Sharma Shailza, Mujumdar Pradeep
Department of Civil Engineering, Indian Institute of Science, Bangalore, 560012, India.
Divecha Center for Climate Change, Indian Institute of Science, Bangalore, 560012, India.
Sci Rep. 2017 Nov 14;7(1):15582. doi: 10.1038/s41598-017-15896-3.
The impacts of concurrent droughts and heatwaves could be more serious compared to their individual occurrence. Meteorological drought condition is generally characterized by low rainfall, but impact of such an event is amplified with simultaneous occurrence of heatwaves. Positive feedback between these two extremes can worsen the rainfall deficit situation to serious soil moisture depletion due to enhanced evapotranspiration. In this study, the concurrence of meteorological droughts and heatwaves is investigated in India using Indian Meteorological Department (IMD) high resolution gridded data over a period of 60 years. Significant changes are observed in concurrent meteorological droughts and heatwaves defined at different percentile based thresholds and durations during the period 1981-2010 relative to the base period 1951-1980. There is substantial increase in the frequency of concurrent meteorological droughts and heatwaves across whole India. Statistically significant trends in the spatial extent of droughts are observed in Central Northeast India and West Central India; however, the spatial extent affected by concurrent droughts and heatwaves is increasing across whole India. Significant shifts are identified in the distribution of spatial extent of concurrent drought and heatwaves in India compared to the base period.
与干旱和热浪单独发生相比，两者同时出现的影响可能更为严重。气象干旱通常表现为降雨量少，但热浪同时出现会加剧这种事件的影响。这两种极端情况之间的正反馈会因蒸散作用增强而使降雨亏缺状况恶化，导致严重的土壤水分消耗。在本研究中，利用印度气象部门（IMD）60年期间的高分辨率网格数据，对印度气象干旱和热浪的同时出现情况进行了调查。相对于1951 - 1980年的基准期，在1981 - 2010年期间，在不同百分位数基准阈值和持续时间定义下的气象干旱和热浪同时出现的情况有显著变化。全印度同时出现气象干旱和热浪的频率大幅增加。在印度中部东北部和印度中西部观察到干旱空间范围的统计显著趋势；然而，全印度受干旱和热浪同时影响的空间范围正在扩大。与基准期相比，印度干旱和热浪同时出现的空间范围分布发生了显著变化。
