The Earth's rotation and atmospheric circulation, from 1963 to 1973

Summary. The zonal angular momentum of the atmospheric circulation has been evaluated month-by-month and compared with astronomical observations of the length-of-day for the 10 years from 1963 May to 1973 April. The reason for undertaking this study is to enable the astronomical observations to be 'corrected' for the zonal wind effect and to investigate the residual excitation function for solid-Earth contributions. The principal conclusions reached are the following: (i) The annual change in length-of-day is almost entirely due to the seasonal changes in the zonal circulation with tidal, oceanographic and hydrologic phenomena contributing together at most 10 per cent of the total excitation, (ii) The semi-annual term is predominantly due to the zonal wind and the body tide, with oceanic and hydrologic terms contributing about 10 per cent, (iii) The atmospheric circulation plays a dominant role in length-of-day changes in the period range from 1 to about 4 yr. This is partly associated with the quasi-biennial oscillation and its harmonics. Both the period and amplitude of these fluctuations are very variable, (iv) At longer periods the atmosphere may still contribute to the total excitation but other excitation functions begin to rise above the spectrum of the meteorological excitation, (v) At periods less than about 1 yr the atmospheric excitation is dominant, and while the presence of other excitation functions cannot be excluded, they cannot exceed 20 per cent of the wind excitation. On the basis of these results the astronomical record from 1962 to 1978 has been 'corrected' for the meteorological 'noise'. The residual excitation exhibits only fluctuations on a time-scale of about 5 yr and longer and it is this result that must be attributed to core-mantle interactions or to other solid-Earth excitation functions.     

Ocean tide perturbations in the orbits of GEOS 1 and GEOS 2

Douglaset al. (1973) have estimated tidal parameters from the orbits of GEOS 1 and GEOS 2. Their results, interpreted in terms of Love numbers, are rather dispersive due in part to their neglect of the ocean tides. The ocean tidal corrections are estimated in this paper, but although they do not explain all of the discrepancy they do emphasise the importance of these perturbations on the motion of close Earth satellites. The remaining discrepancies could result in part from the fact that part of the long period tidal perturbations have been absorbed by the zonal harmonics in the Earth's gravity field.     

Behaviour of iron,manganese, phosphate and humic acid during mixing in a Delaware salt marsh creek

The mixing behaviour of iron, manganese, phosphate and humic acid in a Delaware salt marsh creek was studied using field data, laboratory mixing experiments, and geochemical mass balance equations. Property-salinity diagrams for field data indicated that the removal of iron is 56–70% in the 0–10‰ salinity range. A proposed mechanism of removal is the flocculation of colloidal iron, perhaps with humic acid. Phosphate, however, undergoes 195% addition in the same low salinity region, which may be due to release of phosphate from resuspended sediments. Dissolved manganese is conserved, as is humic acid throughout the salt marsh mixing zone. Within the uncertainty of the data the maximum possible removal of humic acid is 23%.Laboratory mixing experiments that simulated salt marsh mixing along the same salinity gradient as observed in the field (5–25‰) showed only small-scale additions and removals compared to the field results. Such small-scale changes occurred largely at salinities >10‰ in the laboratory experiments, whereas most removals and additions occurred at salinities <10‰ in the field. Mixing studies also showed little difference between prefiltered and unfiltered mixes. The studies suggest that simple mixing of salt marsh waters, with or without suspended material, does not strongly influence the observed behaviour of dissolved constituents in salt marshes, and that other processes (e.g. sediment or intertidal exchange) must dominate their behaviour.     

The Proterozoic,albitite-hosted,Valhalla uranium deposit,Queensland, Australia: a description of the alteration assemblage associated with uranium mineralisation in diamond drill hole V39

