Final answer:
The International Standard Atmosphere is a standardized model that defines atmospheric conditions at various altitudes globally to ensure consistent aerospace performance calculations. It includes standardized temperature, pressure, density, and viscosity values.
Step-by-step explanation:
The International Standard Atmosphere (ISA) can be described as the atmosphere that can be used Worldwide to provide comparable performance results. This standard represents model conditions of the atmosphere's parameters, such as temperature, pressure, density, and viscosity, at various altitudes. The main purpose of ISA is to allow for consistent performance calculations for aeronautical and aerospace applications, and it does not correspond particularly to the atmosphere at any specific geographic location.
Earth's atmosphere is a complex system with different layers, including the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Within these layers, temperature and air density decrease with height, and the pressures vary significantly. The ISA provides a standardized reference for these variables, ensuring that engineers and scientists can reliably compare their findings or test results no matter where they are on the planet.