3.3 Global Distributions of Tropical Cyclones

Tropical cyclone is regional phenomena. The global distribution and regional name of TCs is summarized in Table 2.4.

The monthly TC distribution is summarized in Table 2.5 (note the various periods of the data set), the number of years of data is in parentheses, the unit is number per year, a single 0 indicates no cyclone was recorded. Even through the regional sampling sizes are inhomogeneous, Table 2.5 reveals some characteristics of monthly TC distribution; they are:
(a). There are about 94 tropical cyclones worldwide per year. The minimum (about 4 TCs) occurs in December, and the maximum (about 16 TCs) in August.
(b). The northern hemisphere has more TCs than the southern hemisphere. The western North Pacific (about 27 TCs), South Indian Ocean (16 TCs), eastern North Pacific (15 TCs), North Atlantic (10 TCs), South Pacific (8 TCs) and Australia (7 TCs) are major TC regions.
(c). There are regional difference of the month of maximum number of TCs. In the Pacific, Atlantic, and North Indian Ocean, the maximum numbers of TCs occur in August, September, and October, respectively. In the South Indian Ocean, it occurs in June. In the South Pacific and Australia regions, the maximums are in February and March, respectively.
(d). The three regions, the western North Pacific, Bay of Bengal, and South Indian Ocean, may have TCs in all months. The other regions have at least one TC-free month for the year. For example, in the North Atlantic, there is no TC in January.

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Section 3.2 Appendix: List of Figures

Chapter 2