The stable isotopic composition (Cl/Cl) of dissolved chloride in rainwater

The stable isotopic composition of dissolved Cl^-${\text{Cl}}^{-}$ in rainwater was measured from a coastal and an interior location in eastern Canada. At the interior Bonner Lake, Ontario, site the δ³⁷Cl values of dissolved Cl^-${\text{Cl}}^{-}$ in precipitation ranged from −3.5‰ to −1.2‰ (SMOC) with an amount-weighted annual average of −2.3‰. At the coastal site, Bay D’Espoir, Newfoundland, δ³⁷Cl values of dissolved Cl^-${\text{Cl}}^{-}$ values ranged from −3.1‰ to 0.0‰ with an amount-weighted annual average of −1.3‰. These negative δ³⁷Cl values provide evidence that atmospheric HCl is ³⁷Cl depleted, presumably from acidification of sea-salt aerosols. Accordingly, dissolved Cl^-${\text{Cl}}^{-}$ in the headwaters of two montane rivers in Western Canada had similarly depleted δ³⁷Cl values. These results have implications to the interpretation of the isotopic compositions of dissolved Cl^-${\text{Cl}}^{-}$ in surface waters, formation fluids, and groundwaters.     

A comparison of turbulence measurements by different instruments; Tsimlyansk field experiment 1970

In the summer of 1970 an international intercomparison of turbulence measurement sensors was carried out at the Tsimlyansk field station of the Institute of Atmospheric Physics (IFA) Academy of Sciences of the U.S.S.R. Improved sonic anemometer sensors of the IFA were compared with the Kaijo sonic used by the Canadian group and with the fluxatron from CSIRO, Australia.Results from the experiment indicate that spectral and cospectral shapes are basically similar between the sonic anemometers. The spectra and cospectra of the fluxatron in the high-frequency region showed an attenuation which can be explained in terms of the response characteristics of the fluxatron. The maintenance of absolute calibration of the sensors in the field was found to be difficult, but when properly corrected for this variation, the measurements were found to agree within 13%, with a standard error of 0.2. A single point observation of turbulent fluxes at a few meters above the surface and averaged over a period of the order of one hour was shown to be representative of turbulent fluxes at the site.     

An examination of turbulence statistics in the surface boundary layer

Simulated data derived from random numbers are used to show that the process of relating % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiabeo8aZnaaBa% aaleaacaWG3baabeaakiaac+cacaWG1bWaaSbaaSqaaiabgEHiQaqa% baaaaa!3D7C!\[\sigma _w /u_ * \]and similar properties to the stability parameter % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiaadQhacaGGVa% Gaamitaaaa!3A42!\[z/L\]is highly susceptible to error. An alternative method, making use of Ri as a stability index, is not affected in this way and is used to re-examine the data obtained in the 1968 Kansas micrometeorological experiment. The relationship % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiabeo8aZnaaBa% aaleaacaWG3baabeaakiaac+cacaWG1bWaaSbaaSqaaiabgEHiQaqa% baGccqWIdjYocaaIXaGaaiOlaiaaikdacaaI1aaaaa!419F!\[\sigma _w /u_ * \simeq 1.25\] % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaamaabmaabaGaaG% ymaiabgkHiTiaaikdacaWG6bGaai4laiaadYeaaiaawIcacaGLPaaa% daahaaWcbeqaaiaaigdacaGGVaGaaG4maaaaaaa!4087!\[\left( {1 - 2z/L} \right)^{1/3} \]is found to provide a good fit to the unstable data, but it is unclear as to whether a small peak observed in stable conditions is real (perhaps associated with gravity waves) or not (possibly a consequence of measurement errors).The properties % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiabeo8aZnaaBa% aaleaacaWG1baabeaakiaac+cacaWG1bWaaSbaaSqaaiabgEHiQaqa% baaaaa!3D7A!\[\sigma _u /u_ * \]and % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiabeo8aZnaaBa% aaleaacaWG1baabeaakiaac+cacaWG1bWaaSbaaSqaaiabgEHiQaqa% baaaaa!3D7A!\[\sigma _u /u_ * \] are found to attain a relatively constant value ( 3) in conditions more unstable than about Ri = -0.4. The shape ratio % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiabeo8aZnaaBa% aaleaacaWG1baabeaakiaac+cacqaHdpWCdaWgaaWcbaGaamODaaqa% baaaaa!3E4F!\[\sigma _u /\sigma _v \] is found to decrease to less than unity in very unstable conditions, possibly as a consequence of some undetected error in measurement of _u . In the case of temperature fluctuations, % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqaqpepeea0xe9qqVa0l% b9peea0lb9Lq-JfrVkFHe9peea0dXdarVe0Fb9pgea0xa9W8qr0-vr% 0-viWZqaceaabiGaciaacaqabeaadaqaaqaaaOqaaiabeo8aZnaaBa% aaleaacqaHepaDaeqaaOGaai4laiaadsfadaWgaaWcbaGaey4fIOca% beaakiabg2da9iaaicdacaGGUaGaaGyoaiaaiwdacaGGOaGaeyOeI0% IaamOEaiaac+cacaWGmbGaaiykamaaCaaaleqabaGaeyOeI0IaaGym% aiaac+cacaaIZaaaaaaa!4A30!\[\sigma _\tau /T_ * = 0.95( - z/L)^{ - 1/3} \] is found to provide an excellent fit in unstable conditions (Ri < -0.1), even though this form also agrees well with random behavior.Now With: Atmospheric Turbulence and Diffusion Laboratory, NOAA, P. O. Box E, Oak Ridge Tenn., 37830, U.S.A.     

