On Measurements of the Tide at Churchill,Hudson Bay     

Richard D. Ray 《大气与海洋》2016,54(2):108-116

Since the late 1990s the semi-diurnal tide at Churchill, on the western shore of Hudson Bay, has been decreasing in amplitude, with M₂ amplitudes falling from approximately 154?cm in 1998 to 146?cm in 2012 and 142?cm in 2014. There has been a corresponding small increase in phase lag. Mean low water, decreasing throughout most of the twentieth century, has levelled off. Although the tidal changes could reflect merely a malfunctioning tide gauge, the fact that there are no other measurements in the region and the possibility that the tide is revealing important environmental changes calls for serious investigation. Satellite altimeter measurements of the tide in Hudson Bay are complicated by the seasonal ice cover; at most locations less than 40% of satellite passes return valid ocean heights and even those can be impacted by errors from sea ice. Because the combined TOPEX/Poseidon, Jason-1, and Jason-2 time series is more than 23 years long, it is now possible to obtain sufficient data at crossover locations near Churchill to search for tidal changes. The satellites sense no changes in M₂ that are comparable to the changes seen at the Churchill gauge. The changes appear to be localized to the harbour, or to the Churchill River, or to the gauge itself.  相似文献   

Implications of Jupiter's early contraction history for the composition of the Galilean satellites     

James B. Pollack  Ray T. Reynolds 《Icarus》1974,21(3):248-253

Graboske et al. (1973) have shown that Jupiter's luminosity was orders of magnitude larger during its initial contraction phase than it is today. As a result, during Jupiter's earliest contraction history, ices would have preferentially been prevented from condensing within the region containing the orbits of the inner satellites. The observed variation of the mean density of the Galilean satellites with distance from Jupiter implies that the satellite formation process was operative on a time scale of about five million years. Another consequence of the high luminosity phase is that water should be the only ice present in significant proportions in any of the Galilean satellites.  相似文献   

Trade Patterns Along Zane'S Trace, 1797–1812     

John B. Ray 《The Professional geographer》1970,22(3):142-146

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The Turbulent Lagrangian Time Scale in Forest Canopies Constrained by Fluxes,Concentrations and Source Distributions   总被引：1，自引：1，他引：0  

Vanessa Haverd  Ray Leuning  David Griffith  Eva van Gorsel  Matthias Cuntz 《Boundary-Layer Meteorology》2009,130(2):209-228

One-dimensional Lagrangian dispersion models, frequently used to relate in-canopy source/sink distributions of energy, water and trace gases to vertical concentration profiles, require estimates of the standard deviation of the vertical wind speed, which can be measured, and the Lagrangian time scale, T _L , which cannot. In this work we use non-linear parameter estimation to determine the vertical profile of the Lagrangian time scale that simultaneously optimises agreement between modelled and measured vertical profiles of temperature, water vapour and carbon dioxide concentrations within a 40-m tall temperate Eucalyptus forest in south-eastern Australia. Modelled temperature and concentration profiles are generated using Lagrangian dispersion theory combined with source/sink distributions of sensible heat, water vapour and CO₂. These distributions are derived from a multilayer Soil-Vegetation-Atmospheric-Transfer model subject to multiple constraints: (1) daytime eddy flux measurements of sensible heat, latent heat, and CO₂ above the canopy, (2) in-canopy lidar measurements of leaf area density distribution, and (3) chamber measurements of CO₂ ground fluxes. The resulting estimate of Lagrangian time scale within the canopy under near-neutral conditions is about 1.7 times higher than previous estimates and decreases towards zero at the ground. It represents an advance over previous estimates of T _L , which are largely unconstrained by measurements.  相似文献   

Short-Term Periodicities in Sunspot Activities During the Descending Phase of Solar Cycle 23     

Partha Chowdhury  Manoranjan Khan  P. C. Ray 《Solar physics》2010,261(1):173-191

In the present study, the short-term periodicities in the daily data of the sunspot numbers and areas are investigated separately for the full disk, northern, and southern hemispheres during Solar Cycle 23 for a time interval from 1 January 2003 to 30 November 2007 corresponding to the descending and minimum phase of the cycle. The wavelet power spectrum technique exhibited a number of quasi-periodic oscillations in all the datasets. In the high frequency range, we find a prominent period of 22 – 35 days in both sunspot indicators. Other quasi-periods in the range of 40 – 60, 70 – 90, 110 – 130, 140 – 160, and 220 – 240 days are detected in the sunspot number time series in different hemispheres at different time intervals. In the sunspot area data, quasi-periods in the range of 50 – 80, 90 – 110, 115 – 130, 140 – 155, 160 – 190, and about 230 days were noted in different hemispheres within the time period of analysis. The present investigation shows that the well-known “Rieger periodicity” of 150 – 160 days reappears during the descending phase of Solar Cycle 23, but this is prominent mainly in the southern part of the Sun. Possible explanations of these observed periodicities are delivered on the basis of earlier results detected in photospheric magnetic field time series (Knaack, Stenflo, and Berdyugina in Astron. Astrophys. 438, 1067, 2005) and solar r-mode oscillations.  相似文献   

