Influence of different types of ENSO events on the tropical cyclone rainfall over the western North Pacific

Tropical cyclone (TC) rainfall (TCR) over the western North Pacific (WNP) in TC peak season shows diverse responses to different El Nino flavors. Accumulated TCR increases over the low latitude regions (northwestern quadrant) of the WNP in eastern Pacific (central Pacific) El Nino but decreases over the entire basin in La Nina years. TCR hours are the primary causes of the variations in accumulated rainfall, while TCR rate takes second place. TCR hours are closely related to the total duration of TCs, which can be attributed to the slower translation speed and the longer TC travelling distance in eastern Pacific El Nino, but the increased (decreased) TC number for central Pacific El Nino (La Nina). Meanwhile, the TCR rate is closely related to TC intensity and 850 hPa vorticity. In eastern Pacific El Nino years, the decrease in steering flow and the southeastward displacement of TC genesis locations cause the changes in translation speed and travelling distance over the WNP, and the increased TC intensity over the offshore regions of eastern China. In central Pacific El Nino years, the easterly anomaly of midlatitude steering flow causes the increased TC number entering the corresponding region, and the increase of 850 hPa vorticity over the WNP basin leads to the enhanced TC intensity. In La Nina years, the combined effects of decreased 850 hPa vorticity and enhanced vertical wind shear over the Philippine Sea can result in the suppressed TC number and TC intensity.