Losses of birch foliage due to insect herbivory along geographical gradients in Europe: a climate-driven pattern?

The study reports large-scale geographical variation in foliar damage of Betula pubescens and B. pendula by leaf-chewing and leaf-mining insects in Northern and Central Europe. The data were obtained in late summer of 2004 from 90 study sites located along several latitudinal and longitudinal gradients up to 1275 km in length; repeatability of a pattern detected was checked in 2005. Foliar damage in B. pubescens due to endemic herbivory increased in Fennoscandia from 1–2% at 70°N to 5–7% at 60°N; this pattern was best explained by mean July temperatures. Higher foliar losses in southern Fennoscandia were mostly due to an increase in proportion of damaged leaves, while an average consumption per damaged leaf increased only slightly. Foliar damage in B. pendula in Fennoscandia followed the same pattern as described for B. pubescens, although the overall loss of leaf area was only ca. 70% of that in B. pubescens. In contrast, there was no geographical or climatic pattern in damage of B. pendula by insect herbivores in Central Europe; average foliar losses were around 5% between 48°N and 60°N. These data suggest that damage of northern birch forests by leaf-chewing and leaf-mining insects will at least double with expected climatic warming, while in more southern regions the effects of climate change on birch foliar losses due to insect herbivory may be small or even negligible.     

Numerical stochastic simulation of the solar cycle and quasi-biennial oscillation of wind speed in the equatorial stratosphere

A problem of simulation of a stationary random process (SRP) is studied. A computer program is developed for modeling SRP, should the parameters required be estimated beforehand. The programming methods used are well known, but the numerical scheme of modeling the SRP needs some explanations; therefore, it is considered in detail in the article, being its basic subject for consideration, although basic characteristic features of the program are also considered. Examples show how the program is used to simulate the solar cycle and the quasi-biennial oscillation of the solar wind in the equatorial stratosphere (QBO). A distinguishing feature of this work, compared with the previous one, is also simulation of the solar cycle taking into account the variability of the sunspot dispersion. The SRP parameters are estimated for the QBO. It is found that the annual mean wind speed variation behavior is similar to the SRP.     

Non-monotonous dependence of the ocean surface drag coefficient on the hurricane wind speed due to the fragmentation of the ocean-atmosphere interface

Doklady Earth Sciences - Influence of the spray generation due to the fragmentation of the “bag-breakup” type on momentum exchange in the atmospheric boundary layer above the sea...     

Loss caused by earthquakes: rapid estimates

Timely and adequate action just after a strong earthquake can result in significant benefits in saving lives, as well as other benefits. For these cases, information about possible damage and expected number of casualties is very critical for taking decision about search, rescue operations and offering humanitarian assistance. Such rough and rapid information may be provided by, first of all, “global systems” (i.e., systems that are operated wherever the earthquake has occurred on the globe), in emergency mode. This paper gives a brief history of existing “global systems” and analyzes the factors which influence the reliability of earthquake impact simulation in near real time.     

Seismic risk assessment and mapping at different levels

Earthquakes incur the greatest damage compared with all the other natural deleterious occurrences; when occurring in industrialized and densely populated regions, they can prove devastating. In the Russian Federation, we have more than 20 million people living in regions of moderate and high seismicity. The areas that are hit by earthquakes, with events of intensity VII (MMSK-86 scale) or greater occurring, make up approximately 20% of Russia’s area. The present paper addresses the methodological procedures of risk assessment and databases used for risk computations at different levels. The examples of seismic risk assessment and mapping at different levels: country, region and urban, are given. Special attention is paid to information and web technologies used for verification data on built environment inventory and vulnerability.     

Effect of the tangential component of a force field on convection in a rotating plane layer

Thermal convection in an inclined plane layer having boundaries with different temperatures and rotating around an axis perpendicular to its plane is studied experimentally. It is shown that the convection and heat transfer are determined by two different convective mechanisms—gravitational and thermovibrational ones; they manifest themselves in the threshold excitation of cellular convective structures with different sizes. The thermovibrational convection is caused by the period-averaged mass force arising as a result of tidal oscillations of a nonisothermal fluid with respect to the cavity under the action of the external force-field component tangential to the layer. The map of convection regimes on the plane of governing parameters—the gravitational Rayleigh number and its vibrational analog—has been constructed. It has been found that the thermovibrational convection can develop even in a layer heated from above. The role of the dimensionless velocity of rotation, which has a stabilizing effect on the excitation of both gravitational and thermovibrational convection, has been studied.     

Shock metamorphism of some rock-forming minerals: Experimental results and natural observations

The products of shock metamorphism in the Jänisjärvi astrobleme in Karelia, Russia, are compared with the results of experiments in which spherical converging shock waves affected a spherical rock sample. The sample was loaded by a broad spectrum of shock pressures, which increased from ～20 GPa at the periphery of the rock sphere to > 200 GPa at its center. Experiments with rocks metamorphosed under the effect of spherical converging shock waves imitate collisions of cosmic bodies with the Earth’s surface, when transformations in rocks and minerals are induced by a single impact event. The shock-thermal decomposition of mafic minerals occurs in the same succession in nature and the experiments, with some differences between natural and experimentally produced shock-thermal aggregates likely accounted for by the smaller sizes of the experimental impact rock sample and, correspondingly, its more rapid quenching. Our shock experiments were the first to synthesize ringwoodite that was rich in Al₂O₃ and should be referred to as aluminous ringwoodite. The mineral was produced not via the martensite transition of olivine but by means of biotite replacement coupled with the migration of elements. The transformations of minerals by shock waves (amorphization and shock-thermal decomposition) were determined to be controlled mainly by the crystal structures of these minerals. The experimental products provide evidence of the migration of chemical elements within the crystal structure. The structural setting of ions in a mineral determines the onset of element migrations and the intensity of this process.