The Variations of Precipitable Water Vapor and Rainfall in Puerto Princesa and Legazpi City During the Philippine Southwest Monsoon Season from 2013 to 2022

Precipitable Water Vapor (PWV), the measure of the entire atmospheric water vapor carried in a vertical air column, can be used to represent measurements of water vapor (Mina in Mongabay 2021). The variations and correlation between PWV and rainfall over Puerto Princesa, Palawan, and Legazpi City, Albay, during the Philippine Southwest Monsoon (SWM) Season from 2013 to 2022 are presented through the use of radiosonde databases of both PWV and Rainfall, as extracted from Integrated Global Radiosonde Archives (IGRA) and Global Surface Summary of the Day (GSOD). It was interpreted by Microsoft Excel and MATLAB. A time series analysis with the Lomb-Scargle periodogram, Mann–Kendall test, and One-Way ANOVA graph was used to examine the temporal variations and analyze the correlations of the data extracted from respective sources. The results demonstrated an intriguing trend between the two stations and their locations. In the ten-year course of the study, Legazpi provided a higher peak of PWV and rainfall than Puerto Princesa, despite being the opposite course of SWM winds. PWV and Rainfall usually peak during the start of the SWM Season (June) and fall during the end of it (October). Lomb-Scargle presented apparent periodicities of 4.4 and 6.7 years for Puerto Princesa and Legazpi, while the Mann–Kendall test showed a downward trend for PWV and an upward trend for Rainfall. No significant difference exists between the variables presented, and the stations have a strong correlation, according to the One-Way ANOVA Graph. This study can be a reference for future studies of the Philippines’ shifting climate.