Towards Direct Simulation of Future Tropical Cyclone Statistics in a High-Resolution Global Atmospheric Model

Table 4

The average number of tropical storms across the globe during the August–November period as characterized by the Saffir-Simpson scale simulated by fvCAM2.2 as shown in Figure 10. Percent change is shown in the 4th column relative to the 1990–1999 ensemble average. Student’s test statistic, calculated with 14 degrees of freedom is shown in the 5th column. The last column shows the level of confidence for the rejection of the null hypothesis of no change in the number of tropical storms. The “present” ensemble is forced with 1990–1999 sea surface conditions. The “future” ensemble is forced with sea surface conditions representative of the SRES A1B scenario at the end of the 21st century.

	Present no. of tropical storms	Future no. of tropical storms	Percent change	Student’s test statistic	Statistical significance of change
All named storms	62.7	87.7	40%	11.5	>99.9%
Tropical storm	25.8	40.9	59%	6.7	>99.9%
Category 1	20.1	24.3	21%	3.04	>99.5%
Category 2	8.3	9.5	15%	1.09	<90%
Category 3	7.9	10.3	29%	2.24	>97.5%
Category 4	0.5	2.6	387%	3.76	∼99.9%