Changes in climate extremes over West and Central Africa at 1.5 °C and 2 °C global warming
Changes in climate extremes over West and Central Africa at 1.5 °C and 2 °C global warming
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DOI：
10.1088/1748-9326/aac3e5
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发表时间：
2018-06-01
影响因子：
6.7
通讯作者：
Affholder, Francois
中科院分区：
文献类型：
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作者：
Diedhiou, Arona;Bichet, Adeline;Affholder, Francois
在这项研究中，我们调查的变化，在西部和中部非洲（以下简称WAF域）作为全球平均温度的函数，重点是全球变暖的影响1.5摄氏度和2摄氏度根据巴黎协定。我们采用了一种尺度方法来捕捉WAF域中几个次区域的极端气候变化，这些次区域是：西萨赫勒，萨赫勒中部，萨赫勒东部，几内亚海岸和中非（包括刚果盆地）。虽然温度和降水指数的预测存在一些不确定性和较大的集合分布，但大多数模型显示了次区域尺度上极端气候的高影响变化。在这些较小的尺度上，WAF区域内的温度上升预计将高于全球平均温度上升（1.5摄氏度和2摄氏度），热浪预计将更加频繁和持续时间更长。在萨赫勒干旱地区、萨赫勒中部，特别是萨赫勒东部，观察到最强烈的变暖，在全球变暖1.5摄氏度时，那里的降水和土壤湿度异常预计增加的可能性最大。在几内亚海岸和中非的潮湿地区，模型预测总降水量变化微弱，潮湿期长度减少，而这两个地区在全球变暖1.5摄氏度时，WAF域的强降雨量增加最多。80%的模型预测，西萨赫勒地区将经历最严重的干旱，干旱期的长度将显著增加，标准化降水蒸散指数将下降。这项研究表明，“干得更干，湿得更湿”的范例是无效的WAF域。
In this study, we investigate changes in temperature and precipitation extremes over West and Central Africa (hereafter, WAF domain) as a function of global mean temperature with a focus on the implications of global warming of 1.5 degrees C and 2 degrees C according the Paris Agreement. We applied a scaling approach to capture changes in climate extremes with increase in global mean temperature in several subregions within the WAF domain: Western Sahel, Central Sahel, Eastern Sahel, Guinea Coast and Central Africa including Congo Basin.While there are several uncertainties and large ensemble spread in the projections of temperature and precipitation indices, most models show high-impact changes in climate extremes at subregional scale. At these smaller scales, temperature increases within the WAF domain are projected to be higher than the global mean temperature increase (at 1.5 degrees C and at 2 degrees C) and heat waves are expected to be more frequent and of longer duration. The most intense warming is observed over the drier regions of the Sahel, in the central Sahel and particularly in the eastern Sahel, where the precipitation and the soil moisture anomalies have the highest probability of projected increase at a global warming of 1.5 degrees C. Over the wetter regions of the Guinea Coast and Central Africa, models project a weak change in total precipitation and a decrease of the length of wet spells, while these two regions have the highest increase of heavy rainfall in the WAF domain at a global warming of 1.5 degrees C. Western Sahel is projected by 80% of the models to experience the strongest drying with a significant increase in the length of dry spells and a decrease in the standardized precipitation evapotranspiration index. This study suggests that the 'dry gets drier, wet gets wetter' paradigm is not valid within the WAF domain.