Science Source

Trends in meteorological and agricultural droughts in Iran

States that every year, droughts affect agriculture, water resources, and ecosystems of Iran
States that most parts of Iran suffer from water scarcity, and droughts can substantially exasperate the pressure on the water resource systems—these systems are sensitive to climatic change and variability and, hence, changes in droughts could affect water availability
Investigates the trends and patterns of meteorological and agricultural droughts in Iran and several subregions with different climatic conditions using precipitation and soil moisture data from NASA’s MERRA-Land
Evaluates the overall meteorological–agricultural drought conditions using a composite model, known as the MSDI
Observes a significant drying trend at 95 % confidence level in the northern, northwestern, and central parts of Iran
Unable to identify a country-wide trend, or a trend in the eastern and northeastern Iran (Khorasan and Sistan and Balouchestan)
Finds the ENSO phenomenon (particularly, prolonged La Niña) significantly alters precipitation patterns across Iran and is one of the main drivers of droughts
Finds that MSDI, detects the drought onset similar to SPI, but describes the drought persistence more similar to SSI; however, in arid and hyperarid regions (e.g., Sistan and Balouchestan and Khorasan), the three indices (SPI, SSI, and MSDI) were more consistent, and MSDI did not provide additional information