Drought and Trend Analysis of Rize Station with Standardized Precipitation Index and Standardized Precipitation Evapotranspiration Index Methods

Abstract

Since ancient times, drought has been one of the worst natural disasters that humanity has experienced. Drought, which is likely to occur locally or regionally can be defined as the lack of precipitation in a certain period of time. Objectively determining long-term droughts in advance enables taking measures against drought. Estimation of drought is of great importance in order to reduce the socio-economic, agricultural, and environmental negative effects that drought may cause. One method used in determining drought is the drought indices, which are found with the help of precipitation values. Indicators used frequently in drought monitoring include the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI). SPEI takes precipitation and temperature into account, but SPI only takes precipitation into account. The aim of this study was to make a drought analysis at the Rize station located in the Eastern Black Sea Region of Turkey. SPI and SPEI were used as drought analysis methods. Analysis was carried out between 1982 and 2020 hydrological years. Monthly total precipitation and monthly average temperature were used as data. Droughts were investigated in monthly, seasonal, and annual periods. Drought index values were found for each period. SPIE and SPI values were plotted. The Mann-Kendall trend analysis method was preferred. As a result of the analysis, it was revealed that both wetness and drought were seen in and around the station.