Rapid Intensification of Typhoon Haiyan 2013: Atmospheric and Climatological Analysis using Open-source Data

Abstract Typhoon Haiyan 2013, one of the most powerful typhoons in the Western North Pacific (WNP) Basin, had undergone rapid intensification (RI) before landfall, resulting to destructive storm surges in the southeastern part of the Philippines. This research aims to investigate the environmental conditions that had led to the intensification, through the use of open-source meteorological and climatological data. Observed and long-term averaged values of sea surface temperature (SST), vertical windshear (VWS), mid-tropospheric relative humidity (MTRH), and mean sea level pressure (MSLP) were compared and analyzed. Additionally, the roles of climate variations such as the El Niño-Southern Oscillation (ENSO), the Quasi-biennial Oscillation (QBO) and the Madden-Julian Oscillation (MJO) were also investigated. Results indicate that the intensification was triggered by higher-than-average SST, weak VWS for 1000 − 500 hPa and 850 − 700 hPa levels, and high and increasing MTRH. Findings also imply that the WNP Subtropical High appeared to be strong during the event, ENSO was in neutral phase, QBO was in favorable westerly phase, and MJO was leaning towards its ending phase in the Pacific. This research demonstrates the collaborative use of open-access data for meteorological and climatological analysis, enabling a better understanding of weather extremes, facilitating more accurate predictions in the future.