The Valhalla uranium deposit, located 40 km north of Mount Isa, Queensland, Australia, is an albitite-hosted, Mesoproterozoic U deposit similar to albitite-hosted uranium deposits in the Ukraine, Sweden, Brazil and Guyana. Uranium mineralisation is hosted by a thick package of interbedded fine-grained sandstones, arkoses and gritty siltstones that are bound by metabasalts belonging to the ca. 1,780 Ma Eastern Creek Volcanics in the Western Succession of the Mount Isa basin. Alteration associated with U mineralisation can be divided into an early, main and late stage. The early stage is dominated by laminated and intensely altered rock comprising albite, reibeckite, calcite, (titano)magnetite ± brannerite. The main stage of mineralisation is dominated by brecciated and intensely altered rocks that comprise laminated and intensely altered rock cemented by brannerite, apatite, (uranoan)-zircon, uraninite, anatase, albite, reibeckite, calcite and hematite. The late stage of mineralisation comprises uraninite, red hematite, dolomite, calcite, chlorite, quartz and Pb-, Fe-, Cu-sulfides. Brannerite has U–Pb and Pb–Pb ages that indicate formation between 1,555 and 1,510 Ma, with significant Pb loss evident at ca. 1,200 Ma, coincident with the assemblage of Rodinia. The oldest ages of the brannerite overlap with ⁴⁰Ar/³⁹Ar ages of 1,533 ± 9 Ma and 1,551 ± 7 Ma from early and main-stage reibeckite and are interpreted to represent the timing of formation of the deposit. These ages coincide with the timing of peak metamorphism in the Mount Isa area during the Isan Orogeny. Lithogeochemical assessment of whole rock data that includes mineralised and unmineralised samples from the greater Mount Isa district reveals that mineralisation involved the removal of K, Ba and Si and the addition of Na, Ca, U, V, Zr, P, Sr, F and Y. U/Th ratios indicate that the ore-forming fluid was oxidised, whereas the crystal chemistry of apatite and reibeckite within the ore zone suggests that F⁻ and were important ore-transporting complexes. δ¹⁸O values of co-existing calcite and reibeckite indicate that mineralisation occurred between 340 and 380°C and involved a fluid having δ¹⁸O_fluid values between 6.5 and 8.6‰. Reibeckite δD values reveal that the ore fluid had a δD_fluid value between −98 and −54‰. The mineral assemblages associated with early and main stages of alteration, plus δ¹⁸O_fluid and δD_fluid values, and timing of the U mineralisation are all very similar to those associated with Na–Ca alteration in the Eastern Succession of the Mount Isa basin, where a magmatic fluid is favoured for this style of alteration. However, isotopic data from Valhalla is also consistent with that from the nearby Mount Isa Cu deposit where a basinal brine is proposed for the transport of metals to the deposit. Based on the evidence to hand, the source fluids could have been derived from either or both the metasediments that underlie the Eastern Creek Volcanics or magmatism that is manifest in the Mount Isa area as small pegmatite dykes that intruded during the Isan Orogeny.     

Meereskundlich-chemische Untersuchungen mit Hilfe des Pulfrich-Photometers von Zeiss

Zusammenfassung Die bisherigen Methoden zur Bestimmung des Chlorophylls im Meerwasser benötigen zu ihrer Durchführung Wassermengen von einem bis zu einigen Litern. Sie sind infolgedessen zur Ausfühung serienmäßiger ozeanischer Messungen noch nicht voll geeignet. Durch Ausnutzung der intensiven Rotfluoreszenz des Chlorophylls und Benutzung kleinerer und engerer Kolorimeterröhren läßt es sich ermöglichen, den Wasserbedarf bis auf 100 ccm und weniger je Probe herabzudrücken und somit diesen Mangel zu beheben. Die für diesen Zweck geschaffene gleiche Arbeitsapparatur ermöglicht weiterhin, im Anschluß an die Chlorophyllbestimmung ohne wesentlich erhöhte Arbeitsbelastung die Bestimmung der Eigenfluoreszenz gleichfalls auf dem Wege der Mikromethodik an nur 1 ccm Meerwasser durchzuführen.

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Investigations in chemical oceanography carried out with the aid of the Pulfrich photometer

Summary The old method of determining the chlorophyll content of sea water required a comparatively great quantity of sea water (one or severel litres) and, hence, was not suitable in case of serial measurements. The utilization of the intensive red fluorescence of chlorophyll and the use of small and narrow colorimeter tubes render it possible to minimize the required quantity of water to 100 ccm and less per sample. The apparatus which was especially constructed for this purpose being fit for the determination of both the chlorophyll content and the proper fluorescence, the latter can be easily determined immediately after the determination of the chlorophyll content by means of the micro-method from only 1 ccm of sea water.

