Airborne Microwave Stratospheric Observing System (AMSOS)

Profile retrieval out of a measured spetrum is an inverse problem. We use optimal estimation method (OEM) according to Clive D. Rodgers.

**Table:** AMSOS profile versions
Version	Forward Model	Apriori information	Model parameters (atmosphere)	Model parameters (spectroscopy)
1	BEAM	US-Standard 1976	UK Metoffice
2.0	ARTS	ECMWF mean of monthly means from ERA40 globally / US-Standard76 (>45km)	ECMWF / CIRA86 (for temperatures above ECMWF grid)	HITRAN96