Wei Wei, Zhang Jing, Zhou Liang, Xie Binbin, Zhou Junju, Li Chuanhua
College of Geography and Environmental Science, Northwest Normal University, Lanzhou, 730070, Gansu, China.
Faculty of Geomatics, Lanzhou Jiaotong University, Lanzhou, 730070, China.
Environ Sci Pollut Res Int. 2021 Apr;28(16):20408-20425. doi: 10.1007/s11356-020-12120-0. Epub 2021 Jan 6.
Many indices are used to monitor drought events. However, different indices have different data requirements and applications. Hence, evaluating their applicability will help to characterize drought events and refine the development of effective drought indices. We constructed different drought indices based on multisource remote sensing data and comprehensively evaluated and compared their applicability for drought monitoring throughout China. The characteristics of drought events in 2009 and 2011 were compared using various drought indices. The different time scales of the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Index (SPI) were used to evaluate remote sensing drought indices in different regions. Single drought indices, including the Vegetation Condition Index (VCI), the Temperature Condition Index (TCI) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data, the Precipitation Condition Index (PCI) derived from Tropical Rainfall Measurement Mission (TRMM) data, and the TCI and Soil Moisture Condition Index (SMCI) derived from Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) data, as well as combined drought indices, including the Microwave Integrated Drought Index (MIDI), Optimized Vegetation Drought Index (OVDI), Optimized Meteorological Drought Index (OMDI), Scale Drought Conditions Index (SDCI), and Synthesized Drought Index (SDI), were analyzed and compared to evaluate their applicability. The results showed that different drought indices have specific characteristics under different land use types in China. The VCI and TCI can better monitor long-term drought conditions, but they have a weak correlation with the in situ drought index in forestland and grassland areas. The correlation of SPI-1 with the PCI is higher than that with other single indices, which indicates that the PCI is a good short-term drought index. The SMCI has a better correlation with the short-term in situ drought index, but it is not conducive to drought monitoring in areas such as densely forested land and grassland. The correlations of the in situ drought index with the combined drought indices (the MIDI, OVDI, OMDI, SDCI, and SDI) are better than those with the single drought indices.
许多指标被用于监测干旱事件。然而，不同的指标有不同的数据要求和应用场景。因此，评估它们的适用性将有助于刻画干旱事件，并完善有效的干旱指标的发展。我们基于多源遥感数据构建了不同的干旱指标，并全面评估和比较了它们在中国全境干旱监测中的适用性。利用各种干旱指标比较了2009年和2011年干旱事件的特征。使用帕尔默干旱严重度指数（PDSI）和标准化降水指数（SPI）的不同时间尺度来评估不同地区的遥感干旱指标。分析并比较了包括植被状况指数（VCI）、从中分辨率成像光谱仪（MODIS）数据导出的温度状况指数（TCI）、从热带降雨测量任务（TRMM）数据导出的降水状况指数（PCI）以及从用于地球观测系统的先进微波扫描辐射计（AMSR-E）数据导出的TCI和土壤湿度状况指数（SMCI）等单一干旱指标，以及包括微波综合干旱指数（MIDI）、优化植被干旱指数（OVDI）、优化气象干旱指数（OMDI）、尺度干旱状况指数（SDCI）和综合干旱指数（SDI）等综合干旱指标，以评估它们的适用性。结果表明，在中国不同土地利用类型下，不同的干旱指标具有特定的特征。VCI和TCI能更好地监测长期干旱状况，但它们在林地和草地地区与现场干旱指数的相关性较弱。SPI-1与PCI的相关性高于与其他单一指标的相关性，这表明PCI是一个良好的短期干旱指标。SMCI与短期现场干旱指数的相关性较好，但不利于在森林茂密地区和草地等区域进行干旱监测。现场干旱指数与综合干旱指标（MIDI、OVDI、OMDI、SDCI和SDI）的相关性优于与单一干旱指标的相关性。
