Filipino researchers develop AI algorithm to detect shear lines

Filipino-led international researchers have developed a new physics-based algorithm using artificial intelligence (AI) to detect and monitor "shear lines," a weather system that can cause extreme rainfall in the Philippines.

A shear line is formed when the northeast monsoon, known as "amihan," converges with warm easterly winds from the Pacific Ocean, creating kilometers-long bands of shifting air.

The new detection method, the first objective index for monitoring shear lines over the Philippines, will help quantify their impact on extreme rainfall events during the amihan season.

Analysis of decades of rainfall data linked to shear lines will also aid in identifying areas prone to heavy rainfall and enhance the understanding of shear line evolution.

Unlike cold fronts or typhoons, shear lines lack universally accepted detection criteria as they lose their structure over warm ocean waters.

The algorithm could improve early warning systems, climate studies, and weather forecasting models, and was published in the Meteorological Society of Japan's Scientific Online Letters on the Atmosphere (SOLA) in November 2025.