Year: 2026
Type: preprint
Abstract: Tropical cyclones (TCs) over the western North Pacific (WNP) are known to intensify El Niño, and recent work has linked the preceding autumn WNP TC activity to the following spring sea ice in the Beaufort Sea. Here we extend this connection into the summer melt season and diagnose, term by term, how the signal reaches the western Arctic. Using the Accumulated Cyclone Energy (ACE) index derived from IBTrACS (1970–2024) together with ERA5, HadISST, and a regression-based decomposition, partial-correlation analysis, Rossby-wave ray tracing, a perturbation hypsometric diagnosis, and a surface-flux decomposition, we show that enhanced August–October ACE is associated with an intensified following-winter El Niño (an amplification attributed by earlier work to the tropical cyclones themselves; Wang et al. 2019), whose tropical-Pacific convective heating excites a stationary Rossby wave train and a Pacific–North American-like pattern that transports energy poleward to the Beaufort Sea. The resulting circulation anomalies reorganize the surface energy budget: net longwave radiation dominates the response during and just after polar night, whereas net shortwave radiation — amplified by the sea-ice–albedo feedback — dominates from spring into summer, with latent and sensible heat fluxes playing a secondary role. The ACE- and El Niño-related pathways drive broadly similar surface-energy changes but differ in the relative importance of longwave versus shortwave radiation. Atmosphere-only CAM5 experiments show that an ENSO-like tropical-Pacific SST anomaly forces this teleconnection: the ACE-congruent forcing reproduces the El Niño 500-hPa response pattern almost exactly (pattern correlation 0.95) at a proportionally reduced amplitude. Finally, evaluated by cross-validation to avoid overfitting on the short record, the preceding ACE index provides a modest but genuine source of predictive information for the following spring–summer Beaufort sea ice: at long lead (≈ 7–10 months) the ACE index alone yields a leave-one-out skill of r ≈ 0.3, and combining it with the observed winter sea-ice state in a shorter-lead configuration raises this to r ≈ 0.45. The ACE contribution is complementary to sea-ice persistence and is most valuable in the melt season, where local persistence carries no memory; its skill beyond the winter Niño-3.4 index is positive but, on this short record, not statistically distinguishable from zero.
Source: Research Square
Authors: Dingjia Ye, Yanping Li, Jianping Li, Xuezhi Bai
Institutions: Hohai University, Ocean University of China
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
OpenAlex ID: W7222687682