Spatiotemporal Analysis of Droughts Over Different Climate Regions Using Hybrid Clustering Method

Assessment of spatiotemporal variations drought is an efficient method for implementing mitigation strategies and reducing its negative impacts. This study aimed to assess the pattern short- long-term droughts area with different climates. Therefore, 31 stations located in Iran were selected Standardized Precipitation Index (SPI) series timescales 3, 6, 12 months computed during 1951-2016 period. A hybrid methodology including Maximal Overlap Discrete Wavelet Transform (MODWT) K-means methods was used obtaining SPIs time-frequency properties multiscale zoning area. The energy amounts decomposed subseries via MODWT applied as inputs K-means. Also, statistics features (i.e. duration, severity, peak) assessed results showed that shorter term SPI-3 -6) more frequent severe northern parts where lowest values obtained duration. It observed regions frequency had highest values. For a direct relationship between mean SPIs, peak, whereas inverse longer drought. found increasing degree SPI led similarity each cluster. homogeneity SPI-12 slightly higher than -6.