A comparison of tropical oceanic heat fluxes determined by airborne eddy correlation and shipboard bulk aerodynamic techniques     

Roger F. Reinking  Gary Barnes 《Boundary-Layer Meteorology》1981,20(3):353-370

Vertical turbulent transports of latent and sensible heat through the tropical marine boundary layer were measured with ship and airborne instruments in the GATE experimental area. The measurements from the two systems are compared for cases of simultaneous sampling in the same locations during undisturbed weather and during the wakes of convective disturbances. The paired average fluxes from the airborne eddy correlation measurements and the shipboard bulk aerodynamic measurements, for undisturbed weather, are related with correlation coefficients in the range of 0.6 to 0.9; the correlations depend primarily on stratifications of the aircraft data according to sampling altitude (15–153 m msl) and flight pattern relative to the mean wind. The agreement between the two types of measurements is best for ship data paired with aircraft samples from the lowest altitudes (15 and 30 m) and from alongwind rather than crosswind flights, as is appropriate since the stationary ships monitor the alongwind characteristics of the turbulence. The use of long (1–3 hr) versus short (10 min) ship samples did not significantly affect the comparability with the aircraft samples during undisturbed periods.The good baseline comparability demonstrated by the undisturbed-weather comparisons was applied to interpret the results from the wakes behind showers. Although these paired measurements were few, not only the sensible heat, but also the latent heat flux was shown to decrease substantially with altitude from 10 m to at least 150 m in the wakes, where the mixing was relatively intense. Variations in the fluxes were much greater at the higher level than nearer the sea surface.  相似文献   

Pathways of manganese in an open estuarine system     

Bjorn Sundby  Norman Silverberg  Roger Chesselet 《Geochimica et cosmochimica acta》1981,45(3):293-307

The distribution of Mn was examined in the bottom sediments and water column (suspended paniculate matter) of the Laurentian Trough. Gulf of St. Lawrence. A characteristic profile of Mn with depth in the sediment consisted of a Mn-enriched surface oxidized zone, less than 20 mm thick, and a Mn-depleted subsurface reducing zone. A subsurface Mn maximum occurred within the oxidized zone. Below this maximum the concentration dropped sharply to nearly constant residual levels in the reducing zone. The accumulating estuarine sediments are deficient in Mn compared to the river input of suspended matter and are definitely not the ultimate sink for manganese. Manganese escapes from the sediment by diffusion and resuspension, forming Mn-enriched, fine-grained particles which are flushed out in the estuarine circulation. 5.0 × 10⁹gyr^?1 of Mn, or 50% more than the river input of dissolved Mn. are exported to the open ocean. In spite of the efficient mobilization and export of Mn, the quantity exported is a small fraction (0.2%) of the total flux to the deep-sea sediments. This is related to the low levels of paniculate matter transported by the St. Lawrence River. The export phénomenon, however, is probably true of many coastal regions of muddy sediments and thus has interesting implications for the oceanic budget of Mn.  相似文献   

Titaniferous phlogopites from the leucite lamproites of the West Kimberley area,Western Australia     

Roger H. Mitchell 《Contributions to Mineralogy and Petrology》1981,76(2):243-251

Phlogopites in the wolgidites, fitzroyites and cedricites (leucite lamproites) of the West Kimberley area range in composition from titaniferous phlogopite to titaniferous tetraferriphlogopite. Two distinct compositional trends are present. In wolgidites micas are characterized by strong total iron enrichment, moderate Al and Mg depletion and little enrichment in tetrahedral ferric iron. Micas in fitzroyites and cedricites are characterized by strong depletion in Al and strong enrichment in tetrahedral ferric iron at approximately constant Mg contents. Individual centers of fitzroyite intrusion are characterized by distinct mica TiO₂ contents. The phlogopite compositional trends at low pressures are very different to those of kimberlite micas. An origin of these lamproites involving differentiation of a kimberlitic magma is considered unlikely.  相似文献   

A general mixing equation with applications to Icelandic basalts   总被引：4，自引：0，他引：4  

