Conversion of profile difference quotients to true gradients at the geometric mean height in the surface layer     

Charles R. Stearns 《Boundary-Layer Meteorology》1970,1(2):146-154

Theoretical profiles of wind speed and air temperature can provide synthetic measurements at discrete levels which may be compared with actual field measurements. In addition to wind and temperature gradients at any height, profile theory permits us to determine the difference quotients from measurements at discrete levels. It is shown that corrections are required to obtain the gradients at the geometric mean height of the two discrete levels of measurement. The correction factor depends on the measurement height and spacing, profile structure, surface roughness and the measured Richardson number. The correction can be reduced by close spacing of the measurement levels.  相似文献   

Movements of spawning rainbow smelt,Osmerus mordax,in a massachusetts estuary     

Steven A. Murawski  Gary R. Clayton  Roger J. Reed  Charles F. Cole 《Estuaries and Coasts》1980,3(4):308-314

Movements of spawning rainbow smelt, Osmerus mordax, were followed in the Parker River estuary, Massachusetts during 1974 and 1975. Fish marked with vinyl subcutaneous tags (n=1,492) or fin clips (n=577) were recaptured on three separate spawning sites in three different tributaries; the distribution patterns of marked fish indicated a homogeneous spawning stock. Interstream movement may have been facilitated by tidal transport since smelt ascended to the spawning sites on flood tides and moved downstream as tides ebbed. Rates of recapture of fish tagged on the spawning areas were 2.61 and 5.61 times greater for males than females in 1974 and 1975 respectively. Individual tagged males were recovered up to four times during the spawning period; females were recaptured a maximum of once. The proportion of age II and older females sampled from the angling fishery prior to spawning in 1975 (47.38%) was greater than the cumulative proportion sampled on the spawning sites (11.93%) due to longer spawning period of individual males.  相似文献   

Mineral equilibria in a six-component seawater system,Na-K-Mg-Ca-SO₄-Cl-H₂O,at 25°C     

Hans P. Eugster  Charles E. Harvie  John H. Weare 《Geochimica et cosmochimica acta》1980,44(9):1335-1347

Phase relations in the 6-component system Na-K-Mg-Ca-SO₄-Cl-H₂O have been calculated for halite saturation, 25°C and 1 atm pressure. Using a Jänecke projection with the apices Ca-Mg-K₂-SO₄, 27 stable invariant points have been located which are connected by 69 univariant curves. Polyhalite is the only quaternary solid, but anhydrite occupies the bulk of the interior tetrahedral space. Consequently, 24 of the invariant points lie very close to the Ca-free base, Mg-K₂-SO₄. The remaining three points involve tachyhydrite and/or antarcticite. All points but two (20,27) represent peritectic conditions. Metastable equilibria have been calculated for the Ca-free system and yield relations corresponding to the solar diagram.Seawater lies in the subspace anhydrite-halite-carnallite-kieserite-bischofite (point 20) and its evaporation has been discussed for conditions of equilibrium and fractional crystallization. After gypsum is converted to anhydrite, halite precipitates. The next phase, under equilibrium conditions, is glauberite, crystallizing at the expense of anhydrite. Continued evaporation leads to glauberite resorption and eventual replacement by polyhalite. Then follow the magnesium sulfates epsomite, hexahydrite and kieserite, which are joined by carnallite. Polyhalite is replaced by anhydrite and bischoflte is added at the final invariant condition. Kainite does not appear as a primary phase under equilibrium conditions, but it is an important phase during fractional crystallization, where Ca-phases are not allowed to back-react with the brine.Up to the appearance of glauberite, thickness ratios of halite: anhydrite couplets (equilibrium or fractionation) can vary from 0 to 7, the relative amount of halite increasing with more intense evaporation. During evaporation, the activity of H₂O decreases from 0.98 (seawater) to 0.34 (final invariant brine). The data provided can be used to evaluate the effects of mineral precipitation, evaporation and brine mixing for a wide variety of natural brines.  相似文献   

Open and closed system igneous fractionation within two chilean ophiolites and the tectonic implication     

