Calculation of mass transfer among minerals and aqueous solutions as a function of time and surface area in geochemical processes. I. computational approach     

Harold C. Helgeson  William M. Murphy 《Mathematical Geosciences》1983,15(1):109-130

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Comment on “late Wisconsinan glaciation models of northern Maine and adjacent Canada”     

Thomas V. Lowell  J.Steven Kite  Dale Becker  Harold W. Borns 《Quaternary Research》1983,19(1):136-137

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Instantaneous photochemical rates in the global stratosphere     

Johnston  Harold  Whitten  Gary 《Pure and Applied Geophysics》1973,106(1):1468-1489

Starting with the average actual distribution of ozone (Dütsch [15]) and temperature in the stratosphere, we have calculated the solar intensity as a function of wavelength and the instantaneous rates (molecules cm^–3 sec^–1) for each Chapman reaction and for each of several reactions of the oxides of nitrogen. The calculation is similar to that ofBrewer andWilson [5]. These reaction rates were calculated independently in each volume element in spherical polar coordinates defined by R=1 km from zero to 50, =5° latitude, and ø=15° longitude (thus including day and night conditions). Calculations were made for two times: summer-winter (January 15) and spring-fall (March 22). As input data we take observed solar intensities (Ackerman [1]) and observed, critically evaluated. constants for elementary chemical and photochemical reactions; no adjustable parameters are employed. (These are not photochemical equilibrium calculations.) According to the Chapman model, the instantaneous, integrated, world-wide rate of formation of ozone from sunlight is about five times faster than the rate of ozone destruction, and locally (lower tropical stratosphere) the rate of ozone formation exceeds the rate of destruction by a factors as great as 1000. The global rates of increase of ozone are more than 50 times faster thanBrewer andWilson's [5] estimate of the average annual transfer rate of ozone to the troposphere. The rate constants of the Chapman reactions are believed to be well-enough known that it is highly improbable that these discrepancies are, due to erroneous rate constants. It is concluded that something else besides neutral oxygen species is very important in stratospheric ozone photochemistry. The inclusion of a uniform concentration of the oxides of nitrogen (NO_x as, NO and NO₂) averaging 6.6×10^–9 mole fraction gives a balance between global ozone formation and destruction rates. The inclusion of a uniform mole fraction of NO_x at 28×10^–9 also gives a global balance. These calculations support the hypethesis (Crutzen [10],Johnston [24]) that the oxides of nitrogen are the most important factor in the global, natural ozone balance. Several authors have recently evaluated the natural source strength of NO_x in the stratosphere; the projected fleets of supersonic transports would constitute an artificial source of NO_x about equal to the natural value, thus promising more or less to double an active natural stratospheric ingredient.  相似文献   

Oil and gas production from carbonate rocks: George V. Chilingar,Robert W. Mannon and Herman H. Rieke III (Editors). American Elsevier,New York,N.Y., 1972, 409 pp., 65 illus., Dfl. 96.00     

Harold J. Bissell 《Sedimentary Geology》1973,9(3):229-230

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Lead and strontium isotopes in rocks of the Absaroka volcanic field,Wyoming     

Zell E. Peterman  Bruce R. Doe  Harold J. Prostka 《Contributions to Mineralogy and Petrology》1970,27(2):121-130

The Absaroka volcanic field is comprised of predominant andesitic volcaniclastic rocks and less abundant potassium-rich mafic lavas (shoshonites and absarokites). Strontium and lead isotopic variations preclude a simple derivation from an isotopically uniform source: Sr⁸⁷/Sr⁸⁶, 0.7042 to 0.7090; Pb²⁰⁶/Pb²⁰⁴, 16.31 to 17.30; Pb²⁰⁸/Pb²⁰⁴, 36.82 to 37.64. We postulate that these rocks were derived from a lower crust or upper mantle which underwent a preferential loss of uranium relative to lead approximately 2800±200 m.y. ago. Variations in lead and strontium isotopic compositions are thought to reflect small inhomogeneities in U/Pb and Rb/Sr ratios in the source.Publication authorized by the Director, U.S. Geological Survey.  相似文献   

