Aiming at the defects of weighted comprehensive assessment (WCA) method, this paper proposes a method based on k-means to realize the classification of drought risk. On the basis of calculating the drought risk value of cluster points, the inverse distance weight interpolation (IDWI) method and multidimensional normal diffusion (MND) method were used to quantify the drought risk, and the discrimination between the risk value and grade was improved by interval mapping adjustment. In this paper, the drought risk of Anhui Province from 2000 to 2020 was calculated to verify the above method. The results show that: (1) The drought risk quantification method based on information redistribution of k-means cluster point can not only realize automatic risk classification but also requantify the risk of the assessment object in the same risk grade, which makes up for the defects that the WCA cannot carry out grade division and the conventional clustering classification method cannot assign the risk value of the assessment object. (2) The information redistribution based on MND is closer to the actual drought situation and more reasonable than IDWI. (3) The mapping adjustment of drought risk interval can improve the risk refinement ability of the information redistribution based on k-means cluster.

  • The drought risk was graded based on k-means.

  • The drought risk is quantified by inverse distance weight interpolation method and multidimensional normal diffusion method.

  • The discrimination of drought risk can be improved by mapping the adjustment on interval.

Graphical Abstract

Graphical Abstract
Graphical Abstract
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