Analysis of the Spatial Coherence of Short-Period Acoustic-Gravity Waves in the Atmosphere

Summary The coherence of atmospheric acoustic-gravity waves has been measured in the period range 10–100 s at the Large Aperture Microbarograph Array in south-eastern Montana. The acoustic-gravity waves observed were signals generated by presumed nuclear explosions. The decrease of coherence with increasing distance between pairs of microbarographs is less rapid in the direction of wave propagation than transverse to it. Variation of direction of arrival over a small range of azimuth (±5°) explains the spatial behaviour of coherence in the direction normal to the wave propagation; variation of phase velocity of ±10 ms^-1 explains the behaviour along the direction of wave propagation. Both effects may be due to inhomogeneities in the atmosphere; the velocity variation may be due to the presence in the signal of several normal modes of acoustic- gravity waves, each travelling at a slightly different phase velocity in the range 300–330 ms^-1.     

Causal thinking and support for climate change policies: International survey findings

Few comparative international studies describe the climate change policies people are willing to support and the reasons for their support of different policies. Using survey data from 664 economics and business undergraduates in Austria, Bangladesh, Finland, Germany, Norway, and the United States, we explore how perceived risk characteristics and mental models of climate change influence support for policy alternatives. General green policies such as funding research on renewable technologies and planting trees were the overwhelmingly most popular policy alternatives. Around half the students support carbon reduction policies such as requiring higher car fuel efficiency and increasing taxes on fossil fuels. Least popular were engineering alternatives such as fertilizing the oceans and replacing fossil fuels with nuclear power. Variations among nations are generally small. Support for different policy alternatives corresponds with different causal thinking. Those who hold a pollution model of the causes of climate change, tend to blame environmental harms (e.g., air pollution from toxic chemicals), see general green policy alternatives as effective, and support general green policies. Support of carbon reduction strategies is associated with seeing carbon emissions as the cause and reducing carbon emissions as effective solutions. Support of engineering solutions increases with identifying volcanoes among causes and regarding engineering solutions as effective. Although these international students agree that climate change is a threatening problem, their causal thinking correlates with support for different mitigative policy actions, with the most popular ones not necessarily the most effective.     

Limitations of single-basket trading: lessons from the Montreal Protocol for climate policy

Numerous policy options exist to reduce future greenhouse gas emissions. A single-basket approach, which controls aggregate emissions, was adopted by the Kyoto Protocol. Such an approach allows emissions reductions of one gas to be traded with those of other gases in the “basket”, with the trade “price” determined by some weighting metric like the Global Warming Potential. To reduce stratospheric ozone depletion, the Montreal Protocol also dealt with controlling many compounds, but did so employing an alternative, multi-basket scheme. Trading was allowed within each basket, but not among baskets. While the Montreal Protocol has been highly successful using this approach, we show that if a single-basket approach had been adopted the short-term success could have been at risk due to the non-unique relationship between controls and environmental impacts when using a single basket. Using climate policy as an example, and without considering technological and economic constraints, we further show that the magnitude of the ambiguities in impacts associated with a single-basket approach depends on the rapidity of the emission phaseout. Fast phaseouts lead to less ambiguity than do slow ones. These results suggest that for each set of greenhouse gas control policies considered, the benefit of additional flexibility associated with a single-basket approach should be weighed against the associated increased uncertainties in the impacts to ascertain whether a single- or a multi-basket approach has the greater chance of successfully mitigating climate change.     

Systematic measurement of the radioactivity of atmospheric precipitation and evaluation of the artificial radioactivity of the atmosphere

Резюме В статье приводится описание методики измерений искусственной радиоактивности осадков. В результате измерений более 90 образцов бЫло доказано, что здесь мЫ имеем дело с искусственной радиоактивностью, вЫзЫваемой наличием продуктов распада образующихся в результате опЫтов с атомнЫм оружием. Доказательством этого служит прежде всего убЫвание активности испарений с временем. Абсолютная оценка показала, что здесь речь идет об активности порядка 10⁻¹⁰–10⁻⁹ кюру/л. в воде осадков. ПроведеннЫе работЫ показали, насколько важнЫми могут бЫть подобнЫе измерения для метеорологических целей, но в особенности для фпзики облаков и осадков.

