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| DOI | 10.1175/JCLI-D-20-0194.1 |
| Seasonality and trends of drivers of mesoscale convective systems in Southern West Africa | |
| Klein C.; Nkrumah F.; Taylor C.M.; Adefisan E.A. | |
| 发表日期 | 2021 |
| ISSN | 0894-8755 |
| 起始页码 | 71 |
| 结束页码 | 87 |
| 卷号 | 34期号:1 |
| 英文摘要 | Mesoscale convective systems (MCSs) are the major source of extreme rainfall over land in the tropics and are expected to intensify with global warming. In the Sahel, changes in surface temperature gradients and associated changes in wind shear have been found to be important for MCS intensification in recent decades. Here we extend that analysis to southern West Africa (SWA) by combining 34 years of cloud-top temperatures with rainfall and reanalysis data. We identify clear trends in intense MCSs since 1983 and their associated atmospheric drivers. We also find a marked annual cycle in the drivers, linked to changes in the convective regime during the progression of the West African monsoon. Before the peak of the first rainy season, we identify a shear regime where increased temperature gradients play a crucial role for MCS intensity trends. From June onward, SWA moves into a less unstable, moist regime during which MCS trends are mainly linked to frequency increase and may be more influenced by total column water vapor. However, during both seasons we find that MCSs with the most intense convection occur in an environment with stronger wind shear, increased low-level humidity, and drier midlevels. Comparing the sensitivity of MCS intensity and peak rainfall to low-level moisture and wind shear conditions preceding events, we find a dominant role for wind shear. We conclude that MCS trends are directly linked to a strengthening of two distinct convective regimes that cause the seasonal change of SWA MCS characteristics. However, the convective environment that ultimately produces the most intense MCSs remains the same. © 2020 American Meteorological Society |
| 英文关键词 | Atmospheric humidity; Global warming; Rain; Thermal gradients; Cloud-top temperatures; Extreme rainfall; Increased temperature; Mesoscale Convective System; Rainy seasons; Seasonal changes; Surface temperature gradient; West African Monsoon; Storms; convective system; mesoscale meteorology; rainfall; seasonal variation; seasonality; temperature gradient; trend analysis; wind shear; Sahel [Sub-Saharan Africa] |
| 语种 | 英语 |
| 来源期刊 | Journal of Climate
 |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://gcip.llas.ac.cn/handle/2XKMVOVA/170968 |
| 作者单位 | U.K. Centre for Ecology and Hydrology, Wallingford, United Kingdom; Department of Atmospheric and Cryospheric Sciences, University of Innsbruck, Innsbruck, Austria; University of Cape Coast, Cape Coast, Ghana; National Centre for Earth Observation, Wallingford, United Kingdom; Federal University of Technology, Akure, Nigeria |
| 推荐引用方式 GB/T 7714 | Klein C.,Nkrumah F.,Taylor C.M.,et al. Seasonality and trends of drivers of mesoscale convective systems in Southern West Africa[J],2021,34(1). |
| APA | Klein C.,Nkrumah F.,Taylor C.M.,&Adefisan E.A..(2021).Seasonality and trends of drivers of mesoscale convective systems in Southern West Africa.Journal of Climate,34(1). |
| MLA | Klein C.,et al."Seasonality and trends of drivers of mesoscale convective systems in Southern West Africa".Journal of Climate 34.1(2021). |
| 条目包含的文件 | 条目无相关文件。 | |||||
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