Climatic significance of

the Maritime Continent

 

The Maritime Continent includes the archipelagos of Indonesia, New Guinea, and Malaysia, and the surrounding shallow seas. It is located within the climatological Indo-Pacific warm pool, a region associated with sea surface temperatures (SSTs) higher than ~28°C, where frequent convective storms (Keenan et al. 2000) contribute to the uprising branch of the East-West Walker circulation. This convective activity over the Maritime Continent is thus tightly related to large-scale variations in the climate system (Neal and Slingo 2003). For instance, the Maritime Continent is collocated with the western pole of SST anomalies associated with the El Niño Southern Oscillation (ENSO, Lau and Chan 1983), and with the eastern pole of SST anomalies associated with the Indian Ocean Dipole (IOD, Saji 1999). As convection over the Maritime Continent is involved in these two major climate oscillations, and as the later strongly influence the Australian climate (e.g. Risbey et al. 2009), the Maritime continent has received increasing attention from the Australian community over the last few years. Moreover, a part of the convective systems that form over the Maritime Continent bring rainfall onto North Australia (Keenan and Carbone 2008). A few of the systems originating from the Maritime Continent even develop into tropical cyclones (e.g. McBride and Keenan 1982). Finally, the Maritime Continent is also important because its affects the mid-latitudes, including South Australia (Hinton et al. 2009, Nicholls 2010). Despite its global importance, the Maritime Continent remains one of the regions where global climate models struggle to realistically represent the spatial distribution of rainfall and its variability (Jourdain et al. 2013).

Fig. 1 - Climatological rainfall from December to March (mm/day), from the Tropical Rainfall Measuring Mission (TRMM-3B43) dataset. Surface wind streamlines from the ERAinterim reanalysis over the same months (from Jourdain et al. 2013).