Shiyang River streamflow since AD 1765, reconstructed by tree rings,contains far‐reaching hydro‐climatic signals over and beyond the mid‐latitude Asian continent

In this study, the regional tree‐ring chronology of Picea crassifolia was used to estimate annual (September to August) streamflow of the Shiyang River for the period from AD 1765 to 2010. The linear regression model was stable and could explain 41.5% of the variance for the calibration period of 1955–2005. According to the streamflow reconstruction, dry periods with below average streamflow occurred in AD 1775–1804, 1814–1823, 1831–1856, 1862–1867, 1877–1885, 1905–1910, 1926–1932, 1948–1951, 1960–1963 and 1989–2002. Periods of relatively wet years are identified for AD 1765–1774, 1805–1813, 1824–1830, 1857–1861, 1868–1876, 1886–1904, 1911–1925, 1933–1947, 1952–1959, 1964–1988 and 2003–2010. Comparisons with the precipitation reconstructions from surrounding areas supplied a high degree of confidence in our reconstruction. Our reconstructed streamflow is significantly correlated with sea surface temperature in the eastern equatorial Pacific Ocean and the North Atlantic Ocean. The Multitaper spectral and correlation analyses also suggested that the reconstructed streamflow variation in the Shiyang River could be associated with large‐scale atmospheric‐oceanic variability, such as El Niño‐Southern Oscillation (ENSO). The linkages among the streamflow reconstruction, NAO and ENSO suggest the connection of regional streamflow variations to the Asian monsoon and westerlies circulations. Copyright © 2016 John Wiley & Sons, Ltd.     

Interpolation of the coupling-ray-theory Green function within ray cells

The coupling–ray–theory tensor Green function for electromagnetic waves or elastic S waves is frequency dependent, and is usually calculated for many frequencies. This frequency dependence represents no problem in calculating the Green function, but may pose a significant challenge in storing the Green function at the nodes of dense grids, typical for applications such as the Born approximation or non–linear source determination. Storing the Green function at the nodes of dense grids for too many frequencies may be impractical or even unrealistic. We have already proposed the approximation of the coupling–ray–theory tensor Green function, in the vicinity of a given prevailing frequency, by two coupling–ray–theory dyadic Green functions described by their coupling–ray–theory travel times and their coupling–ray–theory amplitudes. The above mentioned prevailing–frequency approximation of the coupling ray theory enables us to interpolate the coupling–ray–theory dyadic Green functions within ray cells, and to calculate them at the nodes of dense grids. For the interpolation within ray cells, we need to separate the pairs of prevailing–frequency coupling–ray–theory dyadic Green functions so that both the first Green function and the second Green function are continuous along rays and within ray cells. We describe the current progress in this field and outline the basic algorithms. The proposed method is equally applicable to both electromagnetic waves and elastic S waves. We demonstrate the preliminary numerical results using the coupling–ray–theory travel times of elastic S waves.     

Comparison of the anisotropic-ray-theory rays and anisotropic common S-wave rays with the SH and SV reference rays in a velocity model with a split intersection singularity

We describe the behaviour of the anisotropic–ray–theory S–wave rays in a velocity model with a split intersection singularity. The anisotropic–ray–theory S–wave rays crossing the split intersection singularity are smoothly but very sharply bent. While the initial–value rays can be safely traced by solving Hamilton’s equations of rays, it is often impossible to determine the coefficients of the equations of geodesic deviation (paraxial ray equations, dynamic ray tracing equations) and to solve them numerically. As a result, we often know neither the matrix of geometrical spreading, nor the phase shift due to caustics. We demonstrate the abrupt changes of the geometrical spreading and wavefront curvature of the fast anisotropic–ray–theory S wave. We also demonstrate the formation of caustics and wavefront triplication of the slow anisotropic–ray–theory S wave.Since the actual S waves propagate approximately along the SH and SV reference rays in this velocity model, we compare the anisotropic–ray–theory S–wave rays with the SH and SV reference rays. Since the coupling ray theory is usually calculated along the anisotropic common S–wave rays, we also compare the anisotropic common S–wave rays with the SH and SV reference rays.     

