A Note on the Flux-Variance Similarity Relationships for Heat and Water Vapour in the Unstable Atmospheric Surface Layer

Atmospheric surface layer (ASL) experiments over the past 10 years demonstrate that the flux-variance similarity functions for water vapour are consistently larger in magnitude than their temperature counterpart. In addition, latent heat flux calculations using the flux-variance method do not compare as favorably to eddy- correlation measurements when compared to their sensible heat counterpart. These two findings, in concert with measured heat to water vapour transport efficiencies in excess of unity, are commonly used as evidence of dissimilarity between heat and water vapour transport in the unstable atmospheric surface layer. In this note, it is demonstrated that even if near equality in flux-profile similarity functions for heat and water vapour is satisfied, the flux-variance similarity functions for water vapour are larger in magnitude than temperature for a planar, homogeneous, unstably-stratified turbulent boundary-layer flow.     

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Paläomagnetische Untersuchungen im Schilfsandstein (Trias,Km2) Westeuropas

Zusammenfassung Von insgesamt 46 beprobten Profilen aus dem Schilfsandstein (Trias, Km2) Westeuropas wurden bislang 41 Profile mit 343 Einheiten und 870 Handstücken mit 1897 Einzelkernen auf ihren paläomagnetischen Inhalt untersucht.Thermische Entmagnetisierungsversuche an 277 Proben zeigen, daß die natürliche remanente Magnetisierung (NRM) von mehreren, an verschiedene Magnetisierungsträger gebundenen Komponenten getragen wird.Als charakteristische remanente Magnetisierung (CARM), von der angenommen wird, daß sie das zur Ablagerungszeit herrschende Paläofeld abbildet, kristallisiert sich für die Sedimentationsräume Weserbergland und Franken eine Deklination (DR=Deklination rotiert) von 60° und eine Inklination (IR=Inklination rotiert) von 30° (DR/IR 60/30) und für Schwaben und die Nordschweiz DR/IR 240/–30 heraus.Neben der stabilen Paläofeldrichtung werden auch sedimentäre und tektonische Gefüge als weitere stabile Magnetisierungsrichtungen abgebildet. Diese Richtungen liegen der Achse maximaler Suszeptibilität (K1 max) parallel.Unter Annahme einer normalen Polarität des Erdmagnetfeldes zur Zeit der Schilfsandsteinablagerung im Weserbergland und Franken und einer reversen Polarität zur Zeit der Ablagerung in Schwaben und der Nordschweiz errechnet sich ein Paläonordpol bei 111 E 28 N; er fällt damit in die Nähe des Triaspoles der Europäischen Polwanderungskurve (McElhinny, 1973).Für den Ablagerungszeitraum des Raibler Sandsteins in den Südalpen wird ein Paläonordpol bei 128 W 48 N errechnet.Die magnetostratigraphische Zeitskala der Trias (Burek, 1970) kann um die Einstufung des Schilfsandsteins in das höhere obere Karn mit beginnender normaler Polarität und dann reverser Polarität ergänzt werden.

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In the Schilfsandstein (Triassic, Km2) of Western Europe 41 sections with 343 units and 1897 cores were sampled for palaeomagnetic investigations. By thermal demagnetization experiments different magnetic minerals were determined as carriers of the natural rémanent magnetization (NRM).The characteristic remanent magnetization (CARM) reflecting the palaeofield direction is described in the Weserbergland and Franken by DR/IR 60/30 (DR = declination after tectonic correction/IR=inclination after tectonic correction) and in Schwaben and Northern Switzerland by DR/IR 240/–30.In addition stable directions are reported which are related to sedimentary and tectonic fabric. These directions are parallel to the axis of maximum susceptibility (Klmax).Assuming normal polarity for the magnetic field during deposition of the Schilfsandstein in the Weserbergland and Franken and assuming reversed polarity in Schwaben and Northern Switzerland a palaeonorthpole is estimated at 111 E 28 N. This poleposition fits near the Triassic poleposition of the European polar wandering curve (McElhinny, 1973).The poleposition of the Bergamasker Alps (Raibler Sandstein, Southern Alps) is figured out at 128 W 48 N.The triassic magnetostratigraphic time scale ofBurek (1970) can be completed as far as the Schilfsandstein is to arrange into the highest Upper Carnian starting with normal polarity going on with reversed polarity.

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Résumé Dans le Grès à roseaux (Trias, Km 2) de l'Europe occidentale, 343 prélèvements provenant de 41 profils et 1897 carrottes extraites de 870 échantillons ont fait l'objet de recherches paléomagnétiques. — Des essais de démagnétisation thermique sur 277 échantillons ont révélé différents minéraux magnétiques comme étant les porteurs de l'aimantation rémanente naturelle (NRM). — L'aimentation rémanente caractéristique (CARM) reflétant la direction du paléochamp magnétique au moment de la sédimentation donne des valeurs de 60/30 pour DR/IR (DR=déclinaison après correction tectonique, — IR=inclinaison après correction tectonique) dans le Weserbergland et en Franconie et 240/– 30 pour DR/IR en Souabe et dans la Suisse septentrionale. — En plus de la direction stable du paléo champ, on a trouvé d'autres directions d'aimentation stables reliées aux structures sédimentaires et tectoniques. Ces directions sont parallèles à l'axe de la susceptibilité magnétique maximale (K1 max). — En supposant une polarité normale du champ magnétique terrestre au moment de la sédimentation du Grès à roseaux dans le Weserbergland et la Franconie, et une polarité inversée pendant sa formation en Souabe et en Suisse septentrionale, il en résulte une position géographique de 111 E et 28° N pour le paléopôle Nord, ce qui coïncide à peu près avec la position du pôle triasique sur la courbe polaire de l'Europe (McElhinny, 1973). Pendant la sédimentation du Grès de Raibler dans les Alpes bergamasques, le paléopôle Nord se trouvait à 128° O 48° N. — L'echelle magnétostratigraphique pour le Trias (Burek, 1970) peut maintenant être complétée en datant le Grès à roseaux dans la partie supérieure du Carnien supérieur, débutant par une aimantation normale et continuant par une aimantation inversée.

