气候变化领域集成服务门户(CCPortal): The tornadoes of 30–31 May 2019 in south-Central Chile: Sensitivity to topography and SST

CCPortal

DOI	10.1016/j.atmosres.2020.105301
	The tornadoes of 30–31 May 2019 in south-Central Chile: Sensitivity to topography and SST
	Marín J.C.; Barrett B.S.; Pozo D.
发表日期	2021
ISSN	0169-8095
卷号	249
英文摘要	Tornadoes were reported in south-central Chile on 30 and 31 May 2019. To better understand the mechanisms that supported the organization and severity of the storms that generated them, a series of high-resolution sensitivity simulations were conducted using the Weather Research and Forecast (WRF) model. In addition to a control simulation, three simulations were run that successively reduced the topography to 50%, 25%, and 0% of original height; three more simulations were run that increased SST by 2 K everywhere, decreased it by 2 K everywhere, and set all SSTs greater than 16 °C to exactly 16 °C; finally, two more simulations were run to explore the combined effects of SST changes and lower topography. Results indicate that as topography was lowered, a strong northerly low-level jet along the upslope of the Andes weakened and broadened in both vertical and horizontal extent. Values of 0–6-km bulk shear and 0–3-km storm-relative helicity (SRH) over the regions where the tornadoes occurred diminished with successive reduction of the topography. As a result, simulated brightness temperatures were warmer, and swaths of updraft helicity were fewer and shorter. These results indicate that on 30–31 May 2019, flow blocking by the Andes topography generated mesoscale wind shear conditions that favored tornadoes. When SSTs were increased, instability (quantified by convective available potential energy, CAPE) also increased, although primarily offshore, and updraft helicity swath length increased, indicating a positive impact on simulated storm intensity. When SSTs were decreased, CAPE also decreased along with a decline in magnitude of updraft helicity. These results suggest that SSTs also impact storm severity via an influence on atmospheric instability. When the two factors were combined, warmer SSTs were not able to overcome a reduction in wind shear associated with a decrease in the topography. This suggests that in south-central Chile, wind shear is more important than CAPE for tornadic thunderstorms, as has been found for other regions around the world). © 2020
英文关键词	Chile; Mesoscale modeling; Sea-surface temperatures; Topography; Tornadoes
语种	英语
scopus关键词	Oceanography; Offshore oil well production; Potential energy; Shear flow; Storms; Tornadoes; Weather forecasting; Brightness temperatures; Control simulation; Convective available potential energies; High resolution; Sensitivity Simulation; Simulated storms; Tornadic thunderstorms; Weather Research and Forecast models; Topography; atmospheric modeling; sea surface temperature; sensitivity analysis; thunderstorm; topography; tornado; wind shear; Andes; Chile
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145224
作者单位	Department of Meteorology, Universidad de Valparaíso, Chile; Centro de Estudios Atmosféricos y Astroestadística, Universidad de Valparaíso, Chile; Oceanography Department, U.S. Naval Academy, Annapolis, MD 21402, United States
推荐引用方式 GB/T 7714	Marín J.C.,Barrett B.S.,Pozo D.. The tornadoes of 30–31 May 2019 in south-Central Chile: Sensitivity to topography and SST[J],2021,249.
APA	Marín J.C.,Barrett B.S.,&Pozo D..(2021).The tornadoes of 30–31 May 2019 in south-Central Chile: Sensitivity to topography and SST.Atmospheric Research,249.
MLA	Marín J.C.,et al."The tornadoes of 30–31 May 2019 in south-Central Chile: Sensitivity to topography and SST".Atmospheric Research 249(2021).