Özet:

Unlike other natural disasters, drought takes longer to develop and its effects last longer. With this feature, monitoring a possible drought makes it possible to reduce the negative effects of drought more effectively. The Standardized Precipitation Index (SPI) is one of the few drought indexes proposed by researchers to describe droughts between different climatic conditions on different time periods and regions. This study aims to perform the past and future drought analysis of the Eastern Black Sea Basin (EBSB), which is one of the most important hydrological basins in terms of precipitation amount of Turkey, with SPI. In this context, SPI values were calculated using the monthly total precipitation data for the 1981-2010 period, which were measured from 12 meteorological stations in and around the EBSB. In addition, the same processes were applied to the 2021-2050 period outputs of the GFDL-ESM-2M general circulation model in the CMIP5 archive, which was downscaled to regional scale under optimistic (RCP4.5) and pessimistic (RCP8.5) scenarios. For trend analysis of meteorological drought, trend analysis was carried out in three different groups and 95% confidence interval, using Innovative Trend Analysis method on 1- and 3- monthly SPI values. In the observation values and RCP scenarios, about 25% of the stations saw an increase in severe wet class and in severe drought class. However, in the historical period, except for the Akçaabat station (decreasing trend), significant monotonic increasing trends were observed in the SPI values, while a decreasing trend was observed in the next period for both scenarios.

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