Rainfall and the 6–9 day wave-like disturbance in West-Africa during summer 1989

Summary Using ECMWF analyses and daily rain amounts of 569 stations in Western Africa for summer 1989, the study documents the composite structure of the 6–9 day oscillation and its influence on rain. Rain is modulated by vorticity as displayed in the wave composite. There are rainfall maxima coincident with cyclonic vorticity and rainfall minima coincident with anticyclonic vorticity at the 700hPa level, at 17.5°N and 7.5°N.With 6 Figures     

The effect of initial data in adjusting conditional observations

Summary In the introduction the effect of neglecting the accuracy of the initial data is mentioned in adjusting conditional observations, because this essentially causes the accuracy of the adjusted quantities to be overrated. The effect of changes (errors) of the initial data is investigated for two cases: a) when the initial data are given, unmeasured quantities; b) when the initial data are given and measured quantities which form the conditions of adjustment (e.g., gyrotheodolite directional angles). This effect was rejected in a change of the corrections, in the vrst case according to (14), and in the second according to (18). The effect of the changes (errors) of the initial data was also investigated with regard to the matrix of the co-factors of the adjusted quantities. This matrix, taking into account the errors of the initial data described by matrixQww, and the errors of the measurements themselves, described by matrix (26), is expressed by (31).Dedicated to 90th Birthday of Professor Frantiek Fiala     

Compositional variation in three Cascade stratovolcanoes: Jefferson,Rainier, and Shasta

Detailed major and trace element studies of volcanic rocks from Jefferson, Rainier, and Shasta stratovolcanoes in the Cascade Range indicate that each volcano has distinct geochemical distribution patterns. Silica variation diagrams are not smooth nor, in general, continuous for any volcano. Portions of stratigraphic sections within the volcanoes exhibit compositional coherency and are interpreted as eruptive groups which were extruded over time intervals which are short compared to the lifetimes of the volcanoes. The results of this investigation indicate the leasibility of geochemically mapping eruptive groups within stratovolcanoes. Systematic compositional trends are not observed within thick (500–1000 m) eruptive groups but may occur over thicknesses of <200 m. Compositional variations within eruptive groups are commonly non-systematic and show ranges similar to the ranges observed in individual flows. Correlations between the amounts or kinds of phenocryst phases present and intra-group compositional variation is not observed. Inter-group compositional differences are sometimes accompanied by mineralogical differences. Late andesites and dacites at Rainier and Shasta are characterized by decreases in K and Rb while at Jefferson increases in these elements and other compositional changes occur in the late eruptives. Progressive fractional crystallization models do not seem capable of explaining the element distributions observed in the three volcanoes. Existing data are consistent with a model involving varying degrees of melting of some combination of amphibolite, eclogite or peridotite in or above a subduction zone with varying water contents. Segregation and sequential eruption of small batches of magma may produce the eruptive groups characterizing the volcanoes. Late mafic magmas erupted at satellite vents appear to be produced in different (deeper?) mantle source areas.     

Chemical composition and rare gas content of four new detected antarctic meteorites

Within a region of 5 km × 10 km on a downhill slope of the Yamato Mounties, in 1969 the Japanese Expedition Team collected many stones. 9 of them were recognized as meteorites. On 4 of these findings we determined the chemical composition and the rare gas content. According to the mineralogical and the chemical composition, Yamato (a) is an enstatite chondrite, Yamato (b) a Ca-poor achondrite, Yamato (c) seems to be a carbonations chondrite Type III and Yamato (d) a olivine bronzite chondrite. Exposure ages are 1.7, 31, 25 and 4.3 my respectively.     

Versuch einer Begründung für den Wandel in der qualitativen und quantitativen Zusammensetzung des Fischbestandes im Bodensee während der letzten 60 Jahre und eine Bewertung der Besatzmassnahmen

Statistics for all important fish for the past 60 years and the management measures taken, together with the scientific results, have been evaluated, in order to recognize the development trend and the success or failure of the measures. Although total yields have increased by 500%, the catches for some species i.e. pike, pike-perch and lake trout, have decreased in the past 15 years in spite of enormous measures. The possible reasons are discussed. Cannibalism and decimation through rapacious fish regulate the yield and cause oscillations. Therefore studies on the biology of fish must rather consider the correlations between the single species. For good management, it is more important to plant alevins than fry.

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Meinem Mitarbeiter Heinz Quoss danke ich recht herzlich für die Zusammenstellung der einzelnen statistischen Werte und für die zahlreichen Berechnungen.     

Über die echographische Aufzeichnung des Verhaltens von Meeresfischen während der Sonnenfinsternis vom 30. Juni 1954

Summary Echo records from the Atlantic west of the Faroe Islands are presented which, for the first time, give evidence of the influence exerted by day on the vertical movement of pelagic fishes by a considerable reduction of luminous intensity (solar eclipse). This phenomenon corresponds with the fact well known since some years from investigations in the North Sea which prove that by night pelagic fishes move in a vertical direction according to the variation in luminous intensity.

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Sur des enregistrements ultra-sonores caractérisant le comportement des poissons pélagiques pendant l'éclipsé de soleil au 30 juin 1954

Résumé On présente des enregistrements ultra-sonores faits en océan Atlantique à l'ouest de l'archipel de Færoé. Ces enregistrements font, pour la première fois, preuve de l'influence exercée de jour sur le mouvement vertical des poissons pélagiques par une réduction sensible de l'intensité lumineuse (éclipse de soleil). Ce phénomène correspond avec le fait bien connu depuis quelques ans par des recherches dans la mer du Nord. Suivant ces recherches, les poissons pélagiques se meuvent nuitamment dans la direction verticale suivant la variation de l'intensité lumineuse.

     

Recombination rates of small ions and their attachment to aerosol particles

It could be shown by measurements of the air conductivity and using a mean profile for the ionization rate that experimental and theoretical values of the recombination rate of small ions based on a three body recombination process (Thomson) are in very good agreement up to 20 km altitude. The divergency of the experimental and theoretical curves above 20 km can be interpreted by assuming that there exists in this altitude region a crossover from the three body recombination to a two body recombination process. The value of the recombination coefficient is about 4·10^–7 cm³ s^–1 in 25 km altitude, compared with 1.4·10^–6 cm³ s^–1 at ground level. Furtheron it was possible for the first time to get some experimental data of attachment coefficients up to 13 km from simultaneous measurements of the air conductivity and Aitken nuclei concentration. These values are in good agreement with those obtained by theoretical considerations.     

Distribution of airborne pollen and spores and their long distance transport

The atmosphere near the ground contains a mixed population of pollen and spores in the 1 to 90 m diameter range. Continuous sampling at Rothamsted Experimental Station at 2 m above ground level indicated concentrations averaging 12,000 m^–3 over 5 summer months, but 1 million m^–3 can occur for short periods. Concentrations change rapidly with locality, season, time of day or night and weather. Normally concentration in the troposphere decreases logarithmically with height. The occurrence of long distance transport of pollen and spores by wind is demonstrated by sampling from aircraft, and supported by much circumstantial evidence. Possible effects of this air spora on the atmosphere may be sought in alterations to: opacity, ionization, condensation nuclei, and sinks for minor gases.