ANALYSIS OF THE INFLUENCE OF RAINFALL AND WIND SPEED DUE TO CROSS-EQUATORIAL NORTHERLY SURGE ON PM2.5 IN JAKARTA AND BANDUNG (CASE STUDY: DECEMBER 2021–FEBRUARY 2022)

• Main Author: Bahrul Ulum, Muhamad
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/75710
• Institution: Institut Teknologi Bandung

This research aims to investigate the impact of rainfall and wind speed caused by Cross-Equatorial Northerly Surge (CENS) on the concentration patterns of Particulate Matter 2.5 (PM2.5) in the regions of Jakarta and Bandung during the period from December 2021 to February 2022. CENS represents a meteorological phenomenon characterized by the intense surface wind flow crossing the equator originating from the South China Sea. CENS is closely associated with increased rainfall and wind speed in several areas of Indonesia. The study employs direct PM2.5 data measured by 17 sensors owned by PT. Nafas in Jakarta and Bandung. Rainfall data is obtained from the Global Precipitation Measurement (GPM) with a spatial resolution of 10 km × 10 km and an hourly temporal resolution. Wind speed data is collected from the Automatic Weather Stations (AWS) located in Tanjung Priok, Jakarta, and Stageof Bandung, as well as from the ERA5 climate reanalysis data. The research methodology involves the identification of CENS events using ERA5 data for the meridional wind variable. The analysis encompasses the evaluation of composite average rainfall, PM2.5 concentration, and wind speed during both CENS and non-CENS periods to discern prevailing patterns. Subsequently, the study investigates the characteristics and interrelationships among the three variables based on the identified patterns. The results show discernible disparities in rainfall patterns during CENS occurrences in Jakarta and Bandung. In Jakarta, rainfall predominantly transpires during the night and early morning hours, with the peak rainfall observed during the daytime, afternoon until the evening, and early morning hours. Conversely, in Bandung, rainfall declines in the afternoon, reaching its peak during that time period. Moreover, wind speed experiences an overall increase during CENS events in both locations. This elevation manifests throughout the day, ranging from morning until evening, with a noticeable shift in the peak wind speed occurring in Jakarta during CENS events. In terms of PM2.5 concentration, it becomes apparent that CENS significantly influences alterations in PM2.5 concentration in both regions. While a decline in PM2.5 concentration occurs during CENS events, the patterns of concentration change diverge between Jakarta and Bandung. In Jakarta, PM2.5 concentration exhibits a tendency to diminish during the night and early morning hours, whereas in Bandung, it intensifies from the daytime until the afternoon.