Slide 6: Temperature
Temperature is an essential indicator variable, because it provides us with a direct measurement of the energy in the earth's atmospheric system.
Temperature records date from the middle of the 19th century.
Surface air temperature is usually measured at weather stations by means of mercury or alcohol thermometers.
However, much recent work has been done to allow measurement of the temperature of other atmospheric levels, using the TIROS-N series of satellites.
There are now two methods of measuring temperatures at different altitudes: the conventional radiosonde network; and the microwave-sounding unit (MSU) on the TIROS-N series of satellites. The conventional network extends back to 1958 (Angell, 1988) and the MSU data to 1979 (Spencer & Christy, 1990). These satellites are also being gradually replaced by modern satellites with more comprehensive monitoring equipment.
Angell, J.K., 1988. Variations and trends in tropospheric and stratospheric global temperatures, 1958-87. J. Climate, 1, pp. 1296-1313.
Spencer, R.W. & Christy, J.R., 1990. Precise monitoring of global surface temperature trends from satellites. Science, 247, pp. 1558-1561.