Geomagnetic field fluctuations near Kharkov,which accompanied rocket launches from the Baikonur site

The observations of the geomagnetic field variations in the range of periods 1–1000 s, which accompanied the launches of 65 Soyuz and Proton rockets from the Baikonur site in 2002–2006, have been analyzed. The measurements were performed near Kharkov (the distance from the launching site is R ≈ 2100 km). Three groups of disturbances, with delays of 6–7, 30–70, and 70–130 min dependent on the time of day, have been revealed. The disturbance duration was 10–30, 50–70, and 45–70 min, respectively. Periods of 3–6, 6–12, and 6–12 min, respectively, predominated in the geomagnetic pulsations. The amplitudes of these pulsations reached 3–6 nT. The physical model of the observed geomagnetic disturbances, which generally agrees with the measurements, has been proposed.     

Biomass Determination in Some Species Using a Geometric Equivalent Technique of Plankton Organisms

The plankton collected from three fish ponds shows a considerable variability within a pond, between the ponds and in the course of the year. The individual volumes or weights are (minimum—mean—maximum): Gleotrichia echinulata 41–252–879 μg³, Chlorella vulgaris 18–42–94 μm³, Oscillatoria amphigranulata 99–306–827 μm³, Brachionus plicatilis 1–4.918 μg, nauplia 0.5–1.25–2.35 μg, Mesocyclops hyalinus 4–45–369—μg, Heliodiaptomus viduus 41–202–288 μg, Daphnia carinata 186–1468–4578 μg.     

Melting relations in the chloride–carbonate–silicate systems at high-pressure and the model for formation of alkalic diamond–forming liquids in the upper mantle

The experiments in the model system CaMgSi₂O₆–(Na₂CO₃, CaCO₃)–KCl are performed at 5 GPa and 1400–1600 °C in order to study the phase relations, including liquid immiscibility, in the chloride–carbonate–silicate systems with application to alkali and chlorine-rich liquids preserved in kimberlitic diamonds. Experiments in the boundary joins of the system demonstrated that both the carbonate–silicate and chloride–carbonate melts are homogeneous; while high-temperature (above 1800 °C) liquid immiscibility is assumed for the chloride–silicate join of the above system. Addition of silicate component into the chloride–carbonate melts and chloride component into the carbonate–silicate melts results in splitting of the homogeneous liquids into the immiscible chloride–carbonate brine and carbonate–silicate melt. Carbonate–silicate and chloride–carbonate branches of the miscibility gap converge within the carbonate-rich region of the system. Regular temperature evolution of the shape and size of the miscibility gap is deduced. With decreasing temperature, the convergence point moves toward more Si-rich compositions, expanding fields of homogeneous chloride–carbonate silica-saturated melts. This effect is governed by the precipitation of the silicate phases even from silica-bearing chloride–carbonate melts. In addition, experiments revealed regular evolution of both Cl-bearing carbonate–silicate melt and Si-bearing chloride–carbonate brine toward the low-temperature chlorine–bearing carbonatitic liquid with decreasing temperature. These trends are similar to the evolution of the melt and brine inclusions in some diamonds from Botswana, Brazil, Canada, and Yakutia, indicating their growth during cooling. The model for interaction of the chloride–carbonate brine with the mantle rocks is developed on the basis of the present experimental data. This model is applied to the chlorine-enriched kimberlites of the Udachnaya–East pipe.     

A review of: “An introduction to boundary layer meteorology”

Abstract

by R. B. Stull. Kluwer Academic Publishers, ix + 666 pp. US $99.00 (ISBN 90–277–2768–6) and US $35.00 (ISBN 90–277–2769–4 paperback) 1988.     

A review of: “Physical fluid dynamics”

Abstract

by D. J. Tritton, Second Edition, Oxford University Press XVII + 519 pp. Hardback (ISBN 0–19–854489–8) $35.00; paperback (ISBN 0–19–854493–6) $16.95; 1988.     

