Fig. 2: The anomalous SST and atmospheric circulation during JJA and SON 2023.

a–c The anomalous SST (shading; unit: °C) and horizontal wind (vector; unit: m/s) at 850 hPa from JJA to SON in 2023. d–f The anomalous velocity potential (contours; unit: m²/s) at 200 hPa and precipitation (shading; unit: mm). Brown and blue contours indicate high-level convergence and divergence, respectively. Thick brown (blue) contours represent 2 × 10⁶ (−2 × 10⁶) m²/s. Contour interval is 1 × 10⁶ (−1 × 10⁶) m²/s. The wind anomaly of less than 1 m/s is omitted. The red box indicates the main region of TC decline in SON 2023.