Influence of Track Change on the Inconsistent Poleward Migration of Typhoon Activity. Issue 14 (14th July 2022)

• Record Type: Journal Article
• Authors: Guo, Yi‐Peng; Tan, Zhe‐Min
• Is Part Of: Journal of geophysical research. Volume 127:Issue 14(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-14
• Subjects: Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2022JD036640
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Tropical cyclone (TC) lifetime maximum intensity (LMI) positions have been reported to migrate poleward globally during the last several decades. However, during the TC peak season, the trend of TC LMI position over the western North Pacific (WNP) is not as robust as that of genesis position. In this study, we found that the TC track change plays important roles in decreasing the genesis‐to‐LMI latitude distance (G2LD), which therefore leads to the inconsistent long‐term trends of genesis and LMI positions. A statistical approach was applied to quantitatively estimate the contributions by TC track change to the G2LD trend. The results show that the increase of near‐land formed short‐track TCs and the decrease of northwestward moving and eastward posited recurving TCs combined to make the largest contribution to the decreasing trend of the G2LD and thus to the insignificant long‐term trend of LMI position during peak season. Such TC track changes are closely related to the La Niña‐like warming pattern over the Pacific. The northeastward retreatment of the western Pacific subtropical high also plays an important role in reducing the northwestward moving TCs and increasing the recurving TCs over the northwestern WNP. Applying the same statistical approach to TC genesis positions indicates that the decrease of low‐latitude formed TCs makes the largest contribution to the poleward migration of genesis position, and the increase of high‐latitude formed TCs takes the second place. These low‐latitude formed TCs are mainly featured by northwestward moving and recurving tracks. Plain Language Summary: Long‐term changes in tropical cyclone (TC) activity are important to both society and the scientific community. TC activity, particularly over the western North Pacific (WNP), has migrated poleward in recent decades. Most previous studies focused on the trends of TC genesis position and the associated large‐scale environment conditions. In this study, we focus on the trend of the latitudinal distance between the genesis and lifetime maximum intensity (LMI) positions, which is closely related to LMI latitude. We found that the changes in TC tracks play an important role in reducing the latitudinal distance between the genesis and LMI positions, resulting in an inconsistent trend of LMI and genesis latitudes. Further analysis shows that the poleward migration of the WNP TC mean genesis latitudes is primarily caused by the decrease of low‐latitude formed northwestward moving TCs. The increase of near‐land created short‐track TCs and decrease of northwestward moving recurving TCs are the main cause for the inconsistent trends between TC LMI and genesis latitudes. Further investigation indicates that the long‐term change in the Pacific sea surface temperature and the northeastward shift of the western Pacific subtropical high are the primary causes for the long‐term trend of TC tracks. Key Points: The western North Pacific Tropical cyclone (TC) tracks experienced significant long‐term trends TC track change leads to inconsistent trends of TC lifetime maximum intensity and genesis positions Pacific La Niña‐like warming and northeastward shift of western Pacific subtropical high are major responsible for the TC track change