The period of June to September (JJAS) is considered as the peak of wet season in the Philippines. About 20 tropical cyclones, or typhoons as they are called in this part of the world, pass the country and about half make landfall, leaving damages to life and property in their wake. Accurate forecast of a cyclone’s track and intensity is therefore of great importance to minimize the damage it might cause. Forecast may be short-term (3-5 days in advance) or seasonal (more than a month in advance). The latter are produced in low resolution at major weather centers running global circulation models (GCM) on mainframes. Seasonal forecasts are important for medium-term planning of government and industry. However, local research institutions in developing and/or transitioning economies like the Philippines are not capable of running GCMs due to limitations in computational facilities.
Based on a study Seasonal Forecast of Tropical Cyclone Tracks over the Philippines by Dr. Josefina C. Argete of the Institute of Environmental Science and Meteorology and Dr. Raquel V. Francisco of the Department of Science and Technology an economical solution for improving the resolution of the cyclone forecast is to nest a regional climate model within a global model. This model, configured to run on personal computers, is forced at the boundaries by the global model outputs for the region that may be requested from centers running GCMs. The cyclones produced by the regional models have been found to be weaker than observed but are more realistic than the vortices generated by GCMs.
The study of Dr. Argete and Dr. Francisco is a pioneering initiative on investigating the feasibility of making seasonal forecast of tropical cyclone from regional models in the Philippine region. It demonstrates the capability of regional climate model to detect tropical cyclones and simulate their tracks on a seasonal scale (JJAS) in the country. The simulation of the tracks is influenced by the domain configuration of size and placement of boundaries.
By MMRParreño
