[M-IS06] Extreme Weather and Water Related Disasters in Asia

[MIS06-01] Characterizing the southwest monsoon season in the Philippines using multiple localized monsoon indices

★Invited Papers

Nathaniel T. Servando², Lorenzo A. Moron^2,1, *Kimberly Alla Manauis^1,2, Raymond Jess G. Goliat^2,1, Joseph Q. Basconcillo^1,2, Gabriel S. Miro², Robert B. Badrina^1,2, Angelina S. Galang² (1.Philippine Meteorological Society, 2.Philippine Atmospheric, Geophysical and Astronomical Services Administration)

Keywords:Summer monsoon, Monsoon indices, Philippines

The intensity of southwest monsoon (SW) varies in different subregions in the western Philippines. This study characterized the climatology of the southwest monsoon season and its spatiotemporal variability using multiple monsoon indices at a local scale. Derived local monsoon indices include the southerly shear and westerly shear indices, outgoing longwave radiation-, and rainfall-based indices. These metrics were compared and validated with ground-based rainfall datasets and revealed their potential in sufficiently capturing excessive rainfall occurrences in the western Philippines. Results also highlighted the varying capability of the monsoon indices in describing the southwest monsoon onset and propagation, wherein these indices exhibit distinct spatiotemporal characteristics, but generally emphasized the intensification of the season propagating from northern to southern Philippines. Overall insights from this study illustrate the importance of utilizing location-specific based indices in describing and quantifying southwest monsoon intensification, which is essential for enhancing monsoon monitoring and forecasting capabilities in the country.