The Indo-Pacific climate dynamics and teleconnections with a special emphasis on the Indian summer monsoon rainfall
Swadhin K. Behera
Abstract
The climate dynamics in the Indo-Pacific sector is dominated by several modes of interannual climate variations. The El Nio/Southern Oscillation (ENSO) is historically recognized as the dominant mode of climate variations in the global climate system. It affects the weather and climate all over the world including Indian summer monsoon rainfall (ISMR) through direct and indirect pathways. Also, the ENSO-induced basin-wide mode of the tropical Indian Ocean is shown to have a delayed effect, like a capacitor, on the climate variations of the western Pacific and the adjacent land regions of Asia. The Indian Ocean Dipole (IOD) is recently recognized to be the other dominant climate mode that has worldwide impacts on weather and climate including ISMR. In addition, perhaps related to the global warming processes, the characteristics of the ENSO have changed in recent decades and a new ocean-atmosphere coupled mode called ENSO Modoki has emerged. The ENSO Modoki signals are seen centered in the central Pacific with opposite polarity signals appearing on both sides of the basin. Different from ENSO, the ENSO Modoki associated teleconnections can be seen in many parts of the world. Besides the tropical climate mode, the Indo-Pacific sector also has subtropical climate modes related to local air-sea interactions. Particularly, the Indian Ocean subtropical dipole (IOSD) is shown to have a significant correlation with the rainfall variability in southern Africa, Australia, India and even southern China. Several modes of coastal air-sea interactions modes are also discovered recently. The most interesting of them is the Ningaloo Nio/Ningaloo Nia off the western coast of Australia. This coastal Nino has a strong influence not only on the coastal ecosystem but also the regional climate variability in Australia.