Characteristics of Precipitable Water Vapor of Mesoscale Convective System During Heavy Rainfall over Greater Jakarta, Indonesia, March 3-4 2025

Abstract

Across the Indonesian Maritime Continent, pronounced convective activity frequently initiates cloud systems that can further organize and evolve into mesoscale convective system (MCS). This triggers extreme weather and flash flooding; for example, on March 3-4, 2025 in Greater Jakarta. This study investigates the impact of such systems on precipitable water vapor (PWV) using GNSS observations, the ERA5 reanalysis model, and Himawari satellite data. The datasets include rainfall observations, GNSS RINEX data, ERA5 reanalysis, GPM satellite precipitation, and brightness temperature from Himawari-8 channel 8. Analysis was conducted on spasiotemporal variability, timeseries, scatter plots, boxplots, bias, MAE, RMSE standard deviation, correlation, and coefficients of determination. The results indicate that PWV exhibits marked fluctuations that align with the MCS period. The distance of observation and MCS track have a significant influence on modulating PWV, whereas PWV has a weak correlation with MCS intensity. Consistent fluctuations were detected in both the GNSS and ERA5 derived PWV, although GNSS demonstrated higher sensitivity in describing PWV fluctuation compared to ERA5. Variation in brightness temperature in the upper-level moisture demonstrate patterns consistent with PWV, athough the correlation remains weak. MCSs lead to enhanced rainfall, which can trigger extreme weather conditions and flash flooding.