Spectroscopic binaries near the north Galactic pole paper 24: HD 106104, 109281, 109463 and 110743     

R. F. Griffin 《Journal of Astrophysics and Astronomy》2001,22(2-3):187-211

The four stars treated in this paper have been under observation with photoelectric radial-velocity spectrometers for many years. They have proved to be binaries with periods of 30, 1828, 1514 and 822 days respectively; the orbits are of modest eccentricity apart from that of HD 110743 which is indistinguishable from a circle. The mass functions are small, and no companion has been observed for any of the stars. HD 110743, a K dwarf, is much the nearest of the four, and its orbit is of short enough period for the photocentric motion to have been recognized byHipparcos. An eleventh-magnitude star rather more than 1≈ away from HD 106104 is shown to be a genuine physical companion, with practically identical radial velocity, proper motion and distance modulus, although the projected separation is about 13,000 AU.  相似文献   

A spectroscopic orbit for HD 115968     

R. F. Griffin 《Journal of Astrophysics and Astronomy》1981,2(3):309-313

Photoelectric radial-velocity measurements show that the eighth-magnitude star HD 115968 is a spectroscopic binary with a period of 16.195 days. The star has a large proper motion, and is unlikely to have the luminosity corresponding to the spectral type of G8 III favoured by Zaitseva. It is most probably a late-G dwarf.  相似文献   

THE GREFSHEIM (NORWAY) METEORITE: A NEW L5 CHONDRITE     

W.L. Griffin  K.A. Jorgensen 《Meteoritics & planetary science》1979,14(1):117-120

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Benthic exchange of nutrients in Galveston Bay, Texas   总被引：4，自引：0，他引：4  

Kent W. Warnken  Gary A. Gill  Peter H. Santschi  Lawrence L. Griffin 《Estuaries and Coasts》2000,23(5):647-661

Nutrient regeneration rates were determined at three sites increasing in distance from the Trinity River, the main freshwater input source, to Galveston Bay, Texas, from 1994 through 1996. Diffusive fluxes generally agreed in direction with directly measured benthic fluxes but underestimated the exchange of nutrients across the sediment-water interface. While the fluxes of ammonium and phosphate were directed from the sediment into the overlying waters, the fluxes of silicate and chloride changed in both magnitude and direction in response to changing Trinity River flow conditions. Oxygen fluxes showed benthic production during both summer 1995 and winter 1996, while light-dark deployments showed production-consumption, respectively. Benthic inputs of nutrients were higher at either the middle or outer Trinity Bay regions, most likely due to a higher quality and quantity of the autochthonous organic matter deposited. This feature is consistent with and gives evidence for previously observed non-conservative mixing behaviors reported for nutrients in this region of Galveston Bay. Calculated turnover times, between 7 to 135 d for phosphate, 4 to 56 d for silicate, and 0.3 to 10 d for ammonium were significantly shorter than the average Trinity Bay water residence time of 1.5 yr for the period September 1995 through October 1996. During periods of decreased Trinity River flow and increased residence times, benthic inputs of ammonium and phosphate were 1 to 2 orders of magnitude greater than Trinity River inputs and were the dominant input source of these nutrients to Trinity Bay. The sediments, a sink for silicate when overlying water column concentrations of silicate were elevated, became a source of silicate to the overlying waters of Trinity Bay under reduced flow, high salinity conditions.  相似文献   

Atmospheric transmission at submillimetre wavelengths from Mauna Kea     

D. A. Naylor  G. R. Davis  B. G. Gom  T. A. Clark  M. J. Griffin 《Monthly notices of the Royal Astronomical Society》2000,315(3):622-628

The submillimetre atmospheric transmission spectrum above Mauna Kea has been measured at a resolution of 0.005 cm⁻¹ (150 MHz) with a Fourier transform spectrometer at the James Clerk Maxwell Telescope, using the Sun as a source. Column abundances of O₂, H₂O and O₃ determined from these spectra are found to be in excellent agreement with independent measurements. The derived column abundances have been used as inputs to the atmospheric spectral modelling program fascod . The synthetic transmission spectrum is found to be in excellent agreement with the measured spectrum, and provides a template for submillimetre observations from the JCMT.  相似文献   

Ancient mantle lithosphere beneath the Khanka massif in the Russian Far East: in situ Re–Os evidence          下载免费PDF全文

Kuo‐Lung Wang  Vladimir Prikhodko  Suzanne Y. O'Reilly  William L. Griffin  Norman J. Pearson  Victor Kovach  Yoshiyuki Iizuka  Yu‐Hsian Chien 《地学学报》2015,27(4):277-284

