MESO-BETA-SCALE VORTICES DEVELOPING ALONG THE JAPAN-SEA POLAR-AIRMASS CONVERGENCE ZONE (JPCZ) CLOUD BAND - NUMERICAL-SIMULATION
MESO-BETA-SCALE VORTICES DEVELOPING ALONG THE JAPAN-SEA POLAR-AIRMASS CONVERGENCE ZONE (JPCZ) CLOUD BAND - NUMERICAL-SIMULATION
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DOI：
10.2151/jmsj1965.71.1_43
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发表时间：
1993-02-01
影响因子：
3.1
通讯作者：
NAGATA, M
中科院分区：
文献类型：
--
作者：
NAGATA, M
一个高分辨率（6公里网格，36度北纬）单向三套流体静力数值模式成功地模拟了沿日本海极气团辐合带（JPCZ）云带发展的中尺度涡旋。模拟的旋涡的主要特征包括一个直径几十公里的“眼状”结构和周围向上运动的螺旋带。模拟涡首先沿JPCZ以10(-3)s-1量级的正涡量集中带弯曲出现。弯曲变得越来越尖锐，最终涡度带的槽将自身包裹起来，在4-8小时内形成压力不足2-4 hPa的中尺度气旋，伴随着干眼和上升运动的螺旋带。一个温暖的核心特征是眼和邻近潮湿的上升。简单线性理论与模拟结果不仅在空间尺度和时间尺度上一致，而且模拟扰动的能量转换分析表明，正压剪切不稳定是中尺度涡发展的主要机制。
A high-resolution (6.0-km grid at 36-degrees-N) one-way triple-nested hydrostatic numerical model successfully simulates meso-beta-scale vortices developing along the Japan-Sea Polar-airmass Convergence Zone (JPCZ) cloud band. Simulated key features of the vortices include an ''eye-like'' structure with its diameter of several tens of kilometers and surrounding spiral bands of upward motion.The simulated vortices emerge first as bendings in a belt of concentrated positive vorticity on the order of 10(-3) s-1 along the JPCZ. The bendings become increasingly sharp and eventually their troughs of the vorticity belt wrap round themselves to form meso-beta-scale cyclones with a pressure deficit of 2-4 hPa accompanied by a dry eye and spiral bands of upward motion, within 4-8 hours. A warm core characterizes the eye and adjacent moist ascent. Not only agreement in spatial scale and time scale for growth between simple linear theory and the simulation, but energy conversion analysis of the simulated disturbance show barotropic shear instability for the dominant developing mechanism of the meso-beta-scale vortices.