Updating Tropical Cyclone Climatology in the Philippines

by T.A. Cinco, 2010, Proceedings (CD-ROM) of the Earthquake and Severe Wind Exposure and Vulnerability Workshop, Tagaytay City; co-organized by PAGASA, PHIVOLCS, and Geoscience Australia.



Contents:

1. Tropical cyclone zone of formation and dissipation
2. Tropical cyclone statistics
3. Trend of tropical cyclones during the last 58 years (1948-2005)
4. Monthly Tracks
5. Rainfall patterns in the Philippines during occurrences of tropical cyclones
6. Disastrous Tropical Cyclones

The presentation seeks to "update" tropical cyclone statistics in the Philippines.  It indicates that tropical cyclone track data from 1948 to 2005 were gathered and analyzed, for each 1x1 degree latitude and longitude.  

From the presented data, certain provinces in North Eastern Luzon are found to experience the most tropical cyclone landfalls, although the Bicol region as well as the Eastern Visayas region (Samar and Leyte) experienced the most tropical cyclone landfalls on a larger area.

Whereas previously, PAGASA data suggests that the Philippines experiences around 9 landfalling tropical cyclones annually on average, the maximum annual landfalling tropical cyclones in any given 1x1 degree latitude/longitude area is only 2 per year on average.

As expected the peak months for landfalling tropical cyclone occurrence start in the Northern Hemisphere's "summer" month of July and are still considerably strong until November.  Also, February is still the month with the least landfalling tropical cyclones.  The maximum number of extreme typhoons affecting the Philippine Area of Responsibility (PAR) annually is 6 on average.

Typical monthly tracks of tropical cyclones were also presented.  Basically from July to November, tropical cyclones typically form in the Pacific Ocean and move northwestward, crossing the Philippines.  On other months, the cyclones typically move northwestward initially but, change course and move northeastward towards Japan.  Also, there are more landfalling cyclones during El Niño seasons than during La Niña seasons, although even without El Niño or La Niña, there are still a considerable number of landfalling cyclones.

The presentation also included some rainfall statistics as well as statistics of casualties and damages due to disastrous tropical cyclones.