Ionic Composition of the Earth’s Exosphere during a Reversal of the Solar Magnetic Field

Doklady Earth Sciences - This paper analyzes measurement data on the ionic composition of the upper atmosphere at altitudes of 810–830 km in the period from 2009 to 2018; the measurements...     

Thermal thickness of the Earth’s lithosphere: a numerical model

A technique is suggested and the thermal thickness of the lithosphere is calculated, as well as the temperature distribution in the lithosphere on the basis of data on topography, the age of the oceanic bottom, crustal composition and structure, gravity anomalies, and mean annual surface temperatures. The bottom of the lithosphere is determined as the 1300°C isotherm. The calculation resolution is 0.5°×0.5°. All first-order tectonic structures, such as mid-ocean ridges and plume areas in oceans, continental rifts, cratons, and orogenic belts, are expressed in the computed thermal thickness. The comparative analysis of the thermal thickness of oceanic and continental lithosphere, lithosphere of cratons and young platforms, ancient and young orogens, remnant oceanic basins and adjacent continental areas can be used in geodynamical analysis of the corresponding regions.     

Anisotropic Scaling Models of Rock Density and the Earth’s Surface Gravity Field

In this paper we consider an anisotropic scaling approach to understanding rock density and surface gravity which naturally accounts for wide range variability and anomalies at all scales. This approach is empirically justified by the growing body of evidence that geophysical fields including topography and density are scaling over wide range ranges. Theoretically it is justified, since scale invariance is a (geo)dynamical symmetry principle which is expected to hold in the absence of symmetry breaking mechanisms. Unfortunately, to date most scaling approaches have been self-similar, i.e., they have assumed not only scale invariant but also isotropic dynamics. In contrast, most nonscaling approaches recognize the anisotropy (e.g., the strata), but implicitly assume that the latter is independent of scale. In this paper, we argue that the dynamics are scaling but highly anisotropic, i.e., with scale dependent differential anisotropy. By using empirical density statistics in the crust and a statistical theory of high Prandtl number convection in the mantle, we argue that is a reasonable model for the 3-D spectrum (K is the horizontal wavevector and K is its modulus, k _z is a vertical wavenumber), (s,H _z ) are fundamental exponents which we estimate as (5.3,3), (3,3) in the crust and mantle, respectively. We theoretically derive expressions for the corresponding surface gravity spectrum. For scales smaller than ≈100 km, the anisotropic crust model of the density (with flat top and bottom) using empirically determined vertical and horizontal density spectra is sufficient to explain the (Bouguer) g _z spectra. However, the crust thickness is highly variable and the crust-mantle density contrast is very large. By considering isostatic equilibrium, and using global gravity and topography data, we show that this thickness variability is the dominant contribution to the surface g _z spectrum over the range ≈100–1000 km. Using estimates of mantle properties (viscosity, thermal conductivity, thermal expansion coefficient, etc.), we show that the mantle contribution to the mean spectrum is strongest at ≈1000 km and is comparable to the variable crust thickness contribution. Overall, we produce a model which is compatible with both the observed (horizontal and vertical) density heterogeneity and surface gravity anomaly statistics over a range of meters to several thousand kilometers.     

Predicting the resilience of transport infrastructure to a natural disaster using Cox’s proportional hazards regression model

Transport infrastructure is at significant risk of direct damage from extreme climate events such as flooding, where the cost implications of delayed recovery are generally significant. Previous research in this regard has focused on the technical and engineering aspects of infrastructure construction. The risk management of resilient transport infrastructure is poorly considered, and little has been done to quantify the capacity of transport infrastructure to recover from the impact of natural disasters under varying conditions. This paper applies Cox’s proportional hazards regression model to determine the rate of recovery and cumulative probability that recovery occurs for transport infrastructure across regional areas in New South Wales, Australia. Data for post-disaster reconstruction projects over the period 1992–2012 are used to analyze recovery rate against geographic region, natural disaster type and post-disaster transport infrastructure reconstruction cost. Results demonstrate that transport infrastructure recovered slowest when the failure is the result of a flood rather than bushfire or storm, and in regions with a riverine geography. To validate the accuracy of the model, a bootstrap resampling technique is used. The bootstrap result confirms that the model is robust and reasonable.

