Zur Bestimmung des Schneeanteils am Gesamtniederschlag

Zusammenfassung Aus den Monatsberichten einiger hydrographischer Stationen der Ostalpen in verschiedenen Höhenlagen wird bestimmt, welche Niederschlagsmengen 1 cm der gemessenen Neuschneehöhen entsprechen, im Monats- und im Jahresmittel. In Abhängigkeit von der Höhenlage weist die Niederschlagsmenge pro Zentimeter Neuschneehöhe ein ausgeprägtes Minimum bei 1350 m Seehöhe auf. Durch Multiplikation des der Seehöhe entsprechenden Wertes dieser Kurve mit der an einer Station der Ostalpen gemessenen Neuschneehöhe der Periode 1896/97–1915/16 erhält man den Schneeanteil dieser Station am Gesamtniederschlag. Die auf diese Art bestimmten Anteilmengen sind in der Regel dann größer bzw. kleiner als die nachV. Conrad berechneten Werte, wenn die Anomalien der jährlichen Neuschneehöhen nachE. Ekhart positiv bzw. negativ sind.

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Summary On the base of monthly reports of several hydrographic stations in the Eastern Alps, the amounts of precipitation corresponding to 1 cm of fresh snow-depth have been calculated in the monthly and yearly average. As a function of the altitude the amount of precipitation per cm fresh snow-depth shows a marked minimum at the altitude of 1350 m. By multiplication of the fresh snow-depths, measured at a station of the Eastern Alps during the period 1896/97–1915/16, with the corresponding value of the above curve the snow fraction of the total precipitation of this station can be obtained. As a rule, the fractions determined in this way are greater or smaller than those calculated byV. Conrad according as the anomalies of the yearly fresh snow-depths given byE. Ekhart are respectively positive or negative.

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Résumé On calcule la quantité d'eau météorique correspondant à 1 cm. de neige fraîche (moyennes mensuelles et annuelles) sur la base des rapports mensuels de quelques stations hydrographiques des Alpes orientales. Cette quantité, considérée en fonction de l'altitude, présente un minimum net vers 1350 m. En multipliant la valeur correspondant à l'altitude d'une station des Alpes orientales où furent mesurées les hauteurs de neige fraîche pendant la période 1896/97 à 1915/16 par cette hauteur même, on obtient la fraction en neige des précipitations totales en ce point. Les fractions ainsi calculées sont dans la règle plus grandes ou plus petites que les valeurs établies parV. Conrad selon que les anomalies des hauteurs annuelles de neige fraîche, d'aprèsE. Ekhart, sont respectivement positives ou négatives.

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Mit 2 Textabbildungen.     

An anthropo-ecological approach to landscape use optimization

A method of landscape evaluation based on the anthropo-ecological approach is worked out. The procedure consists of three stages, viz., general, special and optimization. Within the general stage, the structural arrangement of the landscape is evaluated by means of the concept of geo-ecological sites (GES), which are distributed into four zones (A, B, C, D) according to the degrees of their anthropic disturbance. The zoning performed makes it possible to select those geo-ecological sites where eco-critical relationships can be expected to appear; in order to eliminate such situations, transition zones are calculated for the geo-ecological sites concerned. The outcome of this approach is a proposal of a new structural arrangement of the geo-ecological sites, solving eco-critical situations and serving as a basis for the special and optimization stages of the anthropo-ecological method.     

Northern Adriatic phytoplankton response to short Po River discharge pulses during summer stratified conditions

A 275‐km‐long transversel Northern Adriatic profile from the mouth of the Po River (Italian Adriatic coast) to the Kvarner region (Croatian coastal island area) was investigated in three successive case studies in August 2008, 2009 and 2010. The short Po River pulses in August result in the surface advection of riverine water, nutrients and phytoplankton from the western to the eastern side of the Adriatic. This surface spreading exhibits inter‐annual variability depending on the riverine discharge in the preceding period. The Po River discharge pulse in August 2010 in particular resulted in an extraordinary tongue‐like advection of riverine water, nutrients, and phytoplankton towards the Eastern Adriatic coast. The phenomenon was detected using both satellite imagery and classical oceanographic measurements. In the advective water, toxic dinoflagellates were most abundant in August 2010, when the influence of the Po was greatest.     

