To control weather over large areas of the world would seem, at this time, to be impossible. However, man has been highly successful in his attempts to 1 the weather 2 a very small scale. He has 3 microclimates inside and outside homes and offices.
Micro means small, and microclimate refers to the climate conditions 4 a small area. There are many things that might cause the climate in a small area to be different from the 5 climate of the region in which it is located.
6 , within cities there might be smaller areas where the climate is different. The microclimate in the yard of one home may be 7 different from 8 in the yard across the street. It is the 9 of trees and their position in a yard that 10 the microclimate. One could probably name many other things that 11 change the microclimate of a yard.
Heaters and air-conditioners now in houses and automobiles are good examples of the methods man uses to control microclimates. A completely air-conditioned house is one 12 the microclimate can be controlled to suit man’s comfort.
High-altitude flying and recent developments in space flight 13 situations which require complete control of microclimates. Before passenger planes can fly in the air of the stratosphere (同 温层) the cabins have to be pressurized. This must be done 14 passengers can obtain the oxygen they need. 15 airplane cabins in the stratosphere, air from the outside can be pumped into the cabin.
In space, 16 , there is no air. Astronauts have to take their air with them. Ways have been developed by which this air can be safely used over and over. In space, astronauts also have to be protected 17 harmful radiations which do not reach the earth 18 the atmosphere screens them out. The principal problem that has to be solved 19 man can exist in space is 20 of providing a microclimate in which he can survive.