Comments on ‘the characteristics of turbulent velocity components in the surface layer under convective conditions’, by H. A. Panofsky,H. Tennekes,D. H. Lenschow,and J. C. Wyngaard

Panofsky et al. (1977) have presented an analysis which seems to show a clear dependence of the dimensionless turbulence statistics _u /u _* and _v/u _* on the planetary boundary-layer stability parameter z _i/L. However it is possible that much of the apparent relationship results from artificial correlations introduced by the use of inter-related dimensionless parameters. Apparent dependencies of similar statistical quantities on z/L in the surface boundary layer might also be contaminated.This work was supported by the U.S. Department of Energy, and is a contribution of the Multistate Atmospheric Power Production Pollution Study (MAP3S).     

Propeller anemometers as sensors of atmospheric turbulence

Even though propeller anemometers are found to give outputs which deviate from the desired cosine relationship by an amount which varies with wind speed, their overall performance is consistent with many atmospheric requirements. Their output per unit wind speed is a function of angle of attack, such that when used as sensors of the vertical or horizontal cross-wind components in the atmosphere, calibration factors may differ by as much as 30 % from those obtained in a normal wind-tunnel calibration procedure (in which wind velocity is parallel to the anemometer shaft). These characteristics are sufficiently important that great care should be taken in using these devices inu-v-w orthogonal arrays.For use in eddy-correlation equipment, it appears that it is best to vane-mount the horizontal sensor to ensure that the appropriate calibration factor is employed.The response lengths of propeller anemometers also vary with angle of attack. Near=0 °, the axially-referred response length appears to depend linearly on cos, but near=90 ° a dependence on cos^1/2 fits the data. No strong effect of wind speed is found.Due to their limited response characteristics, these anemometers give rise to underestimates of the Reynolds stress measured near the surface. The extent of the loss is about 8 % when anemometers in good condition are employed at a height of 5m. Operation at a greater height would allow this error to be reduced. After exposure in the atmosphere for some time, the anemometers tend to respond more slowly and greater losses (of the order 25 %) can occur. Some improvement in performance is possible by the choice of a suitable spatial separation of the sensors.     

Centrifuge modeling of load-deformation behavior of rocking shallow foundations

Shallow foundations supporting building structures might be loaded well into their nonlinear range during intense earthquake loading. The nonlinearity of the soil may act as an energy dissipation mechanism, potentially reducing shaking demands exerted on the building. This nonlinearity, however, may result in permanent deformations that also cause damage to the building. Five series of tests on a large centrifuge, including 40 models of shear wall footings, were performed to study the nonlinear load-deformation characteristics during cyclic and earthquake loading. Footing dimensions, depth of embedment, wall weight, initial static vertical factor of safety, soil density, and soil type (dry sand and saturated clay) were systematically varied. The moment capacity was not observed to degrade with cycling, but due to the deformed shape of the footing–soil interface and uplift associated with large rotations, stiffness degradation was observed. Permanent deformations beneath the footing continue to accumulate with the number of cycles of loading, though the rate of accumulation of settlement decreases as the footing embeds itself.     

Slope aspect, slope length and slope inclination controls of shallow soils vegetated by sclerophyllous heath—links to long-term landscape evolution

