Post-Millennium Atmospheric Temperature Trends Observed From Satellites in Stable Orbits

We develop a post-millennium mid-tropospheric temperature time series from continuous observations by advanced microwave sounders onboard satellites in stable sun-synchronous orbits. Such observations have high radiometric stability and do not experience diurnal sampling changes over time, allowing us to develop merged time series from multiple satellites with an accuracy better than 0.012 Kelvin/Decade. With such high accuracy, the resulting time series can be used as a reference measurement of climate variability and trends in atmospheric temperatures. The warming rate from this time series for the atmospheric layer between surface and 10 km is 0.230 +/- 0.134 Kelvin/Decade during the period from 2002 to 2020, which is similar to 14% higher than the existing satellite microwave sounder datasets. Our finding provides new insight on trend differences among microwave sounder temperature data sets developed by different research groups, and is also helpful in reconciling trend differences between satellite observations and climate model simulations.