In this paper, the sea surface temperature (SST) based statistical seasonal forecast model (S4CAST) is utilized to examine the spatial and temporal prediction skill of Sahel heavy and extreme daily precipitation events. As in previous studies, S4CAST points out the Mediterranean Sea and El Niño Southern Oscillation (ENSO) as the main drivers of Sahel heavy/extreme daily rainfall variability at interannual timescales (period 1982–2015). Overall, the Mediterranean Sea emerges as a seasonal short-term predictor of heavy daily rainfall (1 month in advance), while ENSO returns a longer forecast window (up to 3 months in advance). Regarding the spatial skill, the response of heavy daily rainfall to the Mediterranean SST forcing is significant over a widespread area of the Sahel. Contrastingly, with the ENSO forcing, the response is only significant over the southernmost Sahel area. These differences can be attributed to the distinct physical mechanisms mediating the analyzed SST-rainfall teleconnections. This paper provides fundamental elements to develop an operational statistical-seasonal forecasting system of Sahel heavy and extreme daily precipitation events.

中文翻译：

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萨赫勒地区日常强降水的熟练海洋预报者的统计观测分析

本文利用基于海表温度（SST）的统计季节预报模型（S4CAST）来检验萨赫勒地区强降水和极端日降水事件的时空预测技巧。与以前的研究一样，S4CAST指出，在每年的时间尺度上（1982-2015年），地中海和厄尔尼诺南部涛动（ENSO）是萨赫勒地区强/极端日降水变化的主要驱动因素。总体而言，地中海将成为每日强降雨的季节性短期预报（提前1个月），而ENSO返回的预报窗口更长（提前3个月）。关于空间技巧，在萨赫勒大面积地区，每日强降雨对地中海海温强迫的响应非常重要。相反，在ENSO强制下，响应仅在最南端的萨赫勒地区有意义。这些差异可以归因于介导所分析的SST-降雨远程连接的不同物理机制。本文提供了开发萨赫勒强降水和极端日降水事件的业务统计季节预报系统的基本要素。