Understanding moisture information ahead of tropical cyclone (TC) convection is very important for predicting TC track, intensity, and precipitation. The advanced Himawari imager onboard the Japanese Himawari‐8/‐9 satellite can provide high spatial and temporal resolution moisture information. Three‐layered precipitable water (LPW) with its three water vapor absorption infrared bands can be assimilated to generate better understanding and prediction of TC evolution. The impacts of LPW assimilation in the Weather Research and Forecasting model with nine combinations of physical parameterization schemes, including three cumulus parameterization (CP) and three microphysics parameterization (MP) schemes on TC prediction, have been comprehensively analyzed using Typhoon Hato as a case study. The results indicate that LPW assimilation reduces the average track error and speed up TC movement by better adjustment of the atmospheric circulation fields via changing the vertical structure of moisture and thermal profile. The track forecasts retain sensitivity to CP schemes after LPW assimilation. Also, LPW assimilation improves TC intensity prediction because the latent heat release process is accurately adjusted. It has been revealed that LPW assimilation can weaken the intensity sensitivity to MP schemes more than to CP schemes. Skill scores were used to evaluate precipitation forecasts after Hato's landfall. The results indicate that heavy precipitation forecasts are more sensitive to the choice of MP schemes. After LPW assimilation, the equitable threat scores among different results become similar and all forecast skills are increased. In addition, group statistic results with different initial time show the same conclusions.

In this paper, the phenomenon of the asymmetric energy transmission is numerically investigated in the forbidden band of the electrical transmission line formed by two nonlinear segments which are identical in structure but different in inductor parameter. By considering the driving voltage at the frequency within the forbidden bands of both segments, the carrier of the asymmetric energy flux is the nonlinear wave beyond the band, instead of the linear wave in the passband, and the mechanism is closly related to the nonlinear supratransmission. To further understand this phenomenon in electrical transmission line, we also study the correlations between the energy intensity and the circuit parameters. Finally, we investigate the dependency of the voltage threshold on the driving frequency in physical experiment, and the result is qualitatively identical with that calculated by using equation.

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Icing in winter is an important disaster that affects the normal operation of transmission lines. Among them, icing is easy to lead to tower collapse and disconnection. Due to long recovery time, great economic loss and social impact, it poses an important threat to the stable operation and reliable power supply of power grid. At present, the research on ice covered tower breaking fault of transmission lines mainly focuses on the finite element simulation analysis and calculation or exponential function fitting calculation. Due to the complexity of the mechanism of transmission line icing tower breakage, the current physical mechanism research conclusion cannot explain the occurrence of icing tower breakage. The existing analysis methods cannot accurately describe the characteristics of transmission line icing tower broken fault probability. Therefore, this paper proposes a probability calculation model based on probability distribution statistics, which can quantitatively calculate the failure probability of transmission line icing tower breakage. It has important theoretical significance and practical application value to provide scientific basis for transmission line to deal with icing disaster in advance.

Ice galloping is one of the disasters that have the greatest impact on the safe operation of transmission lines in winter. This article analyze the characteristics and prevention method of ice galloping of electric grid transmission lines based on finite element method. The amplitude and time response of transmission line during ice galloping can be obtained. A new type of efficient anti-galloping interface spacer is proposed, which can reduce the galloping amplitude. The effectiveness of the proposed method and model is verified by application examples.

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