The Os‐isotope compositions of sulphides in mantle xenoliths hosted by Late Miocene alkali basalts from the Sviyaginsky volcano, Russian Far East, reveal the presence of Archaean–Proterozoic subcontinental lithospheric mantle beneath the Khanka massif. Their T_MA and T_RD model ages reveal similar peaks at 1.1 and 0.8 Ga suggesting later thermotectonic events in the subcontinental lithospheric mantle, whereas T_RD model ages range back to 2.8 ± 0.5 (2σ) Ga. The events recognized in the subcontinental lithospheric mantle are consistent with those recorded in the crust of the Khanka massif. The sulphide Os‐isotope data show that the subcontinental lithospheric mantle beneath the Khanka massif had formed at least by the Mesoproterozoic, and was subsequently metasomatized by juvenile crustal‐growth events related to the evolution of the Altaids. The Khanka massif is further proposed to have tectonic affinity to the Siberia Craton and should originate from it accordingly.  相似文献   

Relative role and extent of marine and groundwater inundation on a dune‐dominated barrier island under sea‐level rise scenarios          下载免费PDF全文

Alex K. Manda  Michael S. Sisco  David J. Mallinson  Michael T. Griffin 《水文研究》2015,29(8):1894-1904

Climate change and sea‐level rise will have severe impacts on coastal water resources around the world. However, whereas the influence of marine inundation is well documented in the literature, the impact of groundwater inundation on coastal communities is not well known. Here, core analysis, groundwater monitoring, and ground penetrating radar are utilized to assess the groundwater regime of the surficial aquifer on Bogue Banks Barrier Island (USA). Then, geospatial techniques are used to assess the relative roles and extents of groundwater and marine inundation on the dune‐dominated barrier island under sea‐level rise scenarios of 0.2, 0.5, and 1.0 m above current conditions by 2100. Additionally, the effects of rising water tables on onsite wastewater treatment systems (OWTS) are modelled using the projected sea‐level rise scenarios. The results indicate that the surficial aquifer comprising fine to medium sands responds quickly to precipitation. Water‐level measurements reveal varying thicknesses of the vadose zone (>3 to 0 m) and several groundwater mounds with radial flow patterns. Results from projected sea‐level rise scenarios suggest that owing to aquifer properties and morphology of the island, groundwater inundation may occur at the same rate as marine inundation. Furthermore, the area inundated by groundwater may be as significant as that affected by marine inundation. The results also show that the proportion of land in the study area where OWTS may be perpetually compromised by rising water tables under worst case scenarios may range from ~43 to ~54% over an 86‐year‐period. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Determining policy-efficient management strategies in fisheries using data envelopment analysis (DEA)     

Wade L. Griffin  Richard T. Woodward 《Marine Policy》2011

In this paper, the authors analyze a wide range of recreational management strategies for their impacts on red snapper yield, economic surplus and the fish stock. Simulating a wide range of policies, the authors find Data Envelopment Analysis (DEA) inspired policy efficiency frontiers that lead to finding those management strategies that offer the greatest level of economic surplus for any biological target, looking at both the east and west Gulf of Mexico fisheries. Red snapper has been declared overfished since 1988 and the 2005 SEDAR 7 stock assessment declared red snapper were overfished and undergoing overfishing. In November 2009, the update of the assessment declared that overfishing was no longer occurring but that the red snapper stocks needed to be rebuilt. In this analysis, it was found that red snapper are neither overfished or undergoing overfishing. The main difference between the present model and the SEDAR 7 model is that the latest model uses a higher mortality rate for juveniles and a density dependent model. The authors also suggest that the east and west should be managed as separate units.  相似文献   

The cold-core eddy and strong upwelling off the coast of New South Wales in early 2007     

Peter R. Oke  David A. Griffin 《Deep Sea Research Part II: Topical Studies in Oceanography》2011,58(5):574-591

During the Austral summer of 2006-07 a series of extreme oceanic events occurred in the Tasman Sea. Following a series of strong wind-driven upwelling events, an intense cold-core eddy developed off Sydney, Australia. A data-assimilating, eddy-resolving ocean model is used to create a three-dimensional time-varying reanalysis of these events. The reanalysis indicates that the cold anomalies associated with the upwellings were in excess of −5 °C near the coast, where sea level decreased by as much as 0.2 m. The reanalysed three-dimensional structure of the cold-core eddy shows the eddy "leaning" to the west-north-west, in towards the continental shelf. The diameter of the eddy is about 100 km and the sea-level anomaly at the eddy centre peaks at around −1 m, with an associated sub-surface temperature anomaly in excess of −8 °C at 200 m depth, corresponding to an upward isotherm excursion of 600 m. The circulation around the cyclonic eddy is ageostrophic, with upwelling in the southern sector of the eddy (where flow is onshore and climbing the continental slope) and downwelling in the northern sector (where flow is descending off the slope). Three-dimensional trajectories of water parcels around the eddy involve 50-100-m vertical excursions. Based on the reanalysed circulation and composite satellite images of Chlorophyll-a, we hypothesise that the circulation around the eddy led to significant nutrient enrichment in the euphotic zone around the perimeter of the eddy.  相似文献   

Contribution to the search for binaries among Am stars – IV. HD 100054B and 187258     

N. Ginestet  J.-L. Prieur  J.-M. Carquillat  R. F. Griffin 《Monthly notices of the Royal Astronomical Society》2003,342(1):61-68

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