Tracing suspended organic nitrogen from the Yangtze River catchment into the East China Sea   总被引：2，自引：0，他引：2  

Ying Wu  Thorsten Dittmar  Kai-Uwe Ludwichowski  Gerhard Kattner  Jing Zhang  Zhuo Y. Zhu  Boris P. Koch 《Marine Chemistry》2007

Total suspended matter was collected along the Yangtze River (Changjiang) and in the East China Sea in April to May and in September 2003, respectively, to study origin and fate of particulate organic nitrogen. Concentrations of particulate organic carbon (POC), nitrogen (PN) and hydrolyzable particulate amino acids (PAA; d- and l-enantiomers) were higher in the Yangtze Estuary than in the river and decreased offshore towards the shelf edge. In the coastal area, higher values of PAA were observed in the surface layer than in the bottom water. Stable carbon isotope ratios (δ¹³C) of POC increased from − 24.4‰ in the river to values around − 21‰ on the East China Sea Shelf. Dominant amino acids were aspartic acid + aspartine (Asx), glutamic acid + glutamine (Glx), glycine, alanine and serine. The proportions of Asx, Glx and isoleucine were higher in the marine than in the riverine samples contrary to the distributions of glycine, alanine, threonine and arginine. The proportions of d-amino acids were highest in the riverine suspended organic matter (6% of PAA) decreasing towards the shelf edge (1.5% of PAA). d-arginine, not reported in natural aquatic samples so far, was the most abundant d-amino acid in the river. The amino acid composition of the particulate organic matter (POM) in the Yangtze River indicates an advanced stage of degradation of POM. Highly degraded organic matter from soils is probably a main source of POM in the Yangtze River, but the relatively high δ¹³C values and low C/N ratios (7.7 ± 1.6) also indicate contribution from anthropogenic sources. The degraded riverine material was a dominant organic matter source in the estuary, where aquatic primary production had only a small overall contribution. In the East China Sea, gradual settling of riverine organic matter and the addition of fresher phytoplankton impacted the amino acid composition and δ¹³C values, and on the outer shelf relatively fresh phytoplankton-derived organic matter dominated.  相似文献   

Source of low frequency modulation of ENSO amplitude in a CGCM     

Byung-Kwon Moon  Sang-Wook Yeh  Boris Dewitte  Jong-Ghap Jhun  In-Sik Kang 《Climate Dynamics》2007,29(1):101-111

We study the relationship between changes in equatorial stratification and low frequency El Niño/Southern Oscillation (ENSO) amplitude modulation in a coupled general circulation model (CGCM) that uses an anomaly coupling strategy to prevent climate drifts in the mean state. The stratification is intensified at upper levels in the western and central equatorial Pacific during periods of high ENSO amplitude. Furthermore, changes in equatorial stratification are connected with subsurface temperature anomalies originating from the central south tropical Pacific. The correlation analysis of ocean temperature anomalies against an index for the ENSO modulation supports the hypothesis of the existence of an oceanic “tunnel” that connects the south tropical Pacific to the equatorial wave guide. Further analysis of the wind stress projection coefficient onto the oceanic baroclinic modes suggests that the low frequency modulation of ENSO amplitude is associated with a significant contribution of higher-order modes in the western and central equatorial Pacific. In the light of these results, we suggest that, in the CGCM, change in the baroclinic mode energy distribution associated with low frequency ENSO amplitude modulation have its source in the central south tropical Pacific.  相似文献   

Interactive spatiotemporal modelling of health systems: the SEKS–GUI framework     

Hwa-Lung Yu  Alexander Kolovos  George Christakos  Jiu-Chiuan Chen  Steve Warmerdam  Boris Dev 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(5):647-572

This paper describes the spatiotemporal epistematics knowledge synthesis and graphical user interface (SEKS–GUI) framework and its application in medical geography problems. Based on sound theoretical reasoning, the interactive software library of SEKS–GUI explores heterogeneous (spatially non-homogeneous and temporally non-stationary) health attribute distributions (disease incidence, mortality, human exposure, epidemic propagation etc.); expresses the health system’s dependence structure using (ordinary and generalized) spatiotemporal covariance models; synthesizes core knowledge bases, empirical evidence and multi-sourced system uncertainty; and generates a meaningful picture of the real-world system using space–time dependent probability functions and associated maps of health attributes. The implementation stages of the SEKS–GUI library are described in considerable detail using appropriate screens. The wide applicability of SEKS–GUI is demonstrated by reviewing a selection of real-world case studies. An erratum to this article can be found at  相似文献   

