Characterizing major droughts in the context of dry period in Seyhan River basin, Turkey

Seyhan River Basin has great importance for agricultural production, industry, energy and tourism sectors in Turkey. This study investigates temporal characteristics of meteorological droughts in the river basin at station-scale. Six major droughts were identified lasting 2 years at minimum from the average precipitation time series of 19 meteorological stations over the basin. We have adopted a methodology specifically for the river basin where local meteorological data are limited. The river basin was divided into four sub-basins. Each sub-basin was represented by one meteorological station which has a high correlation with the basin-average precipitation and also covers as many of the major droughts as possible. The Standardized Precipitation Index (SPI) was calculated for the meteorological stations at different time scales. The site-specific drought analysis elucidated the probability of mild, moderate, severe, and extreme droughts. The temporal occurrence illustrates that the river basin has experienced severe prolonged droughts every ten years on average. Mild drought dominates at each time scale and their frequencies increase with increasing time scale although severe and extreme events are observed with a higher probability in some major droughts. A significant change of the probabilities of the drought classes was not found in the representative stations, instead, we observed no consistent change. This analysis presented valuable information for the river basin on the temporal variability of the drought, and also shed light on the need for such analyses for regional drought adaptation and mitigation. Given the limitations that emerged on the determination of the representative stations, it would be advisable to consider additional data (such as remote sensing or satellite) in future studies to gain further insights into the temporal characteristics of drought.