Charles Stern 《Contributions to Mineralogy and Petrology》1979,68(3):243-258

The Sarmiento and Tortuga complexes are two mafic complexes located in southern Chile that represent the remnants of the mafic portion of the floor of an Early Cretaceous extensional back-arc basin. Basaltic dikes and lavas within each complex exhibit tholeiite differentiation trends whereby FeO*, FeO*/MgO, TiO₂, P₂O₅, Zr, and Y increase together without significant increases in SiO₂. In both complexes, as FeO*/MgO increases, REE abundance increases without significant change in Ce/Yb ratio, but with an increasing negative Eu anomaly. The Sarmiento complex contains intermediate icelandites and silicic dikes and lavas which are conspicuously absent in the Tortuga complex. These non-basaltic compositions have higher Zr, Y and REE contents than the associated basalts, but similar Ce/Yb ratios, suggesting co-genetic origin. Thick cumulate gabbro sequences in both complexes suggest shallow level crystal-liquid fractionation as a major cause of the observed wide range of chemical variations. Significantly, in basalts from the Tortuga complex, incompatible elements (Zr, Y, REE) increase in abundance more rapidly with increasing FeO*/ MgO than in the Sarmiento complex. The rapid increase of incompatible elements relative to FeO*/ MgO in the Tortuga complex is best modeled by fractionation within an open magma chamber steadily replenished with new batches of undifferentiated magma. The observed chemical variations within the Sarmiento complex are best modeled by a magma chamber replenished only a limited number of times by a continuously decreasing volume of undifferentiated magma, followed, subsequent to the last input of new parental magma, by closed system fractionation which results in the formation of ferro-basalts, icelandites and silicic differentiates. Ferro-gabbros (FeO* >20 wt °/00) found within the gabbro unit of the Sarmiento complex closely approximate in composition the calculated crystal extracts required to evolve ferro-basalts into icelandites and the more silicic differentiates. The difference between the nature of the postulated magma chambers within the spreading centers at which the Sarmiento and Tortuga complexes originated suggests that the zone of magma intrusion from the mantle may have been diffuse in the region where the Sarmiento complex formed and more localized in the region where the Tortuga complex formed. This is consistent with other geochemical and field evidence suggesting that the Sarmiento complex represents a less developed stage of evolution than the Tortuga complex of the mafic floor of the Mesozoic back-arc basin in southern Chile. The apparent decoupling of major and trace element variations in ocean floor basalts may be explained by shallow level igneous fractionation without involving large proportions of clinopyroxene if the magma chambers within spreading centers at midocean ridges behave as open systems periodically replenished with batches of undifferentiated parental magma as is inferred for the Tortuga complex in southern Chile.  相似文献   

Periodic counts for estimating the size of the spawning population of alewives,Alosa pseudoharengus (Wilson)     

Stephen G. Rideout  James E. Johnson  Charles F. Cole 《Estuaries and Coasts》1979,2(2):119-123

The number of migrating alewives in the Parker River, Massachusetts, can be counted visually by standing at the upper end of each of the 6 fish ladders in the system. Estimating the entire run of up to a month’s duration by this procedure is not economically feasible, but we suggest a subsampling procedure that can provide sufficient accuracy and be economical. The reliability of periodic sample counts when used to estimate population numbers of anadromous alewives (Alosa pseudoharengus) was indicated by the low variance of paired counts, small random errors of individual counts, and by the low variability between counts on days of large runs in the Parker River. Analyses of computer-simulated runs using actual data suggested that short counts taken frequently are superior to longer counts taken less often. Both field and computer-simulated data suggested that ten-minute counts taken hourly will estimate the true population of alewife runs within 10% error at the .05 level of probability.  相似文献   

Temperature preference of the white perch,Morone americana,collected in the Wicomico River,Maryland     

Lenwood W. Hall  Charles H. Hocutt  J. R. Stauffer 《Estuaries and Coasts》1979,2(2):129-132

Temperature preference tests were conducted on fresh water white perch (Morone americana), collected from the Wicomico River, Maryland. Collection temperature was 27 C and acclimation temperatures used in temperature preference tests were 6, 12, 18, 24, 30, and 33 C. The following methods were used to determine the final temperature preference: linear regression, quadratic equation, and “eyeball” plots. Recorded final temperature preference values were 28.9, 29.3 and 30.6 C using each method respectively.  相似文献   

The Use of Microorganisms as Ground-Water Tracers: A Review   总被引：3，自引：0，他引：3  

Bruce H. Keswick  De-Shin Wang  Charles P. Gerba 《Ground water》1982,20(2):142-149

