Li Hua-Peng, Zhang Shu-Qing, Gao Zi-Qiang, Sun Yan
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2013 Mar;33(3):756-61.
The exclusive shortwave bands provided by MODIS sensors offer new opportunities for agricultural drought monitoring, since they are very sensitive to vegetation moisture. In the present work, we selected Songnen Plain in Northeast China as study area aiming at monitoring agricultural drought of dry farmland here. Four types of vegetation water indices and vegetation greenness indices were calculated from the 8-day composite MODIS product (MODO9A1) in vegetation growing season between 2001 and 2010, respectively. Multi-scale standardized precipitation index (SPI) derived from precipitation data of weather stations was used as reference data to estimate drought sensitivity of various vegetation indices, and a pixel-to-weather station paired correlation approach was used to calculate the Pearson correlation coefficient between vegetation index and SPIs. The result indicated that vegetation water indices established by near infrared and shortwave infrared bands outperformed vegetation greenness indices based on visible and near infrared bands. Of these indices, NDII7 performs the best with highest correlation coefficients across all SPIs. The authors' results demonstrated the potential of MODIS shortwave spectral bands in monitoring agricultural drought, and this provides new insights to future research.
中分辨率成像光谱仪（MODIS）传感器提供的专属短波波段为农业干旱监测带来了新机遇，因为它们对植被水分非常敏感。在本研究中，我们选取中国东北的松嫩平原作为研究区域，旨在监测该地区旱田的农业干旱情况。分别从2001年至2010年植被生长季的8天合成MODIS产品（MODO9A1）中计算了四种植被水分指数和植被绿度指数。利用气象站降水数据得出的多尺度标准化降水指数（SPI）作为参考数据，以估算各种植被指数的干旱敏感性，并采用像元与气象站配对相关法计算植被指数与SPI之间的皮尔逊相关系数。结果表明，由近红外和短波红外波段建立的植被水分指数优于基于可见光和近红外波段的植被绿度指数。在这些指数中，NDII7表现最佳，与所有SPI的相关系数最高。作者的研究结果证明了MODIS短波光谱波段在监测农业干旱方面的潜力，这为未来的研究提供了新的见解。
