The vertical representivity of Atmospheric Motion Vectors (AMVs) has been the subject of much discussion over many years. Several recent studies have suggested that the traditional interpretation of AMVs as representative of the wind at cloud top is sub-optimal and that they are in fact more representative of the winds within the cloud. In this study, the vertical representivity of cloudy AMVs is investigated using both real and simulated AMVs. A state of the art convection permitting mesoscale model is used in conjuction with the RTTOV radiative transfer scheme and the Nowcasting SAF (NWCSAF) AMV package to produce synthetic AMVs over a one month period, which are then compared against the model truth from which they were derived. In agreement with previous studies, the results indicated that AMVs are more representative of a layer mean wind with the majority of the layer below the cloud top. This suggests that the use of a layer averaging observation operator may benefit the assimilation of AMVs into NWP models. Improvements in the fit between the AMVs and the model can also be found by simply lowering the assigned height by around 40hPa. The use of either a lower assigned height or a layer average significantly reduced the slow bias commonly seen in upper level AMVs. The utility of the simulation study data in comparison to traditional O-B statistics was assessed. The results for low and medium height clouds were encouraging with the simulated AMV error characteristics similar to those in real AMVs. However, the simulated upper level AMVs suffered from significantly larger height assignment errors than those in reality making the results unrepresentative.
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