Dr. Roy Spencer — CFact — January 26, 2016
The University of Alabama in Huntsville
The official global temperature numbers are in, and NOAA and NASA have decided that 2015 was the warmest year on record. Based mostly upon surface thermometers, the official pronouncement ignores the other two primary ways of measuring global air temperatures, satellites and radiosondes (weather balloons).
The fact that those ignored temperature datasets suggest little or no warming for about 18 years now, it is worth outlining the primary differences between these three measurement systems.
Three Ways to Measure Global Temperatures
The primary ways to monitor global average air temperatures are surface based thermometers (since the late 1800s), radiosondes (weather balloons, since about the 1950s), and satellites measuring microwave emissions (since 1979). Other technologies, such as GPS satellite based methods have limited record length and have not yet gained wide acceptance for accuracy.
While the thermometers measure near-surface temperature, the satellites and radiosondes measure the average temperature of a deep layer of the lower atmosphere. Based upon our understanding of how the atmosphere works, the deep layer temperatures are supposed to warm (and cool) somewhat more strongly than the surface temperatures. In other words, variations in global average temperature are expected to be magnified with height, say through the lowest 10 km of atmosphere. We indeed see this during warm El Nino years (like 2015) and cool La Nina years. Continue reading here….