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A realistic realization of heavy rainfall in the mountainous region in Java is important for weather forecasts and climate simulations due to its potential disaster caused such as flashfloods and landslides. To study the relation between heavy rainfall events and such impacts, high resolution simulations are necessary to account for the appropriate representation of the geographical features and as well as the convection that typically occurred in such settings which lead to heavy rainfall events. The planetary boundary layer (PBL) scheme in a numerical model is a sensitive aspect which may lead to very different results of the rainfall simulation in a mountainous region setting. While such study of the PBL are still quite rare, in this study high-resolution Weather Research and Forecasting (WRF) simulations were carried out for different schemes of the PBL, i.e. Yonsei University (YSU) and Shin-Hong (SH) schemes, for a heavy rainfall event during 28 - 30 November 2018 over Central Java. The numerical model employs nesting with horizontal resolutions of 9 km, 3 km and 1 km for the outer, middle and inner domains, respectively. Some satellite observations, i.e. Global Precipitation Measurement (GPM), CPC Morphing Technique (CMORPH) Global Precipitation Analyses, and Global Satellite Mapping of Precipitation (GSMaP), were used to compare with the model results. The results showed that the heavy rainfall simulated with the SH scheme was closer to both the TRMM and CMORPH dataset than simulation result with the YSU scheme, although both schemes resulted in a similar spatial rainfall pattern. The findings suggest that the SH scheme can be used at a kilometer resolution to adequately replicate the scale and evolution of the observed rolls in heavy rainfall events in the mountainous area with steep slopes. This research is a part of the project A Blueprint for an Indonesian Landslide Early Warning System (BILEWS).
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