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343 41 ( ) 1897 870 . 277 , — NRM — . — CARM —, , , , , (DR = Deklination rotiert) 60°, (IR = Inklination rotiert) 30° (DR/IR 60/30), DR/IR 240/-30. , . /_1makc. , 111 E 28 N, . ., . 128 W 48 N. (Burek, 1970) . . , .

     

模拟CO_2埋藏的煤储层元素迁移实验研究

采用高压超临界CO2地球化学反应器对CO2在煤储层中的地质埋藏进行模拟,利用电感耦合等离子体发射光谱仪(ICP-OES)以及电感耦合等离子体质谱(ICP-MS)分别对淋滤液和煤样中的10种微量元素进行测试,对煤中微量元素在CO2的地质埋藏过程中的迁移进行了实验研究。结果表明:在CO2的地质埋藏过程中对煤的有机组成和无机矿物等均具有改造作用,从而影响到煤中微量元素的赋存和迁移特征,Cr、Zn、Cu等元素迁移能力相对较强,而Co、Ba、V等元素相对较弱;元素迁移能力大小顺序为:CrZnCuNiCdMnCoBaV。     

Seismotectonic deformations related to the 2010 Maule earthquake at different stages of the seismic cycle from satellite geodetic observations

Doklady Earth Sciences - The interpretation of multiannual satellite geodetic observations after the 2010 Maule earthquake is given on the basis of the keyboard concept of the subduction region...     

Wind sedimentation in the Jafurah sand sea, Saudi Arabia

The Jafurah sand sea of the Eastern Province of Saudi Arabia extends along the Arabian Gulf coastline from Kuwait in the north to the Rub Al Khali in the south, a distance of about 800 km. Sand drifts southward to south-eastward from regions of high wind energy in the north to low wind energy in the south. The aeolian landscape is zoned, with areas of deflation, transport and deposition from north to south. Drift rates in the zone of transport, near Abqaiq, range from 2 m³ m-w^-1 yr^-1 on sabkhas, to 29 m³ m-w^-1 yr^-1 on the crests of dunes. Average drift rates of approximately 18 m³ m-w^-1 yr^-1 observed during the study can cause about 1 m of accumulation per 5500 yr in a 100 km zone of deposition downwind, not including the bulk transport represented by the forward advance of dunes. Dune advance ranged from 23 m (2.9 m high dune) to 3 m (23 m high dune) during April-October 1980. The study area consists of dune, interdune, sand sheet and siliciclastic sabkha terrains, each of which is characterized by differing drift rates, and differing rates of erosion or deposition. Sedimentation occurs by lateral movement of dunes and interdunes, and vertical accretion by sand sheets and sabkhas.     

Hydrochemical and Multivariate Statistical Evaluation of Heavy Metals in Shallow Alluvial Aquifers of North Brahmaputra Plain,India

The aim of this study was to display distribution and relationships of heavy elements in the unconfined, shallow alluvial aquifers of the lower Jia Bharali catchment and adjoining areas in central part of North Brahmaputra Plain (NBP), India using hydrochemical as well as multivariate statistical techniques such as principal component analysis (PCA) and cluster analysis. The original matrix was made up of 10 trace elements (As, Cd, Cu, Co, Cr, Fe, Mn, Pb, Ni and Zn) estimated from 50 shallow alluvial dug wells in both the wet and the dry season for a duration of 3 hydrological years (2008–2011). Except As, Cu and Zn all the other toxic metals in the shallow aquifers were found exceeding the WHO maximum permissible limits for drinking water. PCA extracted five varimax factors as geogenic, agricultural and anthropogenic explaining about 71.2% of the total variance in the wet season and 69.3% total variance in the dry season. Hierarchical cluster analysis classified the dug wells into two groups in the wet season and three groups in the dry season with respect to the heavy elements. The results emphasized the need for routine monitoring and management in order to avoid contamination of groundwater sources in the NBP with respect to the dissolved trace elements.     

A direct comparison of C and Th ages at Searles Lake, California

Thorium-230 dating on saline of the Lower Salt unit in pluvial Searles Lake, California, shows that this unit was formed between 24,500 and 32,000 years ago. The initial apparent ¹⁴C age of the lake is estimated to be about 900 years. After correcting for nonradiogenic ²³⁰Th and for the initial ¹⁴C age, excellent agreement between ²³⁰Th and ¹⁴C ages is obtained. The reliability of ²³⁰Th dating on salt deposit opens a new way for continuation of absolute chronology below the Lower Salt in Searles Lake.