The 2018 Kerala floods: a climate change perspective
The 2018 Kerala floods: a climate change perspective
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DOI：
10.1007/s00382-020-05123-7
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发表时间：
2020-02-01
期刊：
影响因子：
4.6
通讯作者：
Menon, Arathy
中科院分区：
文献类型：
--
作者：
Hunt, Kieran M. R.;Menon, Arathy
2018年8月，印度喀拉拉邦因月初附近的低压系统和几天后的季风低气压而遭受长时间的强降雨。洪水造成400多人死亡，100多万人流离失所。在这里，一个高分辨率设置（4公里）的天气研究和预报（WRF）模型与水文模型（WRF-Hydro，运行在125米的分辨率）一起使用，以探索造成洪水的情况。除了对照实验外，还通过扰动边界条件进行了两个额外的实验，以模拟工业化前和RCP8.5背景气候中的事件。在研究期间，模拟的降雨量与观测结果密切匹配，发现由于最近季风低压系统的减弱，这将在工业化前增加约18%，但由于热带对流层的湿润，在RCP8.5气候中将增加36%。模拟的河流流量相应地作出反应：它表明，为国家服务的六个主要水库将需要有34%的能力来处理强降雨，43%的洪水被RCP8.5气候放大。它进一步表明，这种未来的气候将显着扩大南部边界的洪水。因此得出的结论是，虽然迄今为止气候变化很可能减轻了洪水的影响，但未来的气候变化可能会加剧这些影响。
In August 2018, the Indian state of Kerala received an extended period of very heavy rainfall as a result of a low-pressure system near the beginning of the month being followed several days later by a monsoon depression. The resulting floods killed over 400 people and displaced a million more. Here, a high resolution setup (4 km) of the Weather Research and Forecasting (WRF) model is used in conjunction with a hydrological model (WRF-Hydro, run at 125 m resolution) to explore the circumstances that caused the floods. In addition to a control experiment, two additional experiments are performed by perturbing the boundary conditions to simulate the event in pre-industrial and RCP8.5 background climates. Modelled rainfall closely matched observations over the study period, and it is found that this would this would have been about 18% heavier in the pre-industrial due to recent weakening of monsoon low-pressure systems, but would be 36% heavier in an RCP8.5 climate due to moistening of the tropical troposphere. Modelled river streamflow responds accordingly: it is shown the six major reservoirs that serve the state would have needed to have 34% more capacity to handle the heavy rainfall, and 43% had the deluge been amplified by an RCP8.5 climate. It is further shown that this future climate would have significantly extended the southern boundary of the flooding. Thus it is concluded that while climate change to date may well have mitigated the impacts of the flooding, future climate change would likely exacerbate them.