On upland Triassic sandstone slopes of the western Blue Mountains, nonswamp, sclerophyllous heath (shrub-dominated vegetation) on shallow soils is commonly found downslope and adjacent to sclerophyllous forest on deeper soils. Some consider heath—and thus shallow soils—as favouring west-facing slopes, which are expected to experience drier microclimates due to insolation, strong and desiccating winds, and severe summer fires. However, our analysis of extensive areas with heath on shallow soils, based on vegetation and topographic maps, and fieldwork of uplands with various degrees of dissection, suggests that aspect is a poor predictor of shallow soils. Rather, shallow soils and heath are found on short slopes and the lower segments of longer slopes with the latter significantly steeper than forested segments.The shallow–deep soil boundary, marked by contrasting modern vegetation structures, does not signify a catchment area threshold, and correspondingly, the vegetation patterns are not in balance with distributary catchment processes, as short slopes are mantled exclusively by shallow soils. Instead, the soil depth boundary represents the propagation of base-level lowering signals, which takes place not only by the headward retreat of knickpoints but also via increased lowering of slope segments adjacent to drainage lines. This leads to steep slopes immediately adjacent to canyons, narrow gorges, and small steep valleys, that are mantled by shallow, discontinuous soils undergoing rapid erosion. These steep slopes persist in the landscape for ≥ 10 My after upland stream rejuvenation until incision of more weatherable Permian sediments, underlying the Triassic cliff-forming sandstones, triggers rapid lateral expansion of gorges. Once shallowly mantled and steeper slopes adjacent to streams are consumed by gorge widening, slopes adjacent to wide gorge clifflines reflect former upland drainage patterns rather than the redirected flow to rapidly widening gorges. Hence, modern vegetation patterns reflect a significant phase of landform development, perhaps combined with enhanced erosion during the Last Glacial Period that is compounded by a humped soil production function on bedrock.     

The Hill End goldfield,NSW, Australia —early metamorphic deposition of auriferous quartz veins

Summary Gold-bearing quartz veins in the Hill End goldfield, NSW Australia, comprise bedding parallel vein sets and lesser cleavage parallel and fault controlled veins which are hosted by a multiply deformed Late Silurian slate-metagreywacke turbidite sequence. Open to ptygmatic folds and boudinage are characteristic features of the veins. Metamorphic P, T estimates of 2.9 kb and 420°C during Early Carboniferous deformation and vein emplacement are obtained from the calcite, ferroan-magnesian calcite geothermometer and the Si-content of white mica. Fluid inclusions from vein quartz represent unmixed H₂O-rich and CO₂-rich low salinity fluids which have been trapped close to the solvus of the H₂O-CO₂-(NaCl-CH₄) system. Homogenisation temperatures (range 260–361°C) therefore represent true trapping temperatures. A preliminary sulphur isotope study of the vein sulphides indicates that the underlying turbidite sequence has acted as a source of sulphur (range –2.8 to 17.8 per mil). Formation of most veins early in the deformation and the lack of an obvious igneous intrusive source suggests that the gold, as for the sulphur has been derived from the metasedimentary sequence. Deposition of gold has resulted from complex destabilisation due to H₂S loss during transient vein opening and fluid pH changes accompanying CO₂-consuming wallrock reactions.

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Die Goldlagerstdtte Hill End, NSW, Australien—Bildung von goldführenden Quarzgdngen mit beginnender Metamorphose

Zusammenfassung Die goldführenden Quarzgange der Lagerstätte Hill End, NSW, Australien, treten in einer aus Schiefern und Metagrauwacken bestehenden, mehrfach deformierten, obersilurischen Turbitit-Abfolge auf Schichtparallele Quarzgange dominieren, während schieferungsparallele und an Störungen gebundene Gänge untergeordnet auftreten. Die Quarzgänge zeigen offen bis pygmotische Falten und Boudinagen als charakteristische Deformationsstrukturen Die Metamorphosehediuguogen während der unterkarboncu Deformation und Quarzgangbildung konnten mit Hilfe des Kalzit/Fe-Mg-Kalzit Geothermometers und dem Si-Gehalt der Hellglimmer abgeschätzt werden. Es ergaben sich P-T Bedingungen von 2.9 kb und 420°C. Flüssigkeitseinschlüsse im Gangquarz zeigen das Vorhandensein eines entmischten H₂O-reichen und CO₂-reichen Fluidums von geringer Salinität, welches nahe der Solvuskurve des H₂O-CO₂-(NACl-CH₄) Systems eingeschlossen worden ist. Eine vorläufige Untersuchung der Schwefelisotopen der Gangsulfide (–2.8 bis 17.8 per mil) deutet an, dass der Schwefel aus der unterlagernden Turbidit-Abfolge bezogen worden ist. Es wird vermutet, dass nich nur der Schwefel, sondern auch das Gold aus der metasedimentären Abfolge stammen, da die Qurzgänge zu einem frühen Zeitpunkt der Deformation gebildet worden sind, und intrusive magmatische Gesteine, als mögliche Erzbringer, fehlen. Destabilisierung der Goldkomplexe, verursacht durch Verlust von H₂S Zuge der Öffnung der Gangspalten, Änderungen des pH-Wertes des Fluidums und CO₂-konsumierende Reaktionen mit dem Muttergestein, führten zur Ablagerung des Goldes.

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With 6 Figures