Journal of Earth System Science ( IF 1.3 ) Pub Date : 2020-09-19 , DOI: 10.1007/s12040-020-01460-7 Prabir Kumar Das , Sushant Chandra , Dilip Kumar Das , Subrata Kumar Midya , Arati Paul , Soumya Bandyopadhyay , Vinay Kumar Dadhwal
Abstract
The present study aims at analysing the relationship between meteorological and soil moisture droughts over different meteorological regions of India based on change-point, trends and probability analysis. The long term gridded standardized-precipitation-evapotranspiration-index (SPEI) and standardized-soil-moisture-index (SSMI) data during 1980–2015 were used to address the meteorological and soil-moisture drought, respectively. The significant changes in the time-series SPEI and SSMI data at different time-scales were estimated using Pettitt’s test. The variations in change-points among different time-scales of SSMI were much lower than SPEI, specifically in parts of NW and central India. The inter-annual variability of drought parameters, i.e., duration and magnitude, showed good agreement between meteorological and soil moisture droughts for mild drought conditions. However, under moderate drought conditions, the behaviour of meteorological and soil moisture drought was different, specifically over peninsular India. The trend analysis revealed that SSMI based drought occurrences were significantly decreasing over all the four meteorological regions, whereas in case of SPEI, significant trends were observed only over peninsular India for mild drought condition. The probability of occurrences of both meteorological and soil moisture droughts were higher over major parts of India in case of mild droughts, whereas the values were lower for moderate drought conditions.
Research Highlights
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The Pettitt’s change point analysis revealed that variations of the period of significant changes among different time scale SSMI was much lower comparison to SPEI.
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In major parts of the country, good agreement between SPEI and SSMI derived drought parameters, i.e., duration and magnitude, were observed for mild drought conditions. However, it was quite low in moderate drought conditions, more specifically over peninsular and central India.
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The trend analysis revealed that the soil moisture drought was decreasing during the study period. Similar observations were recorded in meteorological drought also, but with some increasing drought duration and magnitude in parts of NW and NE India.
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The probability of occurrences of both meteorological and soil moisture droughts were higher over major parts of India in case of mild droughts, whereas the values were lower for moderate drought conditions.
中文翻译：
了解印度地区气象与土壤水分干旱之间的相互作用
摘要
本研究旨在基于变化点，趋势和概率分析，分析印度不同气象区域的气象与土壤水分干旱之间的关系。使用1980-2015年的长期网格标准化降水-蒸散指数（SPEI）和标准化土壤水分指数（SSMI）数据分别处理了气象干旱和土壤水分干旱。使用Pettitt的检验估计了在不同时间范围内，时间序列SPEI和SSMI数据的显着变化。SSMI不同时间尺度之间变化点的变化远低于SPEI，特别是在西北和印度中部。干旱参数的年际变化，即持续时间和强度，在轻度干旱条件下，气象干旱与土壤水分干旱之间显示出良好的一致性。但是，在中等干旱条件下，气象干旱和土壤水分干旱的行为有所不同，特别是在印度半岛上。趋势分析显示，在所有四个气象区域中，基于SSMI的干旱发生率均显着下降，而在SPEI的情况下，仅在印度半岛上观察到了轻度干旱条件下的显着趋势。在温和干旱的情况下，印度主要地区发生气象干旱和土壤水分干旱的可能性较高，而在中等干旱条件下则较低。特别是在印度半岛。趋势分析显示，在所有四个气象区域中，基于SSMI的干旱发生率均显着下降，而在SPEI的情况下，仅在印度半岛上观察到了轻度干旱条件下的显着趋势。在温和干旱的情况下，印度主要地区发生气象干旱和土壤水分干旱的可能性较高，而在中等干旱条件下则较低。特别是在印度半岛。趋势分析显示，在所有四个气象区域中，基于SSMI的干旱发生率均显着下降，而在SPEI的情况下，仅在印度半岛上观察到了轻度干旱条件下的显着趋势。在轻度干旱的情况下，印度主要地区发生气象干旱和土壤水分干旱的可能性较高，而在中度干旱条件下则较低。
研究重点
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Pettitt的变化点分析显示，与SPEI相比，不同时间尺度SSMI之间的显着变化周期的变化要低得多。
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在该国大部分地区，对于轻度干旱条件，在SPEI和SSMI得出的干旱参数（即持续时间和强度）之间达成了良好的协议。但是，在中等干旱条件下，特别是在印度半岛和中部地区，这一比例非常低。
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趋势分析表明，研究期间土壤水分干旱正在减少。在气象干旱中也记录了类似的观察结果，但在西北和印度北部部分地区干旱持续时间和幅度有所增加。
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在轻度干旱的情况下，印度主要地区发生气象干旱和土壤水分干旱的可能性较高，而在中度干旱条件下则较低。
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