the major elements, the weathering of rare earth elements (REE) was not restricted to the E-horizon: the measured REE concentrations continued to increase with depth in the C-horizon. In addition, REE released by weathering in the upper parts of the soil profile were partly secondarily retained at deeper levels. Therefore, the dissolved Nd released by weathering in the upper soil horizons was trapped and did not enter the groundwater directly. Rather, the Nd in the groundwater largely originated from weathering within the groundwater zone. However, this was not the only source of Nd in the stream water. The Nd isotope composition and Sm/Nd ratio were determined by the mixing between of Nd and Sm in the groundwater and REE-carrying organic material washed out of the soil profile. The groundwater close to the stream reaches the upper soil horizons during high discharge events such as snowmelts, and organic matter carrying Nd and Sm is washed out of the soils and thus released into the stream. Therefore, the Nd exported from catchment is derived from both the weathering within the groundwater zone, and the organic matter washed out from the soil. If longer timescales with more advanced weathering stages in the groundwater zone are considered, it cannot be ruled out that there will be a shift towards more radiogenic values in the exported Nd. Recorded shifts in the Nd isotopic composition in the ocean may thus not only reflect changed source regions, but also the weathering history of the same source region.  相似文献   

Farmers’ assessments of private adaptive measures to climate change and influential factors: a study in the Mekong Delta,Vietnam   总被引：2，自引：0，他引：2  

Hoa Le Dang  Elton Li  Ian Nuberg  Johan Bruwer 《Natural Hazards》2014,71(1):385-401

Adaptation to climate change in agricultural settings depends on understanding farmers’ perceptions of the nature of climate change, their agency in adapting and the efficacy of adaptive measures themselves. Such knowledge can improve mitigation and adaptation strategies. This study addresses the limited understanding of how farmers appraise their private adaptive measures and influential factors. It uses data from structured interviews with 598 rice farmers in the Mekong Delta, Vietnam. Based on protection motivation theory, farmers’ assessments of private adaptive measures were measured by perceived self-efficacy, perceived adaptation efficacy and perceived adaptation cost. Multiple regressions were used to understand significant factors affecting those assessments. Some demographic and socio-economic factors, belief in climate change, information and objective resources were found to influence farmers’ adaptation assessments. It is shown that the sources and quality of information are particularly important. The improvement of both the accessibility and usefulness of local services (e.g. irrigation, agricultural extension, credit and health care) is deemed a necessity for successful adaptation strategies in the Mekong Delta. The paper also shows the application of PMT in measuring farmers’ appraisals of private adaptive measures to climate change, thereby opening this area for further research.  相似文献   

Processes controlling solubility of biogenic silica and pore water build-up of silicic acid in marine sediments   总被引：1，自引：0，他引：1  

Suvasis Dixit  Philippe Van Cappellen  A. Johan van Bennekom 《Marine Chemistry》2001,73(3-4)

Dissolution experiments in batch and flow-through reactors were combined with data on sediment composition and pore water silicic acid profiles to identify processes controlling the solubility of biogenic silica and the build-up of silicic acid in marine sediments. The variability of experimentally determined biogenic silica solubilities is due, in part, to variations in specific surface area and Al content of biosiliceous materials. Preferential dissolution of delicate skeletal structures and frustules with high surface areas leads to a progressive decrease of the specific surface area. This may cause a reduction of the solubility of deposited biosiliceous debris by 10–15%, relative to fresh planktonic assemblages. Dissolution of lithogenic (detrital) minerals in sediments releases dissolved aluminum to the pore waters. This aluminum becomes structurally incorporated into deposited biogenic silica, further decreasing its solubility. Compared to Al-free biogenic silica, the solubility of diatom frustules is lowered by as much as 25% when one out of every 70 Si atoms is substituted by an Al(III) ion.The build-up of silicic acid in pore waters of sediments with variable proportions of detrital matter and biogenic silica was simulated in batch experiments using kaolinite and basalt as model detrital constituents. The steady-state silicic acid concentrations measured in the experiments decreased with increasing detrital-to-opal ratios of the mixtures. This trend is similar to the observed inverse relationship between asymptotic pore water silicic acid concentrations and detrital-to-opal ratios in Southern Ocean sediments. Flow-through reactor experiments further showed that in detrital-rich sediments, precipitation of authigenic alumino-silicates may prevent the pore waters from reaching equilibrium with the dissolving biogenic silica. This agrees with data from Southern Ocean sediments where, at sites containing more than 30 wt.% detrital material, the pore waters remain undersaturated with respect to the experimentally determined in situ solubility of biogenic silica.The results of the study show that interactions between deposited biogenic silica and detrital material cause large variations in the asymptotic silicic acid concentration of marine sediments. The production of Al(III) by the dissolution of detrital minerals affects the build-up of silicic acid by reducing the apparent silica solubility and dissolution kinetics of biosiliceous materials, and by inducing precipitation of authigenic alumino-silicate minerals.  相似文献