Comparison of Aircraft and Radiosonde Data with Implications for Bias Correction

Bradley Ballish


It is shown that the three classes of aircraft AIREPS, ACARS and AMDAR have overall warm bias differences compared to the guess near 250 hPa with radiosondes colder. These biases are due in part to the sonde radiation correction, bias in the guess mainly around the tropopause, vertical interpolation problems and numerous factors for aircraft, especially the aircraft type. These temperature bias variations are consistent with both the collocation statistics between radiosondes and ACARS units as well as between different aircraft types with each other. Aircraft temperature and wind statistics also vary with pressure and the Phase of Flight (POF). Discussion is made of how these different biases may be used for bias correction.