Cyclonic activity in Yugoslavia and surrounding areas

Summary A precise statistics of the cyclones in Yugoslavia and surrounding areas for the period 1951–1960 has been made. By that statistics eight different cyclogenetic regions in South Europe have been identified. They are: the Gulf of Genoa, the Tyrrhenian Sea, the Northern Adriatic, the Southern Adriatic, the Aegean Sea, the Black Sea, the Panonean Lowland and the Walachian Plain. Further, some features of cyclonic activity in the cyclogenetic regions such as the frequency of cyclogenesis, as well as the distribution, the duration and the intensity of cyclones have been discussed.

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Zusammenfassung Es werden die Ergebnisse einer eingehenden Statistik der in den Jahren 1951 bis 1960 in Jugoslawien und in den angrenzenden Gebieten aufgetretenen Zyklonen mitgeteilt. Daraus können acht verschiedene zyklogenetische Regionen in Südeuropa unterschieden werden. Es sind dies der Golf von Genua, das Thyrrhenische Meer, die nördliche Adria, die südliche Adria, das Ägäische Meer, das Schwarze Meer, das Pannonische Tiefland und die Walachische Ebene. Ferner wird als Kennzeichen der Zyklonenaktivität in den erwähnten Gebieten die Häufigkeit der Zyklogenese und die Verteilung, die Dauer und die Intensität der Zyklonen diskutiert.

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Résumé On communique le résultat d'une étude statistique complète des dépressions ayant évolué sur la Yougoslavie et les pays circonvoisins entre 1951 et 1960. De cette étude, on peut déterminer huit régions de l'Europe méridionale spécialement favorables à la cyclogénèse. Il s'agit du Golfe de Gênes, de la Mer Tyrrhénienne, du nord de l'Adriatique, du sud de l'Adriatique, de la Mer Egée, de la Mer Noire ainsi que des deux plaines de Pannonie et de Valachie. On discute enfin, comme critères de l'activité dépressionnaire dans ces régions, la fréquence des cyclogénèses ainsi que la répartition, la durée et l'intensité des dépressions.

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With 12 Figures     

Uptake of Dissolved and Oil Phase Organic Chemicals by Bacteria

Hydrophobic organic chemicals (HOCs) discharged into soil and ground water will partition into gaseous, aqueous, oil, and sorbed phases. Knowledge of how bacteria assimilate HOCs is important to individuals involved in evaluating intrinsic, or engineered, bioremediation. The majority of bacteria isolated from the subsurface are gram-negative. The outer membrane of gram-negative organisms acts as a selective barrier to many solutes, including hydrophobic chemicals. Thus, diffusional transport of a hydrophobic solute through the outer membrane may be the rate-limiting step in biodegradation. Bacteria may also produce biosurfactants that can facilitate cell-oil contact or assist solubilization of oil and sorbed phases.     

The Belgrade Vertical Circle

An analysis of the results of the observations shows that the Belgrade Vertical Circle is not free of a significant residual flexure.     

On the Exchange of NO3 Radicals with Aqueous Solutions: Solubility and Sticking Coefficient

The exchange of NO₃ radicals with the aqueous-phase was investigated at room temperature (293 K) in a series of wetted denuders. From these experiments, the uptake coefficient of NO₃ was determined on 0.1 M NaCl solutions and was found to be (NO₃) 2 × 10^-3 in good agreement with recent studies. The Henry coefficient of NO₃ was estimated to be K_H(NO₃) = 1.8 M · atm^-1, with a (2) uncertainty of ±3 M · atm^-1. From the upper limit for the Henry coefficient (K_H = 5 M · atm^-1) and available thermodynamic data, the redox potential of dissolved NO₃/NO ₃ ^– is estimated to be in the range of 2.3 to 2.5 V. This range is at the lower boundary of earlier estimates. The results are discussed in the light of a recent publication. Based on our data and a model of the transport and chemistry in the liquid film, an upper limit is derived for the product of the Henry coefficient K_H and the rate coefficient k ₁₀ of the potential reaction NO₃ + H₂O HNO₃ + OH. For K_H = 0.6 M · atm^-1, we find k ₁₀ < 0.05 s^-1 · atm^-1, i.e., about 100 times smaller than what was suggested by Rudich and co-workers. Because of its small solubility, heterogeneous removal of NO₃ is only important under conditions where the dissolved NO₃ is removed quickly from equilibrium, for example by reactions with Cl^– or HSO ₃ ^– ions in the liquid-phase. Otherwise, heterogenous removal should mainly proceed via N₂O₅.     

Free Radicals and Fast Photochemistry during BERLIOZ

The free radicals OH, HO₂, RO₂, and NO₃ are known to be the driving force for most chemical processes in the atmosphere. Since the low concentration of the above radicals makes measurements particularly difficult, only relatively few direct measurements of free radical concentrations have been reported to date.We present a comprehensive set of simultaneous radical measurements performed by Laser Induced Fluorescence (LIF), Matrix Isolation –Electron spin Resonance (MI-ESR), Peroxy Radical Chemical Amplification (PERCA), and Differential Optical Absorption Spectroscopy (DOAS) during the BERLIner OZonexperiment (BERLIOZ) during July and August of 1998 near Berlin, Germany. Most of the above radical species were measured by more than one technique and an intercomparison gave good agreement. This data set offered the possibility to study and quantify the role of each radical at a rural, semi-polluted site in the continental boundary layer and to investigate interconnections and dependencies among these free radicals.In general (box) modelled diurnal profiles of the different radicals reproduced the measurements quite well, however measured absolute levels are frequently lower than model predictions. These discrepancies point to disturbing deficiencies in our understanding of the chemical system in urban air masses.In addition considerable night-time peroxy radical production related to VOC reactions with NO₃ and O₃ could be quantified.     

Low-cost water-lifting from groundwater sources: a comparison of the EMAS Pump with the Rope Pump

In sub-Saharan Africa, low-cost groundwater supply systems offer great opportunities for the current unserved population of >300 million to access drinking water. A comparative study was performed in Uganda of the EMAS Pump (designed by Escuela Móvil Aguas y Saneamiento Básico) with the trade-named Rope Pump, two low-cost manual water-lifting devices appropriate to pumping from shallow groundwater sources. Pumping rates, energy expended, material costs, and construction requirements were analyzed. Focus was on low-cost application for use in shallow groundwater systems at the household level in developing countries, particularly in sub-Saharan Africa. The study site was northern Uganda, with testing performed at several drilled boreholes. Two variants of each pump were tested by a male and female user, pumping from multiple static water-level depths ranging from 5 to 28 m. Results demonstrated the most common version of the EMAS Pump to perform similarly to the comparable version of the Rope Pump in terms of average pumping rate at depth range 5 to 18 m (93–111%), but less so at deeper depths (63–85%). Normalized pumping rates (considering energy expended) accentuated differences between these versions of the EMAS Pump and Rope Pump (47–97%). Cost of materials to construct the EMAS Pump were 21–60% those of the Rope Pump, and EMAS Pump construction requirements were also less. Based on the assessed factors, it is concluded that the EMAS Pump has potential for success in “self-supply” groundwater systems in sub-Saharan Africa and is particularly appropriate to link with low-cost shallow groundwater sources.