The objective of this study was to assess the hail damage to corn that occurred on July 14, 2010 in Gannan County, Qiqihar City, China, using two Huan Jing (HJ)-1-B (pre-hailstorm) and HJ-1-A (post-hailstorm) charge-coupled device (CCD) images of China. According to the change characteristics of normalised difference vegetation index (NDVI) of thirty field sampling points of post-hailstorm, a third-order polynomial was built between the NDIV difference (ΔNDVI) and Band 4 of the HJ-1-A CCD image. As a result, the coefficient of determination (R2) of this model reached 91.62%; twenty sampling points were used to validate the model and R2 reached 96.31%. Consequently, 8,575 ha of affected corn were monitored and the seriously affected corn area was 2,302.47 ha. Furthermore, the damage levels (light, moderate and serious) were also specified, the accuracy of which was validated by constructing a confusion matrix based on fifty ground truth points. The overall accuracy and Kappa coefficient (κ) were 86% and 0.7826, respectively. The results show that the degree of severity of injured corn gradually descended from the center to the margins, and the potential yield loss reached about 10,840 tons estimated by the serious damage level. This study suggests that multi-temporal and multispectral imagery of broadband HJ-1 CCD images of China are sufficient to assess hail-damaged areas and specify relative damage levels in corn.
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