Thermodynamic Impact of the Heated Landmass on the Nocturnal Evolution of a Cloud Cluster over a Meiyu-Baiu Front
Thermodynamic Impact of the Heated Landmass on the Nocturnal Evolution of a Cloud Cluster over a Meiyu-Baiu Front
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DOI：
10.2151/jmsj.85.663
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发表时间：
2007-10
影响因子：
3.1
通讯作者：
H. Yamada;B. Geng;H. Uyeda;K. Tsuboki
中科院分区：
文献类型：
--
作者：
H. Yamada;B. Geng;H. Uyeda;K. Tsuboki
利用非流体静力模式对梅雨-白锋面上的云团进行了数值模拟。目的是为了证明中国大陆的日加热对星团夜间演化的热力学影响。模拟在覆盖中国东部和南部的区域内进行，以重现锋面南侧的地表加热。模拟的个案是与该星团有关的一个雨带，该星团于2003年6月22日下午晚些时候形成。环境的特征是对流层低层暖湿空气向南流入的天气尺度。控制模拟成功地再现了该雨带，并表明这一演变是由于锋面辐合区上方暖湿空气向南流入造成的强烈潜在不稳定所致。这种空气的来源是锋面以南无云地区的地表热通量。加热的重要性通过没有日照的灵敏度模拟得到了证明，该模拟未能重现深对流上升气流。水分收支分析表明，在雨带演化之前，可降水量的增加主要是由地面蒸发而非水汽辐合造成的。因此，这项研究表明，大陆表面在日晒加热下，对梅雨-白雨锋面云团的夜间演化有显著影响。
Numerical simulations of a cloud cluster over a Meiyu-Baiu front were conducted using a cloud-resolving non-hydrostatic model. The purpose was to demonstrate thermodynamic impact of the diurnal heating of the mainland China upon the nocturnal evolution of the cluster. Simulations were conducted within a domain covering eastern and southern China to reproduce land-surface heating on the southern side of the front. The case simulated was a rainband associated with the cluster, which formed on the late afternoon of 22 June 2003. The environment is characterized by a synoptic-scale southerly inflow of warm and moist air in the lower troposphere. A control simulation reproduced the rainband successfu11y, and showed that the evolution resulted from the strong latent instability over the frontal convergence zone, due to the southerly inflow of the warm and moist air. The origin of this air was the surface heat flux over a cloud-free area to the south of the front. The importance of the heating was proved by a sensitivity simulation without insolation, which failed to reproduce deep convective updrafts. The water budget analysis demonstrated that the evaporation from the ground, rather than the moisture convergence, contributed to the increase in the precipitable water before the rainband evolution. This study, thus, indicates that the continental surface, heated by insolation, has a significant impact upon the nocturnal evolution of a cloud cluster over a Meiyu-Baiu front.