Geoarchaeological evidence on a Late Bronze Age earthquake,Ohrid Basin (North Macedonia)

Geoarchaeological investigations on the northeastern shore of Lake Ohrid revealed 3.5 m thick deepwater lacustrine sediments overlying terrestrial vegetation macrofossils, worked wood and abundant potsherds dated to the Late Bronze Age (LBA). Distinct contact of deepwater sediment with the sub-aerial weathered limestone bedrock point to a sudden increase in lake level. According to radiocarbon data, catastrophic flooding occurred shortly after 1214 yr bc. Because the area is located in a highly active seismic zone, we propose that this event was caused by tectonically induced, metre-scale coseismic subsidence related to faults bordering the Ohrid alluvial plain. Moreover, this event coincides well with a dramatic switch in the habitation and settlement strategy in the region. More important, however, is the finding that the age of the proposed massive tectonic event and change in habitation lies within the interval of the proposed ‘earthquake storm’ in the eastern Mediterranean dated to 1225–1175 bc. As the Ohrid-Korça zone belongs to the same tectonic province, a relationship between the abovementioned earthquakes and the proposed event can be expected. This research therefore might provide the first direct evidence of a large-scale earthquake event linkable to the LBA collapse of Europe's first urban civilisation in the Aegean.     

Automatic Location of Swarm Earthquakes from Local Network Data

An advanced method of automated seismic phase picking and exact location and magnitude determination of swarm micro-earthquakes from local network data is presented. The phase picker is applied in two steps: first, S-wave groups are identified using a polarisation detector, and then corresponding P-wave groups are searched for. The times of maximum P- and S-amplitudes are then used as starting points for the determination of accurate P- and S-arrival times. The maximum S-wave amplitudes are utilised for determining local magnitudes. The whole procedure is checked by simultaneous preliminary hypocentre location providing estimates of local magnitudes and a compatibility check of the candidate P- and S-phases. The closest station to the earthquake cluster is used as a master, and the phase search at the remaining stations is governed by the P- and S-phases identified at the master station. Thanks to the use of apriori information on the approximate position of hypocentres, the procedure is also capable of picking the individual P- and S-phases of sequences of overlapping swarm events. The performance of the procedure was tested by comparison of the automatically and interactively created catalogues of the January 1997 NW-Bohemia micro-earthquake swarm. With stations located at epicentral distances between 0 and 20 km, the difference between hypocentre coordinates obtained by automatic and interactive processing did not exceed 80 m for 86% events. All events above magnitude 0.5 were identified, and the automatically determined polarity of first P-wave motion proved to be correct in 89% of them.     

Sudden ionospheric disturbances and flare activity in the course of the solar cycle no 20

a¶rt;a ma nu an u u (SID) u nu n a (a n¶rt; au) mu 1965–1975 . u u SID na¶rt;am nau, mum u nm R.     

Comparison of analytical and numerical calculations of the first class periodic orbits

The analytic construction of the direct periodic orbits in the circular 3-body problem is given in explicit form to the linear terms in . It is shown to be in good agreement with the numerically found orbits for large values of .     

Lithium in the interlayer space of synthetic trioctahedral micas

This paper gives several new and strong arguments in favour of the possibility of fixation of anhydrous lithium in the interlayer space of trioctahedral potassium micas. From the chemical viewpoint Li⁺ can replace K⁺, but is located out of the alkaline cation site; it enters pseudo-octahedral cavities limited by the triangular bases of two aluminous tetrahedra of two consecutive sheets. The solubility limit of Li⁺ in the interlayer is a function of the Al^IV content of the mica. It is given by the relation (Li/Li + K)_max = 2[(Al/Si + Al)^IV]². In both micas investigated — phlogopite, KMg₃(Si₃Al)O₁₀(OH)₂, and eastonite, K(Mg_2.5Al_1.5)(Si_2.5Al_1.5)O₁₀(OH)₂ — there is a remarkable agreement between the calculated values of the solubility limits and those measured by exchange reactions with hydrothermal solutions, at 600°C, 2 kbar. In high-Al micas, the interlayer Li content can be very important, with about one-third of K⁺ replaced by Li⁺.

The fixation of Li⁺ according to this model provokes a strong flattening of the interlayer (strong decrease of the reticular distance d₀₀₅) and a slight increase of the reticular distance d₀₆₀. Infra-red (IR) absorption spectrometry shows that vacant K⁺ sites are created when Li⁺ enters the interlayer; one observes low-frequency OH stretching bands attributed to OH dipoles lying towards these empty sites. Fixation of Li⁺ does not provoke any modification of the IR spectra in the region 1200-300 cm⁻¹, indicating that Li⁺ is really out of the sheet. For both cell dimensions and IR spectra, a comparison is made with “ordinary” lepidolites, having Li⁺ in the octahedral sheet; it provides a guide for the distinction between the two species of Li-bearing micas.     

The Earth-Moon tidal force function

The concept “the tidal force function of the Earth-Moon system” is introduced and its exact determination based on the Stokes constants (harmonic coefficients) in the external gravitational potential of both bodies is outlined. The exact determination of the torque due to the Moon exerted on the Earth may be performed in terms of the Stokes constants of both bodies and the mutual position of both ellipsoids of inertia.