Different Pacific Ocean Warming Decaying Types and Northwest Pacific Tropical Cyclone Activity

• Published in: Journal of climate Vol. 26; no. 22; pp. 8979 - 8994
• Main Authors: Ha, Yao, Zhong, Zhong, Yang, Xiuqun, Sun, Yuan
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 01.11.2013
• Subjects: Anomalies; Asian; Circulation anomalies; Climate change; Coastal environments; Cold; Cyclones; Cyclonic activity; Cyclonic circulation; Datasets; Decay; Early experience; Earth, ocean, space; El Nino; El Nino phenomena; Equatorial regions; Exact sciences and technology; External geophysics; Genesis; Global warming; Hurricanes; La Nina; Life span; Marine; Meteorology; Ocean temperature; Ocean warming; Oceans; Philippines; Sea surface; Sea surface temperature; Sea surface temperature anomalies; Statistical analysis; Statistical methods; Storms, hurricanes, tornadoes, thunderstorms; Studies; Surface temperature; T tests; Temperature anomalies; Tropical cyclone activity; Tropical cyclones; Wind shear; Northwest Pacific; Pacific Ocean; North Pacific; Indian Ocean; East Asia; ISW, East Indian Ocean; I, Central Pacific; ISEW, Philippine Sea; ISEW, Philippines; IS, Tropical Pacific; IN, North Pacific; intensity; localization; Severe weather; Tropical cyclone; Occurrence frequency; warming; Sea surface temperature; ocean-atmosphere interaction; trajectory; Cyclogenesis
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/JCLI-D-13-00097.1

This study focuses on statistical analysis of anomalous tropical cyclone (TC) activities and the physical mechanisms behind these anomalies. Different patterns of decaying of the warm sea surface temperature anomaly (SSTA) over the equatorial central-eastern Pacific are categorized into three types: eastern Pacific warming decaying to La Niña (EPWDL), eastern Pacific warming decaying to a neutral phase (EPWDN), and a central Pacific warming decaying year (CPWD). Differences in TC activity over the western North Pacific (WNP) corresponding to the above three types are discussed, and possible mechanisms are proposed. For EPWDL, TC genesis shows a significant positive (negative) anomaly over the northwestern (southeastern) WNP and more TCs move westward and make landfall over the southern East Asian coast. This is attributed primarily to the combined modulation of La Niña and the warm equatorial east Indian Ocean SSTA. For EPWDN, enhanced TC genesis is observed over the northeastern WNP, and suppressed TC activity is located mainly in the zonal region extending from the Philippine Sea to the eastern WNP, close to 160°E. Most of the TCs formed over the eastern WNP experience early recurvature east of 140°E, then move northeastward; hence, fewer TCs move northwestward to make landfall over the East Asian coast. For CPWD, the enhanced TC activity appears over the western WNP. This is due to the weak anomalous cyclonic circulation over the Philippines, primarily caused by the weaker, more westward-shifting warm SSTA compared to that in the previous warming year over the central Pacific.