Bibliographic Details
| Title: |
How Does Asymmetric Heating near the Upstream Peninsula Modulate Extreme Rainfall on the South China Coast? |
| Authors: |
Gao, Xiaoyu1 (AUTHOR), Su, Lin2 (AUTHOR) sulin8@mail.sysu.edu.cn, Du, Yu2 (AUTHOR), Yin, Jinfang1 (AUTHOR), Zhong, Wenxiu2 (AUTHOR), Zhang, Murong3 (AUTHOR) |
| Source: |
Advances in Atmospheric Sciences. Aug2026, Vol. 43 Issue 8, p1614-1632. 19p. |
| Subject Terms: |
*Peninsulas, *Latent heat release in the atmosphere, *Heat engineering, *Atmospheric boundary layer, *Atmospheric circulation, *Coasts, *Rainstorms |
| Geographic Terms: |
Indochina, South China Sea, China |
| Abstract (English): |
Southerly flow within marine atmospheric boundary layer (MABL) plays an important role in the production of extreme rainfall (ER) on the South China coast (SCC). This study proposes a new perspective in that the Indochina Peninsula, which is upstream of the northern South China Sea (SCS) in the monsoon airflow, augments the southerlies in the MABL through thermodynamic forcing and thus enhances ER on the SCC. Using the 99th percentile hourly rainfall as the threshold, this study defines 337 coastal ER days in 30 early summers from 1988 to 2017. The ER days feature strong diabatic heating and downdraft-related adiabatic heating over the Indochina Peninsula, enhancing the southwestward low-level temperature gradient over the northern SCS, which is key to strengthening the southerlies within the MABL. Strong MABL southerly winds produce pronounced water vapor convergence over the SCC. Moreover, the diurnal variation in heating near the peninsula has an impact on the diurnal variation in the MABL wind velocities over the northern SCS, which is closely related to the diurnal ER cycle on the SCC. In numerical simulations of a typical heavy rainfall episode, ER on the SCC is significantly weakened by eliminating diabatic heating or terrain of the Indochina Peninsula in the sensitivity experiments. Weakened heating over the peninsula leads to weaker MABL southerlies and horizontal convergence near SCC, thus substantially inhibiting coastal convection. [ABSTRACT FROM AUTHOR] |
| Abstract (Chinese): |
摘 要: 海上大气边界层(MABL)中的偏南气流对华南沿海极端降水具有重要作用。本研究提出了一个新的观点,即在季风气流中处于上游的中南半岛通过热力强迫增强了南海北部MABL的偏南风,从而增强了华南沿海的极端降水。本研究统计了1988-2017年间30个华南前汛期的小时降水量,以第99百分位的降水量为阈值,定义了337个华南沿海的极端降水日。在这期间,中南半岛具有较强的非绝热加热,背风坡下沉增温更强,增强了南海北部低层大气中东北-西南向的温度梯度,从而导致了MABL中偏南风的加强。此外,半岛地区温度的日变化影响着南海北部MABL风速的日变化,这与华南沿海极端降水的日变化密切相关。在一次典型暴雨个例的数值模拟中,降低中南半岛地形或关闭其非绝热加热均可以显著减弱华南沿海极端降水。半岛地区加热的减弱导致MABL的偏南风减弱,从而显著抑制了华南沿海的辐合与对流发展。 [ABSTRACT FROM AUTHOR] |
| Database: |
Energy & Power Source |
