ABSTRACT
Figures 1.1(a)–(d) and 1.2(a),(b) illustrated that tropical cyclones develop only in certain geographic oceanic regions and generally only during certain seasons of the year. Since an annual average of only 99 tropical cyclones was observed globally over the period 1952–71, these storms are relatively rare weather events. (In contrast, thousands of extratropical cyclones develop annually along the polar front.)
