An Investigation of Diagnostic Relations between Stratiform Fractional Cloud Cover and Other Meteorological Parameters in Numerical Weather Prediction Models

Abstract

The main objective of this study has been to find model parameters that may be used to diagnose or parameterize the stratiform fractional cloud cover. Observational data are obtained from satellite radiance measurements. Cloudiness parameters are derived by use of the measurements in three channels: 0.58?0.68 ?m (visible), 0.7-1.1 ?m (near infrared), 10.5?11.5 ?m (infrared). The derived cloud parameters, fractional cloud cover, cloud-top height, and cloud depth have been put on a grid with 50-km resolution. The inferred cloud parameters have been investigated and compared to several quantities derived from analyzed fields on the same grid, nearly coincident in time to the two satellite passages. A fairly distinct relationship to cloud cover is found only for relative humidity. On this basis two parametric relations are discussed.