DEVELOPMENTS IN PHOTOGRAPHIC LENSES     

S. F. Ray 《The Photogrammetric Record》1994,14(83):713-728

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Tectonic Speleogenesis of Devils Hole, Nevada, and Implications for Hydrogeology and the Development of Long, Continuous Paleoenvironmental Records     

Alan C. Riggs  W. J. Carr  Peter T. Kolesar  Ray J. Hoffman 《Quaternary Research》1994,42(3)

Devils Hole, in southern Nevada, is a surface collapse into a deep, planar, steeply dipping fault-controlled fissure in Cambrian limestone and dolostone. The collapse intersects the water table about 15 m below land surface and the fissure extends at least 130 m deeper. Below water, most of the fissure is lined with a >30-cm-thick layer of dense maxillary calcite that precipitated continuously from groundwater for >500,000 yr. The thick mammillary calcite coat implies a long history of calcite-supersaturated groundwaters, which, combined with the absence of dissolutional morphologies, suggests that Devils Hole was not formed by karst processes. Devils Hole is located in a region of active extension; its tectonic origin is shown by evidence of spreading of its planar opening along a fault and by the orientation of its opening and others nearby, perpendicular to the northwest-southeast minimum principal stress direction of the region. Most Quaternary tectonic activity in the area, including seismicity and Quaternary faults and fractures, occurs on or parallel to northeast-striking structures. The hydrogeologic implications of this primarily structural origin are that fracture networks and caves opened by extensional tectonism can act as groundwater flowpaths functionally similar to those developed by karst processes and that, during active extension, transmissivity can be maintained despite infilling by mineral precipitation. Such extensional environments can provide conditions favorable for accumulation of deposits preserving long, continuous paleoenvironmental records. The precipitates in Devils Hole store chronologies of flow system water-level fluctuations, hydrochemistry, a half-million-yr proxy paleoclimate record, evidence of Devils Hole's tectonic origin, and probably atmospheric circulation.  相似文献   

Surface drag contribution to the depth of monsoon depression over Indian region     

Dr. S. P. Ray 《Meteorology and Atmospheric Physics》1982,31(3):237-241

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The Barnacle,Balanus subalbidus,as a salinity bioindicator in the Oligohaline Estuarine Zone     

Michael A. Poirrier  Mickel Ray Partridge 《Estuaries and Coasts》1979,2(3):204-206

The distribution and size of the barnacle Balanus subalbidus were studies along salinity gradients in coastal Louisiana and Mississippi. It was common in gradient estuaries occurring in salinities ranging from near fresh water to 16 ppt. It was the dominant barnacle species in the oligohaline zone, but at salinities above 6 ppt its relative abundance decreased and it was replaced by B. improvicus and B. eburneus. Its low-salinity limit corresponded to the boundary between the oligohaline and fresh water estuarine salinity zones and there was a high negative correlation between size (basal rostral-carinal diameter) and salinity. Its size and distribution could be used to determine prevailing salinity at a site because of its abundance and uniform distribution in oligohaline areas.  相似文献   

The inner city: In search of the problem     

Ray Forrest  John Lloyd  Nick Rogers  Peter Williams 《Geoforum》1979,10(1):109-116

This paper explores the theoretical content of the inner-city debate in Britain and seeks to examine the extent to which the ‘problem’ is either new or primarily economic. It is argued that the inner-city issue, while subject to specific political and ideological forces, is associated with the general processes of uneven capitalist development. In this sense, metropolitan decline is a further manifestation of the relationship between the built environment, the transience of economic activity and social change. More specifically the decline of the inner city relates to the incipient role of Britain in the development of capitalism and its current position in the world economy. The emergence of this as a ‘problem’ for the British state is combined with a convenient spatial determinism, which isolates the inner city as an anomaly even as the search for palliatives is erected to the status of a major social task.  相似文献