Dendroclimatology and dendroecology     

Harold C. Fritts 《Quaternary Research》1971

Dendrochronology is the science of dating annual growth layers (rings) in woody plants. Two related subdisciplines are dendroclimatology and dendroecology. The former uses the information in dated rings to study problems of present and past climates, while the latter deals with changes in the local environment rather than regional climate.  相似文献   

Effects of metals on sea urchin development: A rapid bioassay     

Harold H. Lee  C.H. Xu 《Marine pollution bulletin》1984,15(1):18-21

Embryos of sea urchins show a differential response to Cd, Cu, Cr, Ni and Zn. The responses are also stage-specific. The different morphological effects of various metals reflect the differentiation of the early embryonic cells. Since fertilization can be inhibited in the presence of metals, especially Cu, the ability of the gametes to undergo fertilization can then be used as a biological indicator for a rapid assay, 10–20 min., of marine pollutants. Since embryo-genesis up to plutei stage requires only 20 h, this duration is also short compared to other systems utilizing embryonic or larval forms.  相似文献   

Magnetic flux transport of decaying active regions and enhanced magnetic network     

Haimin Wang  Harold Zirin  Guoxiang Ai 《Solar physics》1991,131(1):53-68

Several series of coordinated observations on decaying active regions and enhanced magnetic network regions have been carried out jointly at Big Bear Solar Observatory (BBSO) and Huairou Solar Observing Station of the Bejing Astronomical Observatory in China. The evolution of magnetic fields in several regions was followed closely for 3 to 7 days. The transport of magnetic flux from the remnants of decayed active regions was studied. Three related topics are included in this paper. (1) We studied the evolution and lifetime of the magnetic network which defines the boundaries of supergranules. The results are consistent with our earlier studies: network cells have an average lifetime of about 70 hours; 68% of new cells appeared by growing from a single network magnetic element; 50% of decaying cells disappeared by contracting to a network element. (2) We studied the magnetic flux transport in an enhanced network region in detail, and found the diffusion rate to be negative, i.e., there was more flux moving towards the decayed active region than away from it. We found several other cases where the magnetic diffusion rate does not agree with Leighton's model. The slow diffusion rate is likely due to the fact that the average velocity of larger magnetic elements, which carry most of the magnetic flux, is less than 0.1 km s^–1; their average lifetime is longer than 100 hours. (3) We briefly described some properties of Moving Magnetic Features (MMFs) around a sunspot (detailed discussion on MMFs will be presented in a separate paper). In this particular case, the MMFs did not carry net flux away from the central spot. Instead, the polarities of MMFs were essentially mixed so that outflowing positive and negative fluxes were roughly balanced. During the 3-day period, there was almost no net flux accumulation to form a moat. The cancellation of MMFs of opposite polarities at the boundary of the super-penumbra caused quite a few surges and H brightenings.  相似文献   

On the comparison of filter magnetographs and the advanced stokes polarimeter     

Harold Zirin 《Solar physics》1995,159(1):203-206

Liteset al. (1994) (hereafter LMS) have recently published a comparison of the response of their magnetograph (the Advanced Stokes Polarimeter (ASP)) to that they expect from filter-based magnetographs (FM). Not surprisingly, they conclude the ASP is better. They claim that only their instrument is quantitative, and others are not, and that the transverse field strength and azimuth measured by filter magnetographs may be in error by up to 50%. While the calculation is formally correct it ignores the high sensitivity attained by real FM's accumulating thousands of difference frames. Further, FM's have been cross-compared and tested empirically, without any such errors appearing. We point out that the two instruments have different roles, but the functional use of the FM is far superior to the ASP for solar research. The ASP may give accurate results for unresolved unipolar fields; it gives totally erroneous results when the field rapidly changes direction within its resolution element, as occurs in delta spots.  相似文献   

The Hα/Hβ ratio in solar flares     

Harold Zirin  Margaret Liggett  Alan Patterson 《Solar physics》1982,76(2):387-392

We have measured the ratio of H to H central intensities in the peak kernels of 14 flares, using simultaneous filtergrams. The ratio is typically one with some scatter. By contrast, in stellar flares the ratio is about 0.8.  相似文献