Westerly wind belts

At 30°N, the air descending to the surface that does not move south toward the equator in the Hadley cell begins to move north. As it does so, it is deflected toward the right by the Coriolis force. In these regions north and south of the trade wind belt (in the Northern and Southern Hemispheres, respectively), winds tend to blow from west to east (westerlies) these are referred to as westerly wind belts. 

The information on the quantities of combusted materials, and on aerosol and elemental carbon production, which is collected in Tables II-V, has been combined in Table VI to derive the state of the atmosphere during the nuclear war. We assume that the war would last for only a few days the aerosol particles would also be given off to the atmosphere in such a short time. Most fire produced aerosol would initially be located between 30°N and 60 N, where most of the nuclear targets are located. If the nuclear explosions would occur over a period of three days, the fire plumes produced on the West and East coast of the US and over Europe (including the USSR) could cover most of the 30-60°N latitude belt, except the Pacific Ocean. This is based on an average westerly wind speed of 20 m/s in tbe middle and upper troposphere (Oort and Rasmussen, 1971). Spread in South-North direction within the latitude zone should... 

Many features of atmospheric chemical transport can be inferred by inspection of the global-scale atmospheric circulation pattern. The west-to-east movement of industrial chemicals, such as acid rain precursors, is a familiar example in the midlatitudes of the Northern Hemisphere. Of course, these belts of wind, such as the midlatitude westerlies, are subject to modification on a smaller scale by a variety of local and regional conditions. For example, a wind rose from Chicago (Fig. 4-14) shows that despite the dominant southwesterly direction of the wind, wind from other directions also occurs. To explain such departures from the average global circulation pattern, atmospheric processes on smaller scales must be considered. 

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