The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Platform Idexlab - One of the best experts on this subject based on the ideXlab platform.
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real-time-pricing-v2.pdf
internal, 2021Co-Authors: Platform IdexlabAbstract:+ Smart Parking System 1 0 + Ride-hailing platforms 1 0 + power scheduling 3 0 + Electric Vehicle Charging 1 0 + WHOLESALE ELECTRICITY MARKET 2 0 … the vehicle assignment problem of an operating entity with dispatchable vehicles (e.g., an urban Integrated Energy-Traffic System (IETS) coordinator or an e-hailing
Alexander V. Ryzhkov - One of the best experts on this subject based on the ideXlab platform.
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Comparison of polarimetric signatures of Hail at S and C bands for different Hail sizes
Atmospheric Research, 2013Co-Authors: Rudolf Kaltenboeck, Alexander V. RyzhkovAbstract:Abstract In this study, severe Hail cases in Oklahoma/USA are investigated by analyzing the data simultaneously collected by two closely located polarimetric weather radars operating at S and C bands. Polarimetric radar variables measured in the presence of Hail at C band are quite different from the ones at S band due to more pronounced effects of resonance scattering and much stronger impact of attenuation. The differences are particularly strong in melting Hail below the freezing level, but they can be substantial even at higher altitudes where Hail is dry or grows in wet regime. As a consequence, the algorithms for Hail detection and determination of its size developed at S band can't be directly applied to C band. Differences between vertical profiles of radar reflectivity Z, differential reflectivity Z DR , and cross-correlation coefficient ρ hv in Hail-bearing parts of the storms have been examined for large and giant Hail. It is shown that in the presence of Hail, Z DR (C) is usually higher than Z DR (S) and ρ hv (C) hv (S). The height of radar resolution volume with respect to the freezing level has to be taken into account in polarimetric Hail detection/sizing. It is also demonstrated that giant Hail is commonly associated with pronounced depression of ρ hv in the areas of Hail generation above the freezing level and the corresponding drop in ρ hv at C band is much stronger than at S band. These results are compared to C-band polarimetric data collected in Hail-bearing thunderstorms in Austria, where additional small Hail size reports are available.
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the role of ccn in precipitation and Hail in a mid latitude storm as seen in simulations using a spectral bin microphysics model in a 2d dynamic frame
Atmospheric Research, 2011Co-Authors: A Khain, Daniel Rosenfeld, A Pokrovsky, Ulrich Blahak, Alexander V. RyzhkovAbstract:Abstract A Hail storm at Villingen-Schwenningen, southwest Germany, on 28.06.2006 was simulated using the Hebrew University Cloud Model (HUCM) with spectral (bin) microphysics. The model allows the simulation of Hail stones with diameters up to 6.8 cm. To investigate whether the amount of Hail is sensitive to atmospheric instabilities, the simulations were performed for two different temperature gradients within the boundary layer. The response of precipitation, the Hail mass and Hail size distribution to aerosol was investigated in the simulations with cloud condensation nuclei (CCN) concentrations ranging between 100 cm − 3 and 6000 cm − 3 (at the supersaturation of 1%). An increase in the surface temperature by one degree leads to an increase in accumulated rain by ~ 80% and nearly doubles the mass of Hail falling to the surface. An increase in CCN concentration from 100 cm − 3 to 3000 cm − 3 leads to a certain increase in accumulated rain and to a dramatic increase in the Hail mass, as well as to the increase in the Hail diameter from a few mm to 1–4 cm. The mechanisms by means of which aerosols affect precipitation and Hail stones size are discussed. It is shown that formation of Hail increases the precipitation efficiency of deep convective clouds.
William R Cotton - One of the best experts on this subject based on the ideXlab platform.
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the impact of Hail size on simulated supercell storms
Journal of the Atmospheric Sciences, 2004Co-Authors: Susan C Van Den Heever, William R CottonAbstract:Variations in storm microstructure due to updraft strength, liquid water content, and the presence of dry layers, wind shear, and cloud nucleating aerosol concentrations are likely to lead to changes in Hail sizes within deep convective storms. The focus of this paper is to determine how the overall dynamics and microphysical structure of deep convective storms are affected if Hail sizes are somehow altered in a storm environment that is otherwise the same. The sensitivity of simulated supercell storms to Hail size distributions is investigated by systematically varying the mean Hail diameter from 3 mm to 1 cm using the Regional Atmospheric Modeling System (RAMS) model. Increasing the mean Hail diameter results in a Hail size distribution in which the number concentration of smaller Hailstones is decreased, while that of the larger Hailstones is increased. This shift in the Hail size distribution as a result of increasing the mean Hail diameter leads to an increase in the mean terminal fall speed of the Hail species and to reduced melting and evaporation rates. The sensitivity simulations demonstrate that the low-level downdrafts are stronger, the cold pools are deeper and more intense, the left-moving updraft is shorter-lived, the right-moving storm is stronger but not as steady, and the low-level vertical vorticity is greater in the cases with smaller Hail stones. The maximum Hail mixing ratios are greater in the larger Hail simulations, but they are located higher in the storm and farther away from the updraft core in the smaller Hail runs. Changes in the Hail size distribution also appear to influence the type of supercell that develops.
Dejan Janc - One of the best experts on this subject based on the ideXlab platform.
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The Hail characteristics influence on its accretional growth
Atmospheric Research, 1997Co-Authors: Mladjen Ćurić, Dejan JancAbstract:A new method for partitioning of graupel and Hail in modeled Hail accretion rates as used in bulk parameterization schemes is derived. The influence of the diameter size limit between graupel and Hail populations on new rates is also considered. The new Hail accretion rate for the Hail/rain case is over thirty-seven times higher than its former value with Hail alone if the total Hail mixing ratio is greater than 10−3 kg kg−1. This increase is over ten times for the Hail/snow case, while the new rate of Hail accreting cloud water (ice) differs little from its former value. The truncating effects (effect of the diameter size limit between graupel and Hail) are also important, especially in the Hail/snow case (new accretion rate is 23 times lower compared to its former value). Such difference is due entirely to the large lower end of the Hail spectrum.
Daniela Řezáčová - One of the best experts on this subject based on the ideXlab platform.
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Radar-based Hail detection
Atmospheric Research, 2014Co-Authors: Kateřina Skripniková, Daniela ŘezáčováAbstract:Abstract Damaging Hailstorms are rare but are significant meteorological phenomena from the point of view of economic losses in central Europe. Because of the high spatial and temporal variability of Hail, the proper detection of Hail occurrences is almost impossible using ground station reports alone. An alternate approach uses information from weather radars. Several algorithms that use single-polarisation radar data have been developed for Hail detection. In the present study, seven algorithms were tested on well documented recent Hail events from Czechia and southwest Germany from 2002 to 2011. The study aimed to find the optimal threshold values for the applications of these techniques over the Czech territory and for evaluating the climatology of Hail events. The results showed that the Waldvogel technique and the NEXRAD severe Hail algorithm were the most accurate methods for Hail detection over the area of interest. A combined criterion was proposed based on a combination of previously tested techniques. The precision of this “combi-criterion” was demonstrated for a severe Hail event. The abilities of the tested criteria to provide information about a Hail-fall area distribution and Hail damage risk over the Czech territory were shown and discussed.