Charles H. Langmuir  Robert D. Vocke  Gilbert N. Hanson  Stanley R. Hart 《Earth and Planetary Science Letters》1978,37(3):380-392

The mixing equation applied by Vollmer [1] to Pb and Sr isotope ratios is shown to be a general equation applicable to consideration of element and isotope ratios. The mixing equation is hyperbolic and has the form:Ax + Bxy + Cy + D = 0where the coefficients are dependent on the type of plot considered: i.e. ratio-ratio, ratio-element, or element-element. Careful use of this equation permits testing whether mixing is a viable process, places constraints on end member compositions, allows distinction between mixing of sources and mixing of magmas, and should allow distinction between recent mixing and long-term evolution of sources.The available chemical data for postglacial basalts from Iceland and along the Reykjanes Ridge are not consistent with either mixing of magmas or simple mixing of an enriched ocean island source with a depleted ocean ridge source. If the available analyses for basalts are representative of the source regions, the data are consistent with at least two models neither of which can be properly tested with the available data.(1) There are two separate mixing trends: one beneath Iceland with the alkali basalt source and a depleted Iceland source as end members; the second along the Reykjanes Ridge with a heterogeneous ocean ridge basalt source and a source similar to that for intermediate basalts on Iceland as end members. The depleted Iceland source and the depleted ocean ridge source are not the same.(2) The chemistry of the basalts is not determined by mixing. Instead the basalts are derived from a multiplicity of sources with a similar history which have been isolated for hundreds of millions of years.  相似文献   

Water atlas of the United States: J.J. Geraghty et al., 1973. Water Information Center,Port Washington,N.Y., 200 pp., US $35.00     

Roger DeWiest 《Earth》1975,11(3):259-260

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Erratum     

G. G. Baxter  S. M. Cargill  A. H. Chidester  P. E. Hart  G. M. Kaufman  F. Urquidi-Barrau  D. D. Picklyk 《Mathematical Geosciences》1979,11(3):343-343

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The composition and origin of metal in howardites     

Roger H Hewins 《Geochimica et cosmochimica acta》1979,43(10):1663-1673

Howardites can be divided into two main groups, Ni-rich (>350ppm Ni) and Ni-poor (<150ppm Ni). In the Ni-rich group Ni occurs principally in metal grains associated with melt rocks and is largely derived from projectiles which caused the melting. The metal in Bununu, Kapoeta and Malvern melt rocks plots in the meteoritic Ni-Co range and in Bununu and Kapoeta is enriched in P. By contrast, most metal grains in primary lithic and crystal clasts in howardites are Ni-poor and plot mainly in the composition field of pristine lunar anorthosite metal. However, there are variations in the abundance and exact composition of primary metal from howardite to howardite and each therefore represents a discrete source region. The matrix metal in Bholgati, Bununu, and Kapoeta shows the diversity of compositions expected in a polymict breccia, with compositions plotting in and between the anorthositic and meteoritic Ni-Co fields. Other howardites show a more limited range of matrix metal compositions, because of limited metal-bearing clasts.Petersburg differs from other howardites in several ways. The metal in primary clasts has a unique $\text{Ni}\text{Co}$ ratio of about 40, which indicates derivation from a different reservoir from other howardite primary clasts. The metal in the matrix consists of large grains intergrown with silicates with compositions clustering tightly at 3.3% Ni, 0.2% Co. This is interpreted as equilibration, possibly as the result of deeper burial for Petersburg than for other howardites.  相似文献   

An analysis of the Chow-Kulandaiswamy GHS model     

Roger C. McCann  Vijay P. Singh 《Advances in water resources》1980,3(4):173-180

The Chow-Kulandaiswamy general hydrologic system (GHS) model is revisited. Based on a mathematical study by Singh and McCann the GHS model is simplified. Explicit solutions are obtained for special cases which can satisfactorily determine watershed surface runoff response due to given rainfall excess. A rational criterion is developed to determine the number of derivative terms to be retained in the model. In order to determine the coefficients in the GHS model the method of moments is proposed. Criteria are developed to determine complex roots and oscillations for these coefficients. By analysing Chow-Kulandaiswamy's results it is found that in a majority of cases which they studied roots are complex. Moreover, for the cases which have complex roots, a majority of the solutions oscillate. A brief sensitivity analysis of the GHS model is performed with regard to: (a) its leading coefficient, and (b) the order of the differential equation. Finally, the peak characteristics are specified for the second order case and their qualitative properties are shown for the third order case.  相似文献   

