气候变化领域集成服务门户(CCPortal): Effects of Local-Scale Orography and Urban Heat Island on the Initiation of a Record-Breaking Rainfall Event

CCPortal

DOI	10.1029/2021JD034839
	Effects of Local-Scale Orography and Urban Heat Island on the Initiation of a Record-Breaking Rainfall Event
	Wu Y.; Sun J.; Ying Z.; Xue L.; Chen D.; Lin W.
发表日期	2021
ISSN	2169-897X
卷号	126 期号:16
英文摘要	A record-breaking rainfall event was initiated between the urban heat island (UHI) and a small trumpet-shaped mountain (Huadu Mountain) to its north in Guangzhou City at midnight of May 6, 2017. Numerically simulating the convection initiation (CI) was challenging due to insufficient model resolution and inaccurate boundary layer parameterization, this study therefore examined the pre-convective mesoscale processes based on their four-dimensional analyses obtained through data assimilation of radar and surface observations using the four-dimensional Variational Doppler Radar Analysis System (VDRAS). Results suggested that the Huadu Mountain to the north of Guangzhou City played a crucial role in the CI through orographic blocking and nighttime cooling. Dynamically, the mountain blocked the upstream airflow causing an accumulation of water vapor in boundary layers; thermally, the large near-surface temperature gradients between the mountain and its southern foot area induced northerly downslope winds and low-level convergences and updrafts. The downslope winds enhanced the accumulation of boundary-layer water vapor, which was then transported to higher altitudes over the CI region by the updrafts, thus resulting in the formation and growth of cloud water above the altitude of 1 km. In addition to the mountain, the UHI also played an important role by increasing the magnitude of the low-level convergence and influencing its horizontal distribution. These findings urge attentions to the critical roles of small-scale orography and its interaction with urban underlying surface in initiating local rainstorm events. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	Convergences; mesoscale processes; observational analyses; orographic blocking
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/237110
作者单位	Guangdong-Hong Kong-Macao Greater Bay Area Weather Research Center for Monitoring Warning and Forecasting (Shenzhen Institute of Meteorological Innovation), Shenzhen, China; National Center for Atmospheric Research, Boulder, CO, United States; School of Atmospheric Sciences, Sun Yat-Sen University, Guangzhou, China; Key Laboratory of Regional Numerical Weather Prediction / Guangzhou Institute of Tropical & Marine Meteorology, Guangzhou, China
推荐引用方式 GB/T 7714	Wu Y.,Sun J.,Ying Z.,et al. Effects of Local-Scale Orography and Urban Heat Island on the Initiation of a Record-Breaking Rainfall Event[J],2021,126(16).
APA	Wu Y.,Sun J.,Ying Z.,Xue L.,Chen D.,&Lin W..(2021).Effects of Local-Scale Orography and Urban Heat Island on the Initiation of a Record-Breaking Rainfall Event.Journal of Geophysical Research: Atmospheres,126(16).
MLA	Wu Y.,et al."Effects of Local-Scale Orography and Urban Heat Island on the Initiation of a Record-Breaking Rainfall Event".Journal of Geophysical Research: Atmospheres 126.16(2021).