Graphical Abstract

Tochimoto, E., and T. Kawano, 2017: Numerical investigation of development processes of Baiu frontal depressions. Part I : Case studies. J. Meteor. Soc. Japan, 95, 91-109.
https://doi.org/10.2151/jmsj.2017-005 Graphical Abstract with highlights

This work investigates development processes of Baiu frontal depressions (BFDs) using WRF model. Two typical cases were selected from BFDs that appeared in June and July, 2000-2007: a BFD that developed in the western part of the Baiu frontal zone (W-BFD) and a BFD that had formed in the eastern part of the Baiu frontal zone (E-BFD).
The effect of latent heating is dominant during the W-BFD development, while baroclinicity as well as latent heating is important to the E-BFD development.
The W-BFD has a development mechanism driven by latent heating. In the early developmental stage, PV near the W-BFD center is enhanced. This feature is consistent with the nonlinear conditional instability of the second kind mechanism. In the later developmental stage, PV is produced in front of the W-BFD center, in which low-level baroclinicity is large. This process is consistent with a diabatic Rossby vortex.