Cross‐hole resistivity tomography using different electrode configurations

This paper investigates the relative merits and effectiveness of cross‐hole resistivity tomography using different electrode configurations for four popular electrode arrays: pole–pole, pole–bipole, bipole–pole and bipole–bipole. By examination of two synthetic models (a dipping conductive strip and a dislocated fault), it is shown that besides the popular pole–pole array, some specified three‐ and four‐electrode configurations, such as pole–bipole AM–N, bipole–pole AM–B and bipole–bipole AM–BN with their multispacing cross‐hole profiling and scanning surveys, are useful for cross‐hole resistivity tomography. These configurations, compared with the pole–pole array, may reduce or eliminate the effect of remote electrodes (systematic error) and yield satisfactory images with 20% noise‐contaminated data. It is also shown that the configurations which have either both current electrodes or both potential electrodes in the same borehole, i.e. pole–bipole A–MN, bipole–pole AB–M and bipole–bipole AB–MN, have a singularity problem in data acquisition, namely low readings of the potential or potential difference in cross‐hole surveying, so that the data are easily obscured by background noise and yield images inferior to those from other configurations.     

Distribution of geochemical fractions of phosphorus and its ecological risk in sediment cores of a largest brackish water lake,South Asia

The current study focuses on the vertical profile of different geochemical fractions of phosphorus-loosely bound(Lo–P),aluminium bound(Al–P),iron bound(Fe–P),calcium bound(Ca–P),and organic bound phosphorus(O–P)along with ecological risk assessment of sediment cores from Chilika Lake,eastcoast of India.The percentage contribution of the different fractions to the sedimentary phosphorus in the sediment column of the whole lake are on the order:O–P(33.2%)>Ca–P(20.3%)>Fe–P(18%)>Al–P(6.7%)>Lo–P(0.35%).The Phosphorus Pollution Index(PPI)revealed the contamination of lake sediment with phosphorus.The principal component and cluster analyses highlighted the anthropogenic contribution of phosphorus.The negative loading of Ca–P with Ca points towards its origin from marine shells.The discriminate analysis showed that the variables like Ca–P,bio-available phosphorus(BAP),and pH were able to effectively discriminate the sectors in a significant manner.     

Water isotopic-geochemical composition in the Trekhtsvetnoe meromictic lake on the White Sea coast

The isotopic features of Lake Trekhtsvetnoe in the White Sea coast area were studied in 2012–2015 in both winter and summer. Lake Trekhtsvetnoe is a water body, separating from the sea, with constant vertical stratification throughout the observation period. Its isotopic, hydrophysical, and biological characteristics have been studied. By the isotopic profile of lake water body, three zones can be identified in the lake: (1) 0–1 m: mixolimnion zone with δ¹⁸O varying from–12 to–11.1‰; (2) 1.0–3.0 m: zone with transitional properties with δ¹⁸O varying from–11.1 to–5.5‰; (3) 3.0–7.6 m: monimolimnion zone with highest values of δ¹⁸O—from–5.5 to–4.7‰.     

Registration of weak ULF/ELF oscillations of the surface electric field strength

Measurements of the atmospheric electric field strength made by an electrostatic fluxmeter with a unique threshold sensitivity for such devices (6 × 10^–2–10^–3 V m^–1 Hz^–1/2 in the 10^–3–25 Hz frequency range) and wide dynamic (120 dB) and spectral (0–25 Hz) ranges, are presented. The device parameters make it possible to observe the electric component of global electromagnetic Schumann resonances and long-period fluctuations in the atmospheric electric field strength.     

A technique for the analysis of the response of dams to earthquakes

A finite element technique is developed for two-dimensional problems of dynamics of dam–water–foundation systems taking into account all interactions rigorously. Water–foundation interaction, which previous developments have only simulated, is considered by imposing proper conditions at the fluid–solid interface. Furthermore, the technique permits treatment of layered foundations. An application to a concrete gravity dam–water–foundation system is presented and discussed.     

