Most rainfall onset definitions in West Africa were estimated using station-based data. These data and hence the rainfall onset definitions may, however, not be a good representative for the entire climatic zone of the station. Based on existing definitions, a new rainfall onset definition is developed from the Tropical Rainfall Measurement Mission 3B42 gridded rainfall observations. 16 years of data were analyzed, which were taken between mid-April to mid-July over rainforest zones (west coast rainforest, dry rainforest and Nigeria–Cameroon rainforest) and between mid-May to mid-August over savannah zones (Nigeria savannah, and “Central African and South Sudan savannah”). While both definitions yield rather similar results in west coast rainforest, Nigeria–Cameroon rainforest and Nigeria savannah zones; results differ, however, substantially over dry rainforest and the Central African and South Sudan savannah. The new onset definition is further justified using an event-based analysis of mesoscale convective systems, flash counts and other convective parameters. Results have proved the new onset definition to be reliable and relevant for applications in agricultural productivity.

中文翻译：

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使用源自 TRMM 降水雷达数据的对流特性对两种降雨开始定义进行简明比较

西非的大多数降雨开始定义是使用基于站点的数据估算的。然而，这些数据以及降雨开始的定义可能不能很好地代表该站的整个气候带。在现有定义的基础上，根据热带降雨测量任务 3B42 网格降雨观测开发了新的降雨起始定义。分析了 16 年的数据，这些数据是在 4 月中旬至 7 月中旬的热带雨林区（西海岸雨林、干旱雨林和尼日利亚-喀麦隆雨林）和 5 月中旬至 8 月中旬的热带草原区（尼日利亚大草原、和“中非和南苏丹大草原”）。虽然这两种定义在西海岸雨林、尼日利亚-喀麦隆雨林和尼日利亚大草原地区产生了相当相似的结果；结果不同，然而，基本上在干燥的热带雨林以及中非和南苏丹大草原上空。使用中尺度对流系统、闪光计数和其他对流参数的基于事件的分析进一步证明了新的起始定义是合理的。结果证明，新的发病定义是可靠的，并且与农业生产力的应用相关。