Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1175/JCLI-D-17-0221.1 |
On the Likelihood of Tropical-Extratropical Cloud Bands in the South Indian Convergence Zone during ENSO Events | |
Hart, Neil C. G.1; Washington, Richard1; Reason, Chris J. C.2 | |
2018-04-01 | |
发表期刊 | JOURNAL OF CLIMATE
![]() |
ISSN | 0894-8755 |
EISSN | 1520-0442 |
出版年 | 2018 |
卷号 | 31期号:7页码:2797-2817 |
文章类型 | Article |
语种 | 英语 |
国家 | England; South Africa |
英文摘要 | The Southern Hemisphere subtropical convergence zones are important regions of rainfall in the subtropics. The south Indian Ocean convergence zone (SICZ) has the strongest seasonality and exhibits substantial interannual variability in strength and position during austral summer. On synoptic time scales, the SICZ is a preferred region for the formation of tropical-extratropical (TE) cloud bands with local maxima over the southern African mainland and Madagascar. This study investigates how the seasonality in satellite-observed cloud band frequency emerges from the interplay between the asynchronous seasonal cycles in convective instability and upper-level flow, as represented by reanalysis data. These atmospheric mean states are diagnosed with a gross convective instability metric and a method to distinguish between subtropical and eddy-driven jet axes. Month-by-month analysis of these diagnostics elucidates how mean-state perturbations during ENSO events modify cloud band likelihood. Typically, 150%-200% more cloud bands develop during La Nina seasons supported by 5 degrees-10 degrees latitudinal separation between the local subtropical and eddy-driven jets and higher values of convective instability, especially in semiarid parts of mainland southern Africa. During El Nino events, fewer cloud bands develop over southern Africa in a more convectively stable environment without a distinct subtropical jet. However, east of Madagascar cloud bands are 150% more likely. Plausible teleconnection pathways based on these ENSO-related perturbations are discussed. The paper concludes with a conceptual framing of the seasonal cycle in the mean-state pertinent to TE cloud band likelihood. |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000429456500014 |
WOS关键词 | SEA-SURFACE TEMPERATURE ; SST DIPOLE EVENTS ; AFRICAN RAINFALL ; EL-NINO ; SUMMER MONSOON ; AUSTRAL SUMMER ; OCEAN ; VARIABILITY ; CIRCULATION ; AMERICA |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/19710 |
专题 | 气候变化 |
作者单位 | 1.Univ Oxford, Sch Geog & Environm, Oxford, England; 2.Univ Cape Town, Dept Oceanog, Cape Town, South Africa |
推荐引用方式 GB/T 7714 | Hart, Neil C. G.,Washington, Richard,Reason, Chris J. C.. On the Likelihood of Tropical-Extratropical Cloud Bands in the South Indian Convergence Zone during ENSO Events[J]. JOURNAL OF CLIMATE,2018,31(7):2797-2817. |
APA | Hart, Neil C. G.,Washington, Richard,&Reason, Chris J. C..(2018).On the Likelihood of Tropical-Extratropical Cloud Bands in the South Indian Convergence Zone during ENSO Events.JOURNAL OF CLIMATE,31(7),2797-2817. |
MLA | Hart, Neil C. G.,et al."On the Likelihood of Tropical-Extratropical Cloud Bands in the South Indian Convergence Zone during ENSO Events".JOURNAL OF CLIMATE 31.7(2018):2797-2817. |
条目包含的文件 | 条目无相关文件。 |
除非特别说明,本系统中所有内容都受版权保护,并保留所有权利。
修改评论