Fig. 3: Diverse impacts of the two NTA modes on Atlantic hurricane activity.

Spatial patterns of composite anomalies of JJAS TCGF for (a) six positive BNTA events (as in 1983, 1995, 1998, 2005, 2010, 2024) and (b) six positive CNTA events (as in 1987, 1997, 2000, 2008, 2020, 2023). Stippled areas indicate where composite anomalies are statistically significant above the 90% confidence level according to the two-tailed t-test. c, d Same as (a, b), but for TCTD. e, f Same as (a, b), but for ACE. A positive BNTA event has an overall stronger impact on Atlantic hurricane activity due to its more westward and persistent warm anomaly pattern.