Love wave tomography in Italy from seismic ambient noise

We estimate Love wave empirical Green's functions from cross-correlations of ambient seismic noise to study the crust and uppermost mantle structure in Italy.Transverse-component ambient noise data from October 2005 through March 2007 recorded at 114 seismic stations from the Istituto Nazionale di Geofisica e Vulcanologia (INGV) national broadband network,the Mediterranean Very Broadband Seismographic Network (MedNet) and the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) yield more than 2 000 Love wave group velocity measurements using the multiple-filter analysis technique.In the short period band (5-20 s),the cross-correlations show clearly one-sided asymmetric feature due to non-uniform noise distribution and high local activities,and in the long period band (20 s) this feature becomes weak owing to more diffusive noise distribution.Based on these measurements,Love wave group velocity dispersion maps in the 8-34 s period band are constructed,then the SH wave velocity structures from the Love wave dispersions are inverted.The final results obtained from Love wave data are overall in good agreement with those from Rayleigh waves.Both Love and Rayleigh wave inversions all reveal that the Po plain basin is resolved with low velocity at shallow depth,and the Tyrrhenian sea is characterized with higher velocity below 8 km due to its thin oceanic crust.     

Panta Rhei 2013–2015: global perspectives on hydrology,society and change

ABSTRACT

In 2013, the International Association of Hydrological Sciences (IAHS) launched the hydrological decade 2013–2022 with the theme “Panta Rhei: Change in Hydrology and Society”. The decade recognizes the urgency of hydrological research to understand and predict the interactions of society and water, to support sustainable water resource use under changing climatic and environmental conditions. This paper reports on the first Panta Rhei biennium 2013–2015, providing a comprehensive resource that describes the scope and direction of Panta Rhei. We bring together the knowledge of all the Panta Rhei working groups, to summarize the most pressing research questions and how the hydrological community is progressing towards those goals. We draw out interconnections between different strands of research, and reflect on the need to take a global view on hydrology in the current era of human impacts and environmental change. Finally, we look back to the six driving science questions identified at the outset of Panta Rhei, to quantify progress towards those aims.

Editor D. Koutsoyiannis; Associate editor not assigned     

Putative Meteoritic Craters in Río Cuarto (Central Argentina) Interpreted as Eolian Structures

Ten oblong aligned depressions in the Río Cuarto area (provincia de Córdoba, Argentina) were supposed to be the result of very-low-angle Holocene meteoroid impacts. However, we consider that authors that studied the structures did not demonstrated their extraterrestrial origin. We suggest that an eolian origin for the structures of Río Cuarto is more likely. Actually, these landforms integrate large systems of similar deflation/accumulation geoforms aligned according to predominant winds during different periods.     

Recovering the real-space correlation function from photometric redshift surveys

Measurements of clustering in large-scale imaging surveys that make use of photometric redshifts depend on the uncertainties in the redshift determination. We have used light-cone simulations to show how the deprojection method successfully recovers the real-space correlation function when applied to mock photometric redshift surveys. We study how the errors in the redshift determination affect the quality of the recovered two-point correlation function. Considering the expected errors associated with the planned photometric redshift surveys, we conclude that this method provides information on the clustering of matter useful for the estimation of cosmological parameters that depend on the large-scale distribution of galaxies.     

Correlation of precipitable water vapour values over the united states with physical and chemical parameters. Part III: Annual and seasonal trends,a further approximation

Summary Deviations from a law previously established, which correlates the precipitable water vapour values in a vertical column of air over a measuring station with the latter's temperature and altitude, are reduced by multiple regression analysis, and implications are discussed.Contribution of the «Centro Nucleazione Aerosoli» of the National Research Council of Italy, Via Vettore 4 (Monte Sacro)Roma.     

On the preferential electrification of some dusts Part II: Release of gas from monodisperse powders of porous alumina,following adsorption of nitrous oxide

Summary Rates of release of nitrous oxide, from monodisperse fractions of activated alumina, are measured at room temperature and atmospheric pressure. The values obtained follow a simple first-order law with respect to the gas adsorbed, the relative parameters depending strongly on the size of the particulates examined (5 to 50 micron).     

Importance of tropical coastal environments

On a global basis, a very large fraction (>50%) of the mass flux from land to the marine environment enters from tropical rivers. A broad range of processes active in the adjacent coastal ocean determines the fate of this material. The tropical setting causes many of the coastal processes to be fundamentally distinct from those operating in temperate and polar regions. Therefore, their operation cannot necessarily be understood by extrapolation from empirical observations at higher latitudes. Other coastal processes are influenced by the extremely large water, particulate, and solute discharges from tropical rivers. Further complexity is added by the diverse range of geographic settings through which tropical rivers flow and into which they empty. In summary, coastal—ocean processes in the wet tropics are: globally important, fundamentally different than at higher latitudes, and diverse in operation. Many recent advances have been made in the understanding of the tropical coastal ocean, and it is hoped these will continue into the future. Such understanding is important for predicting processes of river—ocean interaction and terrestrial fluxes to the global ocean, which affect and are affected by human populations. It also can be combined with knowledge of temperate and polar settings to provide a comprehensive understanding of the coastal ocean.     

Subharmonic oscillations in nonlinear rolling

In this paper the rolling motion of a ship is examined with particular regard to the possibility of obtaining oscillations which are subharmonic to the excitation frequency. Three different mechanisms are found to be responsible for this phenomenon, the importance of which has already been recognized in the context of ship stability. The first is related to a strong symmetric or non-symmetric nonlinearity in the righting arm. The second is linked to the harmonic composition of sea waves and the third to the well known parametric excitation caused by coupling between different ship motions in a following sea.The onset of subharmonics is related to a threshold value for the excitation strongly depending on damping. The more appropriate analytical methods for a theoretical study of each mechanism are suggested.