     

Measurement of the difference in the Earth’s gravitational potentials with the help of a transportable quantum clock

The results of the Russia’s first ground-based experiment for determination of the difference in the Earth’s gravitational potentials on the basis of the measurement of the gravitational effect of the time delay with the help of a high-stability transportable atomic clock are provided. The reference atomic clock was placed in Moscow oblast, and a transportable quantum clock with an instability of 3 × 10^–15 was placed in the Caucasus Mountains, with a difference in height of the clocks of 1804 m. The measured difference in the gravitational potentials between the positions of the two quantum clocks was (182.0 ± 3.1)10²m²s^-2 at a relative measurement error of no more than 1.7%.     

Protons of Radiation Belts as a Source of Hydrogen in the Earth’s Atmosphere

Doklady Earth Sciences - A scenario is proposed for replenishing the Earth’s exosphere with atomic hydrogen of cosmic origin. An assessment was made, and the coincidence of the total atomic...     

Identification of a karst system’s intrinsic hydrodynamic parameters: upscaling from single springs to the whole aquifer

For water management purposes, information about an entire aquifer system is generally more important than information about a specific spring. Since a karstic aquifer system might drain to several outlets, conclusions derived from a single spring can be misleading for characterization and modeling. In this study we apply a conceptual model to an Alpine dolomite karst system in Austria. The particular challenge was that several small springs with strongly varying hydrological behavior and diffuse flow into surrounding streams drain this system. Instead of applying the model to a single spring, it was calibrated simultaneously to several observations within the system aiming to identify the karst system’s intrinsic hydrodynamic parameters. Parameter identification is supported by modeling the transport of water isotopes (δ¹⁸O). The parameters were transferred to the whole system with a simple upscaling procedure and a sensitivity analysis was performed to unfold influence of isotopic information on parameter sensitivity and simulation uncertainty. The results show that it is possible to identify system intrinsic parameters. But the sensitivity analysis revealed that some are hardly identifiable. Only by considering uncertainty reasonable predictions can be provided for the whole system. Including isotopic information increases the sensitivity of some intrinsic parameters, but it goes along with a sensitivity decrease for others. However, a possible reduction of prediction uncertainty by isotopic information is compensated by deficiencies in the transport modeling routines.     

Long-Period Variations in Oscillations of the Earth’s Pole due to Lunar Perturbations

A numerical–analytical approach is used to investigate irregular effects in oscillations of the Earth’s pole related to variations in the Chandler and annual components. An approach to studying oscillations in the motion of the Earth’s pole based on a joint analysis of the Chandler and annual components of this motion is proposed. A transformation to a new coordinate system in which the motion of the pole is synchronous with the precession of the lunar orbit can be found in this approach. Estimates of the precision of predictions of the coordinates of the Earth’s pole taking into account additional terms due to lunar perturbations are presented.

     

Toward a more transformative participation in the conservation of Madagascar’s natural resources

For nearly two decades, participatory conservation projects in Madagascar have failed to gain the backing of rural populations. I believe that the concept of participation as it is currently theorized and practiced by conservationists in Madagascar lies at the heart of the problem. It is essential, therefore that the notion of participation be unpacked, an egalitarian framework for the notion be formulated and the theoretical and methodological infrastructure needed to enable effective conservation praxis reconstructed. Toward this end, this paper considers two general theories of democratic political action: a Habermasian-inspired conception of deliberative democracy and Jacques Rancière’s post-structuralist account of dissensus politics. I argue that by tacking between the results of a critique of the notions of normative legitimacy and political efficacy in the deliberative model and Rancière’s politics of radical equality, users and managers of natural resources in Madagascar and elsewhere will have a set of conceptual tools toward reconstructing a more powerful, transformative participatory conservation. Ethnographic data collected from the Ifanadiana/Ranomafana region of southeastern Madagascar helps illuminate the argument.     

El Ni?o as a consequence of the global oscillation in the dynamics of the earth’s climatic system

During study of the physical nature and potential precursor features of the El Ni?o phenomenon in the Pacific, it was found that a negative large-scale temperature anomaly on the Indian Ocean surface may be one of its significant precursors. This anomaly appears prior to the occurrence of El Ni?o and is accompanied by growth in atmospheric pressure. It gradually extends eastwards along the equator until the zone of planetary convection in the area of the Indonesian Region. The west wind that emerges on the eastern peripherals of the mentioned pressure anomaly leads to reversal of the Pacific segment of the Walker equatorial atmospheric circulation and to a subsequent change in the zonal thermal dipole polarity in the tropical zone of the Pacific (the latter means culmination of the El Ni?o phenomenon). In addition to the mentioned thermobaric anomaly in the Indian Ocean, other obvious signs of large-scale pressure anomalies have been found in the global atmospheric pressure field; these anomalies may be interpreted as manifestations of the intradecadal global oscillation in the dynamics of the modern climatic system. It is suggested that the whole known complex of events related to the El Ni?o phenomenon in the Pacific is a consequence and a regional link of the planetary structure of this global atmospheric phenomenon.     

