Early lunar differentiation: 4.42-AE-old plagioclase clasts in Apollo 16 breccia 67435

We report on a⁴⁰Ar-³⁹Ar study of the Apollo 16 breccia 67435 and present ages of five samples representing matrix, lithic clasts and plagioclase clasts. While the matrix age spectrum does not have a well-defined plateau, the two lithic clasts gave plateau ages of 3.96 and 4.04 AE. Since all samples had apparent ages of ～1 AE in the fractions ≤600°C extraction temperature, the breccia might have been assembled in a rather mild process at about that time or even more recently out of material with different metamorphic ages. The two plagioclase samples, of which one was a single 9-mg mineral clast and the other a 15-mg composite of several clasts, also have ages of ～1 AE in the low-temperature release fractions, but are apparently undisturbed by any ～4-AE events since they both have well-defined plateaux at 4.42 AE. The age of these strongly calcic plagioclase clasts, believed to be remnants of the anorthositic lunar crust, establishes a lower age limit to the end of the early lunar differentiation and thus places a strong constraint to the lunar evolution.     

Richardson's number in the free atmosphere

Summary From an example of high-resolution FPS-16 wind measurements in the free atmosphere it is shown that Richardson's number is strongly dependent on the scale of the layer over which it is measured. This may be one of the reasons for the discrepant results obtained by various authors in correlating the occurrence of clear-air turbulence with this number.

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Zusammenfassung An Hand eines Beispiels detaillierter FPS-16 Windmessungen in der freien Atmosphäre wird gezeigt, daß die Richardsonsche Zahl wesentlich von der Größenordnung der Schichtdicke abhängt, über welche sie gemessen wird. Dies mag einer der Gründe dafür sein, daß die Versuche verschiedener Autoren, diese Zahl mit dem Auftreten von clear-air turbulence (Flugturbulenz im wolkenfreien Raum) zu korrelieren, zu widerspruchsvollen Ergebnissen führten.

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Résumé Sur la base d'un exemple de mesure détaillée du vent en atmosphère libre au moyen d'un système FPS-16, on peut démontrer que le nombre deRichardson dépend en grande partie de l'orde de grandeur de l'épaisseur de la couche au-dessus de laquelle il est mesuré. Ceci est une des raisons pour lesquelles les essais de différents auteurs qui recherchent la corrélation entre ce nombre et la turbulence en atmosphère claire (clear-air turbulence) conduisent à des résultats contradictoires.

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With 3 Figures     

青藏高原在影响行星环流反馈机制中的作用

一些时间以来,人们认为,青藏高原对于产生行星长波具有很大的作用,这种长波与洛矶山脉形成的类似波动发生谐振,一起形成了在高空月平均气压形势图上观测到的熟悉的准静止罗斯贝波型。这种波动在旋转圆筒流体实验中也能产生。作为第一近似位势涡度守恒原理可说明这些大山脉在形成行星波中的作用。 在青藏高原地区,对流型的季节强迫作用是很强的。许多作者指出,在春季融雪之后,高原加热地表的作用特别显著,可启动副热带高压带向北移动和夏季风发展。这些环流以后在很大程度上是靠潜热释放来维持的。 最近研究提出青藏高原也可能被包含在以一种重要方式控制大气环流年际变化的反馈机制中。陈烈庭的看法值得注意,他认为高原上雪盖可能为地—气系统提供一种“存储器”,以此使中国上空的夏季环流在多雪盖冬季后的情况不同于少雪盖冬季后的情况。从中华人民共和国进行的工作看来,这些环流的差异对南亚和东亚大多数地区的季风天气型带来显著的影响。 我们自己的研究提出,这种在青藏高原上观测到的冬季和来年夏季环流之间的“存储器”,可能是包括南半球环流特征和海气关系等在内的复杂反馈机制系统中的一部分。从少台风年和多台风年对比研究表明,它们分别与少雪年和多雪年后的夏季在青藏高原上空的环流变化相似。这些变化似乎影响到太平洋、印度洋甚至非洲的广大区域。有迹象表明,调整沃克环流强部的“南方涛动”与用来说明某些观测到的环流变化的“遥相关”有关系。从这个结论可以推测,由赤道也可能由湿带的海湿异常所表示的海气相互作用以及西藏高原的热力作用都与青藏高原上观测到的雪盖年际变化、台风频率以及其它环流特征有关系。 近年来论述甚多的有关青藏高原对亚洲上空大气环流年际变化的影响,仅仅是秘鲁海岸的爱厄尼诺问题和萨赫勒地区干旱等大气反馈机制中的一种重要表现。如果我们能深入理解上述各种现象的机制,将会使我们对某些地区的国民经济有显著影响的天气现象作出较为成功的长期预报。     

The detailed structure of the atmosphere near jet streams

Summary A short survey is given of results obtained from «Project Jet Stream» Research Flights. Several features of the atmospheric structure in the vicinity of the jet-stream core seem to be rather characteristic and shall be described in detail. The most prominent among these are: the «Jet-Stream Front»above and below the jet core, stable baroclinic zones on the anticyclonic side of the jet, and an upward bulge of the isentropic surfaces south of the jet stream, the so-called «isentrope hump». Some of theses features seem to have far-reaching implications upon the dynamics of the jet stream.

