Anthropogenic Greenhouse Gases Reshape Orbital-scale Seasonal Asynchrony of the Tropical Pacific West-East Temperature Gradient
Clicks：18
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DOI
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10.12262/IEECAS.EAPSD2026001
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Key words
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Transient Simulation， Seasonal asynchrony， Tropical Pacific SST gradient
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Related data
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The zonal sea surface temperature gradient (SSTG) between the western Pacific warm pool (PWP) and eastern Pacific cold tongue (PCT) is a key driver of the Walker circulation and global air-sea interactions. However, the short span of observational records has hindered the attribution of its long-term trends to natural versus anthropogenic forcings. Through a pair of transient Holocene simulations—one with natural forcings only and another including anthropogenic greenhouse gases—this study reveals that human emissions have fundamentally disrupted the orbital-scale seasonal asynchrony of zonal SST trends in the tropical Pacific. Under natural forcing, increased winter insolation led to stronger warming in the PCT than in the PWP, weakening the winter SSTG, whereas decreased summer insolation produced more pronounced cooling in the PCT, thereby strengthening the summer SSTG. These opposing trends were further amplified by orbital-scale differences in ocean mixed-layer depth. With added anthropogenic greenhouse gases, the PCT warmed substantially faster than the PWP across all seasons, which reinforced the winter SSTG decline while offsetting the summer SSTG increase. Future projections indicate a continued, anthropogenically driven amplification of PCT warming, leading to the loss of the Holocene’s characteristic seasonal SSTG contrast. Consequently, winter, summer, and annual SSTG are all projected to decline significantly, accompanied by a persistent weakening of the Walker circulation. The data mainly include the winter, summer and annual average sea surface temperatures of the Pacific Warm Pool (PWP) and Cold Tongue (PCT) regions, as well as the PWP and PCT gradients (SSTG) from the output of the CESM1.2-H, CESM1.2-MIS19 and CCSM3.0-TraCE experiments.
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Data description
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a. Description of Intellectual Property Rights
No public.
b. Contacts
Name: Xinzhou Li & Data processing group
Company: Institute of Earth Environment, Chinese Academy of Sciences
Tel: 029-62336214
Email: lxz@ieecas.cn
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Dataset format
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Excel
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Data type
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Climate and environment modeling/Climate and environment modeling/Climate and environment modeling
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Data sources
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authors supply
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Enclosure
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[download]
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Related pictures
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 Contact card |
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Name：Dr. Zhao |
E-mail：zhaohl@ieecas.cn |
| Company：IEECAS |
Telephone：029-62336213 |