Abstract
Abstract. This article analyzes the relationship between off-season tropical cyclone (TC) frequency and climate variability and change for the Pacific Ocean and Atlantic Ocean basins. TC track data were used to extract the off-season storms for the 1900–2019 period. TC counts were aggregated by decade, and the number of storms for the first 6 decades (presatellite era) was adjusted. Mann–Kendall nonparametric tests were used to identify trends in decadal TC counts and multiple linear regression (MLR) models were used to test if climatic variability or climate change factors explained the trends in off-season storms. MLR stepwise procedures were implemented to identify the climate variability and change factors that explained most of the variability in off-season TC frequency. A total of 713 TCs were identified as occurring earlier or later than their peak seasons, most during the month of May and in the West Pacific and South Pacific basins. The East Pacific (EP), North Atlantic (NA) and West Pacific (WP) basins exhibit significant increasing trends in decadal off-season TC frequency. MLR results show that trends in sea surface temperature, global mean surface temperature and cloud cover explain most of the increasing trend in decadal off-season TC counts in the EP, NA and WP basins. Stepwise MLR results also identified climate change variables as the dominant forces behind increasing trends in off-season TC decadal counts, yet they also showed that climate variability factors like El Niño–Southern Oscillation, the Atlantic Multidecadal Oscillation and the Interdecadal Pacific Oscillation also account for a portion of the variability.
Highlights
Scientific evidence has shown a link between tropical cyclones (TCs) and global warming, especially following the dramatic rise in both the intensity and the frequency of storms during the first 2 decades of the present century (Goldenberg et al, 2001; Holland and Webster, 2007)
When grouping the basins into the Northern and Southern hemispheres, we find that 89 % of all off-season TCs occurred north of the Equator for the 1900–2019 period (Fig. 1a, b)
The frequency of TCs that developed outside of their primeseason months was analyzed to determine if trends in higher storm totals in the Pacific Ocean and Atlantic Ocean basins were associated with natural variability, climate change or both
Summary
Scientific evidence has shown a link between tropical cyclones (TCs) and global warming, especially following the dramatic rise in both the intensity and the frequency of storms during the first 2 decades of the present century (Goldenberg et al, 2001; Holland and Webster, 2007). Scientific studies (Landsea, 2005; Emanuel, 2005; Trenberth and Shea, 2006; Trenberth, 2007) are not in agreement as to whether sea surface temperatures have a measurable effect on the frequency of tropical cyclones, and other studies (Camargo and Sobel, 2005; Mahala et al, 2015; Zhao et al, 2018) have evaluated cyclonic activity on a timescale longer than interannual and have associated it with variability in the El Niño–Southern Oscillation (ENSO), the Atlantic Multidecadal Oscillation (AMO) and the Interdecadal Pacific Oscillation (IPO). A number of recent papers (Wang and Lee, 2008; Knutson et al, 2010; Emanuel, 2013) have documented global increases in the proportion of very intense cyclones as well as latitudinal trends in maximum tropical cyclone (TC) intensity, which are consistent with future climate projections. Another study (Mann et al, 2009) found that re-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
