INADVERTENT WEATHER AND PRECIPITATION MODIFICATION BY URBANIZATION.

The paper describes in, and immediately downwind of, major urban areas the annual precipitation may be increased from 5%-30%, the annual thunderstorm frequency is increased 15%-30%, the heavy (2-in. ) daily rainstorm frequencies are increased by 20%-40%. Increases in local runoff may be from 15%-20%. Local crop yields may be increased 2%-10% by this rain modification.