Projection of Meteorological Drought under a Changing Climate in the Urmia Lake Basin, Iran

Abstract Arid and semi-arid regions are more susceptible to climate change impacts, leading to recurrent and sustained meteorological droughts as a natural hazard. Therefore, this study is established to assess the meteorological drought characteristics in the Urmia Lake Basin under a changing climate in Iran. To that end, General Circulation Models (GCMs) were evaluated using observed and Global Precipitation Climatology Centre (GPCC) datasets. Then, the selected GCMs were applied to project drought conditions until 2046 under Representative Concentration Pathway 2.6 and 8.5 (RCP2.6 and RCP8.5). Afterward, we developed eight combined scenarios (A1, A2, A3, A4, B1, B2, B3, and B4) to assess future drought characteristics. Ultimately, the Standardized Precipitation Index (SPI) was calculated using the Drought Indices Package (DIP) for the historic (1985–2015) and future (2016–2046) periods under two temporal scales, namely the medium-term (SPI-6) and long-term (SPI-18). According to the results, precipitation is expected to increase from 16.3–34% while the northeast and south parts of the basin will be affected by future drought effects. The projected SPI-18 under RCP8.5 indicated that the basin will suffer from the most severe and long-standing meteorological drought, anticipated to happen around 2045–2046 (A4 scenario). The increase was projected for severe low-frequency drought events in A4 (long-term) and, B1 and A3 (medium-term) scenarios. While, in most cases, the decrease was shown for the high-frequency with less intensity drought events mainly in medium-term assessment.