ANALYSIS OF THE EFFECT OF CLOUD COVER ON PM2.5 CONCENTRATION AT NIGHT (CASE STUDY : DKI JAKARTA)

• Main Author: Alfat Rahmadani, Sanggita
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/65179
• Institution: Institut Teknologi Bandung

Particulate Matter (PM2.5) concentrations in the Jakarta area generally always increase at night. Previous research has shown an increase in PM2.5 concentrations at night during winter associated with cloud cover causing a weakening of cooling of the surface radiation. During winter, cloud cover is generally dominated by stratiform cloud cover, while in Indonesia the type of cloud cover in the rainy season varies more from the three altitude levels (low, medium, high). Therefore, in this study, it will be analyzed whether surface radiation due to cloud cover also has an impact on PM2.5 concentrations for different cloud types during the rainy season in the tropics. In this study, we used PM2.5 concentration data, cloud cover data from European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 and Himawari-8, surface net thermal radiation (STR) and surface thermal radiation downwards (STRD) data, wind speed data and radiosonde data from the Soekarno Hatta Meteorological Station. The results of this study indicate that the increase in PM2.5 concentration with the highest rate occurs when atmospheric conditions are stable and a temperature inversion is detected at an altitude of <200 m which is thought to be triggered by cooling surface radiation due to low downward longwave radiation emitted by clouds at night. Meanwhile, the decrease in PM2.5 concentration with the highest rate occurred when cloud cover at low and medium levels at night was above 40% which was thought to be triggered by heating of the surface radiation due to the large amount of cloud cover.