Precipitation periodicities in Kurdistan – Iraqi region

Abstract

Periodicities in the annual precipitation of Sulaimani, Erbil and Duhok cities of Kurdistan, Iraq have been studied visualising the data for 70 years. The three precipitation series, North Atlantic oscillation (NAO) index series and Southern oscillation index series were subjected to spectral analysis by Blackman-Tukey method to investigate the possible periodicities exist that in the rainfall series and their relations to NAO, ENSO and solar cycle. It was found that the cycles of 2, 2.7, 3.6, 4 and 10 years are related to NAO cycles, 5.4 year cycle is related to ENSO cycle and 11.1 year cycle is related to the solar cycle at Sulaimani site. The common rainfall cycles among the three sites were 2.8, 4.8 and 10 years.

Keywords

• Precipitation Periodicity
• Iraq
• NAO
• ENSO
• SOI