TY - JOUR
T1 - Numerical investigation of development processes of Baiu frontal depressions part I
T2 - Case studies
AU - Tochimoto, Eigo
AU - Kawano, Tetsuya
N1 - Funding Information:
We would like to thank Prof. C. Davis of MMM of the Earth and Sun Systems Laboratory at NCAR for providing the program for the piecewise PV inversion technique. We are grateful to Prof. H. Itoh and R. Kawamura of Kyushu University, Prof. C. H. Kuo of National Taiwan University, Prof. H. Niino and Dr. W. Yanase of the Atmosphere and Ocean Research Institute, the University of Tokyo, and Dr. A. Yamazaki of Japan Agency for Marine-Earth Science and Technology for their useful comments. We also would like to thank Dr. T. Kato and two anonymous reviewers for their constructive comments. This work was supported by JSPS KAKENHI Grant Number 25400466.
Publisher Copyright:
© 2017, Meteorological Society of Japan.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017
Y1 - 2017
N2 - This work investigates the development processes of Baiu frontal depressions (BFDs) using a numerical model. To investigate the effects of upper-level disturbances, latent heating, and baroclinicity on the development of BFDs, case-study numerical simulations are performed. In the present study, 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) from 26 to 27 June, 2003, and a BFD that had formed in the eastern part of the Baiu frontal zone (E-BFD) from 1 to 3 July, 2003. An available potential energy diagnosis shows that 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. A sensitivity experiment excluding upper-level potential vorticity (PV) anomalies shows that upperlevel disturbances are important contributors to the development of E-BFDs. The low-level PV and its production associated with latent heating suggest that 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. In contrast, the E-BFD develops through a baroclinic instability- like mechanism in the moist atmosphere.
AB - This work investigates the development processes of Baiu frontal depressions (BFDs) using a numerical model. To investigate the effects of upper-level disturbances, latent heating, and baroclinicity on the development of BFDs, case-study numerical simulations are performed. In the present study, 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) from 26 to 27 June, 2003, and a BFD that had formed in the eastern part of the Baiu frontal zone (E-BFD) from 1 to 3 July, 2003. An available potential energy diagnosis shows that 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. A sensitivity experiment excluding upper-level potential vorticity (PV) anomalies shows that upperlevel disturbances are important contributors to the development of E-BFDs. The low-level PV and its production associated with latent heating suggest that 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. In contrast, the E-BFD develops through a baroclinic instability- like mechanism in the moist atmosphere.
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U2 - 10.2151/jmsj.2017-005
DO - 10.2151/jmsj.2017-005
M3 - Article
AN - SCOPUS:85015783514
VL - 95
SP - 91
EP - 109
JO - Journal of the Meteorological Society of Japan
JF - Journal of the Meteorological Society of Japan
SN - 0026-1165
IS - 2
ER -