5:15 PM - 6:45 PM
[AAS08-P03] Influence of Japanese mountains on the structure of explosive cyclones
Keywords:Explosive cyclone, Mountains, structure change
The explosive development of explosive cyclones in the mid-latitude pressure zone can lead to severe meteorological disasters such as high tides, high waves, storms, and heavy snowfall in a short period, particularly in the vicinity of Japan. In recent years, the damage caused by explosive cyclones has been significant in northern Japan and Hokkaido. The explosive cyclone that occurred in March 2013, near Hokkaido, suggested that a structural change near the center of the low-pressure system contributed to the occurrence of blizzard conditions. This structural change was indicated to be influenced by the sea ice in the Okhotsk Sea, but the possibility of the complex terrain in mountains of Honshu, Japan contributing to the complication of the low-pressure system cannot be ruled out. In fact, the Changbai Mountains, with elevations comparable to the mountains in Honshu, Japan, is suggested to have a significant impact on the formation of the Japan Sea Polar Current Zone (JPCZ) and the structure of low-pressure systems, unleashing its influence in the Japan Sea. Therefore, this study focuses on the explosive cyclone that passed through Hokkaido in February 2013. The objective is to investigate the impact of Japan's mountainous terrain on the structure of explosive cyclones through elevation modification experiments and to clarify its influence on the increasing blizzards in Hokkaido.
As aresult,Through modification experiments, it was observed that the barrier effect of mountains of Honshu played a role in influencing the structural changes of the low-pressure system during the rapid development process. The comparison of south-north winds and specific humidity revealed that, in contrast to the CTL run, the MOD run exhibited a weakening of northward moisture transport toward the center of the low-pressure system. Consequently, there was a reduction in precipitation associated with the Warm Conveyor Belt (WCB).
The comparison of horizontal wind speeds at 950[ hPa] and sea-level corrected atmospheric pressure revealed that, in the MOD run, the meso-low-pressure system observed off the Sanriku coast in the CTL run was absent. Furthermore, during the peak development phase, the axisymmetric structure near the center of the low-pressure system was more distinct in MOD compared to CTL, resulting in differences in the wind speed distribution.
As aresult,Through modification experiments, it was observed that the barrier effect of mountains of Honshu played a role in influencing the structural changes of the low-pressure system during the rapid development process. The comparison of south-north winds and specific humidity revealed that, in contrast to the CTL run, the MOD run exhibited a weakening of northward moisture transport toward the center of the low-pressure system. Consequently, there was a reduction in precipitation associated with the Warm Conveyor Belt (WCB).
The comparison of horizontal wind speeds at 950[ hPa] and sea-level corrected atmospheric pressure revealed that, in the MOD run, the meso-low-pressure system observed off the Sanriku coast in the CTL run was absent. Furthermore, during the peak development phase, the axisymmetric structure near the center of the low-pressure system was more distinct in MOD compared to CTL, resulting in differences in the wind speed distribution.