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

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

Assessing a Tornado Climatology from Global Tornado Intensity Distributions

Recent work demonstrated that the shape of tornado intensity distributions from various regions worldwide is well described by Weibull functions. This statistical modeling revealed a strong correlation between the fit parameters c for shape and b for scale regardless of the data source. In the present work it is shown that the quality of the Weibull fits is optimized if only tornado reports of F1 and higher intensity are used and that the c–b correlation does indeed reflect a universal feature of the observed tornado intensity distributions. For regions with likely supercell tornado dominance, this feature is the number ratio of F4 to F3 tornado reports R(F4/F3) = 0.238. The c–b diagram for the Weibull shape and scale parameters is used as a climatological chart, which allows different types of tornado climatology to be distinguished, presumably arising from supercell versus nonsupercell tornadogenesis. Assuming temporal invariance of the climatology and using a detection efficiency function for tornado observations, a stationary climatological probability distribution from large tornado records (U.S. decadal data 1950−99) is extracted. This can be used for risk assessment, comparative studies on tornado intensity distributions worldwide, and estimates of the degree of underreporting for areas with poor databases. For the 1990s U.S. data, a likely tornado underreporting of the weak events (F0, F1) by a factor of 2 can be diagnosed, as well as asymptotic climatological c,b values of c = 1.79 and b = 2.13, to which a convergence in the 1950–99 U.S. decadal data is verified