Numerical Simulation of Episodes of Organized Convection in Tropical Northern Africa
Numerical Simulation of Episodes of Organized Convection in Tropical Northern Africa
复制标题
北非热带地区有组织对流发作的数值模拟
DOI：
10.1175/mwr-d-11-00330.1
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发表时间：
2012
影响因子：
3.2
通讯作者：
C. Davis
中科院分区：
文献类型：
--
作者：
A. Laing;S. Trier;C. Davis
本文用一个允许大范围对流的数值模式模拟了白天在埃塞俄比亚高原上空产生并向西传播到非洲北方萨赫勒地区东部和中部（5°-20 ° N）的深对流。模拟包括12.5天内的非洲季风多学科分析（AMMA）在2006年的实地活动。在此期间，在模拟和观测中，埃塞俄比亚高地的背风面每2-3天才会发生一次持续时间超过一个日周期的长期降水事件。这与其他一些主要地形背风的纬度走廊，如美国中部，长寿命的强降水事件经常发生在连续的夜晚。尽管沿上游地形沿着每天有规律地触发对流，但目前情况下长寿命事件的不稳定性仍然发生，并且与对流层低层的强稳定和减少有关。
AbstractA large-domain convection-permitting numerical model is used to simulate episodes of deep convection, which are generated during the day over the Ethiopian Highlands and then propagate westward over the eastern and central Sahel region (5°–20°N) of northern Africa. The simulation comprises 12.5 days within the African Monsoon Multidisciplinary Analysis (AMMA) field campaign in 2006. During this period, long-lived precipitation episodes that survived beyond a single diurnal cycle occurred in the lee of the Ethiopian Highlands only every 2–3 days in both the simulation and observations. This contrasts with some other latitudinal corridors in the lee of major topography, such as the central United States, where long-lived heavy precipitation episodes frequently occur on successive nights.The intermittency of long-lived events for the current case occurs despite regular daily triggering of convection along the upstream orography, and is linked to strong lower-tropospheric stabilization and reduction o...