Tertiary period - See Cenozoic era . During frontogenesis or frontolysis, there is not a thermal wind balance because ageostrophic motions are occurring to cause the wind parallel to the isobars to depart from geostrophic. During frontogenesis, for example, the horizontal pressure gradient increases with height due to the increase in the low-level horizontal temperature gradient. The Coriolis force responds to this new wind speed and eventually adjusts its direction back parallel to the isobars. An instrument with a graded scale used to measure temperature.
Some devices make use of the temperature's dependence on electric resistance to measure changes.
The transitional layer between the thermosphere, where temperature increases with height, and the exosphere. The height of the thermopause varies between about 200 and 500 kilometers depending on solar activity. The temperature of the thermosphere can reach 2,000 K in active Sun periods. The thermosphere extends above about 80 kilometers. The features of the Earth's surface including mountains, water surfaces, forests, and deserts.