The Impact of Human-Induced Climate Change on Regional Drought in the Horn of Africa
The Impact of Human-Induced Climate Change on Regional Drought in the Horn of Africa
复制标题
人为气候变化对非洲之角区域干旱的影响
DOI：
10.1029/2018jd030085
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Marthews T
中科院分区：
文献类型：
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作者：
Marthews T
2014年，一场严重干旱袭击了大非洲之角（GHA），但目前尚不清楚这一极端事件是由人为气候变化造成的，还是长期自然循环的一部分。众所周知，整个GHA的降水模式正在发生变化，但陆地表面变量的轨迹却鲜为人知。我们模拟了GHA陆地表面环境，以评估自然循环和人为引起的气候变化之间的平衡。使用一种新的事件归因研究形式，我们既关注气候变量，也直接模拟地表变量，我们将公开志愿的分布式计算与地表模拟相结合，以量化地表响应。对气候模式和陆地表面模式输出的不确定性进行了量化。我们在2014年3 - 5月（长雨季）GHA双峰季节性区确定了两个不同的“干旱轨迹”。人类引起的气候变化可能导致从Nalubaale湖（维多利亚湖）到肯尼亚北部的地区本季度降水减少，干旱水平蒸散速率的可能性增加了20%（干旱加剧）。相比之下，本季节模拟的人为气候变化信号使埃塞俄比亚东部、索马里南部和肯尼亚沿海地区的条件略微湿润，干旱水平蒸散的概率降低了20%（干旱减少）。我们的模拟系统中的不确定性因区域和焦点变量而异，但总的来说，我们发现陆地表面模拟的不确定性既没有显著增加气候模式的不确定性，也没有显著降低它。
A severe drought hit the Greater Horn of Africa (GHA) in 2014, but it remains unclear whether this extreme event was attributable to anthropogenic climate change or part of longer‐term natural cycles. Precipitation patterns are known to be changing across the GHA, but trajectories in land surface variables are much less well known. We simulated the GHA land surface environment to assess the balance between natural cycles and human‐induced climate change. Using a new form of event attribution study where we focused on both climate variables and also directly simulated land surface variables, we combined publicly volunteered distributed computing with land surface simulations to quantify land surface responses. Uncertainty was quantified both for climate model and land surface model outputs. We identified two distinct “drought trajectories” in the GHA bimodal seasonality area during the March–May (Long Rains season) of 2014. Human‐induced climate change may have resulted in regions from Lake Nalubaale (Lake Victoria) to Northern Kenya receiving less precipitation in this season and having up to 20% higher probability of drought‐level evapotranspiration rates (increasing drought). In contrast, the simulated anthropogenic climate change signal for this season induced somewhat wetter conditions and up to 20% lower probability of drought‐level evapotranspiration in Eastern Ethiopia, Southern Somalia, and coastal Kenya (decreasing drought). Uncertainties in our modeling system varied by region and variable of focus, but broadly we found that land surface simulation uncertainty neither added significantly to climate model uncertainty nor significantly reduced it.