Origin of Strong Winds in an Explosive Mediterranean Extratropical Cyclone
Origin of Strong Winds in an Explosive Mediterranean Extratropical Cyclone
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DOI：
10.1175/mwr-d-19-0009.1
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发表时间：
2019-09
影响因子：
3.2
通讯作者：
M. Brâncuş;D. Schultz;B. Antonescu;C. Dearden;S. Stefan
中科院分区：
文献类型：
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作者：
M. Brâncuş;D. Schultz;B. Antonescu;C. Dearden;S. Stefan
2012年12月2日至3日，黑海和罗马尼亚东海岸受到一场迅速加深的地中海气旋的影响。气旋发展出一个沿着的后向锋，气旋中心赤道方向测得持续时间短（2-4小时）的风速高达38 m s−1。中尺度模式模拟被用来分析风场的演变，调查的物理过程，负责强风和他们的加速，并调查的相对重要性，这些强风的边界层的稳定性。气旋中心赤道方向最大风区的空气来源有两个方面。第一次是与一个刺喷流有关，这是一股从云头中层和温暖传送带气旋分支下部下降的气流。刺式急流开始从气旋中心以西下降，最后到达后弯锋的溶锋尖端。第二股是与冷传送带相关的低空气流，起源于气旋中心东北部，沿着弯曲锋面的冷侧在900百帕以下行进，结束于冷锋后面。两股气流都受到顺流压力梯度力的加速，在进入近地面强风区之前，最大的加速度作用在刺射流上。感热通量使气旋中心以南的边界层变得不稳定，接近中性条件，促进向下混合，并允许下降的空气到达地面。中尺度的不稳定性似乎是不重要的刺射流的形成。
During 2–3 December 2012, the Black Sea and east coast of Romania were affected by a rapidly deepening Mediterranean cyclone. The cyclone developed a bent-back front along which short-lived (2–4 h) strong winds up to 38 m s−1 were recorded equatorward of the cyclone center. A mesoscale model simulation was used to analyze the evolution of the wind field, to investigate the physical processes that were responsible for the strong winds and their acceleration, and to investigate the relative importance of the stability of the boundary layer to those strong winds. The origin of the air in the wind maximum equatorward of the cyclone center was twofold. The first was associated with a sting jet, a descending airstream from the midlevels of the cloud head and the lower part of the cyclonic branch of the warm conveyor belt. The sting jet started to descend west of the cyclone center, ending at the frontolytic tip of the bent-back front. The second was a low-level airstream associated with the cold conveyor belt that originated northeast of the cyclone center and traveled below 900 hPa along the cold side of the bent-back front, ending behind the cold front. Both airstreams were accelerated by the along-flow pressure gradient force, with the largest accelerations acting on the sting-jet air before entering into the near-surface strong-wind area. The sensible heat fluxes destabilized the boundary layer to near-neutral conditions south of the cyclone center, facilitating downward mixing and allowing the descending air to reach the surface. Mesoscale instabilities appeared to be unimportant in the sting-jet formation.