Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1016/j.atmosres.2020.105315 |
Downstream development during South African cut-off low pressure systems | |
Thando Ndarana, Tsholanang S. Rammopo, Mary-Jane Bopape, Chris J.C. Reason, Hector Chikoore | |
2020-10-17 | |
发表期刊 | Atmospheric Research |
出版年 | 2020 |
英文摘要 | Using 39 years of ECMWF renalysis data, an established energetics framework and simple composite analysis this study has shown that South African cut-off low (COL) pressure systems are preceded by downstream development of a baroclinic wave. Downstream development is characterised by the evolution of two energy centres, one located upstream in the midlatitudes and another downstream in the subtropics. The upstream eddy kinetic energy, which is associated with a midlatitude jet streak, develops and reaches its maximum before the formation of the closed COL cyclonic circulation. The downstream eddy kinetic energy centre maximises at the point where the closed circulation forms. The upstream eddy kinetic energy centre grows from baroclinic conversion from eddy available potential energy to eddy kinetic energy, whilst the downstream centre grows by receiving energy by means of ageostrophic geopotential fluxes that transport eddy kinetic energy in a north-eastward direction from the upstream centre. These ageostrophic geopotential fluxes are induced, increased in magnitude and directed by processes associated with Rossby wave breaking (RWB) on the midlatitude dynamical tropopause. and so the downstream energy transfer connects South African COLs to midlatitude processes. The study has further shown that the baroclinic kinetic energy configuration previously associated with wet seasons over South Africa is consistent with times when COLs forms over the country. |
领域 | 地球科学 |
URL | 查看原文 |
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/299160 |
专题 | 地球科学 |
推荐引用方式 GB/T 7714 | Thando Ndarana, Tsholanang S. Rammopo, Mary-Jane Bopape, Chris J.C. Reason, Hector Chikoore. Downstream development during South African cut-off low pressure systems[J]. Atmospheric Research,2020. |
APA | Thando Ndarana, Tsholanang S. Rammopo, Mary-Jane Bopape, Chris J.C. Reason, Hector Chikoore.(2020).Downstream development during South African cut-off low pressure systems.Atmospheric Research. |
MLA | Thando Ndarana, Tsholanang S. Rammopo, Mary-Jane Bopape, Chris J.C. Reason, Hector Chikoore."Downstream development during South African cut-off low pressure systems".Atmospheric Research (2020). |
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