ON THE FORMATION OF TYPHOONS

Abstract

Abstract A typical example of cyclogenesis in the western tropical Pacific Ocean is investigated. In the low troposphere, data do not support the concept of an equatorial front extending across the entire Pacific Ocean. They indicate the presence of several large clockwise-rotating eddies in the equatorial trough. Typhoon development begins in consequence of instability of the northern-hemisphere trades, not as a result of interaction between currents from northern and southern hemispheres. No evidence can be adduced in the low troposphere that suggests a reason for this instability. Large vortices are found at 200 mb instead of the easterlies characteristic of low levels. Their spacing and speed are studied, and it is found that they are systems of the order of magnitude of long waves in the westerlies. After computations on the structure of the basic zonal current in the trade-wind belt, relations between high-tropospheric vortices and waves in the easterlies are discussed. These two types of perturbati...