A spatial length scale analysis of turbulent temperature and velocity fluctuations within and above an orchard canopy

Turbulent flow within and above an almond orchard was measured with three-dimensional wind sensors and fine-wire thermocouple sensors arranged in a horizontal array. The data showed organized turbulent structures as indicated by coherent asymmetric ramp patterns in the time series traces across the sensor array. Space-time correlation analysis indicated that velocity and temperature fluctuations were significantly correlated over a transverse distance more than 4m. Integral length scales of velocity and temperature fluctuations were substantially greater in unstable conditions than those in stable conditions. The coherence spectral analysis indicated that Davenport's geometric similarity hypothesis was satisfied in the lower frequency region. From the geometric similarity hypothesis, the spatial extents of large ramp structures were also estimated with the coherence functions.     

Das Grundgebirge der Anden im Chonos-Archipel,Region Aisén,Chile

Zusammenfassung Im schwach bis mäßig metamorphen Grundgebirge des Chonos-Archipels in Südchile werden erstmals drei Formationen unterschieden: Die wahrscheinlich kambro-ordovizische Canal-King-Formation besteht überwiegend aus Phylliten und Glimmerschiefern mit Einlagerungen von Grünschiefern. Die schwächer metamorphe Potranca-Formation ist im wesentlichen devonisch und besteht aus Tonschiefern, unreinen Sandsteinen, Phylliten und Quarziten. Die vermutlich jungpaläozoische Canal-Pérez-Sur-Formation besteht aus Tonschiefern und Sandsteinen und zeigt fast gar keine Metamorphose.Das Gebiet ist mehrfach kompliziert gefaltet worden. Nach einer vermutlich vorvariszischen, nur noch stellenweise erkennbaren Faltung und schwachen Metamorphose folgte etwa im Unterkarbon eine kräftige variszische Faltung, die ein NNW—SSE-streichendes Gebirge schuf. Spätere, vermutlich oberpermische bis höchstens mitteltriassische Nachläufer der variszischen Faltung schufen Faltenachsen in NNE—SSW-Richtung.Das Untersuchungsgebiet stellt ein Glied in der Kette von präandinen Orogenen im südlichen Südamerika dar, deren Alter im großen ganzen gesehen nach Süden hin abnimmt.

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Three formations are distinguished for the first time within the weakly to moderately metamorphic basement of the Chonos Archipelago in southern Chile: The probably Cambro-Ordovician Canal King Formation consists mainly of phyllites and micaschists with intercalations of greenschists. The less metamorphic Potranca Formation is essentially of Devonian age and consists of slates, impure sandstones, phyllites and quartzites. The Canal Pérez Sur Formation is probably of Upper Paleozoic age; it consists of slates and sandstones and shows nearly no metamorphism at all.The area has been folded complexly several times. After a supposed pre-Hercynian folding and metamorphism which can be recognized only in places, about in the Lower Carboniferous a strong Hercynian folding occurred, causing a NNW—SSE striking mountain chain. Possibly between Upper Permian and Middle Triassic times, late phases of the Hercynian folding created NNE—SSW striking fold axes.The investigated area forms a part of the pre-andine orogenic chains of southern South America, whose ages are on the whole decreasing from North to South.

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Resumen En el basamento débil a moderadamente metamórfico del Archipiélago de los Chonos en Chile Austral, por primera vez se distinguen tres formaciones: La Formación Canal King, de probable edad cambroordovícica, contiene mayormente filitas y micaesquistos con algunas intercalaciones de esquistos verdes. La Formación Potranca, de edad esencialmente devónica, consiste de pizarras, areniscas impuras, filitas y cuarcitas. La Formación Canal Pérez Sur, de presunta edad permocarbonífera, consiste de pizarras y areniscas, y aparentemente no muestra metamorfismo.La región ha sido plegada varias veces y de manera compleja. Después de un plegamiento probablemente pre-varíscico y un metamorfismo débil que sólo en ciertas partes se reconocen, alrededor del Carbónico inferior un plegamiento fuerte varíscico produjo un orógeno de rumbo NNW—SSE. Fases tardías del ciclo varíscico, acontecidas probablemente entre el Pérmico superior y el Triásico medio, crearon ejes de pliegues en dirección NNE—SSW.El área investigada forma un eslabón de la cadena de orógenos pre-andinos en el cono Sur de Sudamérica cuya edad en grandes rasgos disminuye hacia el Sur.

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Die Bedeutung moderner Funkpeiler für die Richtungs- und Standortsbestimmung auf See

Zusammenfassung Nach kritischen Betrachtungen über die Mängel des subjektiven Hörbefunds bei Funkpeilungen werden die Vorteile einer objektiven Sichtanzeige des Peilbefundes erläutert, und ihre Bedeutung für die Richtungs- und Standortsbestimmung an Hand von Schirmbildaufnahmen wird anschaulich demonstriert.

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The importance of modern radio direction finders for direction and position fixing at sea

Summary After critical remarks on the deficiencies of the subjective aural results of radio direction finding the advantages of an objective visual indication of bearing results are explained and their importance in direction and position fixing are demonstrated by the aid of electronic screen photos.

