CALCULATION OF MAXIMUM WIND VELOCITY RADIUS OF TROPICAL CYCLONE ON SEA SURFACE

By the agency of Fujita pressure formula, a method to calculate the maximum wind velocity radius of mobile asymmetric tropical cyclone (TC) over the sea in the circumstance that the strength keeps constant is developed in terms of the horizontal momentum equations with frictions in the polar coordinates after the reasonable simplification and derivation in the presence of the maximum wind speed. The result suggests that the maximum wind velocity radius will be large under the conditions that the maximum wind is small, the central pressure is low, the environmental air temperature and pressure are high, and the TC locates at a the low latitude or the friction coefficient is small, and vice versa. The maximum wind speed with minimum inner deflection angle resides at the right back side of the TC moving direction. The case studies of 9109 and 9115 TC indicate that the maximum wind radius increases in the initial stage of the TC development, decreases in the mature period, and enhances rapidly in the decay phase.