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1.
S. Madronich D. R. Hastie B. A. Ridley H. I. Schiff 《Journal of Atmospheric Chemistry》1984,1(2):151-157
The photodissociation coefficient, J
NO2 of NO2 in the atmosphere was calculated at 235 and 298 K using the measured temperature dependences of the absorption cross-sections and quantum yields. These calculations gave a ratio J
NO2(298 K)/J
NO2(235 K)=1.155±0.010 which is only weakly dependent on altitude, surface albedo and solar zenith angle. 相似文献
2.
S. Madronich D. R. Hastie B. A. Ridley H. I. Schiff 《Journal of Atmospheric Chemistry》1983,1(1):3-25
An instrument, specifically designed for measurements from a balloon platform in the stratosphere, has been used to obtain ground-level values of the atmospheric photodissociation coefficient of nitrogen dioxide, J NO 2.A typical clear-sky value is 8.0×10-3 s-1 when the solar zenith angle is 40°. Measurements were made as a function of solar zenith angle and correlated with a calibrated Eppley UV radiometer. It is shown that J NO 2may be expressed as a simple function of the radiometer output so that estimates of J NO 2can be made using just an upward looking radiometer to an accuracy of about 20%. The measurements are also found to be in good agreement with calculations of J NO 2using a simplified isotropic multiple scattering computer routine. 相似文献
3.
S. Madronich D. R. Hastie H. I. Schiff B. A. Ridley 《Journal of Atmospheric Chemistry》1985,3(2):233-245
The photodissociation coefficient of NO2, J
NO
2, has been measured from a balloon platform in the stratosphere. Results from two balloon flights are reported. High Sun values of J
NO
2 measured were 10.5±0.3 and 10.3±0.3×10-3 s-1 at 24 and 32 km respectively. The decrease in J
NO
2 at sunset was monitored in both flights. The measurements are found to be in good agreement with calculations of J
NO
2 using a simplified isotropic multiple scattering computer routine. 相似文献
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R. J. Hastie 《Astrophysics and Space Science》1997,256(1-2):177-204
8.
A series of precisely repeated magnetic surveys has been carried out over a five year period, during the filling of Lake Gordon, Tasmania, following construction of a dam. After subtraction of the secular variation gradient over the region, a mean decrease of 1.6 nT in total field intensity is found over the survey area, which exceeds 600 km2, corresponding to the expected form of a tectonomagnetic anomaly due to ground loading. During the survey period there were several local magnetic events, coinciding with more rapid, local changes in benchmark levels, that may be attributed to aseismic movements on faults in the area. 相似文献
9.
Alan R. Hastie Simon F. Mitchell Matthew J. Minifie 《Geochimica et cosmochimica acta》2011,75(17):5049-5072
Compositionally, high-Nb basalts are similar to HIMU (high U/Pb) ocean island basalts, continental alkaline basalts and alkaline lavas formed above slab windows. Tertiary alkaline basaltic lavas from eastern Jamaica, West Indies, known as the Halberstadt Volcanic Formation have compositions similar to high-Nb basalts (Nb > 20 ppm). The Halberstadt high-Nb basalts are divided into two compositional sub-groups where Group 1 lavas have more enriched incompatible element concentrations relative to Group 2. Both groups are derived from isotopically different spinel peridotite mantle source regions, which both require garnet and amphibole as metasomatic residual phases. The Halberstadt geochemistry demonstrates that the lavas cannot be derived by partial melting of lower crustal ultramafic complexes, metasomatised mantle lithosphere, subducting slabs, continental crust, mantle plume source regions or an upper mantle source region composed of enriched and depleted components. Instead, their composition, particularly the negative Ce anomalies, the high Th/Nb ratios and the similar isotopic ratios to nearby adakite lavas, suggests that the Halberstadt magmas are derived from a compositionally variable spinel peridotite source region(s) metasomatised by slab melts that precipitated garnet, amphibole, apatite and zircon. It is suggested that high-Nb basalts may be classified as a distinct rock type with Nb > 20 ppm, intraplate alkaline basalt compositions, but that are generated in subduction zones by magmatic processes distinct from those that generate other intraplate lavas. 相似文献
10.
Summary. A new method of calculating magneto-telluric surface impedances in terms of a layered anisotropic model is developed by considering reflections from the interface between two anisotropic layers. An algorithm for propagating impedances from one layer boundary to the next is given. The method is rapid and uses a simple representation of the layer parameters. 相似文献