Erratum to: Early-season agricultural drought: detection, assessment and monitoring using Shortwave Angle and Slope Index (SASI) data

Erratum to: Environ Monit Assess

DOI 10.1007/s10661-013-3299-8

The original version of this article unfortunately contained a mistake.

The presentation of equation 1 was incorrect.

The corrected equation is given below.

$$ {\beta}_{\mathrm{SWIR}1}={ \cos}^{-1}\left[\left({\mathrm{a}}^2+{\mathrm{b}}^2-{\mathrm{c}}^2\right)/\left(2\ast \mathrm{a}\ast \mathrm{b}\right)\right] $$

(1)