Dependence of precipitation on precipitable water vapor over the
Maritime Continent and implications to the Madden-Julian Oscillation
The weakening of the Madden-Julian Oscillation (MJO) as it propagates
over the Maritime Continent (MC) is often referred to as the MC barrier.
Here, we use 3-hourly precipitable water vapor (PWV) data obtained from
the Sumatran GPS Array and the ERA5 reanalysis to investigate the role
played by the column moisture over the MC. Over Sumatra and the whole
MC, we find a stronger dependence of precipitation on PWV over the ocean
as compared to both inland and coastal regions. The MJO modulates the
PWV over the ocean and over the MC by roughly the same amount, and the
weaker precipitation variations over the MC between the MJO phases may
be interpreted in terms of its weaker dependence on PWV over the MC.
This different precipitation dependence on column moisture between the
MC and the ocean may contribute to the MC barrier effect.