Comparison of Lightning Activity and Radar-Retrieved Microphysical Properties in EULINOX Storms

A combined analysis of microphysical thunderstorm properties derived by C-band polarimetric Doppler radar measurements and lightning observations from two ground-based systems are presented. Three types of storms, a multicell, a supercell, and a squall line, that were observed during the European Lightning Nitrogen Oxides project (EULINOX) are investigated. Correlations are sought between the mass of rain, graupel, hail, and snow derived form radar observations at different height levels and the electrical activity, represented either by cloud-to-ground or intracloud flashes. These relationships are explained by connecting the radar-derived properties with the non-inductive charging process. For the multicell and the supercell storm, the lightning activity can be linearly correlated to both the hydrometeor total mass and class specific mass in the upper part of the storm. It is shown that the fractions of graupel and hail above the −20 °C-level in these storms positively correlate with the intracloud flash activity in the supercell, and negatively for the cloud-to-ground lightning frequency in the multicell. No such relation can be established for the squall line, indicating that the convective organization plays a crucial role in the lightning development. The analysis of the masses in the different storms shows that lightning activity cannot be parameterized by total mass alone, other parameters have to be identified. The results provide important information for all lightning studies that rely on bulk properties of thunderstorms, e.g., the parameterization of lightning in mesoscale models or the nowcasting of lightning by radar

Zwischen Schutz und struktureller Benachteiligung: Weibliche Erwerbsarbeit in Leipziger Fabriken im Spiegel der sächsischen Gewerbeaufsicht 1879-1914

Konkret zeigt Sarah Dotzek in Zwischen Schutz und struktureller Benachteiligung: Weibliche Erwerbsarbeit in Leipziger Fabriken im Spiegel der sächsischen Gewerbeaufsicht 1879-1914, wie im Kontext der einsetzenden Industrialisierung und dem Durchbruch freier Lohnarbeit im 19. Jahrhundert Frauen, die einem außerhäuslichen Erwerb nachgingen, vom Gesetzgeber kritische Beachtung fanden, beispielsweise durch die Gewerbeordnungsnovelle von 1891. Der Beitrag analysiert die Umsetzung und Bedeutung dieser geschlechtsspezifischen Arbeitsschutzbestimmungen für Fabrikarbeiterinnen in Leipzig und zeigt anhand der Berichte der Leipziger Gewerbeaufsicht, dass Schutzmaßnahmen häufig nur unzureichend umgesetzt wurden. In einem zweiten Schritt legt der Beitrag dar, wie in der geschlechtsspezifischen Formulierung der Bestimmungen Aspekte struktureller Benachteiligung zu erkennen sind, und dass auch den Berichten der Leipziger Gewerbeinspektoren bürgerliche Geschlechterideale zugrunde liegen, woraus wiederum folgt, dass die Perspektive und die Bedürfnisse der Leipziger Fabrikarbeiterinnen letztlich kaum in den Blick genommen wurden

Precipitation Type Specific Radar Reflectivity-Rain Rate Relationships for Warsaw, Poland

Penelitian ini bertujuan untuk mengetahui peningkatan penguasaan konsep dan kemampuan literasi sains siswa dengan menggunakan model pembelajaran kontekstual berbantuan multimedia. Metode dan desain penelitian yang digunakan adalah quasi experiment dengan pretest-posttest control group design. Subjek penelitiannya adalah kelas XI di kabupaten Subang, Jawa-Barat. Hasil penelitian menunjukkan Model Pembelajaran Kontekstual berbantuan multimedia secara signifikan mampu meningkatkan penguasaan konsep dan kemampuan literasi sains siswa. Peningkatan penguasaan konsep siswa dengan nilai N-Gain 0.50 (kategori sedang) untuk kelas eksperimen dan 0,30 (kategori sedang) untuk kelas kontrol. Peningkatan kemampuan literasi sains siswa dengan nilai N-Gain 0.45 (kategori sedang) untuk kelas eksperimen dan 0,30 (kategori sedang) untuk kelas kontrol. This study aims to determine the concepts mastery and skills increase scientific literacy of students by using multimedia-assisted contextual learning model. The method used quasi experiment with pretest-posttest control group design. Subjects of study are class XI in Subang districts, West-Java. The result of study showed that contextual model’s aided by multimedia significantly enhance student’s concepts mastery and skills scientific literacy. The enhancement of student’s concepts mastery with N-Gain value is 0.50 (medium category) for experiment class and 0,30 (medium category) for control class. The enhancement of student's skills scientific literacy with N-Gain value is 0.45 (medium category) for experiment class and 0,30 (medium category) for control class

