Strong Correlation of Electrons in Mesoscopic Ring under Magnetic Field

The influence of the electron-electron Hubbard interaction on the magnetoconductance fluctuations in disordered ring system is studied by using the recursion real-space Green\u27s function technique in the tight-binding model. The numerical calculations show that the Hubbard interaction decreases the range of the nonzero magnetoconductance as a function of Fermi level and the amplitudes of the magnetoconductance fluctuations under low magnetic flux, which is consistent with experimental results

Radar Echo Population of Thunderstorms and Feasibility Study on Nowcasting of Thunderstorm-induced Local Heavy Rainfalls

This study shows a statistical analysis of air-mass type thunderstorms generated in the Tokyo Metropolitan Area on 5 August 2008 using three-dimensional radar reflectivity data. Possibility of nowcasting local heavy rainfalls induced by the thunderstorms is also examined by using the radar data and the lightning data

Radar Echo Population of Air-Mass Thunderstorms and Nowcasting of Thunderstorm-Induced Local Heavy Rainfalls Part 1: Statistical Characteristics

A radar echo population of 179 thunderstorms generated in the Tokyo metropolitan area on August 5, 2008, when the Zoshigaya rainstorm occurred in the center of Tokyo, is presented. Analysis was made using three-dimensional radar data from the Japan Meteorological Agency. One third of total convective cells had diameters of less than 3.5 km and the average diameter was 5.5 km. The mode of lifetimes of cells was from 20 to 40 minutes, and 88% of cells disappeared within 60 minutes after their initiation. The echo-top height of half of the cells reached 15 km, which was the limit of radar observation. Although the rainfall amount estimated from the radar echo was less than 40 mm for half of the cells, whereas one third of total cells counted were estimated atmore than 60 mm. Vertically integrated liquid water (VIL) ranged from 1.4 to 42.4 kgm[-2]. Maximum VIL was equivalent to 70% of precipitable water estimated from upper sounding on that day. The speed of cell travel was less than 2 ms[-1] in accordance with the weak wind velocities in the lower to middle troposphere. The time from echo initiation to rainfall peak was as short as 10 to 30 minutes for almost all cells. Thunderstorms composing the Zoshigaya rainstorm ranked at the highest class in horizontal size, lifetime and total rainfall amount among 179 thunderstorms. The horizontal size of cells in the thunderstorms was nearly equal to those reported for other areas in the world, whereas the echo top height was higher than in the other cases

Radar Echo Population of Air-Mass Thunderstorms and Nowcasting of Thunderstorm-Induced Local Heavy Rainfalls Part II: A Feasibility Study on Nowcasting

Many air-mass thunderstorms were generated in the Tokyo metropolitan area on August 5, 2008, when a severe local rainstorm caused a flash flood in the center of Tokyo. Using three-dimensional radar reflectivity data from the Japan Meteorological Agency (JMA), nowcasting was examined concerning the peak time and peak rainfall intensity of thunderstorms. Four qualitative forecastmethods – precipitation cores aloft, time changes in vertically integrated liquid water, time changes in echo-top height, lightning activity – and three quantitative forecast methods using three parameters were adopted in eight thunderstorms related to heavy-rainfall warnings issued by the JMA on August 5, 2008. While there is much worth further examination in the method using precipitation core aloft, the other methods are not in the stage of operational use in order to forecast time and rainfall intensity at the rainfall peak of each thunderstorm