Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, 411008, India.
Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India.
Nat Commun. 2017 Oct 3;8(1):708. doi: 10.1038/s41467-017-00744-9.
Socioeconomic challenges continue to mount for half a billion residents of central India because of a decline in the total rainfall and a concurrent rise in the magnitude and frequency of extreme rainfall events. Alongside a weakening monsoon circulation, the locally available moisture and the frequency of moisture-laden depressions from the Bay of Bengal have also declined. Here we show that despite these negative trends, there is a threefold increase in widespread extreme rain events over central India during 1950-2015. The rise in these events is due to an increasing variability of the low-level monsoon westerlies over the Arabian Sea, driving surges of moisture supply, leading to extreme rainfall episodes across the entire central subcontinent. The homogeneity of these severe weather events and their association with the ocean temperatures underscores the potential predictability of these events by two-to-three weeks, which offers hope in mitigating their catastrophic impact on life, agriculture and property.Against the backdrop of a declining monsoon, the number of extreme rain events is on the rise over central India. Here the authors identify a threefold increase in widespread extreme rains over the region during 1950-2015, driven by an increasing variability of the low-level westerlies over the Arabian Sea.
由于印度中部地区总降雨量减少，极端降雨事件的强度和频率同时上升，导致当地 5 亿居民面临越来越多的社会经济挑战。季风环流减弱，当地可利用的水分和孟加拉湾带来的富含水分的低气压的频率也有所下降。在这里，我们表明，尽管存在这些负面趋势，但在 1950 年至 2015 年间，印度中部地区广泛发生极端降雨事件的频率增加了两倍。这些事件的增加是由于阿拉伯海低层季风西风的变化增加，导致水汽供应激增，从而导致整个中央次大陆发生极端降雨事件。这些恶劣天气事件的同质性及其与海洋温度的关联，突出了这些事件具有两到三周的潜在可预测性，这为减轻其对生命、农业和财产造成的灾难性影响带来了希望。在季风减弱的背景下，印度中部地区的极端降雨事件数量正在增加。在这里，作者确定在 1950 年至 2015 年间，该地区广泛发生的极端降雨事件增加了两倍，这是由于阿拉伯海低层西风的变化增加所致。