Book Reviews of Lin, Y.-L.: Mesoscale Dynamics

Buchbesprechung Lin, Y.-L., 2007: Mesoscale Dynamic

Reconstruction of near-surface tornado wind fields from forest damage

Tornado intensity is usually inferred from the damage produced. To foster postevent tornado intensity assessments, the authors present a model to reconstruct near-surface wind fields from forest damage patterns. By comparing the structure of observed and simulated damage patterns, essential parameters to describe a tornado near-surface wind field are derived, such as the ratio Gmax between circular and translational velocity, and the deflection angle a between peak wind and pressure gradient. The model consists of a wind field module following the Letzmann analytical tornado model and a tree module based on the mechanistic HWIND tree model to assess tree breakage. Using this method, the velocity components of the near-surface wind field, the track of the tornado center, and the spatial distribution of the Fujita scale along and across the damage path can be assessed. Necessary requirements to apply the model are knowledge of the tornado translation speed (e.g., from radar observations) and a detailed analysis of the forest damage patterns. One of the key findings of this analysis is that the maximum intensity of the tornado is determinable with an uncertainty of only (Gmax 1 1) times the variability of the usually well-known tornado translation speed. Further, if Letzmann�s model is applied and the translation speed of the tornado is known, the detailed tree model is unnecessary and could be replaced by an average critical velocity for stem breakage ycrit independent of the tree species. Under this framework, the F3 and F2 ratings of the tornadoes in Milosovice, Czech Republic, on 30 May 2001 and Castellcir, Spain, on 18 October 2006, respectively, could be verified. For the Milosovice event, the uncertainty in peak intensity was only 66.0 m s21. Additional information about the structure of the near-surface wind field in the tornado and several secondary vortices was also gained. Further, this model allows for distinguishing downburst damage patterns from those of tornadoes

Quantitative comparison of METEOSAT-based thunderstorm detektion and nowcastin with in-situ reports in the European Severe Weather Database (ESWD)

Severe thunderstorms constitute a major weather hazard in Europe, with an estimated total damage of € 5-8 billion each year. Yet a pan-European database of severe weather reports in a homogeneous data format has become available only recently: the European Severe Weather Database (ESWD). We demonstrate the large potential of ESWD applications for storm detection and forecast evaluation purposes and complement an earlier case-based study. The analysis of all warm-season (JJA) severe weather days in Europe in 2008 corroborated our earlier findings. There is a good agreement between ESWD reports and Cb-TRAM detected thunderstorms, even though no exact correspondence between ESWD reports and Cb-TRAM cells is required (e.g. due to storm morphology). Correspondingly, a large portion of ESWD reports regarded as misses by our strict in/out-of-Cb-TRAM-polygon criterion were still located close to a Cb-TRAM cell. Quantitatively, only the probability of detection (POD) can be evaluated due to the different characteristics of the two data sources. The POD for storm detection was 0.24 on average, with maximum values up to 0.58. The respective analysis for the 30 and 60 minutes nowcasts yielded average POD values of 0.11 and 0.08, respectively, with maximum values of POD exceeding 0.4 on 3 days for the 30 minutes nowcast and on one day for the 60 minutes nowcast

Derivation of physically motivated wind speed scales

A class of new wind speed scales is proposed in which the relevant scaling factors are derived from physical quantities like mass flux density, energy density (pressure), or energy flux density. Hence, they are called Energy- or E-scales, and can be applied to wind speeds of any intensity. It is shown that the Mach scale is a special case of an E-scale. Aside from its foundation in physical quantities which allow for a calibration of the scales, the E-scale concept can help to overcome the present plethora of scales for winds in the range from gale to hurricane intensity. A procedure to convert existing data based on the Fujita-scale or other scales (Saffir-Simpson, TORRO, Beaufort) to their corresponding E-scales is outlined. Even for the large US tornado record, the workload of conversion in case of an adoption of the E-scale would in principle remain manageable (if the necessary metadata to do so were available), as primarily the F5 events would have to be re-rated. Compared to damage scales like the �Enhanced Fujita� or EF-scale concept recently implemented in the USA, the E-scales are based on first principles. They can consistently be applied all over the world for the purpose of climatological homogeneity. To account for international variations in building characteristics, one should not adapt wind speed scale thresholds to certain national building characteristics. Instead, one worldwide applicable wind speed scale based on physical principles should rather be complemented by nationally-adapted damage descriptions. The E-scale concept can provide the basis for such a standardised wind speed scale