By analyzing the Fabry-Perot etalon fringes, we can extract velocity, temperature, and density data. Pictured below is a simulated data example from one of these fringes. Velocity is determined by the magnitude of the Doppler shift. When the velocity of the molecule or aerosol is greater, then the Doppler shift will also be greater. When measuring velocity, you can analyze either the molecular or the aerosol components because small particles in the air will move at the same rate as the air molecules.
Absolute temperature is determined by the width of the molecular signal return.
As the air temperature rises, the molecules vibrate faster. This is realized in the return signal by a broader wavelength region. You cannot analyze the aerosol component of the return when measuring temperature. Aerosols do not vibrate at the same rate as air molecules. You must solely rely on the molecular return, or else you will experience great errors in your measurements.