Effects of Fluctuations of Persian Gulf Sea Surface Temperature and the El Nino-Southern Oecillation (ENSO) on precipitation variability in the South-Central parts of Iran

The present study has made an effort to analyze the individual and the coupled effects of the sea surface temperature (SST) and the El Nino-Southern Oscillation (ENSO) on precipitation variability in the South-Central parts of Iran over the period of 1957-2019. The SST data comprise the monthly time series of this variable over eight grids located in various parts of the Red Sea (1 grid), Persian Gulf (1 grid), Oman Sea (2 grid) and the Arabian Sea (1 grid). In addition to these gridded data, the SST-precipitation relationships are also examined for differential values of these gridded datasets. Correlation coefficients are consistently found to be negative when monthly or seasonal SSTs are regressed with corresponding precipitation data in all considered stations. The strongest correlations are found when differential values of SST (The Red Sea minus eastern parts of the Persian Gulf) are regressed with precipitation data in Sirjan. Differential values have generally yield stronger correlations than if the data of a single grid are used. Fluctuation of the SSTs data over the Red Sea, western Parts of the Persian Gulf and eastern side of the Arabian Sea exhibited strongest relationships with rainfall variability over the study area. In contrast, the less significant associations are observed for the grids that are located over the Oman Sea. The SST-precipitation relationships are found to be negative during both the warm and cold phases of ENSO.