DOI: 10.1073/pnas.2007998117
论文题名: Dry soils can intensify mesoscale convective systems
作者: Klein C. ; Taylor C.M.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2020
卷: 117, 期: 35 起始页码: 21132
结束页码: 21137
语种: 英语
英文关键词: Mesoscale convective systems | propagating convection | soil moisture | dry line
Scopus关键词: article
; drought
; human
; human experiment
; Sahel
; satellite imagery
; severe weather
; soil moisture
; thermodynamics
英文摘要: Soil moisture can feed back on rainfall through the impact of surface fluxes on the environment in which convection develops. The vast majority of previous research has focused on the initiation of convection, but in many regions of the world, the majority of rain comes from remotely triggered mesoscale convective systems (MCSs). Here we conduct a systematic observational analysis of soil moisture feedbacks on propagating MCSs anywhere in the world and show a strong positive impact of drier soils on convection within mature MCSs. From thousands of storms captured in satellite imagery over the Sahel, we find that convective cores within MCSs are favored on the downstream side of dry patches ≥200 km across. The effect is particularly strong during the afternoon–evening transition when convection reaches its diurnal peak in intensity and frequency, with dry soils accounting for an additional one in five convective cores. Dry soil patterns intensify MCSs through a combination of convergence, increased instability, and wind shear, all factors that strengthen organized convection. These favorable conditions tend to occur in the vicinity of a surface-induced anomalous displacement of the Sahelian dry line/intertropical discontinuity, suggesting a strong link between dry line dynamics and soil moisture state. Our results have important implications for nowcasting of severe weather in the Sahel and potentially in other MCS hotspot regions of the world. © 2020 National Academy of Sciences. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164061
Appears in Collections: 气候变化与战略
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作者单位: Klein, C., UK Centre for Ecology and Hydrology, Wallingford, OX10 8BB, United Kingdom, Department of Atmospheric and Cryospheric Sciences, University of Innsbruck, Innsbruck, 6020, Austria; Taylor, C.M., UK Centre for Ecology and Hydrology, Wallingford, OX10 8BB, United Kingdom, National Centre for Earth Observation, Wallingford, OX10 8BB, United Kingdom
Recommended Citation:
Klein C.,Taylor C.M.. Dry soils can intensify mesoscale convective systems[J]. Proceedings of the National Academy of Sciences of the United States of America,2020-01-01,117(35)