气候变化领域集成服务门户(CCPortal): The Role of Convective Self-Aggregation in Extreme Instantaneous Versus Daily Precipitation

CCPortal

DOI	10.1029/2018MS001503
	The Role of Convective Self-Aggregation in Extreme Instantaneous Versus Daily Precipitation
	Bao J.; Sherwood S.C.
发表日期	2019
ISSN	19422466
起始页码	19
结束页码	33
卷号	11 期号:1
英文摘要	The impacts of convective self-aggregation on extreme precipitation and updraft velocity are investigated by using the Weather Research and Forecasting Model in the idealized setting of radiative-convective equilibrium with a 3-km horizontal resolution. Aggregated and unaggregated states are achieved by conducting simulations with fully interactive and fixed radiation, respectively. We find that convective self-aggregation has a negligible impact on extreme instantaneous precipitation but weakens the extreme updrafts and condensation, indicating a negative dynamical contribution from aggregation to extreme instantaneous precipitation. However, this is balanced by higher precipitation efficiency to maintain the same extreme instantaneous precipitation. This balance occurs because updrafts decrease mainly above the freezing level, suppressing graupel production. As graupel has a longer residence time than rain, less graupel formation with aggregation implies enhanced instantaneous local precipitation efficiency. Peak updraft velocity scales with the vertical integral of buoyancy, measured with respect to the local prestorm environment. This local environment is warmer and moister at middle and high levels when convection is aggregated compared to when it is unaggregated, reducing the buoyancy and updraft velocity. Unlike extreme instantaneous precipitation, extreme daily precipitation is stronger in aggregated states, as self-aggregation localizes and sustains updrafts and condensation in relatively fixed locations. Our results imply that extreme instantaneous precipitation is more sensitive to microphysical processes while extreme daily precipitation is more linked to the degree of aggregation. ©2018. The Authors.
英文关键词	convective updraft; extreme precipitation; microphysics; precipitation efficiency; radiative-convective equilibrium; self-aggregation
语种	英语
scopus关键词	Buoyancy; Condensation; Efficiency; Weather forecasting; convective updraft; Extreme precipitation; Microphysics; Precipitation efficiency; Radiative-convective equilibrium; Self aggregation; Rain; atmospheric convection; cloud microphysics; convection; precipitation (climatology); updraft
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/157000
作者单位	Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, NSW, Australia
推荐引用方式 GB/T 7714	Bao J.,Sherwood S.C.. The Role of Convective Self-Aggregation in Extreme Instantaneous Versus Daily Precipitation[J],2019,11(1).
APA	Bao J.,&Sherwood S.C..(2019).The Role of Convective Self-Aggregation in Extreme Instantaneous Versus Daily Precipitation.Journal of Advances in Modeling Earth Systems,11(1).
MLA	Bao J.,et al."The Role of Convective Self-Aggregation in Extreme Instantaneous Versus Daily Precipitation".Journal of Advances in Modeling Earth Systems 11.1(2019).