1:45 PM - 2:00 PM
[MIS19-01] Numerical simulations by bulk lightning model - issues and future development -
★Invited Papers
The bulk lightning model is an extension of the meteorological model, in which the electric charge of the cloud hydrometeor is calculated as a prognostic variable. In addition to the electric charge, the electric field and potential created by the electric charge are also calculated explicitly. The development of this bulk lightning model started about the 1980s (e.g., Takahashi 1984) and, it has been developed in the United States (Mansell et al. 2005, Ziegler et al. 1991, Fierro et al. 2013), France (Barthe et al. 2012), United Kingdom (Coutier et al. 2019), and so on. In Japan, the bulk lightning model was also developed in the 2000s (e.g. Hayashi 2006) and the development has been continued (Sato et al. 2019, 2022). Using this bulk lightning model, three-dimensional structure of electric charges and the electric field for each grid, and the lightning frequency can be calculated based on physical laws. Although there are widely used empirical methods to diagnose lightning frequency using the output of the meteorological models (e.g., MaCaul et al. 2009, 2020), these do not calculate charge or electric field, but rather estimate the lightning frequency based on empirical equations from physical quantities that may be closely related to lightning (e.g., the graupel volume, the strength of the updraft, etc.). A previous studies reported that the bulk lightning model better reproduces the lightning frequencies observed in ground-based observations compared with the conventional empirical methods (Tomioka et al. 2023), and therefore, the bulk lightning model is a powerful tool for reproducing lightning frequencies. However, the use of the bulk lightning models is currently limited to ideal experiments and real case experiments over limited areas, and numerical forecasting with the bulk lightning models has not been conducted yet. In addition, the research using the bulk lightning model to interpret observations or to complement observational studies have not been widely conducted yet.
In order to overcome this situation, it is required to “reduce the computational cost of the bulk lightning models,” “obtain the observational data of atmospheric charges,” and “validate and improve the bulk lightning models through the comparison with the observations of charges”.
In this presentation, the efforts currently being made by the author's group to solve these issues will be presented.
In order to overcome this situation, it is required to “reduce the computational cost of the bulk lightning models,” “obtain the observational data of atmospheric charges,” and “validate and improve the bulk lightning models through the comparison with the observations of charges”.
In this presentation, the efforts currently being made by the author's group to solve these issues will be presented.