Kinds of Inversion

• The standard inversion is a "classical" atmospheric inversion with temporally explicit degrees of freedom. In particular, the estimated interannual variations in NBE (Net Biome Exchange) directly reflect the signals in the atmospheric CO2 data.
• The "NBE-T inversion" (previously called "NEE-T inversion") involves a regression of interannual NBE anomalies against air temperature anomalies (T). The adjustable degrees of freedom are not the NBE variations themselves, but the NBE-T sensitivities. As these sensitivities are the same every year (though allowed to be different in different seasons and locations), the estimated interannual NBE variations originate from the air temperature variations.