Tropical–Extratropical Interactions over Southern Africa: Three Cases of Heavy Summer Season Rainfall
Tropical–Extratropical Interactions over Southern Africa: Three Cases of Heavy Summer Season Rainfall
复制标题
南部非洲热带-温带相互作用：夏季强降雨的三个案例
DOI：
10.1175/2010mwr3070.1
复制
发表时间：
2010
影响因子：
3.2
通讯作者：
N. Fauchereau
中科院分区：
文献类型：
--
作者：
N. Hart;C. Reason;N. Fauchereau
Abstract The synoptic evolution of three tropical–extratropical (TE) interactions, each responsible for extreme rainfall events over southern Africa, is discussed in detail. Along with the consideration of previously studied events, common features of these heavy rainfall producing tropical temperate troughs (TTTs) over southern Africa are discussed. It is found that 2 days prior to an event, northeasterly moisture transports across Botswana, set up by the Angola low, are diverted farther south into the semiarid region of subtropical southern Africa. The TTTs reach full maturity as a TE cloud band, rooted in the central subcontinent, which is triggered by upper-level divergence along the leading edge of an upper-tropospheric westerly wave trough. Convection and rainfall within the cloud band is supported by poleward moisture transports with subtropical air rising as it leaves the continent and joins the midlatitude westerly flow. It is shown that these systems fit within a theoretical framework describing...
