Prediction of Dry-Season Precipitation in Tropical West Africa and Its Relation to Forcing from the Extratropics
Prediction of Dry-Season Precipitation in Tropical West Africa and Its Relation to Forcing from the Extratropics
复制标题
热带西非旱季降水预测及其与温带强迫的关系
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
A. Fink
中科院分区：
文献类型：
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作者：
P. Knippertz;A. Fink
摘要在热带西非的北方冬季旱季降水是罕见的，但偶尔会对当地人口产生重大影响。这种现象的动力学和可预测性研究得很少。本文对7.5° ~ 15 ° N，10°W ~ 10°E区域的气候学、动力学和干季湿事件的预测作了统计评价。该分析是基于全球降水气候学项目（GPCP）合并的卫星测量候降水估计和5天40年的欧洲中期天气预报中心（ECMWF）再分析（ERA-40）降水预报，并涵盖了1979/80-2001/02年期间的23个旱季（11月至2月）。湿事件被定义为相对于平均季节周期，面积平均降水异常超过+200%的五元组。43个已识别事件的合成物表明与非洲西北部的一个槽，其东侧的热带羽流，非洲东部的异常降水，非洲东部的异常降水，以及非洲东部的异常降水有关。
Abstract Precipitation during the boreal winter dry season in tropical West Africa is rare but occasionally results in significant impacts on the local population. The dynamics and predictability of this phenomenon have been studied very little. Here, a statistical evaluation of the climatology, dynamics, and predictions of dry-season wet events is presented for the region 7.5°–15°N, 10°W–10°E. The analysis is based upon Global Precipitation Climatology Project (GPCP) merged satellite–gauge pentad rainfall estimates and 5-day 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) precipitation forecasts, and covers the 23 dry seasons (November–February) during 1979/80–2001/02. Wet events are defined as pentads with an area-averaged precipitation anomaly of more than +200% with respect to the mean seasonal cycle. Composites of the 43 identified events indicate an association with a trough over northwestern Africa, a tropical plume on its eastern side, unusual precipitation at...