• atmospheric remote sensing;
  • climate change monitoring;
  • greenhouse gases;
  • infrared-laser occultation;
  • microwave occultation;
  • thermodynamics and wind

[1] Accurate, long-term, consistent data are fundamental to climate science and satellite observations are the key to obtain such data globally in the Earth's atmosphere. Current methods are unable to jointly and consistently observe essential climate variables including thermodynamic ones (temperature, pressure, humidity), wind, and greenhouse gases. Here we introduce a method that profiles these variables over the upper troposphere and lower stratosphere and beyond as consistent benchmark dataset (e.g., monthly-mean temperature accurate to 0.1 K, wind to 0.5 m s−1, carbon dioxide concentration to within 1 ppm). It combines microwave and infrared-laser occultation between satellites in low Earth orbit for thermodynamic state, greenhouse gas and line-of-sight wind profiling. With adequate scaling it can also be applied beyond Earth's atmosphere such as in planetary atmospheres. The method may become an authoritative reference standard for global monitoring of greenhouse gases and climate change in Earth's free atmosphere over the 21st century.