Application of Effective Drought Index (EDI) in Characterizing Drought Periods (Case study: Tabriz, Bandar Anzali, and Zahedan)

Drought refers to a period of time when water shortage occurs and, therefore, the environment and human life are disrupted. Of course, depending on the regional considerations and the objectives of any research, drought can have different definitions since the lack of water in different regions is defined differently. Drought forecasting is almost impossible and is usually a phenomenon that progresses slowly. As a result, well-timed detection in the early stages makes it possible to reduce the adverse effects on different parts of the environment, agriculture, water resources, etc. Drought characteristics such as duration and severity can be determined by drought indices. Scientists have proposed various indexes to assess this phenomenon. Drought index is a useful tool to assess drought characteristics. Effective Drought Index (EDI) is a new methodwhich is based on the cumulative daily precipitation and uses a weighting method.