These datasets represent meteorological information prepared by KNMI (Peter van Velthoven) for the CARIBIC project. The meteorological analysis of the CARIBIC measurement flights is based on ECWMF first guess fields (6-hour forecasts) with a resolution of 1x1 degree on ECMWF model levels. First guess fields from ECMWF were used until 13 September 2000, because ECMWF used a 3D-var assimilation scheme until then. For 3D-var, first guess fields are somewhat smoother than analyses. After 13 September 2002 ECMWF used 4D-var assimilation and its analyses were used, as first guess fields were no longer available. With 4D-var the analyses are much smoother than in 3D-var. Data format: ECMWF model data interpolated linearly in longitude, latitude, log(pressure) and time to the aircraft location. The following parameters are interpolated: Cloud cover (dimensionless 0-1), Cloud liquid water content (g/kg), Cloud ice water content (g/kg). Special comments to this flight: None.
The quality of ECMWF analyses is monitored and documented at ECMWF (http://www.ecmwf.int). The following expresses a subjective view by Peter van Velt...
The quality of ECMWF analyses is monitored and documented at ECMWF (http://www.ecmwf.int). The following expresses a subjective view by Peter van Velthoven: The accuracy of model parameters that are also measured can easily be checked. See e.g. http://www.knmi.nl/~/velthove/CARIBIC. Errors in cloud cover and ice and water content are quite large, even more so than in humidity. Only the large scale variations correspond to real atmospheric variability. 1x1deg, 60 hybrid sigma levels, 6 h Interpol. to flight position every min.