Climatological variations in the Northern Hemisphere circumpolar vortex in January   总被引：3，自引：0，他引：3  

R. E. Davis  S. R. Benkovic 《Theoretical and Applied Climatology》1992,46(2-3):63-73

Summary Recent secular variations in the January circumpolar vortex over the Northern Hemisphere are examined by digitizing the latitude at which the 546 dam isoheight at 50 kPa crosses every 10° meridian from 1947–90. A statistically significant expansion of the vortex is detected from 1966–90. Most of the expansion occurred over the North Pacific Ocean in the vicinity of the Aleutian Low and a less dramatic but significant expansion also occurred over eastern Canada and northern New England. The only region where the vortex contracted significantly is over the western United States. The trough in the western Pacific expanded eastward across the International Date Line in the past quarter century and, in conjunction with the observed contraction over the western United States, indicates amplification of 50 kPa standing waves in the Western Hemisphere. This change in circulation regimes could account for the increased frequency of warm air masses and the decreased occurrence of the coldest wintertime air masses in Alaska.With 6 Figures  相似文献   

Quantitative assessment of mineral resources with an application to petroleum geology   总被引：2，自引：0，他引：2  

J. Harff  J. C. Davis  R. A. Olea 《Natural Resources Research》1992,1(1):74-84

The probability of occurrence of natural resources, such as petroleum deposits, can be assessed by a combination of multivariate statistical and geostatistical techniques. The area of study is partitioned into regions that are as homogeneous as possible internally while simultaneously as distinct as possible. Fisher's discriminant criterion is used to select geological variables that best distinguish productive from nonproductive localities, based on a sample of previously drilled exploratory wells. On the basis of these geological variables, each wildcat well is assigned to the production class (dry or producer in the two-class case) for which the Mahalanobis' distance from the observation to the class centroid is a minimum. Universal kriging is used to interpolate values of the Mahalanobis' distances to all locations not yet drilled. The probability that an undrilled locality belongs to the productive class can be found, using the kriging estimation variances to assess the probability of misclassification. Finally, Bayes' relationship can be used to determine the probability that an undrilled location will be a discovery, regardless of the production class in which it is placed. The method is illustrated with a study of oil prospects in the Lansing/Kansas City interval of western Kansas, using geological variables derived from well logs.  相似文献   

REPLY TO the preceding Discussion by Stanley N. Davis of "Correlations of Permeability and Grain Size"     

Stanley N. Davis 《Ground water》1990,28(1):116-116

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A Proposal to Use Chlorine-36 for Monitoring the Movement of Radionuclides from Nuclear Explosions     

Fred M. Phillips  Stanley N. Davis  Peter Kubik 《Ground Water Monitoring & Remediation》1990,10(3):106-113

Chlorine-36 has been produced in large amounts by hundreds of nuclear explosions on the Nevada Test Site as well as 12 off-site explosions at eight locations in five states. Continued monitoring of the redistribution of radionuclides by subsurface water is of concern in most of the areas affected by the detonations. Chlorine-36 has the following advantages as a built-in tracer for this redistribution: its mobility is equal to or greater than water, its long half-life assures its continued usefulness over long periods, collection and storage of samples is simple, it is not subject to vapor transport at ordinary temperatures, its natural background is very low, and it does not form insoluble precipitates. Chlorine-36 from the Gnome event near Carlsbad, New Mexico, illustrates how ³⁶C1 can be used to help study the redistribution of radionuclides in the soil profile. Chlorine-36 is also potentially useful as a tracer to study movement of contaminants around large nuclear reactor complexes and near respositories for radioactive waste.  相似文献   

The Uneven Landscape of California's Historical Landmarks          下载免费PDF全文

Samuel M. Otterstrom  James A. Davis 《Geographical review》2016,106(1):28-53

Historical markers help preserve and display history and communicate what a group deems important about a place's past. This paper analyzes the changing themes and landscape relevance of California's official historical landmarks. California's thousand‐plus markers are classified and mapped by themes, analyzed for changing topical emphasis over time, and evaluated for landscape presence. The thematic distribution and relative density of these landmarks is uneven. Gold Rush and Spanish themes have become less prevalent over time as culturally related landmarks have grown in importance. This paper illustrates how historical landmark programs help sustain and define the public's collective memory through designating dispersed geographical locations as particularly important points of reference to the past.  相似文献   

Howchinia bradyana (Howchin) and its distribution in the Lower Carboniferous of England     

A.G. Davis 《Proceedings of the Geologists' Association. Geologists' Association》1951,62(4):248-IN5

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Note on a derived boulder at warden point     

A.G. Davis 《Proceedings of the Geologists' Association. Geologists' Association》1951,62(4):270

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Measurement of sediment resuspension rates in Long Island Sound   总被引：1，自引：0，他引：1  

Henry Bokuniewicz  Larry McTiernan  Wayne Davis 《Geo-Marine Letters》1991,11(3-4):159-161

Resuspension rates have been measured on Long Island Sound sediments (New York/Connecticut, USA) under an oscillating grid, using a flume, and in place, using high frequency acoustics, transmissometers, and sediment traps. Despite differences, the results compare favorably. The methods all provide an order-of-magnitude estimate of the resuspension rate and increases under storm conditions can be estimated.  相似文献   

Use of the half-cycle analysis method to compare measured wave height and simulated Gaussian data having the same variance spectrum     

W.H. Buckley  R.D. Pierce  J.B. Peters  M.J. Davis 《Ocean Engineering》1984,11(4):423-445

Using the half-cycle analysis method, a comparison is made between extreme events in half-hour intervals of hurricane Camille wave data and extreme events in synthesized Gaussian realizations having the same variance spectra as the measured data. While various statistical comparisons of measured and simulated Gaussian data reveal a consistent trend toward Gaussian behavior for the majority of wave events in the hurricane generated data, it is shown using the half-cycle analysis method that the more extreme wave events occurring near the height of the storm were distinctly non-Gaussian.  相似文献   

Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish     

Davis  M. W. 《ICES Journal of Marine Science》2007,64(8):1535-1542

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