Bounds on the Time–history and Holocene Mass Budget of Antarctica from Sea–level Records in SE Tunisia

Solving the sea–level equation for a Maxwell Earth, we analyze the sensitivity of Holocene sea–level records in SE Tunisia to the time–history of remote ice sheets. Assuming that mantle viscosity increases moderately with depth, we find that in this region the sea–level variations driven by the Northern Hemisphere ice sheets cancel, so that the late–Holocene sea–level high–stand suggested by the geological record merely reflects the melting history of Antarctica. New insight into the history of this ice sheet is obtained analyzing the information contained in a revised set of relative sea–level observations for sites across the Mediterranean covering the last 8 kyrs. From a trial–and–error misfit analysis, it holds true that in this region the match between model predictions and observations improves when the volume of water released from Antarctica is well below the value imposed by the ICE3G chronology and when a sudden meltwater pulse is allowed between 8 and 7 kyrs before present, corresponding to the epoch of the catastrophic rise event known as CRE3.     

Latitude and Altitude Dependence of the Interannual Variability and Trends of Atmospheric Temperatures

—The 4-season (12-month) running means of temperatures at five atmospheric levels (surface, 850–300 mb, 300–100 mb, 100–50 mb, 100–30 mb) and seven climatic zones (60°N–90°N, 30°N–60°N, 10°N–30°N, 10°N–10°S, 10°S–30°S, 30°S–60°S, 60°S–90°S) showed QBO (Quasi-biennial Oscillation), QTO (Quasi-triennial Oscillation) and larger periodicities. For stratosphere and tropopause, the temperature variations near the equator and North Pole somewhat resembled the 50mb low latitude zonal winds, mainly due to prominent QBO. For troposphere and surface, the temperature variations, especially those near the equator, resemble those of eastern equatorial Pacific sea-surface temperatures, mainly due to prominent QTO. In general, the temperature trends in the last 35 years show stratospheric cooling and tropospheric warming. But the trends are not monotonic. For example, the surface trends were downward during 1960–70, upward during 1970–82, downward during 1982–85 and upward thereafter. Models of green-house warming should take these non-uniformities into account.     

Noncausal f–x–y regularized nonstationary prediction filtering for random noise attenuation on 3D seismic data

Seismic noise attenuation is very important for seismic data analysis and interpretation, especially for 3D seismic data. In this paper, we propose a novel method for 3D seismic random noise attenuation by applying noncausal regularized nonstationary autoregression (NRNA) in f–x–y domain. The proposed method, 3D NRNA (f–x–y domain) is the extended version of 2D NRNA (f–x domain). f–x–y NRNA can adaptively estimate seismic events of which slopes vary in 3D space. The key idea of this paper is to consider that the central trace can be predicted by all around this trace from all directions in 3D seismic cube, while the 2D f–x NRNA just considers that the middle trace can be predicted by adjacent traces along one space direction. 3D f–x–y NRNA uses more information from circumjacent traces than 2D f–x NRNA to estimate signals. Shaping regularization technology guarantees that the nonstationary autoregression problem can be realizable in mathematics with high computational efficiency. Synthetic and field data examples demonstrate that, compared with f–x NRNA method, f–x–y NRNA can be more effective in suppressing random noise and improve trace-by-trace consistency, which are useful in conjunction with interactive interpretation and auto-picking tools such as automatic event tracking.     

Liquefaction record of the great 1934 earthquake predecessors from the north Bihar alluvial plains of India

The great 1934 Himalayan earthquake of moment magnitude (Mw) 8.1 generated a large zone of ground failure and liquefaction in north Bihar, India, in addition to the earthquakes of 1833 (Mw ~7.7) and 1988 (Mw 6.7) that have also impacted this region. Here, we present the results of paleoliquefaction investigations from four sites in the plains of north Bihar and one in eastern Uttar Pradesh. The liquefaction features generated by successive earthquakes were dated at AD 829–971, 886–1090, 907–1181, 1130–1376, 1112–1572, 1492–1672, 1733–1839, and 1814–1854. One of the liquefaction events dated at AD 829–971, 886–1090, and 907–1181 may correlate with the great earthquake of AD ~1100, recognized in an earlier study from the sections across the frontal thrust in central eastern Nepal. Two late medieval liquefaction episodes of AD 1130–1376 and 1492–1672 were also exposed in our sites. The sedimentary sections also revealed sandblows that can be attributed to the 1833 earthquake, a lesser magnitude event compared to the 1934. Liquefactions triggered by the 1934 and 1988 earthquakes were evident within the topmost level in some sections. The available data lead us to conjecture that a series of temporally close spaced earthquakes of both strong and large types, not including the infrequent great earthquakes like the 1934, have affected the Bihar Plains during the last 1500 years with a combined recurrence interval of 124?±?63 years.     

