Global gravitational changes due to atmospheric mass redistribution as observed by the Lageos nodal residual   总被引：4，自引：0，他引：4  

Benjamin Fong Chao  Richard Eanes 《Geophysical Journal International》1995,122(3):755-764

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Geophysical analysis of zonal tidal signals in length of day   总被引：5，自引：0，他引：5  

Benjamin Fong Chao  James B. Merriam  Yoshiaki Tamura 《Geophysical Journal International》1995,122(3):765-775

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Changes in global gravitational energy induced by earthquakes   总被引：1，自引：0，他引：1  

Benjamin Fong Chao  Richard S. Gross  Da-Nan Dong 《Geophysical Journal International》1995,122(3):784-789

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Weighting of Observed Heads for the Inverse Problem     

Benjamin Ross 《Ground water》1984,22(5):569-572

In using least-squares parameter estimation techniques to solve for hydrogeologic parameters, one may use a weighting function to reflect differing reliabilities of head measurements. In studies published to date, the weighting function has been used in an ad boc manner or not at all. The inverse square of the observed hydraulic gradient, adjusted to reflect the modeler's perception of geologic heterogeneity and data reliability, is typically an appropriate weighting function.  相似文献   

The antiferromagnetic-paramagnetic transition in αFe2O3 in the single prism approximation of the cluster variation method     

Benjamin Burton  Ryoichi Kikuchi 《Physics and Chemistry of Minerals》1984,11(3):125-131

The single prism approximation SPA of the cluster variation method has been used to model the antiferromagnetic-paramagnetic transition in hematite. This calculation yields insight into the accuracy of the SPA and other approximate methods for modeling order-disorder phenomena. Published values of the magnetic coupling constants were used to calculate the Néel temperature, sublattice magnetization, and magnetic specific heat. The calculated Néel temperature is found to be 1.21 times the observed value, as compared to 1.36 times observed for a mean field theory approximation, an improvement that reflects the superior treatment of configurational entropy in the SPA. Qualitative to semiquantitative agreement is obtained between observed and calculated values for sublattice magnetization and magnetic specific heat; however we find that previously published values for the magnetic specific heat are too large by a factor of two.  相似文献   

Fouling community of the Loxahatchee River estuary,Florida, 1980–81     

Benjamin F. McPherson  Wayne H. Sonntag  Maryann Sabanskas 《Estuaries and Coasts》1984,7(2):149-157

Monthly growth of the fouling community at eight test panel sites in the Loxahatchee River Estuary was related to salinity and temperature. Growth was lowest in January 1981 (averaging 23 g per m², dry weight), and increased during spring and early summer with increasing water temperature. Maximum growth occurred during early or midsummer at upstream locations, before river or canal discharge substantially reduced salinity, and in late summer at downstream locations. Growth was greatest at salinities slightly less than that of seawater and decreased at salinities less than about 10‰. Growth was suppressed throughout the estuary in August 1981, probably because of the sudden decrease in temperature and salinity, and perhaps the increase in physical scouring, caused by runoff from Tropical Storm Dennis. Large loads of nutrients transported to the estuary from storm runoff, however, may have subsequently stimulated growth, which increased in September 1981 to the maximum for the year (averaging 683 g per m², dry weight).  相似文献   

Towards the detection and attribution of an anthropogenic effect on climate   总被引：1，自引：0，他引：1  

Benjamin D. Santer  Karl E. Taylor  Tom M. L. Wigley  Joyce E. Penner  Philip D. Jones  Ulrich Cubasch 《Climate Dynamics》1995,12(2):77-100

It has been hypothesized recently that regional-scale cooling caused by anthropogenic sulfate aerosols may be partially obscuring a warming signal associated with changes in greenhouse gas concentrations. Here we use results from model experiments in which sulfate and carbon dioxide have been varied individually and in combination in order to test this hypothesis. We use centered [R (t)] and uncentered [C (t)] pattern similarity statistics to compare observed time-evolving surface temperature change patterns with the model-predicted equilibrium signal patterns. We show that in most cases, the C (t) statistic reduces to a measure of observed global-mean temperature changes, and is of limited use in attributing observed climate changes to a specific causal mechanism. We therefore focus on R (t), which is a more useful statistic for discriminating between forcing mechanisms with different pattern signatures but similar rates of global mean change. Our results indicate that over the last 50 years, the summer (JJA) and fall (SON) observed patterns of near-surface temperature change show increasing similarity to the model-simulated response to combined sulfate aerosol/CO₂ forcing. At least some of this increasing spatial congruence occurs in areas where the real world has cooled. To assess the significance of the most recent trends in R (t) and C (t), we use data from multi-century control integrations performed with two different coupled atmosphere-ocean models, which provide information on the statistical behavior of 'unforced' trends in the pattern correlation statistics. For the combined sulfate aerosol/CO₂ experiment, the 50-year R (t) trends for the JJA and SON signals are highly significant. Results are robust in that they do not depend on the choice of control run used to estimate natural variability noise properties. The R (t) trends for the CO₂-only signal are not significant in any season. C (t) trends for signals from both the CO₂-only and combined forcing experiments are highly significant in all seasons and for all trend lengths (except for trends over the last 10 years), indicating large global-mean changes relative to the two natural variability estimates used here. The caveats regarding the signals and natural variability noise which form the basis of this study are numerous. Nevertheless, we have provided first evidence that both the largest-scale (global-mean) and smaller-scale (spatial anomalies about the global mean) components of a combined CO₂/anthropogenic sulfate aerosol signal are identifiable in the observed near-surface air temperature data. If the coupled-model noise estimates used here are realistic, we can be highly confident that the anthropogenic signal that we have identified is distinctly different from internally generated natural variability noise. The fact that we have been able to detect the detailed spatial signature in response to combined CO₂ and sulfate aerosol forcing, but not in response to CO₂ forcing alone, suggests that some of the regional-scale background noise (against which we were trying to detect a CO₂-only signal) is in fact part of the signal of a sulfate aerosol effect on climate. The large effect of sulfate aerosols found in this study demonstrates the importance of their inclusion in experiments designed to simulate past and future climate change. Received: 10 November 1994 / Accepted: 19 July 1995  相似文献   

