On the relationship between Indian Ocean Dipole events and the precipitation of Pakistan

Abstract

This study investigated the relationship between the Indian Ocean Dipole (IOD) and the precipitation of Pakistan using data for the period of 1958–2010. The long-term evolution of the IOD index did not show interannual patterns similar to those of the annual precipitation of Pakistan. No linkage between the co-occurring trends of the IOD and the precipitation was traced during the period of investigation. The correlation between the IOD and the precipitation of Pakistan indicated a noteworthy impact over the monsoonal regions, especially the coastal area and the western region of Pakistan, which showed a significant positive correlation between the IOD index and annual and summer precipitation. A significant positive relationship was also revealed between the precipitation of the Balochistan Plateau and the IOD index for the summer monsoon season. No connection was observed between the IOD and the precipitation of the northern regions and the upper Indus Plain of Pakistan. Positive phases of the IOD have been noted to occur along with surplus precipitation during active monsoon conditions. The southeasterly wind moves from the Arabian Sea and transports additional moisture from the Arabian Sea to the coastal and southwestern parts of Pakistan during positive phases of the IOD.