Trends and Variability in Droughts in the Pacific Islands and Northeast Australia

Drought is a recurrent climate feature of the Pacific Islands and northeast Australia with meteorological and socioeconomic impacts documented from early European settlement. In this study, precipitation records for 21 countries and territories in the Pacific for the period 1951 to 2010 have been examined to identify trends in drought occurrence, duration, and magnitude. The strength of the relationships between the main climate drivers in the Pacific-El Nino-Southern Oscillation (ENSO), the interdecadal Pacific oscillation (IPO), and the Pacific decadal oscillation (PDO)-and precipitation has been also examined. Station-scale drought trends are largely positive, but the majority are statistically nonsignificant with the significant trends mainly in the subtropics. Spatially, trend patterns are largely heterogeneous. A significant relationship between the oceanic component of ENSO and precipitation is confirmed for a large part of the Pacific Islands and eastern Australia with a strong lagged relationship in the year after the El Nino onset at locations southwest of the South Pacific convergence zone (SPCZ) and north of the intertropical convergence zone (ITCZ). Similarly, a strong relationship was found with the IPO and PDO at most locations. Drought was found to be longer and more severe southwest of the SPCZ and north of the ITCZ during the positive phases of the IPO and PDO.