Climate change exacerbated heavy rainfall in West Africa

本文有大量关于西非降水增加、洪水增多及其危害的信息。

• 亚洲第一，非洲第二：Africa is the second worst continent affected by floods, after Asia, based on extent, casualties, and frequencies (Few, 2003; Tschakert et al. 2010).

• 拉尼娜与萨赫勒地区降水增加由很大关系：This alert was based on the El Niño Southern Oscillation (ENSO) forecast from early April indicating a continuation ofLa Niña during July-August-September 2022 which is associated with more rainfall in the Sahel.

• 西非东部和东北部出现了湿季开始日期提前以及降水增加的现象：The eastern parts of West Africa including the Lake Chad Basin, northern Cameroon, Chad, as well as the central (Burkina Faso, Cote d’Ivoire) and the north-western regions (coastal Senegal and western Mauritania) began witnessing wetter-than-normal conditions, from the beginning of the season (Reliefweb, 27 September 2022).

• 西非降水影响因素：The West African Monsoon circulation is driven by thermodynamic contrast between the cooler ocean (the equatorial Atlantic) and an intense heat low (the Saharan Heat Low) that develops over the western Sahara during the boreal summer. South-westerly winds are established between the equatorial Atlantic and the Saharan Heat Low, bringing moisture into the continent (Nicholson, 2013). African Easterly Waves are synoptic-scale disturbances that propagate westward on the AEJ, from central or eastern Africa across West Africa and into the tropical Atlantic (Cornforth et al., 2017). Their passage is marked by a peak in convection and precipitation (Cornforth et al., 2017).

• 适用于非洲的观测数据：CHIRPS and TAMSAT.

• 历史时期（工业前时期）：1850-1900

  based on the Global Warming Index https://www.globalwarmingindex.org