Taxonomy of drought indices
Commonly, drought indices are categorized based on the
type of impacts they relate to. The taxonomy can also be
based on the variables they relate to (Steinemann et al. 2005)
or use of disciplinary data (Niemeyer 2008). Three popular
categories are meteorological, agricultural and hydrological
drought indices. Niemeyer (2008) adds three categories to
this list: comprehensive, combined and remote-sensing-based
drought indices. Comprehensive drought indices use a variety
of meteorological, agricultural and hydrological variables to
draw a comprehensive picture of drought. The Palmer
Drought Severity Index (PDSI) is an example of this ap-
proach. Remote-sensing-based drought indices use informa-
tion from remote-sensing sensors to map the condition of the
land (e.g., the Normalized Difference Vegetation Index,
NDVI, Tucker (1979)). Combined (also termed hybrid and
aggregate) drought indices are derived by incorporating exist-
ing drought indicators and indices into a single measure. The
US Drought Monitor (Svoboda et al. 2002) is an example.
This paper is based on the categorization by Niemeyer
(2008) omitting the “comprehensive” category