The Falcon 20 aircraft was also carrying in-situ measurements. Ice cloud particles were collected by 2DS, PIP and CIP probes. Lamp provided us with particle size distribution (PSD) derived by combining these probes. The PSD is used to compute in-situ IWC, Nt , Dm and NO* (Mass size is obtained by minimising the difference between valid reflectivity measurement at closest distance to the plane and the one derived from the PSD).
Note that RadOn also retrieves the Mass-Size relationship in an independent way.
It is obvious that RadOn IWC at the closest distance to the plane (above and below) is in a very good agreement with the in-situ values. Dm agrees with the in-situ but with discrepancies in the region before 16.88 UTC. NO* and Nt , at least for the values below the aircraft, are also in good agreement with in-situ data. It is important to note that, although IWC, NO* and Dm depend on the Mass size relationship, Nt is a direct measurement and does not require any assumption.