IDENTIFYING THE CAUSES OF HEAVY RAIN DURING FLOODS USING WRF-ARW MODEL AND DOPPLER WEATHER RADAR IMAGES (CASE STUDY: PADANG, JUNE 11, 2022)

• Main Author: Nabila, Rahmi
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/76087
• Institution: Institut Teknologi Bandung

Indonesia is located in a tropical region that receives a surplus of solar radiation heat energy, increasing the potential for convective cloud growth. This causes heavy rains to occur frequently in Indonesia. Heavy rains with a long duration can cause flood disasters that cause economic losses, environmental damage, and even casualties. One of them is the flood disaster that occurred in Padang City, West Sumatra on June 11, 2022 which caused one person to die, two people were missing, and 34 houses were flooded. Seeing this, it is necessary to conduct research to determine the factors that increase the growth of convective clouds that cause heavy rain in Padang on June 11, 2022, causing flood disasters. In this study, CHIRPS data is used to calculate the maximum rainfall value and GFS data as initial data for the WRF model. WRF model results are used to see the distribution of rainfall and wind direction in Padang City. WRF model results are also used to see the vertical wind speed value. In addition, weather radar data from the class II meteorological station in Padang Pariaman was also used to determine how the process of heavy rain occurred. The process of heavy rainfall is analyzed using reflectivity values obtained from the weather radar CMAX product. The results of this study indicate that the heavy rain that occurred on June 11, 2022 was caused by adiabatic advection lift. Adiabatic advection lift causes air to rise vertically, triggering cloud formation. Cloud growth began to appear at 05:38 UTC and entered the convective initiation phase at 06:38 UTC. Then the clouds grew until they reached the mature phase with the reflectivity value reaching a maximum which occurred at 10:38 UTC. The reflectivity value began to decrease at 11:38 UTC until finally the convective cloud was extinct at 16:08 UTC.