U–Pb zircon ages of the Nakanogawa Group in the Hidaka Belt,northern Japan: Implications for its provenance and the protolith of the Hidaka metamorphic rocks

Zircon U–Pb ages of two acidic tuff and two turbidite sandstone samples from the Nakanogawa Group, Hidaka Belt, were measured to estimate its depositional age and the development of the Hokkaido Central Belt, northeast Japan. In the northern unit, homogeneous zircons from pelagic acidic tuff from a basal horizon dated to 58–57 Ma, zircons from sandstone from the upper part of the unit dated to 56–54 Ma, and zircons from acidic tuff from the uppermost part dated to 60–56 Ma and 69–63 Ma. Both of the tuff U–Pb ages are significantly older than the youngest radiolarian fossil age (66–48 Ma). Therefore, the maximum depositional age of the turbidite facies in the northern unit is 58 Ma and the younger age limit, estimated from the fossil age, is 48 Ma. In the southern unit, homogeneous zircons from turbidite sandstone dated to 58–57 Ma. Thus the depositional age of this turbidite facies was interpreted to be 66–56 Ma from the fossil age, probably close to 57 Ma. Most of the zircon U–Pb ages from the Nakanogawa Group are younger than 80 Ma, with a major peak at 60 Ma. This result implies that around Hokkaido volcanic activity occurred mainly after 80 Ma. Older zircon ages (120–80 Ma, 180–140 Ma, 340–220 Ma, 1.9 Ga, 2.2 Ga, and 2.7 Ga) give information about the provenance of other rocks in the Hidaka Belt. It is inferred that the Nakanogawa Group comprises protoliths of the upper sequence of the Hidaka Metamorphic Zone, which therefore has the same depositional age as the Nakanogawa Group (66–48 Ma). The depositional ages of the lower sequence of the Hidaka Metamorphic Zone and the Nakanogawa Group are probably the same.     

Global nature of the seismogravitational oscillations of the Earth

Direct experimental evidence for the global nature of the seismogravitational vibrations of the Earth within the range of 0.03–0.1 mHz is obtained on the basis of the analysis of synchronous observations with the help of vertical seismographs in Eurasia and North Africa. A number of stable, statistically significant vibrations are discovered. Analysis of 66 observations at ten stations showed that stable global vibrations exist in five frequency bands (45–51, 54–58, 61–65, 67–69, and 81–83 μHz).     

Zircon fission‐track and U–Pb double dating using femtosecond laser ablation–inductively coupled plasma–mass spectrometry: A technical note

We present a new LA–ICP–MS system for zircon fission‐track (FT) and U–Pb double dating, whereby a femtosecond laser combined with galvanometric optics simultaneously ablates multiple spots to measure average surface U contents. The U contents of zircon measured by LA–ICP–MS and standardized with the NIST SRM610 glass are comparable to those measured by the induced FT method, and have smaller analytical errors. LA–ICP–MS FT dating of seven zircon samples including three IUGS age standards is as accurate as the external detector method, but can give a higher‐precision age depending on the counting statistics of the U content measurement. Double dating of the IUGS age standards gives FT and U–Pb ages that are in agreement. A chip of the Nancy 91500 zircon has a homogeneous U content of 84 ppm, suggesting the possibility of using this zircon as a matrix‐matched U‐standard for FT dating. When using the Nancy 91500 zircon as a U‐standard, a zeta calibration value of 42–43 year cm² for LA–ICP–MS FT dating is obtained. While this value is strictly valid only for the particular session, it can serve as a reference for other studies.