The effect of metal complexation on hydrogen sulfide transport across the sea-air interface     

Scott Elliott  F. Sherwood Rowland 《Journal of Atmospheric Chemistry》1990,10(3):315-327

Hydrogen sulfide dissolved in surface seawater is distributed into free forms which include the volatile neutral H₂S and its conjugate anions, and also into a set of involatile metal complexes. Calculation of the sulfide fraction capable of supporting sea-air flux is sensitive to large uncertainties in complexation equilibrium relationships, both for the sulfides themselves, and for organic ligands competing with them to coordinate dissolved copper. Saturation can be achieved relative to the troposphere if metal interactions are minimized, or if strong sulfide binders are titrated.  相似文献   

The formation of circular littoral cones from tube-fed pāhoehoe: Mauna Loa,Hawai'i     

Zinzuni Jurado-Chichay  Scott K. Rowland  George P. L. Walker 《Bulletin of Volcanology》1996,57(7):471-482

Pyroclastic cones along the southwest coast of Mauna Loa volcano, Hawai'i, have a common structure: (a) an early formed circular outer rim 200–400 m in diameter composed mostly of scoria and lapilli, and (b) one or more later-formed inner rims composed almost exclusively of dense spatter. The spatter activity locally fed short lava flows that ponded within the outer rims. Based on various lines of evidence, these cones are littoral in origin: relationships between the cones and associated flows; the degassed nature of the pyroclasts; and (although not unequivocal) the position of the cones relative to known eruptive vent locations on Mauna Loa. Additional support for the littoral interpretation comes from their similarity to (smaller) littoral cones that have been observed forming during the ongoing Kilauea eruption. The structure of these Mauna Loa cones, however, contrasts with that of standard Hawaiian littoral cones in that there is (or once was) a complete circle of pyroclastic deposits. Furthermore, they are large even though associated with tubefed phoehoe flows instead of 'a'. The following origin is proposed: An initial flow of tube-fed phoehoe into the ocean built a lava delta with a base of hyaloclastite. Collapse of an inland portion of the active tube into the underlying wet hyaloclastites or a water-filled void allowed sufficient mixing of water and liquid lava to generate strong explosions. These explosions broke through the top of the flow and built up the outer scoria/lapilli rims on the solid carapace of the lava delta. Eventually, the supply of water diminished, the explosions declined in intensity to spattering, and the initial rim was filled with spatter and lava.  相似文献   

Declining towns in Russia, 1989-1993     

Rowland RH 《Post-Soviet geography》1995,36(7):436-445

This "article based on data for the last census of the former USSR and population estimates for 1993 for urban places of over 15,000 population in the Russian Federation surveys the regional distribution, economic functions, and size characteristics of urban settlements in Russia with declining population over the period 1989-93. Interesting comparisons are drawn with patterns prevailing during previous periods, revealing recent increases in the number of such towns in major manufacturing regions and the North and an increase in the number of large cities. Towns experiencing the very greatest percentage declines (-10.0 percent or more) also are investigated."  相似文献   

Selected urban population characteristics of Moscow     

Rowland RH 《Post-Soviet geography》1992,33(9):569-590

"This paper investigates total and regional population characteristics in Moscow [Russia] during 1979-1989, specifically nationality, age, sex and education and their interrelationships. Population dynamics of Russians, Ukrainians, Jews, and, to a lesser extent, other groups are examined based on a regionalization scheme dividing the city into Inner Zone and Outer Zone [regions]. The same spatial framework is employed in an analysis of changes in the age and sex structures of the city's overall population, as well as in levels of education. Linkages between these characteristics and rates of housing construction, recent demographic history, and city migration policy are explored."  相似文献   

Cones of Influence Developed in the Silurian-Devonian Aquifer, Maumee River Basin, Ohio     

Mark R. Rowland  George R. Kunkle 《Ground water》1970,8(3):37-43

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鲁西新太古代济宁群含铁岩系形成时代——SHRIMP U-Pb锆石定年   总被引：12，自引：7，他引：5  

王伟  王世进  刘敦一  李培远  董春艳  颉颃强  马铭株  万渝生 《岩石学报》2010,26(4):1175-1181

济宁群以隐伏的地质体分布于华北克拉通鲁西地区,以往被划归古元古代。近年来在济宁群的钻探和地球物理研究中,发现存在较大规模条带状硅铁建造,其形成时代引起地学界极大关注。本文对济宁群变质碎屑沉积岩和长英质火山岩进行了锆石SHRIMP年龄测定。含砾绿泥绢云千枚岩的碎屑锆石年龄主要集中在～2.7Ga,可靠的最年轻碎屑锆石年龄为2.61±0.01Ga。变质长英质火山岩岩浆锆石年龄为2.56±0.02Ga。研究表明,济宁群形成于新太古代晚期,而不是以往认为的古元古代。华北克拉通条带状铁建造主要形成于新太古代晚期。济宁群在岩石组合、变质作用方面与鞍山、冀东以及五台地区同时代含硅铁建造的表壳岩系有差别,但是与本溪南芬铁矿的岩石组合有相似之处。这些可能为我国的隐伏太古宙BIF铁矿的研究与勘探提供了重要依据。  相似文献   

