scholarly journals Synoptic-Scale Variations in the Polar Air-Mass Transformed over the Japan Sea

2007 ◽  
Vol 85 (2) ◽  
pp. 171-186 ◽  
Author(s):  
Kozo NINOMIYA
Keyword(s):  
Japan Sea ◽  
Synoptic Scale ◽  
Air Mass ◽  
The Japan Sea

scholarly journals Dynamical Modulation of Wintertime Synoptic-Scale Cyclone Activity over the Japan Sea due to Changbai Mountain in the Korean Peninsula

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Hiroyuki Shimizu ◽  
Ryuichi Kawamura ◽  
Tetsuya Kawano ◽  
Satoshi Iizuka
Keyword(s):  
Korean Peninsula ◽  
Japan Sea ◽  
Changbai Mountain ◽  
Mountain Range ◽  
Synoptic Scale ◽  
Cyclone Activity ◽  
Low Level ◽  
Budget Analysis ◽  
Eddy Heat Flux ◽  
The Japan Sea

The dynamical impact of the Changbai Mountain Range in the Korean Peninsula on the extratropical cyclone activity over the Japan Sea in early winter is examined using the Weather Research Forecasting model. We have conducted two independent long-term integrations over 15 winter months (December only) from 2000 to 2014 with and without modified topography. The results show that the Changbai Mountain Range plays a vital role in increasing cyclone track frequency, low-level poleward eddy heat flux, and the local deepening rate over the Japan Sea through enhancement of the lower-tropospheric baroclinic zone (LTBZ). This mountain range gives rise to activation of the synoptic-scale cyclone activity over that region. From our case study on three typical cyclones, it is found that mesoscale structures in the vicinity of a cyclone’s center are dynamically modulated when it passes through the LTBZ and that cyclogenesis is triggered around that zone. A vorticity budget analysis shows that the stretching term relevant to enhanced low-level convergence plays a dominant role in intensifying cyclonic vorticities. We confirmed that the composite features of the three typical cases are consistent with the statistical ones of the dynamical modulation of the Changbai Mountain on synoptic-scale cyclone activity.

scholarly journals Statistical Characteristics and Composite Environmental Conditions of Explosive Cyclones over the Japan Sea and Kuroshio/Kuroshio Extension

Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 17
Author(s):  
Shuqin Zhang ◽  
Gang Fu ◽  
Yu Zhang ◽  
Jianjun Xu ◽  
Yufeng Xue ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Kuroshio Extension ◽  
Japan Sea ◽  
Early Spring ◽  
Statistical Characteristics ◽  
Synoptic Scale ◽  
Explosive Cyclones ◽  
The Japan Sea ◽  
Upper Level Jet ◽  
The Kuroshio

Statistical characteristics and composite synoptic-scale environmental conditions of explosive cyclones (ECs) over the Japan Sea and Kuroshio/Kuroshio Extension are examined and compared using ERA5 atmospheric reanalysis to give a better understanding of their differences. ECs over the Japan Sea frequently occur in late autumn and early winter and those over the Kuroshio/Kuroshio Extension mainly occur in winter and early spring. The maximum deepening rate, minimum central sea level pressure and explosive-developing lifetime of ECs over the Kuroshio/Kuroshio Extension are generally larger, lower and longer, respectively, than those over the Japan Sea. ECs over the Kuroshio/Kuroshio Extension formed over the East China Sea tend to develop more rapidly, and weak and moderate ECs generally begin to develop explosively over the sea to the east of the Japan Islands, while the strong and super ECs over the sea to the south of Japan Islands have longer explosive-developing tracks. Composite analysis shows that synoptic-scale environmental conditions favoring rapid EC development over these two regions are significantly different. ECs over the Japan Sea have stronger baroclinicity and cyclonic vorticity, but weaker water vapor convergence and upper-level jet stream than those over the Kuroshio/Kuroshio Extension. The key factor contributing to the baroclinicity is the cold air intrusion over the Japan Sea and the strong warm current heating over the Kuroshio/Kuroshio Extension. The potential vorticity shows anomalies in upper and low levels for both EC areas and extends further downwards over the Japan Sea.

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