Diurnal Cloud and Circulation Changes in Simulated Tropical Cyclones
Diurnal Cloud and Circulation Changes in Simulated Tropical Cyclones
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DOI：
10.1029/2018gl081302
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发表时间：
2019-01
影响因子：
5.2
通讯作者：
J. Ruppert;Morgan E. O'Neill
中科院分区：
文献类型：
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作者：
J. Ruppert;Morgan E. O'Neill
对热带气旋（TC）的昼夜周期的观察表明，峰值降雨速率和TC云笼中的Anvil云的最大高度之间存在约12小时的偏移。降雨，垂直云的生长和砧云之间的紧密耦合。从低中间和对流层中的白天进行夜间夜间夜间夜间循环状态，这是由夜间充满活力的深层转换而驱动的在光学厚的TC云冠层中进行加热。 TC云冠层的上层砧云的振兴。
Observations of the diurnal cycle in tropical cyclones (TCs) systematically indicate a ∼12‐hr offset between peak rainfall rate and the maximum height of anvil clouds in the TC cloud canopy. This phasing conflicts with archetypal models of organized deep convection, which suggest a tight coupling between rainfall, vertical cloud growth, and anvil clouds. We show that this phasing owes to the bimodal diurnal evolution of the transverse circulation, which peaks nocturnally from low–midlevels, and during daytime in the upper troposphere. The bottom‐heavy nocturnal circulation state is driven by latent heating from nocturnally invigorated deep convection, while the top‐heavy daytime state is the thermally direct circulation response to strong shortwave‐cloud warming in the optically thick TC cloud canopy. This daytime upper‐level circulation response manifests in a lifting of the maximum height of the TC outflow and, in turn, a lifting and invigoration of the upper‐level anvil clouds of the TC cloud canopy.