Zoning and Determination of the Best Drought Index in a Case Study of Lorestan Province

Drought is a climate phenomenon that there is possibility of this phenomenon, anywhere in the world and under anyDrought is a climate phenomenon that there is possibility of this phenomenon, anywhere in the world and under any climatic conditions. Based on this, monitoring systems are very important in preparing plans to deal with drought and its management. In this study, in order to investigate the drought in Lorestan province from annual rainfall data of Kamandan, Ab Barik, Dere Takht, Borujerd Organization, Kazem Abad, Tirroud, Azna, Golroud, Sabze Ab, Rahim Abad, Surkhab during a statistical period of 49 year (1969-2018) was used. Drought Status Based on the mentioned data using Standard Precipitation Indexes (SPI), Chinese Z (CZI), using DIP software, these data were entered into ArcGIS software. And then, using Kriging method, the drought zoning was done for the last 30-year study period (1988-2018). The results indicated that drought zoning does not follow a regular trend in any of the indices, during the study period. The results of the zoning of CZI and SPI indices showed that severe drought occurred in 1991 and 1999 and 2008 years for SPI index and1990, 1999, 2008 and 2012 years for CZI index, respectively, and severe humidity for both indices, has spread in the whole province 1992 and 1995 years. The results of both indices show that the maximum severe drought on the SPI index for the Ab Barik station in (1998-1999) and (1969-1970), and the Azna station in the years (2008-2009 and 2011- 2012), and the CZI index relates to the Ab Barik Station (1969-1970 and 1997-1998), and two cases are related to Rahimabad station during the years (1985-2003).