by Jonathan M. Stern
In previous discussions of the flight instruments, you considered some of the effects of pressure and temperature on the measurement of altitude and airspeed and on the performance of the airplane. These considerations obviously relate to meteorology. There are additional meteorological considerations that play a role in the instrument flying experience on Flight Simulator.
Perhaps most important is the subject of clouds. After all, it is clouds that necessitate your reference to instruments rather than outside visual references. Amongst the clouds, you may also find an occasional thunderstorm—a most hazardous creature in real flight, however docile they may turn out to be in Flight Simulator (see Figure 13.1).
Figure 13.1. Flight Simulator does not yet reflect the ferocity of a real thunderstorm. This mature stage thunderstorm contains no wind shear, no turbulence, no hail, no lightning, and. for that matter, no thunder. With version 5.1, however, thunderstorms and certain types of clouds contain turbulence and icing.
Most weather occurs within the troposphere, the atmospheric layer that extends from the Earth's surface to approximately 25,000 feet at the poles and 55,000 feet at the equator. The heat from the sun is the indirect cause of all weather in the Earth's atmosphere. The uneven heating of the Earth leads to winds, both vertical and horizontal, development of clouds and rain showers, and thunderstorms. Many factors affect the uneven heating of the atmosphere. For example, a layer of clouds inhibits terrestrial radiation (the transmission of heat from the Earth toward space), and large bodies of water moderate local temperatures because water is slower to change temperature than is land.