Cretaceous and Paleogene geologic history of coastal Ecuador     

Dr. Tomas Feininger  Dr. C. Roger Bristow 《International Journal of Earth Sciences》1980,69(3):849-874

Following a general review of the Cretaceous and Paleogene geology of Ecuador, we propose a geologic history from early Cretaceous through Oligocene time with emphasis on the coastal part of the country that is based on the interpretive interaction of three oceanic plates (the Bolívar, proto-Nazca, and Nazca) and the continental South American plate. The proposed history invokes large lateral displacements, the intervention of the previously unrecognized Bolívar plate, the development of three successive subduction zones, the formation of a distant oceanic island arc and its subsequent collision with the South American plate, the emplacement of a major olistostrome complex, and an intricate record of displacement on a currently inactive transform fault. The proposed history offers a viable solution to four major problems of the geology of coastal Ecuador.

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Zusammenfassung Aus der Kreide- und Paläogen-Geschichte Ecuadors läßt sich die Entwicklung der Küstenregion ableiten. Sie wird vom Zusammenwirken von drei ozeanischen Platten (Bolivar, Proto-Nazca und Nazca) und der kontinentalen Platte Südamerikas bestimmt. Die Entwicklung umfaßt ausgedehnte Seitenverschiebungen, das Auftreten einer bisher nicht erkannten Bolivar-Platte, die Anlage von drei aufeinanderfolgenden Subduktionszonen, die Bildung eines Inselbogens und die folgende Kollision mit der Südamerikanischen Platte, die Ablagerung eines großen Olisthostrom-Komplexes und die Verschiebungen entlang einer heute inaktiven Transform-Verwerfung. Damit sind eine Reihe von Problemen der Geologie des Küstenabschnittes Ecuadors gelöst.

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Résumé Passant en revue la géologie de l'Equateur au Crétacique et Paléogène, les auteurs proposent une histoire géologique allant depuis le Crétacique inférieur à l'Oligocène en mettant l'accent sur la région cÔtière, et en se basant sur l'interaction de trois plaques océaniques (bolivienne, proto-Nasca et Nasca) et de la plaque continentale de l'Amérique du Sud. L'histoire proposée fait appel à de grands déplacements, à l'intervention de la plaque bolivienne non reconnue antérieurement, au développement de trois zones de subduction successives, à la formation d'une guirlande d'Îles océaniques distante et sa collision subséquente avec la plaque de l'Amérique du Sud, à la mise en place d'un grand complexe olistostromique et à un déplacement sur une faille transformante inactive. L'histoire proposée apporte une solution viable à quatre problèmes de la géologie de la Région cÔtière de l'Equateur.

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. (, protoNazca Nazca) . : , , , , , Olistostrome . .

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Contribution No. 6 A, Departamento de Geología, Escuela Politécnica Nacional, Quito, Ecuador.  相似文献   

The respective effects of water vapor and temperature on the turbulent fluxes of sensible and latent heat     

Roger F. Reinking 《Boundary-Layer Meteorology》1980,19(3):373-385

Various aspects of the Brook correction for the effects of moisture fluctuations or gradients on atmospheric specific heat and, consequently, on the vertical flux of sensible heat are discussed, and additional forms of the complete and approximate equations are derived. Corollary expressions for the influence of temperature fluctuations or gradients on vertical latent heat flux are presented. Errors due to neglecting these temperature and moisture effects on the respective fluxes are compared in terms of the Bowen ratio. Either of these normally neglected effects can change the direction (sign) and very substantially affect the magnitude of the corresponding flux. The effects sometimes compensate in the total, sensible plus latent, heat flux. Calculations include practical examples from the very different climates of the tropical Atlantic Ocean and the Great Plains of Nebraska.  相似文献