In WNP Typhoon active years a cyclonic anomaly extends from central Pacific to the East China Sea and to the east of Philippine, providing a favorable environment for Typhoon development.

• 在活跃年时，气旋式环流槽线由中太平洋延伸至东海以及菲律宾东方海面，提供台风发展有利之气候条件，并与该区台风活跃度骤增趋势一致。