Keywords: drought index, SPI, PNI, DI, EDI, CZI, MCZI, ZSI, RAI

A meteorological drought can be seen as a result of a precipitation shortage or which is defined as the lack of precipitation over a region for a period of time. It is usually region-specific because the atmospheric conditions in different areas are highly variable in space and time. Depending of the duration of meteorological drought, the soil humidity will be reduced (shorter term) and the groundwater table can be dropped (longer term). Meteorological drought is signaled by indicators intrinsic to weather data and precedes the onset of specic impacts, i.e. additional kinds of drought. There are different indices for monitoring and assessing the amount of meteorological droughts. Through the rain-based meteorological drought, we can track the amount of drought We developed the MDM (Meteorological Drought Monitoring) software application for calculating eight rain-based meteorological drought indices, namely: SPI (Standardized Precipitation Index), DI (deciles index), PN (Percent of Normal Index), RAI (Rainfall Anomaly Index), EDI (effective drought index), CZI (China-Z index), MCZI (modified CZI), and ZSI (Z-Score Index) in form of yearly, seasonally, monthly and moving average for 3, 6, 9, 12, 18, 24, and 48 months. Because using different drought indices at a given time can show drier or wetter than usual conditions (Smakhtin and Hughes, 2007), user-friendly software is a critical tool for calculating and comparing multiple locations, time periods, and data source influences efficiently. The MDM software package currently bases calculations on two sources of data. The first is a synoptic station data file, which includes daily precipitation in excel format. The second one is a database of daily precipitation from AgMERRA, available for the Middle-East region. The user can click the map on the desired point in the package and calculate all indices for that 0.25 degree grid location. There is a complete help file in the package, which describes all setup steps.