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Address: Vojenská lékařská akademie J. Ev. Purkynê, Hradec Králové.

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Address: Geofysikální ústav ĈSAV, odd. meteorologie, Hradec Králové 8.     

Detection of Contaminant Plumes by Borehole Geophysical Logging

Two borehole geophysical methods—electromagnetic induction and natural gamma radiation logs—were used to vertically delineate landfill leachate plumes in a glacial aquifer. Geophysical logs of monitoring wells near two land-fills in a glacial aquifer in west-central Vermont show that borehole geophysical methods can aid in interpretation of geologic logs and placement of monitoring well screens to sample landfill leachate plumes.
Zones of high electrical conductance were delineated from the electromagnetic log in wells near two landfills. Some of these zones were found to correlate with silt and clay units on the basis of drilling and gamma logs. Monitoring wells were screened specifically in zones of high electrical conductivity that did not correlate to a silt or clay unit. Zones of high electrical conductivity that did not correlate to a silt or clay unit were caused by the presence of ground water with a high specific conductance, generally from 1000 to 2370 μS/cm (microsiemens per centimeter at 25 degrees Celsius). Ambient ground water in the study area has a specific conductance of approximately 200 to 400 μS/cm. Landfill leachate plumes were found to be approximately 5 to 20 feet thick and to be near the water table surface.     

Spatio-temporal analysis of industrial composition with IVIID: an interactive visual analytics interface for industrial diversity

The industrial composition of places has received considerable attention because of the widespread belief that industrial diversity buffers regional economies from economic shocks. Subsequently, a variety of toolkits and indices have been developed with the goal of better capturing the compositional dynamics of regions. Although useful, a key drawback of these indices is their static nature, which limits the utility of these indices in a space–time context. This paper provides an overview of and applications of an interface called interactive visualization tool for indices of industrial diversity, which is a visual analytics tool developed specifically for the analysis and visualization of local measures of industrial composition for areal data. This overview will include a discussion of its key features, as well as a demonstration of the utility of the interface in exploring questions surrounding diversity and the dynamic nature of composition through space and time. A focus of this demonstration is to highlight how the interactivity and query functionality of this interface overcome several of the obstacles to understanding composition through space and time that prior toolkits and comparative static approaches have been unable to address.     

The CLASS blazar survey – II. Optical properties

This paper presents the optical properties of the objects selected in the CLASS blazar survey. Because an optical spectrum is now available for 70 per cent of the 325 sources present in the sample, a spectral classification, based on the appearance of the emission/absorption lines, is possible. A wide variety of optical spectral types is found. Besides 'classical' BL Lacs (42), BL Lac candidates (5) and high-power     flat spectrum radio quasars (67), a significant number of 'passive' elliptical galaxies (41) is also found. Moreover, 33 broad emission line objects with a low radio power     are discovered, suggesting that at least a fraction (∼     per cent) of low-power blazars have a broad line region. Finally, 34 objects showing only narrow emission lines, either as a result of some starburst activity in the host galaxy or as a result of the presence of an active galactic nucleus, appear in the sample.     

The three-dimensional dynamic displacement discontinuity method: Theory and applications

A boundary element technique has been developed for solving three-dimensional elastodynamic problems in rock mechanics, such as joint slip and the sudden advance of excavations. Both implicit and explicit versions of the technique have been implemented. Comparisons of accuracy and computational efficiency are made for a simple verification problem. Examples in which the technique has been used to investigate the dynamic response of supported and unsupported excavations in tabular orebodies are presented.     

The velocity structure of S54 and S142

The velocity structures of two extended, low-density and low-temperature Hii, regions S54 and S142, have been examined. Both exhibit an ionized sheet structure.