Multivariate and multi-temporal analysis of meteorological drought in the northeast of Thailand
Multivariate and multi-temporal analysis of meteorological drought in the northeast of Thailand
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DOI：
10.1016/j.wace.2021.100399
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发表时间：
2021-11-20
影响因子：
8
通讯作者：
Collins, Matthew
中科院分区：
文献类型：
--
作者：
Khadka, Dibesh;Babel, Mukand S.;Collins, Matthew
这项研究评估干旱的特点，在门河流域，位于泰国东北部。从农业的角度来看，该盆地是重要的，因为总面积的约75%是耕地（其中大部分没有灌溉设施）。然而，它也是该国最容易发生干旱的地区之一，适当了解干旱特点有助于在该流域规划和执行干旱缓解和管理战略和措施。使用标准化降水蒸散指数（SPEI），根据1979-2017年期间的高分辨率气候数据计算，我们发现该流域大约每6年发生一次重大干旱事件。介绍了一种使用阈值消除小干旱影响的新方法。它被发现有改进的干旱表征长期干旱事件与低强度。干旱事件的严重程度，持续时间和频率（SDF）进行评估，使用单变量和多变量的方法在9个时间尺度（1周到24个月）。广义极值（GEV）和对数逻辑（LL）分布是最适合的SPEI计算在研究区，虽然所有的三参数分布有很好的拟合在较长的时间尺度。以每周时间尺度计算的SPEI，特别是在作物生长的营养阶段，与产量有很好的相关性;因此，它们可以用于规划农业活动。利用干旱持续时间和严重程度的联合发生概率进行的干旱脆弱性评估表明，西部大部分地区和东部部分地区是流域最易发生干旱的地区。值得注意的是，该流域的易旱地区与年降雨量无关，但受其时间变化的影响。
This study evaluates drought characteristics in the Mun River Basin, located in the northeast of Thailand. The basin is important from an agriculture perspective, as about 75% of the total area is under cultivation (a majority of which is without irrigation facilities). It is, however, also one of the most drought-prone regions in the country, and a proper understanding of drought characteristics can aid in planning and implementing drought mitigation and management strategies and measures in the basin. Using the Standardized Precipitation Evapotranspiration Index (SPEI), calculated from high-resolution climatic data during 1979-2017, we find that major drought events recur approximately every 6 years in the basin. A new approach to the use of thresholds to remove the effects of minor droughts is introduced. It is found to have improved drought characterization for prolonged drought events with low intensity. Drought events are evaluated for severity, duration, and frequency (SDF) using univariate and multivariate approaches at nine timescales (1-week to 24-months). Generalized Extreme Value (GEV) and Log-logistic (LL) are the most suitable distributions for SPEI calculation in the study area, though all three-parameter distributions have good fit at longer timescales. SPEI calculated at weekly timescales, especially during the vegetative stage of crop growth, show a good correlation with yields; thus, they can be useful for planning agricultural activities. Drought vulnerable assessment using joint occurrence probabilities of drought duration and severity indicates that most of the area in the western part and some area in the eastern part are the highest drought-prone regions in the basin. It is interesting to note that the drought prone areas of the basin are independent of the annual rainfall amount but are influenced by its temporal variability.