There are:
1. Land-based thermometer measurements.
2. Ocean-based sea surface temperature measurements.
3. Above-ground measurement of temperature in the stratosphere and troposphere by radiosonde balloons, and weather satellite instruments, and
4. Proxy data sets for estimates of historical temperatures before 1900, such as tree rings, ice cores, deep sea cores, stalactites/stalagmites, etc.
Sensors (microwave sounding units) are aboard weather satellites that have orbited the Earth since the late 1970s.
"Global warmunists" pretend they do not exist.
Satellites allow scientists to calculate the average temperature of the atmosphere at various heights above sea level.
This average is calculated from a series of satellites, not from a single satellite, so it is called a "composite".
The level closest to the surface is the lower troposphere.
The lower troposphere data are most heavily weighted to the altitudes of less than 3000 meters.
(1) UAH LOWER TROPOSPHERE TEMPERATURE ANOMALY COMPOSITE (UAH TLT)
The monthly UAH lower troposphere temperature composite is from the Earth System Science Center of the University of Alabama in Huntsville (UAH).
The UAH lower troposphere temperature is for the latitudes of 85 South to 85 North (99% of the surface of the globe).
In sharp contrast, surface temperature measurements are based on raw data for less than half of the globe (the globe is divided into rectangular grids, each requiring temperature numbers for use in Global Climate Models).
Surface temperature measurements are heavily manipulated numbers that are barely related to the original (incomplete) surface source data, and they are also contradicted by measurements from satellites and weather balloons (both of which are similar).
Reasons:
Wild guess surface temperature estimates are used as substitutes for no longer operating weather stations, stations not reporting that month, and then repeated “adjustments” are made to historical data every year ("adjustments" that always creating a steeper global warming trend).
Wild guess surface temperature estimates are used as substitutes for no longer operating weather stations, stations not reporting that month, and then repeated “adjustments” are made to historical data every year ("adjustments" that always creating a steeper global warming trend).
Monthly "data" for a majority of the surface grids are wild guesses made by people with a financial conflict of interest -- many of their jobs exist to study the alleged problem of global warming, so it's no surprise that surface measurements AFTER "adjustments" always show more warming than satellites and weather balloons do!
The November 2015 UAH (Release 6.0 beta) lower troposphere temperature was +0.33 degrees C. above the 1981 to 2010 average temperature.
(2) RSS LOWER TROPOSPHERE TEMPERATURE ANOMALY COMPOSITE
Remote Sensing Systems (RSS) calculates lower troposphere temperature from microwave sounding units aboard a series of NOAA satellites.
RSS lists their composite as extending from the latitudes of 82.5 South to 82.5 North.
The November 2015 RSS (RSS TLT) lower troposphere temperature anomaly was +0.43 degrees C. above the 1979 to 1998 average temperature.