Climatological analysis of the Southwest Monsoon (Habagat) in Type 1 Climate Areas in the Philippines from 1949 to 2018
POLINA S. ESPINO, ALYSA MARIE M. ONG, DANIELLE MARI J. YORAC, and JULNAFE B. LIBO-ON
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHSWVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
The Southwest Monsoon (SWM) brings heavy rainfall that can negatively affect Philippine agriculture. The historical behavior and trends of the SWM rainfall in the Philippines were identified using collected rainfall data from fourteen (14) meteorological stations situated in Type 1 climate areas of the country, where the impact of SWM is well-pronounced. The time series analysis from 1949 to 2018 for the months of June to September showed an overall increase in accumulated rainfall with a slope of +1.8047, as well as in the decadal frequencies of high precipitation event days (HPE) at the 85th, 95th, and 99th percentile with slopes of +1.0586, +0.4740, and +0.1030, respectively. The trendline for the no-rain days graph has a slope of -0.1177, indicating a decreasing trend. These findings suggest a possibility of an increase in SWM rainfall in the coming decades.
Keywords: southwest monsoon, habagat, rainfall, climatological analysis, precipitation