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Investigations chimiques dans le domaine océanographique à l'aide du photomètre de PulfrichVII^e communication. Les micro déterminations de la teneur en chlorophylle et de la fluorescence propre de l'eau de mer

Résumé La quantité minimale nécessaire pour déterminer la teneur en chlorophylle selon la méthode en usage jusqu' à présent se montait d'un à plusieurs litres; à cause de cela cette méthode n'était pas convenable pour des mensurations en séries. En se servant de l'intensive fluorescence rouge de la chlorophylle et en employant un petit tube étroit à colorimètre il est possible de limiter la quantité d'eau à 100 ccm et moins par échantillon. En outre, on peut se servir du même appareil pour déterminer la fluorescence propre selon la nouvelle méthode. Pour cette détermination qui peut être effectué sans peine immédiatement après celle de la chlorophylle on a besoin de seulement 1 ccm d'eau de mer.

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Die sechs vorhergehenden Mitteilungen sind in den Annalen der Hydrographie und maritimen Meteorologie erschienen, und zwar I:59, 1931, 313; II:61, 1933, 124; III:62, 1934, 65; IV:63, 1935, 58: V:63, 1935, 195; VI:65, 1937, 276.     

Polarimetric NIR reflectance measurements of regolith simulants at zero phase angle

Polarimetric reflectance measurements have been made at a wavelength of for a suite of predominantly lunar regolith simulants in support of development efforts for the BepiColombo Laser Altimeter (BELA). Measurements were made using an instrument at the University of Bern, Switzerland, that has been modified to accommodate photometric characterizations of laboratory samples down to 0^° phase angle (g) with linearly polarized illumination and a linearly polarized receiver. The data reveal opposition surges that are dominated by polarization state-conserving reflectance terms for all samples. Relative strengths of the trans-state reflectance terms are lowest for the darkest samples, suggesting that multiple scattering is responsible for state conversions. Normal albedo measurements of the lunar simulants range from 0.13 to 0.22 at zero illumination angle (i=0^°). The total reflectance of the regolith simulants at g=0^° were found to decrease with increasing i, which is inconsistent with predictions of reflectance models for Mercury. However, the g=0^° reflectance remains higher at i>0^° than would be expected for a gray Lambert surface that is scaled to the g=i=0^° reflectance value. Polarization ratios for reflectance under polarized illumination but unconstrained emission show that the samples scatter light in the in-plane polarization state more efficiently than in the transverse state at g=0^° and i>0^°. The opposite is true for g>0^° polarization ratios, which indicate that transverse polarized illumination scatters more efficiently at high g. The polarization effect appears to correlate with the sample's characteristic grain size, but the statistical basis of this trend is weak. The implications of these measurements upon the performance of the BELA instrument are discussed.     

Graph theory for analyzing pair-wise data: application to geophysical model parameters estimated from interferometric synthetic aperture radar data at Okmok volcano,Alaska

Graph theory is useful for analyzing time-dependent model parameters estimated from interferometric synthetic aperture radar (InSAR) data in the temporal domain. Plotting acquisition dates (epochs) as vertices and pair-wise interferometric combinations as edges defines an incidence graph. The edge-vertex incidence matrix and the normalized edge Laplacian matrix are factors in the covariance matrix for the pair-wise data. Using empirical measures of residual scatter in the pair-wise observations, we estimate the relative variance at each epoch by inverting the covariance of the pair-wise data. We evaluate the rank deficiency of the corresponding least-squares problem via the edge-vertex incidence matrix. We implement our method in a MATLAB software package called GraphTreeTA available on GitHub (https://github.com/feigl/gipht). We apply temporal adjustment to the data set described in Lu et al. (Geophys Res Solid Earth 110, 2005) at Okmok volcano, Alaska, which erupted most recently in 1997 and 2008. The data set contains 44 differential volumetric changes and uncertainties estimated from interferograms between 1997 and 2004. Estimates show that approximately half of the magma volume lost during the 1997 eruption was recovered by the summer of 2003. Between June 2002 and September 2003, the estimated rate of volumetric increase is \((6.2 \, \pm \, 0.6) \times 10^6~\mathrm{m}^3/\mathrm{year} \). Our preferred model provides a reasonable fit that is compatible with viscoelastic relaxation in the five years following the 1997 eruption. Although we demonstrate the approach using volumetric rates of change, our formulation in terms of incidence graphs applies to any quantity derived from pair-wise differences, such as range change, range gradient, or atmospheric delay.