Methyl halide hydrolysis rates in natural waters     

Scott Elliott  F. Sherwood Rowland 《Journal of Atmospheric Chemistry》1995,20(3):229-236

International regulations are under consideration for methyl bromide because of its high time dependent ozone depletion potential. Geocycling of the species is not well understood, and removal may occur in several types of natural water incuding the oceanic and those in soils. The hydrolysis reaction is a dominant loss pathway in environmental aqueous systems, but rate constants have generally been reported only in distilled water and at greater than room temperature. Here we present measurements in sodium chloride solutions and in seawater in addition to pure water, and at temperatures across the oceanographic range. The reaction could be followed even in solutions near the freezing point because product methanol was monitored in the method of initial rates. Time constants for methyl bromide hydrolysis fall between 10 and 1000 days over the temperatures of the sea, and are always within an order of magnitude of the fastest abiotic destruction mode, chlorination. Activation energies for the two processes are similar so that the ratio of their time scales does not vary with oceanic location. Hydrolysis rate constants are also listed for the closely related compounds methyls iodide and chloride. Solvolysis of the methyl halides in natural waters acts as a source of methanol to the ocean and atmosphere.  相似文献   

Toxicity and compositional analysis of aromatic hydrocarbon fractions of two pairs of undegraded and biodegraded crude oils from the Santa Maria (California) and Vienna basins     

Verena Reineke  Jürgen Rullktter  Emma L. Smith  Steven J. Rowland 《Organic Geochemistry》2006,37(12):1885

The monoaromatic and total aromatic hydrocarbon fractions of two pairs of undegraded and moderately biodegraded crude oils from the Santa Maria basin (California) and the Vienna basin (Austria), all dominated by unresolved complex mixtures, were studied regarding their composition and toxicity towards the feeding rate of the marine mussel Mytilus edulis. Total aromatic and monoaromatic hydrocarbon fractions from sulphur-rich Monterey Formation crude oils were slightly more toxic than the fractions isolated from sulphur-lean Vienna basin oils. The ecotoxicity tests did not show any significant differences in toxicity of aromatic compounds from undegraded or in-reservoir biodegraded crude oils from the same oilfield although some differences in composition were observed. Organic sulphur compounds are suspected to cause the slightly higher toxicity of the aromatic hydrocarbon fractions from the Monterey oils.  相似文献   

Calculation of lava effusion rates from Landsat TM data   总被引：1，自引：0，他引：1  

Andrew J. L. Harris  Luke P. Flynn  Laszlo Keszthelyi  Peter J. Mouginis-Mark  Scott K. Rowland  Joseph A. Resing 《Bulletin of Volcanology》1998,60(1):52-71

 We present a thermal model to calculate the total thermal flux for lava flowing in tubes, on the surface, or under shallow water. Once defined, we use the total thermal flux to estimate effusion rates for active flows at Kilauea, Hawaii, on two dates. Input parameters were derived from Landsat Thematic Mapper (TM), field and laboratory measurements. Using these parameters we obtain effusion rates of 1.76±0.57 and 0.78±0.27 m³ s^–1 on 23 July and 11 October 1991, respectively. These rates are corroborated by field measurements of 1.36±0.14 and 0.89±0.09 m³s^–1 for the same dates (Kauahikaua et al. 1996). Using weather satellite (AVHRR) data of lower spatial resolution, we obtain similar effusion rates for an additional 26 dates between the two TM-derived measurements. We assume that, although total effusion rates at the source declined over the period, the shut down of the ocean entry meant that effusion rates for the surface flows alone remained stable. Such synergetic use of remotely sensed data provides measurements that can (a) contribute to monitoring flow-field evolution, and (b) provide reliable numerical data for input into rheological and thermal models. We look forward to being able to produce estimates for effusion rates using data from high-spatial-resolution sensors in the earth observing system (EOS) era, such as Landsat 7, the hyperspectral imager, the advanced spaceborne thermal emission spectrometer, and the advanced land imager. Received: 25 July 1997 / Accepted: 26 February 1998  相似文献   

Declining towns in the former USSR     

Rowland RH 《Post-Soviet geography》1994,35(6):352-365

"The paper comprises an update of an earlier study...focused on towns with declining population during the 1959-1970 period. Based on recently published data on individual urban centers with 15,000 or more inhabitants reported in the 1979 and 1989 censuses, it identifies centers where population declined from 1970 to 1989. The study also assesses selected geographical aspects, economic functions, and size characteristics of such urban centers. Comparisons with data from the 1959-1970 period are made to arrive at a 30-year perspective."  相似文献