Highway congestion during evacuation: examining the household’s choice of number of vehicles to evacuate

Hurricane evacuations in coastal counties have been reviewed and analyzed for the role of household preparedness and decisions before and during a disaster. However, one of the several emerging problems in the hurricane evacuation is transportation. Transportation issues have become more important in coastal evacuations as traffic problems impinge on people’s ability to get out of harm’s way and ultimately influence their decisions to evacuate. To add to the complexity, when families evacuate in multiple vehicles, it leads to additional vehicular traffic on roads and increased pressure on the transportation systems. However, little has been investigated on the characteristics that influence a household’s decision to evacuate in one or multiple vehicles. The outcome from such an analysis can help both the emergency managers and the transportation planners to targets groups that report taking more vehicles to develop policies that result in efficient evacuation. This study investigates the responses of evacuees surveyed after Hurricane Rita in the counties of Galveston, Brazoria and Harris County. The ordinary least square regression analysis revealed that access to transportation characteristics of a household such as number of registered vehicles in a household and number of eligible drivers was positively and significantly related to evacuating in more vehicles. Meanwhile, the risk of reaching destination safely was negatively related to taking more vehicles for evacuation even though both the risk index and deterrence index were positively significant. The time of decision and evacuation did not report any statistical significance.     

Melting of iron–silicon alloy up to the core–mantle boundary pressure: implications to the thermal structure of the Earth’s core

The melting temperature of Fe–18 wt% Si alloy was determined up to 119 GPa based on a change of laser heating efficiency and the texture of the recovered samples in the laser-heated diamond anvil cell experiments. We have also investigated the subsolidus phase relations of Fe–18 wt% Si alloy by the in-situ X-ray diffraction method and confirmed that the bcc phase is stable at least up to 57 GPa and high temperature. The melting curve of the alloy was fitted by the Simon’s equation, P(GPa)/a = (T _m(K)/T ₀) ^c , with parameters, T ₀ = 1,473 K, a = 3.5 ± 1.1 GPa, and c = 4.5 ± 0.4. The melting temperature of bcc Fe–18 wt% Si alloy is comparable with that of pure iron in the pressure range of this work. The melting temperature of Fe–18 wt% Si alloy is estimated to be 3,300–3,500 K at 135 GPa, and 4,000–4,200 K at around 330 GPa, which may provide the lower bound of the temperatures at the core–mantle boundary and the inner core–outer core boundary if the light element in the core is silicon.     

Is better to be a kayayei than to be unemployed: reflecting on the role of head portering in ghana’s informal economy

The implementation of neoliberal economic reforms with its resultant effects on rural agricultural economies has facilitated the migration of young girls from northern to southern Ghana to seek for alternative livelihoods in the urban informal economy as head porters (Kayayei). Using semi-structured questionnaires and interviews with 45 Kayayei in Makola and Agbogbloshie Markets, Accra, this study examines how migration as a livelihood strategy contributes to an improvement in the living conditions of young girls and their families. The paper also looks more closely into the pathways through which the livelihoods of these young female migrants may contribute to local economic development. The study highlights that Kayayei contribute to local economic development through market exchange and revenue generation, also there is significant perceived positive impact of head portering on standard of living of these young girls through improved access to income, health care and asset accumulation while their families benefit from remittances. The study concludes by advocating for the need to provide access to credit and skills training in enhancing the livelihood of Kayayei.     

Platinum group element (PGE) geochemistry to understand the chemical evolution of the Earth’s mantle

Platinum group elements (PGE: Os, Ir, Ru, Rh, Pt, Pd) are important geochemical and cosmochemical tracers. Depending on physical and chemical behaviour the PGEs are divided into two subgroups: IPGE (Ir, Os, Ru) and PPGE (Pd, Pt, Rh). Platinum group elements show strong siderophile and chalcophile affinity. Base metal sulfides control the PGE budget of the Earth’s mantle. Mantle xenoliths contain two types of sulfide populations: (1) enclosed within silicate minerals, and (2) interstitial to the silicate minerals. In terms of PGE characters the included variety shows IPGE enriched patterns — similar to the melt-depleted mantle harzburgite, whereas the interstitial variety shows PPGE enriched patterns — resembling the fractionated PGE patterns of the basalt. These PGE characters of the mantle sulfides have been interpreted to be representative of multi-stages melting process of the mantle that helped to shape the chemical evolution of the Earth.