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Zusammenfassung Es wird ein kurzer Überblick über die Ergebnisse einiger «Project-Jet-Stream»-Forschungsflüge gegeben. Einige Merkmale der atmosphärischen Struktur in der Umgebung des Strahlstromkernes scheinen für eine Vielzahl der Fälle charakteristisch zu sein und sollen im folgenden noch näher beschrieben werden. Am deutlichsten treten hervor: Die «Jet-Stream-Front»oberhalb und unterhalb des Strahlstromkernes; stabile und barokline Zonen auf der antizyklonalen Seite des Strahlstromes; eine Aufwölbung der Isentropenflächen südlich der Strahlstromachse, der sogenannte «Isentropenbuckel» («isentrope hump»). Einige dieser Merkmale scheinen weitreichende Einflüsse auf die Dynamik der Strahlströmung zu besitzen.

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Paper presented at the I.U.G.G. Meeting in Helsinki, 1960.     

Die Verwendung von Kontinuitätsdiagrammen in der nordalpinen Wetterprognose

Zusammenfassung Mit Hilfe desHovmöller-Diagrammes wird die Überlagerung von Wellenbewegung und Gruppengeschwindigkeitseffekt studiert und das Ergebnis für eine 4- bis 5tägige Mittelfristprognose im nordalpinen Raum verwendet. Die Föhn- und Stauwirkung wird dabei durch die geostrophische Meridionalkomponente der Strömung im 500 mb-Niveau berücksichtigt, deren Einfluß mittels eines zu diesem Zwecke entwickelten Kontinuitätsdiagrammes (Meridional-Zirkulations-Diagramm=MZD) prognostisch abgeschätzt werden kann. Die Anwendungsmöglickeit für solche Diagramme wird schließlich durch die Monate Januar und Februar 1957 mit Beispielen belegt.

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Summary With the aid ofHovmöller's trough-and-ridge diagram the superposition of wave motion and group velocity is studied and the results are being applied to four to five-days extended range forecasts for the northern alpine region. The influence of foehn and barrage is taken into account by the geostrophic meridional component of the 500 mb circulation at 45 degrees northern latitude. A continuity diagram (Meridional Circulation Diagram=MZD) has been devised which allows to estimate this influence for prognostic purposes. The applications of MZD andHovmöller-diagram are discussed by using January and February of 1957 as an example.

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Résumé Etude de la superposition d'un mouvement ondulatoire et de l'effet de vitesse de groupe à l'aide du diagramme deHovmöller; application à la prévision de 4 à 5 jours dans l'espace nord-alpin. L'effet de foehn et de remous s'introduit par la composante méridienne du vent au niveau de 500 mb; il s'apprécie au moyen d'un diagramme de continuité (MZD) dressé dans ce but. Les possibilités d'application de ce diagramme sont illustrées par l'exemple des mois de janvier et de février 1957.

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Mit 6 Textabbildungen     

On temperature initialization in primitive equation forecast models

Four procedures of specifying model initial temperature were described and tested in the present study. It was found that the use of observed temperatures along with a proper vertical interpolation scheme was not only acceptable, but produced less error than the use of temperatures derived from geopotential height through the hydrostatic equation did. Use of the difference form of the hydrostatic equation would produce unacceptable errors in the initial temperatures, unrealistic horizontal and vertical distribution of temperature, and these errors would influence the calculation of the pressure gradient force, resulting in substantial, artificial disturbances within the model domain.In addition, an approach to check the initial data was described. Taking advantage of the fact that the geostrophic wind in sigma coordinates should be nondivergent, geopotential height and temperature were used to calculate the pressure gradient force terms and an initial divergence of the geostrophic wind. This approach can he used for comparing different initialization schemes for identical input data.     

Marine litter prediction by artificial intelligence

Artificial intelligence techniques of neural network and fuzzy systems were applied as alternative methods to determine beach litter grading, based on litter surveys of the Antalya coastline (the Turkish Riviera). Litter measurements were categorized and assessed by artificial intelligence techniques, which lead to a new litter categorization system. The constructed neural network satisfactorily predicted the grading of the Antalya beaches and litter categories based on the number of litter items in the general litter category. It has been concluded that, neural networks could be used for high-speed predictions of litter items and beach grading, when the characteristics of the main litter category was determined by field studies. This can save on field effort when fast and reliable estimations of litter categories are required for management or research studies of beaches--especially those concerned with health and safety, and it has economic implications. The main advantages in using fuzzy systems are that they consider linguistic adjectival definitions, e.g. many/few, etc. As a result, additional information inherent in linguistic comments/refinements and judgments made during field studies can be incorporated in grading systems.