Search

The Convective and Orographically-driven Precipitation Study (COPS) carried out in summer 2007 over northeastern France and southwestern Germany provided a fairly comprehensive description of the low-troposphere water-vapour field, thanks in particular to the deployment of two airborne differential absorption lidar systems. These lidar observations were assimilated using the 3D-Var assimilation system of the Application of Research to Operations at MEsoscale (AROME) numerical weather prediction mesoscale model. The assimilation was carried out for the period 4 July-3 August by running a three-hour forward intermittent assimilation cycle. First, the impact of the lidar observations was assessed by comparing the analyses with a set of more than 200 independent soundings. The lidar observations were found to have a positive impact on the analyses by reducing the dry bias in the first 500 m above ground level and by diminishing the root-mean-square error by roughly 15% in the first km. Then the impact of the lidar observations was assessed by comparing the precipitation forecasts (obtained with and without the lidar observations for the period 15 July-2 August) with the gridded precipitation observations provided by the Vienna Enhanced Resolution Analysis. In general, the impact was found to be positive but not significant for the 24 h precipitation and positive and significant for the 6 h precipitation, with an improvement lasting up to 24 h. Some selected case studies show that the improvement was obtained through a better depiction of convection initiation or through a more accurate positioning of the precipitation systems. © 2011 Royal Meteorological Society.

International audience; In the afternoon of 15 July 2007, a thunderstorm was initiated within a line of cumulus clouds which formed parallel to the crest of the Black Forest mountains during the Intensive Observation Period (IOP) 8b of the Convective and Orographically-induced Precipitation Study (COPS). This paper extends the analysis of processes that led to convection initiation (CI), i.e. the transition from shallow to deep convection, on this day with the data from several COPS instruments that have not been considered in previous studies. In particular, the boundary-layer structure, lids and the water-vapour field in the pre-convective environment of the event are discussed. For this purpose, we investigated measurements of water-vapour lidars, temperature lidars and wind lidars, profiles from radiosondes, in situ aircraft data and gridded data of weather stations as well as GPS integrated-water-vapour data and satellite imagery. Thermally driven circulation systems formed over both the Black Forest and the Vosges mountain ranges which resulted in local convergence zones. These superimposed with the large-scale convergence in the Black Forest area. In the presence of sufficient moisture and updraught, clouds formed close to the mountain crests. The related latent-heat release allowed larger thermals to be produced, which may have had a positive feedback on stabilizing these convergence zones as a whole. We believe that differences in the moisture field explain why convection remained shallow and sparse over the Vosges mountains because these differences were responsible for differences in convective inhibition (CIN). The stationary location of the convergence zone over the southern Black Forest was probably decisive for CI because it constantly transported sensible and latent heat into the area in which CI took place.

M. Starkl, M. Ornetzeder, E. Binner, P. Holubar, M. Pollak, M. Dorninger, F. Mascher, M. Fuerhacker and R. Haberl;Water Science & Technology, 56 (2007): 5, 105-113This paper reports a recently finished, interdisciplinary project on rural wastewater management in Austria. The objective of the project was to study alternative wastewater management options based on separation of the wastewater into its constituent parts, and to compare them with conventional ones. Thereby, a feasibility study of both conventional and alternative options for wastewater management in six model regions was carried out. Life cycle costs and social acceptance were analysed by using a case study-based assessment approach. However, hygienic and environmental risks were evaluated on a more general level. In order to complement the findings, a survey on urine separation system users in the Solar City of Linz was conducted. Based on these assessments and empirical findings, the paper concludes that options using a full separation of all wastewater fractions should be considered with care. Options based on a separation of only grey water and black water or in the liquid/solid phase can offer ecological and financial advantages over conventional options. Further, options combining wastewater management and regional biogas plants were identified as an interesting solution. However, legal constraints restrict this option currently.

Im vorliegenden Beitrag werden die betriebs- und volkswirtschaftlichen Effekte einer großflächigen Bewirtschaftung nach den Prinzipien des ökologischen Landbaus am Beispiel der Veredelungsbetriebe in der Region Mostviertel-Eisenwurzen (NÖ) diskutiert. Der Vergleich zwischen biologischer und konventioneller Produktionsweise erfolgt anhand sieben verschiedener Betriebsmodelle (Betriebstypen Mastschweinehaltung, Zuchtsauenhaltung, kombinierte Mastschweine- & Zuchtsauenhaltung mit jeweils einem extensiven und einem intensiven Betriebsmodelle, ein Betriebsmodell des Betriebstyps Mastrinderhaltung). Mittels Linearer Planungsrechnung werden der Gesamt- sowie der Vergleichsdeckungsbeitrag, der systembedingte Mehrkosten im Biobetrieb (Verbands- und Kontrollkosten, Investitionen, Mehrarbeit) zusätzlich berücksichtigt, errechnet. Anschließend werden für die Betriebsmodelle Bilanzen der Treibhausgasemissionen erstellt, die monetär bewertet werden. Die Berechnungen dieser Arbeit zeigen, dass in biologisch wirtschaftenden Schweine haltenden Betrieben bei entsprechend höheren Marktpreisen bessere Gesamt- und Vergleichdeckungsbeiträge erzielt werden können, als in vergleichbaren konventionellen Betrieben. Demgegenüber ist der Mastrinder haltende Betrieb selbst bei Bezahlung von Biopremiumpreisen nicht in der Lage, seinen Gesamt- bzw. Vergleichsdeckungsbeitrag über das konventionelle Ausgangsniveau hinaus anzuheben. Bei Annahme eines konventionellen Preisniveaus sinken insbesondere in den Schweine haltenden Betrieben die Gesamt- und Vergleichdeckungsbeiträge weit unter den konventionellen Wert ab. Die externen Kosten nehmen bei biologischer Bewirtschaftung v.a. durch den Verzicht auf leichtlösliche mineralische Stickstoffdünger und geringere zugekaufte Mengen an Kraftfutter in den Mastrinderbetrieben um -58%, in den Mastschweinebetrieben um -61 %, in den Zuchtsauenbetrieben um -44 % und in den Mastschweine- & Zuchtsauenbetrieben um -19 % ab. Werden sämtliche Betriebsmodelle auf Regionsebene aggregiert, so können die externen Kosten durch die biologische Bewirtschaftung der Betriebe um rund -45 % gesenkt werden. Bezogen auf die produzierte Menge an Output in 1000 MJ Output werden aufgrund des Produktionsmengenrückgangs im ökologischen Landbau allerdings um +25 % höhere externe Kosten verursacht. Niedrigere absolute externe Kosten bei ökologischer Wirtschaftsweise unterstützen somit die Forderung nach einem umfassenden Maßnahmenpaket zur Förderung der Ausbreitung des Biolandbaus, der Sicherung von Biopremiumpreisen und damit der betriebswirtschaftlichen Rentabilität der biologischen Landwirtschaft.