STUDY OF DIURNAL VARIATION OF CONVECTIVE ACTIVITY OVER PAMEUNGPEUK, WEST JAVA WITH XBAND DOPPLER RADAR DURING RAINY SEASON AND TRANSITION

• Main Author: SINATRA (NIM : 22412015); Pembimbing : Dr. Nurjanna Joko Trilaksono , TIIN
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20579
• Institution: Institut Teknologi Bandung

Intensive observations using radar transportable has conducted at Pameungpeuk, West Java, focusing on the convective activity in the southern coastal areas of West Java during the rainy season. Structures of spatial and vertical were analized during the observation period of 21 days from 12 February to 4 March 2014. The threshold of 10 dBZ was chosen to classify the type of rain clouds (convective / stratiform). The radar echo coverage was used in the following analyses to investigate diurnal variation. Whereas the vertical structure was characterized by calculating the radar echo coverage at each altitude. Results showed that convective cloud growth in all areas of radar coverage reached a maximum at about 18.00-20.00 and minimum at 7.00-11.00 local time (LT). The result showed that the frequency over land was greater than over the ocean, both for the type of convective and stratiform rain clouds in the rainy season. But, it was not occured in the early transition phase. Convective activity occured over mountainous region. Analysis of the vertical structure showed that the variation of radar echo reached a maximum at an altitude of 5 km above mean sea level (AMSL) with radar echo coverage over the land was greater than over the ocean. In the rainy season, convection over the sea accured in the early morning which then migrated to the coastal. The small clouds formed over the mountains at noon. Increasingly afternoon, the clouds began to spread and developed larger convective systems. Whereas, in the transitional phase, in the early morning clouds formed over the mountains and it decayed over it. In the afternoon, convection concentrated in the coastal area. So, the clouds only detected only over the coastal and mountain. This happened probably due to the presence of wind shear detected by radar data.