Wet and Dry Season Precipitation over the Maritime Continent: Variations and Prediction

Abstract:

The authors analyze the seasonal-interannual variations of precipitation over the Maritime Continent (MC) and their relationships with large-scale climate anomalies. They also investigate the predictability of MC precipitation variations. The hindcast of the NCEP Climate Forecast System version 2 (CFSv2) and several other NOAA data sets are mainly analyzed.

The seasonal evolution of MC precipitation does not exhibit features for four seasons (spring, summer, fall, and winter) apparently as the precipitation variations over many places of the world do. Instead, it is clearly characterized by a wet season (from December to March) and a dry season (from July to October). Both the wet-season precipitation and the dry-season precipitation over MC are significantly related to ENSO and Asian-Australian monsoon features. When ENSO signal is removed, the MC precipitation is more strongly related to climate features over East Asia in the wet season and tropical Australia in the dry season.

The NCEP CFSv2 shows a high skill in predicting the main features of MC precipitation variations and their relationships with larger-scale climate anomalies. It can predict the total amount and the most dominant mode of MC precipitation skillfully by several months in advance, especially for the dry season.