Recent Trends in the Daily Rainfall Regime in Southern West Africa
Recent Trends in the Daily Rainfall Regime in Southern West Africa
复制标题
西非南部每日降雨量的最新趋势
作者：
F. Nkrumah;T. Vischel;G. Panthou;N. Klutse;D. C. Adukpo;A. Diedhiou
与干旱或极端降水有关的极端气候事件是非洲的主要关切，因为非洲的经济和人口极易受到气候灾害的影响。然而，在这片调查不足的大陆上，气候事件的最新趋势往往没有记录。这项研究利用了1950年至2014年覆盖西非南部（从10° W到10° E，从4° N到12° N）的大量每日雨量计数据。在年和季节尺度上分析了日降雨事件，特别是极端事件的数量和强度的演变。在第一个雨季（4月至7月），由于过去二十年来主要沿着西非南部（SWA）海岸的降雨频率较低但强度较高，观察到平均年降雨量呈小幅趋势。南北季节变化表明，在过去十年中，第二个雨季（9月至11月）的年平均降雨量有所增加，这与过去十年中雨天发生频率的增加以及平均强度和极端事件的增加有关。该研究还提供了证据表明，西南偏南地区西部和东部之间存在差异，东部记录了第二个雨季（9月至11月）期间潮湿天数和极端降雨量平均强度的更大增加。
Extreme climate events, either being linked to dry spells or extreme precipitation, are of major concern in Africa, a region in which the economy and population are highly vulnerable to climate hazards. However, recent trends in climate events are not often documented in this poorly surveyed continent. This study makes use of a large set of daily rain gauge data covering Southern West Africa (extending from 10° W to 10° E and from 4° N to 12° N) from 1950 to 2014. The evolution of the number and the intensity of daily rainfall events, especially the most extremes, were analyzed at the annual and seasonal scales. During the first rainy season (April–July), mean annual rainfall is observed to have a minor trend due to less frequent but more intense rainfall mainly along the coast of Southern West Africa (SWA) over the last two decades. The north–south seasonal changes exhibit an increase in mean annual rainfall over the last decade during the second rainy season (September–November) linked by both an increase in the frequency of occurrence of rainy days as well as an increase in the mean intensity and extreme events over the last decade. The study also provides evidence of a disparity that exists between the west and east of SWA, with the east recording a stronger increase in the mean intensity of wet days and extreme rainfall during the second rainy season (September–November).