ABSTRACT
There are numerous definitions of drought since it has been recognized as a very costly natural disaster. The recent special report of the IPCC (2012) defines drought as “a period of abnormally dry weather long enough to cause a serious hydrological imbalance.” Drought can also be defined for three types: a meteorological drought refers to “a period with an abnormal precipitation deficit,” soil moisture (SM) drought or agricultural drought is “a deficit of SM,” and hydrological drought refers to “negative anomalies in streamflow, lake, and/or groundwater levels.”
