THE IMPACT OF INTERACTION BETWEEN COLD SURGE, BORNEO VORTEX, AND MADDEN-JULIAN OSCILLATION (MJO) ON RAINFALL IN WESTERN INDONESIA

• Main Author: Achmad Al Maududi, Briandi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/38718
• Institution: Institut Teknologi Bandung

Cold Surge (CS), Borneo Vortex (BV), and MJO activities can influence atmospheric conditions and the intensity of rainfall in Western Indonesian. This study examines whether the relationship if the three phenomena occur simultaneously will be linear or not to increase convection and rainfall activity in Western Indonesian during the Asian Winter Monsoon period from 1998/1999 to 2015/2016. The data used to identify the three phenomena includes the ERA-Interim reanalysis data from the European Center for Medium-Range Weather Forecast (ECMWF) and the index of RMM 1 and RMM 2 from Bureau of Meteorology (BOM). Tropical Rainfall Measuring Mission (TRMM) satellite datasets are used for rainfall analysis. The method used is composite anomalies for rainfall parameters, moisture transport, and potential vorticity. The results of the identification show a total of 93 days of the phenomenon occurring simultaneously. The combination of Weak CS, BV, and phases 4 of MJO most influences the increase on rainfall in Sumatra and Peninsular Malaysia. While the combination of Strong CS, BV, and phases 4 of MJO has the highest influence on increasing rainfall in Kalimantan, South China Sea, Java, Java Sea, Bali and Nusa Tenggara. The results of the moisture transport analysis can be concluded that a significant increase on rainfall in each region can be explained by the existence of a strong convergence pattern of moisture transport.