    

Hwa-Lung Yu  Alexander Kolovos  George Christakos  Jiu-Chiuan Chen  Steve Warmerdam  Boris Dev 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(5):647

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Gamma-ray bursts from synchrotron self-Compton emission   总被引：1，自引：0，他引：1  

Boris E. Stern  Juri Poutanen † 《Monthly notices of the Royal Astronomical Society》2004,352(3):L35-L39

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The global solution of the problem of the critical inclination     

Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1973,8(1):25-44

The publication of the solution of the Ideal Resonance Problem (Garfinkelet al., 1971) has opened the way for a complete first-orderglobal theory of the motion of an artificial satellite, valid for all inclinations. Previous attempts at such a theory have been only partially successful. With the potential function restricted to $$V = - 1/r + J_2 P_2 (\sin \theta )/r^3 + J_4 P_4 (\sin \theta )/r^5 ,$$ the paper constructs aglobal solution of the first order in √J ₂ for the Delaunay variablesG, g, h, l and for the coordinatesr, θ, and ?. As a check, it is shown that this solution includes asymptotically theclassical limit with the critical divisor 5 cos² i?1. The solution is subject to thenormality condition $$eG^2 /(1 + \frac{{45}}{4}e^2 ) \geqslant O\left[ {\left| {\frac{1}{5}(J_2 + J_4 /J_2 )} \right|^{1/4} } \right],$$ which bounds the eccentricitye away from zero in deep resonance. A historical section orients this work with respect to the contributions of Hori (1960), Izsak (1962), and Jupp (1968).  相似文献   

    

Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1969,1(1):11

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‘Application of a New Spectral Theory of Stably Stratified Turbulence to the Atmospheric Boundary Layer over Sea Ice’   总被引：7，自引：5，他引：2  

Semion?Sukoriansky  Boris?GalperinEmail author  Veniamin?Perov 《Boundary-Layer Meteorology》2005,117(2):231-257

A new spectral closure model of stably stratified turbulence is used to develop a K–ε model suitable for applications to the atmospheric boundary layer. This K–ε model utilizes vertical viscosity and diffusivity obtained from the spectral theory. In the ε equation, the Coriolis parameter-dependent formulation of the coefficient C ₁ suggested by Detering and Etling is generalized to include the dependence on the Brunt-Väisälä frequency, N. The new K–ε model is tested in simulations of the ABL over sea ice and compared with observations from BASE as simulated in large-eddy simulations by Kosovic and Curry, and observations from SHEBA.  相似文献   

Mechanisms of tropical Pacific interannual-to-decadal variability in the ARPEGE/ORCA global coupled model     

Carole Cibot  Eric Maisonnave  Laurent Terray  Boris Dewitte 《Climate Dynamics》2005,24(7-8):823-842

Spatial and temporal structures of interannual-to-decadal variability in the tropical Pacific Ocean are investigated using results from a global atmosphere–ocean coupled general circulation model. The model produces quite realistic mean state characteristics, despite a sea surface temperature cold bias and a thermocline that is shallower than observations in the western Pacific. The periodicity and spatial patterns of the modelled El Niño Southern Oscillations (ENSO) compare well with those observed over the last 100 years, although the quasi-biennial timescale is dominant. Lag-regression analysis between the mean zonal wind stress and the 20°C isotherm depth suggests that the recently proposed recharge-oscillator paradigm is operating in the model. Decadal thermocline variability is characterized by enhanced variance over the western tropical South Pacific (~7°S). The associated subsurface temperature variability is primarily due to adiabatic displacements of the thermocline as a whole, arising from Ekman pumping anomalies located in the central Pacific, south of the equator. Related wind anomalies appear to be caused by SST anomalies in the eastern equatorial Pacific. This quasi-decadal variability has a timescale between 8 years and 20 years. The relationship between this decadal tropical mode and the low-frequency modulation of ENSO variance is also discussed. Results question the commonly accepted hypothesis that the low-frequency modulation of ENSO is due to decadal changes of the mean state characteristics.  相似文献   

Magnetic study of metamorphosed sedimentary rocks of the Hatrurim formation, Israel     

Boris Khesin  Shimon Feinstein  Yevgeny Vapnik  Sophia Itkis  Roman Leonhardt 《Geophysical Journal International》2005,162(1):49-63

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