Low-Level Cloud and Low-Level Jet Occurrence during Warm ENSO Events in Indonesia and Northern Australia

Over the last decade, there were three strong warm ENSO events, namely in July 2002- February 2003, August 2006-February 2007, and June 2009-May 2010. These events decreased precipitation over the West Pacific causing severe droughts to the most part of Indonesia and Australia. Since precipitation is closely related to the formation of low-level cloud, it is important to understand the change of the low-level cloud patterns during the warm ENSO events to predict the precipitation. This research studies the formation of low-level clouds from 1999 to 2014 over Indonesia and Northern Australia (5.50N – 23.50S and 95.00E – 150.00E) based on the daily ground-based observations of 340 weather stations, Radionsonde Observations (RAOBs) of 96 weather stations, and satellite data from MODIS both in Aqua and Terra. This study also includes the effect of low-level jet on the low-level cloud formation and the influence of seasonal variability such as monsoon season, and interannual variability such as cold ENSO on the low-level cloud formation in the 16-year period.