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L'importance de radiogoniomètres modernes en navigation

Résumé Après avoir examiné dans un but critique les défauts des résultats subjectifs obtenus par l'oreille pendant des relèvements radiogoniométriques on expose les avantages de l'indication matérielle visuelle du relèvement en démontrant à l'aide de plusieurs photographies de l'écran d'un radiogoniomètre à lecture directe l'importance d'une telle indication pour la détermination de la direction et de la position.

     

On the heat budget of the moon and the surface temperature variation during a lunar eclipse

Summary The analysis of surface temperature variations of the moon is based on the equations of heat conduction and heat continuity in the interior of the moon andStefan's law. During a well-defined process, as exemplified by a lunar eclipse, the local heat budget equation establishes a boundary condition at the moon surface which must be satisfied by solutions of the thermal diffusion equation in the interior. Three simplified models of the general case are discussed. They are characterized by special assumptions regarding the depth and time dependency of the thermic qualities of the material underlying the moon's surface. In short, the thermal diffusivity is assumed to be constant in the first model, a linear depth function in the second and a time function in the third. A unique solution can be obtained for model No. I such that the absolute surface temperature is approximately inversely proportional to the 6th root of time during the phase of total eclipse.Epstein's conclusion that the average surface of the moon might consist of highly porous rocks or fine dust is confirmed by the order of magnitude of the heat conductivity which produces the best fit between the theoretical curves and a plot ofPettit's observational data during the lunar eclipse of 1939. Existing differences between the observed and theoretical curves during the totality phase of the eclipse can be reduced by the employment of the second model. A crude estimate shows that the average dust cover resting on more solid ground of lunar rocks might possibly have a thickness of approximately 0.5 meters.     

Mother-of-pearl clouds and their problems

Summary At first the results of the investigations on mother-of-pearl clounds are summarized. In the second section fit methods are suggested in order to further research.

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Zusammenfassung Zunächst werden die Forschungsergebnisse über Perlmutterwolken zusammengefasst. Im zweiten Teil werden geeignete Methoden zur weiteren Forschung vorgeschlagen.

     

Post-Chippewa oxygen isotope record from Cowles Bog, southern Lake Michigan basin

Previous studies of sediments and molluscs recovered from vibracores at Cowles Bog, a fen located in the Indiana Dunes National Lakeshore, along the south shore of Lake Michigan, reveal long and short term water level fluctuations during the last 6000 years. Low water events are indicated by zones of organic detritus, in which occasionally, iron oxide and calcium carbonate nodules, as well as selenite crystals have been precipitated. Oxygen isotope data from aragonitic shells of the gastropod Amnicola limosa (Say) collected from a sediment core provide a record of Middle to Late Holocene environmental changes for the fen. These data are in good agreement with previous interpretations of water level fluctuations based on changes in lithology and molluscan faunal abundance and composition. Below 366 cm the molluscan record is either absent or represented by shell fragments. The condition of shells in this interval suggests that the molluscs may have been exposed to subaerial weathering and reworking of older Holocene lake sediments, possibly during the low water Chippewa phase in the Lake Michigan basin (10000 YBP to 6000 YBP). Above 366 cm the core is characterized by a well preserved molluscan fauna. Relatively light isotopic values for the interval between 366 cm to 300 cm correlate with the transition from non-fossiliferous sands, peat and diamict to silty marl and calcareous sand, with a molluscan fauna dominated by taxa associated with permanent water bodies. The event producing these alterations, the Nipissing Transgression, marks a change from subaerial to permanent lacustrine conditions that were not characterized by high net evaporation. Evidence for another series of environmental changes occurs between 284 cm and 198 cm. This evidence includes the: (1) appearance of aquatic molluscs at 280 cm that are associated with water bodies subject to significant seasonal water level changes; (2) intermittent accumulations of iron oxide nodules, calcium carbonate nodules, and organic layers interbedded with crudely horizontal layers of fine, calcareous, sand, suggesting periodic water level oscillations; (3) onset of major excursions in the oxygen isotopic values between 260 cm to 198 cm. Relatively high ¹⁸O (PDB) values, possibly indicating evaporative enrichment of the water, correlate with a prominent shell debris layer at a depth of about 235 cm. Taken together, this evidence suggests that the core site was in the process of becoming isolated from Lake Michigan. This isolation occurred during a series of low water events during the later part of the Nipissing Transgression.     

ON THE WAVELENGTH DEPENDENCY (AND ITS VARIATIONS) OF THE RATIO DISK-AVERAGED TO DISK-CENTER INTENSITY,F/I 0 (λλ0.385 TO 10 µm)

In the whole wavelength range, 0.385 to 10.0 µm, the ratios F/I ₀ of disk-averaged intensity F to disk-center intensity I ₀ follow very closely the simple relation F/I ₀ = 0.975 - 0.091^-1 - 0.00024^-5. The residuals exhibit a well-defined structure with minima and maxima in the order of± 5 × 10^-3 , which reflect the wavelength-dependency of the source function B(,) and the continuous absorption coefficient . The fact that the scatter of the coefficients of the relevant limb-darkening functions is usually much larger than the scatter of the F/I ₀ ratios seems to confirm the occurrence of limb-darkening variations, which however leave the F/I ₀ ratios almost unchanged. Nevertheless, minor differences between different observations, which concern the details in the wavelength-dependency of the F/I ₀ residuals, seem to indicate that even the F/I ₀ ratios undergo minor variations.