Vietnam National Space Center,, Vietnam Academy of Science and Technology, No. 18 Hoang Quoc Viet Rd., Cau Giay Dist., Hanoi, Vietnam.
Department of Geodesy & Geomatics Engineering, Faculty of Bridge and Road, Hanoi University of Civil Engineering, Hanoi, Vietnam.
Environ Monit Assess. 2024 Sep 3;196(10):883. doi: 10.1007/s10661-024-13060-9.
Drought is one of the common natural disasters with a wide range of occurrences in terms of space and time, and with varying levels of severity, that may result in economic damage and health issues to humans. This study focuses on assessing drought severity in the Central Highlands of Vietnam based on ground meteorological stations and multispectral remote sensing data. A Modification of the Normalized Difference Drought Index (MNDDI) was developed to enhance the effectiveness of remote sensing indices in the drought assessment. Results indicate that MNDDI outperforms Normalized Difference Drought Index and other investigated indicators, such as Normalized Difference Vegetation Index, Normalized Difference Latent Heat Index, and Normalized Difference Water Index, in representing the Earth's surface response to drought events. Correlations ranging from 0.85 to 0.63 were identified between MNDDI and various time scales of the commonly used meteorological drought indicator, namely the Standardized Precipitation Index, during the drought year of 2015. This work also reveals the superiority of MNDDI in portraying the response of land cover types to drought situations. The finding of a severe drought phenomenon in critical agricultural zones is highly consistent with the report from the Ministry of Agriculture and Rural Development of Vietnam. This study contributes valuable insights to the preliminary assessment of drought through remote sensing data, offering a foundation for precise drought outlooks and effective risk management strategies.
干旱是一种常见的自然灾害，在空间和时间上发生范围广泛，且严重程度不一，可能会对人类造成经济损失和健康问题。本研究基于地面气象站和多光谱遥感数据，评估越南中高原地区的干旱严重程度。本研究开发了归一化差异干旱指数（MNDDI）的修正方法，以提高遥感指数在干旱评估中的有效性。结果表明，MNDDI 比归一化差异干旱指数和其他研究的指标，如归一化差异植被指数、归一化差异潜在热指数和归一化差异水指数，更能代表地球表面对干旱事件的响应。在 2015 年干旱年份，MNDDI 与常用气象干旱指标标准降水指数的各种时间尺度之间存在 0.85 到 0.63 的相关性。本研究还揭示了 MNDDI 在描绘土地覆盖类型对干旱情况的响应方面的优越性。在关键农业区发现严重干旱现象的结果与越南农业和农村发展部的报告高度一致。本研究通过遥感数据对干旱进行初步评估提供了有价值的见解，为精确的干旱展望和有效的风险管理策略奠定了基础。
