Potential impact of the Pacific Decadal Oscillation and sea surface temperature in the tropical Indian Ocean\u2013Western Pacific on the variability of typhoon landfall on the China coast

Lei Yang,Xin Wang,Chunzai Wang,Sheng Chen,Dongxiao Wang

doi:10.1007/s00382-017-4037-7

Abstract

The landfall activity of typhoons (TYs) along the coast of China during July–August–September (JAS) shows significant interdecadal variation during 1965–2010. We identify three sub-periods of TY landfall activity in JAS along the China coast in this period, with more TY landfall during 1965–1978 (Period I) and 1998–2010 (Period III), and less during 1982–1995 (Period II). We find that the interdecadal variation might be related to the combined effects of Pacific Decadal Oscillation (PDO) phase changes and sea surface temperature (SST) variation in the tropical Indian Ocean and Western Pacific (IO–WP). During the negative PDO phase in Periods I and III, a cyclonic anomaly is located in the western North Pacific (WNP), inducing easterly flow in its northern part, which favors TY landfall along the eastern China coast. Warm SST anomalies over the tropical IO–WP during Period III induce an anomalous anticyclonic circulation in the WNP through both the Gill-pattern response to the warm SST in the tropical IO and the anomalous meridional circulation induced by the warm SST in the tropical WNP. As a result, the northern South China Sea and WNP (10°–20° N) are dominated by southeasterly flow, which favors TYs making landfall on both the southern and eastern China coast. With both landfalling-favorable conditions satisfied, there are significantly more TYs making landfall along the China coast during Period III than during Period I, which shows cool SST anomalies in the tropical IO–WP.

Highlights

Tropical cyclones (TCs) that make landfall can cause severe economic losses in coastal regions
When we further compare the TY genesis location between the two negative Pacific Decadal Oscillation (PDO) phases, we find that the high number of western North Pacific (WNP) TYs generated east of the Philippines area is more obvious during Period III than during Period I
During a negative PDO phase, the persistent easterly flow anomalies associated with the largescale circulation over the WNP favors TY landfall on the east China coast

Summary

Introduction

Tropical cyclones (TCs) that make landfall can cause severe economic losses in coastal regions. The variations in the TC occurrence pattern led to more (fewer) TCs making landfall along the South China coast during 1964–1976, 1977–1988 and 1989–1997 (1998–2005), and more (fewer) along the East China coast during 1977–1988 and 1998–2005 (1964–1976 and 1989–1997) This interdecadal variability may be partly related to the PDO (Liu and Chan 2008). To further confirm the potential influence of tropical IO–WP SSTs and the PDO on the interdecadal variability of steering flow, several numerical experiments are conducted with version 5.0 of the National Center for Atmospheric Research (NCAR) Community Atmospheric Model (CAM5), which has a horizontal resolution of 3.75° × 3.75° and 30 vertical levels. We use the HadISST dataset as the lower boundary conditions to drive all model runs

Datasets and models

Effects of PDO phase and tropical IO–WP SST

Simulated influences of the PDO and IO– WP on steering flows

Summary and discussion