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Polymerization of silicate and aluminate tetrahedra in glasses,melts, and aqueous solutions—III. Local silicon environments and internal nucleation in silicate glasses     

B.H.W.S de Jong  Keith D Keefer  Gordon E Brown  Charles M Taylor 《Geochimica et cosmochimica acta》1981,45(8):1291-1308

The local, up to second nearest neighbor, around Si atoms in alkali and alkaline earth-silicate glasses has been characterized by SiKβ X-ray emission spectroscopy. Principally two types of Si atoms can be distinguished. These are Si atoms with only other Si atoms as second nearest neighbours, and those with one or more alkali or alkaline earth atoms in their second coordination sphere. The spectroscopic results indicate that the lower molecular weight alkali and alkaline earth-silicate glasses tend towards a bimodal distribution of local Si environments, which is designated Q₄-Q₀ following the assignment by Engelhardtet al. (1975) for silica species in aqueous solutions. From a different perspective the outcome of these experiments suggests that, though the concentration of bridging oxygens (O(br)) and non-bridging oxygens (O(nbr)) is fixed by the stoichiometry of the glass, the distribution of O(nbr) in the glass varies according to the kind of alkali or alkaline earth atom present. From observed nucleation data on R₂O-SiO₂ (R = Li, Na, K) glasses it is inferred that a bimodal Q distribution and in particular the presence of Q₀ species dominates the internal nucleation process in the alkali and alkaline earth-silicate glasses studied. Using this inference rationalizations can readily be found to explain the observed resistance to thermal shock and devitrification rates of these glasses.  相似文献   

Canyon Creek: A late Pleistocene vertebrate locality in interior Alaska     

Florence R. Weber  Thomas D. Hamilton  David M. Hopkins  Charles A. Repenning  Herbert Haas 《Quaternary Research》1981,16(2):167-180

The Canyon Creek vertebrate-fossil locality is an extensive road cut near Fairbanks that exposes sediments that range in age from early Wisconsin to late Holocene. Tanana River gravel at the base of the section evidently formed during the Delta Glaciation of the north-central Alaska Range. Younger layers and lenses of fluvial sand are interbedded with arkosic gravel from Canyon Creek that contains tephra as well as fossil bones of an interstadial fauna about 40,000 years old. Solifluction deposits containing ventifacts, wedge casts, and rodent burrows formed during a subsequent period of periglacial activity that took place during the maximum phase of Donnelly Glaciation about 25,000–17,000 years ago. Overlying sheets of eolian sand are separated by a 9500-year-old paleosol that may correlate with a phase of early Holocene spruce expansion through central Alaska. The Pleistocene fauna from Canyon Creek consists of rodents (indicated by burrows), Mammuthus primigenius (woolly mammoth), Equus lambei (Yukon wild ass), Camelops hesternus (western camel), Bison sp. cf. B. crassicornis (large-horned bison), Ovis sp. cf.O. dalli (mountain sheep), Canis sp. cf. C. lupus (wolf), Lepus sp. cf. L. othus or L. arcticus (tundra hare), and Rangifer sp. (caribou). This assemblage suggests an open landscape in which trees and tall shrubs were either absent or confined to sheltered and moist sites. Camelops evidently was present in eastern Beringia during the middle Wisconsin interstadial interval but may have disappeared during the following glacial episode. The stratigraphic section at Canyon Creek appears to demonstrate that the Delta Glaciation of the north-central Alaska Range is at least in part of early Wisconsin age and was separated from the succeeding Donnelly Glaciation by an interstadial rather than interglacial episode.  相似文献   

Aspects of the mineralogy and hydrometallurgy of chrysocolla,with special reference to the Cuajone,Peru, ores     

Jonathan M. Horlick  W. Charles Cooper  Alan H. Clark 《International Journal of Mineral Processing》1981,8(1):49-59

Chrysocolla in the Cuajone ores appears to be microcrystalline and to exhibit a fibrous structure.Sulphuric acid leaching of the chrysocolla is facilitated by a microcracked surface structure. A marked surface structural change is evidenced as hydrogen ions replace the copper. The end result is a noncontinuous surface layer of silica from which the copper has been essentially completely removed.The results of this study provide confirmatory evidence for the structure and hydrometallurgy of chrysocolla.  相似文献