Work

Monsoon–ocean competition shapes the record-low 2023 western North Pacific tropical cyclone season

Year: 2026

Type: article

Abstract: Tropical cyclone (TC) activity over the western North Pacific (WNP), the most active TC basin worldwide, is generally viewed as being controlled by remote oceanic forcing, especially the El Niño–Southern Oscillation. However, oceanic forcing alone cannot fully explain variability in TC genesis. Here we show that the record-low WNP typhoon season of 2023 emerged from strong seasonal asymmetry rather than uniform suppression. Despite unfavorable large-scale ocean conditions, summer TC genesis frequency remained near climatology because a weakened Indian summer monsoon (ISM) triggered an atmospheric Kelvin-wave response that induced a WNP cyclonic circulation anomaly. This circulation offset the ocean-forced anticyclone and maintained environmental conditions favorable for TC genesis. In contrast, remote ocean forcing dominated during autumn, producing unprecedented suppression and driving the seasonal minimum. These results highlight a pathway by which ISM variability can counteract basin-scale oceanic forcing and regulate WNP TC variability, with potential implications for improving TC prediction.

Source: npj Climate and Atmospheric Science

DOI: 10.1038/s41612-026-01515-4

Authors: Lixia Pan, Jiepeng Chen, Sheng Chen, Lei Zhou, Chunzai Wang, Xin Wang

Institutions: Shanghai Jiao Tong University, Chinese Academy of Sciences, South China Sea Institute Of Oceanology

Language: English

Topic: Tropical and Extratropical Cyclones Research

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,590