Monitoring of NWP models by use of satellite data

This paper describes some cases where satellite information contributes to beneficial monitoring of NWP model output. The real‐time observations and NWP parameters required for the methods used are described. Selected examples, including successful and less successful NWP developments, are used to illustrate the applicability of the methods. Key elements are the localisation and isentropic advection of potential vorticity (PV). Positive upper and middle tropospheric PV anomalies may in several weather situations be detected in the Meteosat WV imagery as dark areas in the rear of developing cyclones. This study indicates that we may have confidence in the model description of weather development when the NWP model output showing areas with high‐level potential vorticity corresponds in time and space with dry areas inferred from the WV images. However, when such correspondence is only poor, the confidence is shown to be lower. In such cases there is a need to adjust the NWP model output. Also large‐scale isentropic advection fields and cross‐sections from the NWP models are used together with the multi‐spectral AVHRR information from the NOAA polar‐orbiters. Mesoscale events related to deep convection and small‐scale wind fields in connection with polar low developments are investigated.