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Abstract：
Evaluating drought parameters at the basin level is one of the fundamental processes for planning sustainable crop production. This study aimed to evaluate both short-term and long-term meteorological drought parameters within the Vaippar Basin, located in southern India, by employing the standardized precipitation index (SPI). Gridded rainfall values developed from 13 rain gauge stations were employed to calculate the SPI values. Drought parameters, encompassing occurrence, intensity, duration, frequency, and trends, were assessed for both short-term and long-term droughts. The study findings indicated that the occurrence of short-term drought was 51.7%, while that of long-term drought was 49.82%. Notably, the basin experienced extreme short-term droughts in 1980, 1998 and 2016 and long-term droughts in 1981, 2013, and 2017. Utilizing an innovative trend identification method for SPI values, a significant monotonic upwards trend was identified in October and December for short-term drought and in December for long-term drought. This study defined the minimum threshold rainfall, which represents the critical amount required to prevent short-term drought (set at 390 mm) and long-term drought (set at 635 mm). The drought severity recurrence curves developed in this study indicate that when the SPI values fall below - 1.0, short-term drought affects 25% of the basin area, while long-term drought impacts 50% of the basin area at a 20-year recurrence interval. Additionally, the drought hazard index (DHI), which combines drought intensity and severity, demonstrated higher values in the northwestern regions for short-term drought and in the southern areas for long-term drought. The study\'s findings, highlighting areas of drought vulnerability, severity, and recurrence patterns in the basin, direct the attention for timely intervention when drought initiates.
摘要：
在流域一级评估干旱参数是规划可持续作物生产的基本过程之一。这项研究旨在评估Vaippar盆地内的短期和长期气象干旱参数，位于印度南部，采用标准化降水指数(SPI)。使用从13个雨量计站开发的网格降雨值来计算SPI值。干旱参数,涵盖事件，强度,持续时间,频率,和趋势，对短期和长期干旱进行了评估。研究结果表明，短期干旱的发生率为51.7%，长期干旱占49.82%。值得注意的是,该盆地在1980年、1998年和2016年经历了极端的短期干旱，在1981年、2013年和2017年经历了长期干旱。利用创新的SPI值趋势识别方法，短期干旱在10月和12月以及长期干旱在12月发现了显着的单调上升趋势。这项研究定义了最小阈值降雨量，这代表了防止短期干旱(设定为390毫米)和长期干旱(设定为635毫米)所需的临界量。本研究得出的干旱严重度复发曲线表明，当SPI值低于-1.0时，短期干旱会影响流域面积的25％，而长期干旱以20年的复发间隔影响流域50％的面积。此外,干旱灾害指数(DHI)，结合了干旱强度和严重程度，在西北地区短期干旱和南部地区长期干旱表现出较高的值。这项研究的发现，突出干旱脆弱地区，严重程度,和盆地的复发模式，当干旱开始时，引导注意力及时干预。
