Formation, Thermodynamic Structure, and Airflow of a Japan Sea Polar Airmass Convergence Zone
Formation, Thermodynamic Structure, and Airflow of a Japan Sea Polar Airmass Convergence Zone
复制标题
DOI：
10.1175/mwr-d-21-0095.1
复制
发表时间：
2022-01-01
影响因子：
3.2
通讯作者：
Steenburgh, W. James
中科院分区：
文献类型：
--
作者：
West, Tyler K.;Steenburgh, W. James
日本海（SOJ）海岸和毗邻的地形中部本州，日本，每年冬天收到大量的降雪。在冷空气爆发（CAOs）期间，日本海极地气团辐合带（JPCZ）是一个频繁的贡献者，它形成于朝鲜半岛高地地区（即朝鲜高地）的下游，向东南延伸至本州，并产生中尺度降水带。中尺度极涡（mpv）的水平尺度从几十公里（即中尺度气旋）到几百公里（即“极低”）在cao期间也很常见，并且经常与JPCZ相互作用。在这里，我们使用卫星图像和天气研究与预报模型模拟来研究2018年2月2日至7日CAO期间MPV后形成的JPCZ的形成、热力学结构和气流。低压及其相关的暖隐蔽性和后弯锋在靠近朝鲜半岛底部的SOJ上空形成了一个局部温暖、辐合和对流的环境。初生的JPCZ在结构上是连续的，锋面后弯，并随着MPV向东南移动而延长。轨迹说明了在朝鲜高地周围的海气相互作用和气流分裂以及沿着亚洲海岸的低通道和山谷的通道如何影响JPCZ的形成和热力学结构。SOJ上空的气团来源和热力变化的差异影响了跨JPCZ的温度梯度，从亚洲海岸到本州沿JPCZ的温度梯度在符号上反转。这些结果为JPCZ的热力学结构提供了新的见解，JPCZ是日本危险天气的重要贡献者。
The Sea of Japan (SOJ) coast and adjoining orography of central Honshu, Japan, receive substantial snowfall each winter. A frequent contributor during cold-air outbreaks (CAOs) is the Japan Sea polar airmass convergence zone ( JPCZ), which forms downstream of the highland areas of the Korean Peninsula (i.e., the Korean Highlands), extends southeastward to Honshu, and generates a mesoscale band of precipitation. Mesoscale polar vortices (MPVs) ranging in horizontal scale from tens (i.e., meso-beta-scale cyclones) to several hundreds of kilometers (i.e., "polar lows") are also common during CAOs and often interact with the JPCZ. Here we use satellite imagery and Weather Research and Forecasting Model simulations to examine the formation, thermodynamic structure, and airflow of a JPCZ that formed in the wake of an MPV during a CAO from 2 to 7 February 2018. The MPV and its associated warm seclusion and bent-back front developed in a locally warm, convergent, and convective environment over the SOJ near the base of the Korean Peninsula. The nascent JPCZ was structurally continuous with the bent-back front and lengthened as the MPV migrated southeastward. Trajectories illustrate how air-sea interactions and flow splitting around the Korean Highlands and channeling through low passes and valleys along the Asian coast affect the formation and thermodynamic structure of the JPCZ. Contrasts in airmass origin and thermodynamic modification over the SOJ affect the cross-JPCZ temperature gradient, which reverses in sign along the JPCZ from the Asian coast to Honshu. These results provide new insights into the thermodynamic structure of the JPCZ, which is an important contributor to hazardous weather over Japan.