Precision Analytical Calculation of Geodynamical Effects on Satellite Motion

A new analytical method for calculating satellite orbital perturbations due to different disturbing forces is developed. It is based on the Poincaré method of small parameter but takes advantages of modern high-performance computers and of the tools of computer algebra. All perturbations proportional up to and including the 5th-order of small parameters are obtained. The method can precisely calculate the effects of all geodynamical forces on satellite motion given by the most up-to-date IAU and IERS models, such as non-central Earth gravity potential, precession and nutation of the geoequator, polar motion and irregularities in the Earth's rotation, effect of ocean and solid Earth tides, pole tide, and secular variations of gravity coefficients.Numerical tests prove the method's accuracy to be equivalent to 1–2 cm when calculating positions of high altitude geodetic satellites (like ETALON), and/or of GLONASS navigational spacecraft. The accuracy is stable over 1 year at least and comparable to that of the best tracking measurements of satellites.Positions of low altitude geodynamical satellites (like STARLETTE) by the analytical method are calculated to an accuracy of about 70cm over a month's interval. The method is developed for future use in GLONASS/GPS on-board ephemeris computation where it can improve the current scheme of their flight control.This revised version was published online in October 2005 with corrections to the Cover Date.     

Hydrogeochemistry of the permafrost zone in the central part of the Yakutian diamond-bearing province,Russia

The hydrogeochemical characteristics and zonation of the permafrost zone in the central part of the Yakutian diamond-bearing province formed mainly under the influence of cryogenic processes that occurred in the late Cenozoic. On the basis of field and experimental studies, conclusions were formulated that the perennial cryogenesis of the sedimentary cover in this region resulted in increasing the concentration of carbonate and sulfate compounds in groundwaters as well as increasing the concentration of easily soluble compounds (sodium, magnesium, and calcium chlorides).

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Resumen Las características hidrogeoquímicas y la zonación del permafrost existente en el centro de la provincia de Yakutia, rica en diamantes, se formaron fundamentalmente bajo la influencia de procesos criogénicos durante el tramo final del Cenozoico. Con base en estudios de campo y experimentales, se ha concluido que la criogénesis perenne de la cubierta sedimentaria de la región ha provocado un aumento de la concentración de compuestos de carbonato y sulfato en las aguas subterráneas, además de incrementar la concentración de compuestos solubles, como el sodio, magnesio y cloruros de calcio.

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Résumé Les caractéristiques hydrogéochimiques et la zonation de la région de permafrost dans la partie centrale de la province diamantifère de Yakoutie ont été acquises principalement sous l'influence des processus cryogéniques qui existent depuis la fin du Tertiaire. Sur la base d'études expérimentales et de terrain, on conclut que la cryogenèse permanente de la couverture sédimentaire de cette région a provoqué un accroissement de la concentration des composés carbonatés et sulfatés dans les eaux souterraines, en même temps que celui de composés facilement solubles, comme les chlorures de sodium, de magnésium et de calcium.

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Alteration and chemical U-Th-total Pb dating of heterogeneous high-uranium zircon from a pegmatite from the Aduiskii massif,middle Urals,Russia

Mineralogy and Petrology - The U-Th-Pb isotope system in the accessory mineral zircon may be disturbed, as for instance by the secondary loss of radiogenic lead. The recognition of such alteration...     

Lagrangian study of transport of subarctic water across the Subpolar Front in the Japan Sea

The southward near-surface transport of transformed subarctic water across the Subpolar Front in the Japan Sea is simulated and analyzed based on altimeter data from January 1, 1993 to December 31, 2017. Computing Lagrangian indicators for a large number of synthetic particles, advected by the AVISO velocity field, we find preferred transport pathways across the Subpolar Front. The southward transport occurs mainly in the central part of the frontal zone due to suitable dispositions of mesoscale eddies promoting propagation of subarctic water to the south. It is documented with the help of Lagrangian origin and L-maps and verified by the tracks of available drifters. The transport of transformed subarctic water to the south is compared with the transport of transformed subtropical water to the north simulated by Prants et al. (Nonlinear Process Geophys 24(1):89–99, 2017c).     

The modified generalized moveout approximation: a new parameter selection

Non‐hyperbolic generalised moveout approximation is a powerful tool to approximate the travel‐time function by using information obtained from two rays. The standard approach for parameter selection is using three parameters defined from zero‐offset ray and two parameters obtained from a reference ray. These parameters include the travel time and travel‐time derivatives of different order. The original parameter selection implies more fit at zero offset compared with offset from a reference ray. We propose an alternative approach for parameter selection within the frame of generalised moveout approximation by transferring more fit from the zero offset to a reference ray by changing in parameter selection. The modified approximation is tested against the original one in few analytical model examples, including the multi‐layered model.     

Assessment of runoff,water and sediment quality in the Selenga River basin aided by a web-based geoservice

The Selenga River is the main artery feeding Lake Baikal. It has a catchment of ~450000 km² in the boundary region between Northern Mongolia and Southern Siberia. Climate, land use and dynamic socioeconomic changes go along with rising water abstractions and contaminant loads originating from mining sites and urban wastewater. In the future, these pressures might have negative impacts on the ecosystems of Lake Baikal and the Selenga River Delta, which is an important wetland region in itself and forms the last geobiochemical barrier before the Selenga drains into Lake Baikal. The following study aims to assess current trends in hydrology and water quality in the Selenga-Baikal basin, identify their drivers and to set up models (WaterGAP3 framework and ECOMAG) for the prediction of future changes. Of particular relevance for hydrological and water quality changes in the recent past were climate and land use trends as well as contaminant influx from mining areas and urban settlements. In the near future, additional hydrological modifications due to the construction of dams and abstractions/water diversions from the Selenga’s Mongolian tributaries could lead to additional alterations.     

Evaluation of DNA Damage in the Marine Mussel Crenomytilus grayanus as a Genotoxic Biomarker of Pollution

Marine pollution affects all life processes in aquatic organisms. The genotoxic effect of pollution on the mussel Crenomytilus grayanus was assessed. Bivalves were collected from the ‘clean'(Vostochnaya Cove) and polluted(Nakhodka Bay) areas in the Peter the Great Bay. The degree of DNA damage in C. grayanus was determined by alkaline comet assay as mean percentage of DNA in tail, and the genetic damage index was calculated. Our results indicate that almost one-third of DNA in cells of gills and digestive gland of C. grayanus inhabiting the Nakhodka Bay had destructive changes compared to the individuals of this species from the Vostochnaya Cove. This study has shown that chronic pollution of the aquatic environment causes destructive changes to DNA in gill and digestive gland cells of C. grayanus.