Field survey of the East Java earthquake and tsunami of June 3, 1994     

Yoshinobu Tsuji  Fumihiko Imamura  Hideo Matsutomi  Costas E. Synolakis  Puspito T. Nanang  Jumadi  Satoshi Harada  Se Sub Han  Ken'ichi Arai  Benjamin Cook 《Pure and Applied Geophysics》1995,144(3-4):839-854

A field survey of the June 3, 1994 East Java earthquake tsunami was conducted within three weeks, and the distributions of the seismic intensities, tsunami heights, and human and house damages were surveyed. The seismic intensities on the south coasts of Java and Bali Islands were small for an earthquake with magnitudeM 7.6. The earthquake caused no land damage. About 40 minutes after the main shock, a huge tsunami attacked the coasts, several villages in East Java Province were damaged severely, and 223 persons perished. At Pancer Village about 70 percent of the houses were swept away and 121 persons were killed by the tsunami. The relationship between tsunami heights and distances from the source shows that the Hatori's tsunami magnitude wasm=3, which seems to be larger for the earthquake magnitude. But we should not consider this an extraordinary event because it was pointed out byHatori (1994) that the magnitudes of tsunamis in the Indonesia-Philippine region generally exceed 1–2 grade larger than those of other regions.  相似文献   

Effect of rod friction on vane shear tests in very soft organic harbour mud     

Benjamin F. Schlue  Tobias Mörz  Stefan Kreiter 《Acta Geotechnica》2007,2(4):281-289

Very soft organic harbour mud is increasingly used as a filling and construction material in harbour construction and reorganization. The undrained shear strength of such soft sediments is the critical geotechnical soil parameter with regard to any specific construction design. Field and laboratory vane shear testing is a standard method to quickly determine this important parameter. So far, the effect of rod friction on vane shear tests in very soft organic soils is unclear. In this study we present results from laboratory experiments on harbour mud from a construction site in northern Germany. Relations among vane and rod geometry, penetration depth, water content, rod friction and undrained shear strength are derived. Based on these relations the influence of rod friction on vane shear test results is investigated. The results indicate that field and laboratory vane shear test measurements may be significantly influenced by rod friction. Methods are proposed to correct for the rod influence, which is shown to increase with rising water contents.  相似文献   

Simulated effect of a forest road on near‐surface hydrologic response: redux     

Benjamin B. Mirus  Brian A. Ebel  Keith Loague  Beverley C. Wemple 《地球表面变化过程与地形》2007,32(1):126-142

In the work reported here the comprehensive physics‐based Integrated Hydrology Model (InHM) was employed to conduct both three‐ and two‐dimensional (3D and 2D) hydrologic‐response simulations for the small upland catchment known as C3 (located within the H. J. Andrews Experimental Forest in Oregon). Results from the 3D simulations for the steep unchannelled C3 (i) identify subsurface stormflow as the dominant hydrologic‐response mechanism and (ii) show the effect of the down‐gradient forest road on both the surface and subsurface flow systems. Comparison of the 3D results with the 2D results clearly illustrates the importance of convergent subsurface flow (e.g. greater pore‐water pressures in the hollow of the catchment for the 3D scenario). A simple infinite‐slope model, driven by subsurface pore‐water pressures generated from the 3D and 2D hydrologic‐response simulations, was employed to estimate slope stability along the long‐profile of the C3 hollow axis. As expected, the likelihood of slope failure is underestimated for the lower pore pressures from the 2D hydrologic‐response simulation compared, in a relative sense, to the higher pore pressures from the 3D hydrologic response simulation. The effort reported herein provides a firm quantitative foundation for generalizing the effects that forest roads can have on near‐surface hydrologic response and slope stability at the catchment scale. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献